Technical Project Guide Mtu Proj Part 1
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Technical Project Guide Marine Application Part 1 - General
MTU Friedrichshafen GmbH Ship Systems Technology Commercial D-88040 Friedrichshafen Germany Phone +49 7541 90 - 0 www.mtu-friedrichshafen.com Assistance: MTG Marinetechnik GmbH D-22041 Hamburg Germany MTG Ref.: 679/335/2100 - 001 Phone +49 40 65 803 - 0 www.mtg-marinetechnik.de
Technical Project Guide Marine Application Part 1 - General June 2003 Revision 1.0
The illustrations herein are presented with kind permission of the companies listed below. Rolls-Royce AB www.rolls-royce.com S-681 29 Kristinehamn Sweden Schottel GmbH & Co. KG www.schottel.de D-56322 Spay/Rhein Germany Voith Schiffstechnik GmbH & Co. KG www.voith-schiffstechnik.de D-89522 Heidenheim Germany ZF Marine GmbH www.zf-marine.com D-88039 Friedrichshafen Germany
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User Information
USER INFORMATION This –Technical Project Guide- is supposed to give the user general references for the planning, design and the arrangement of propulsion plants and on-board power generation plants. Precise information on the different diesel engine series are to be taken from the specific engine parts. Following engine parts are planned/available:
Technical Projekt Guide Marine Application Part 1 - General
TPG-General.doc Rev. 1.0
+
Technical Project Guide Marine Application Part 2 - Engine Series 2000
+
Technical Project Guide Marine Application Part 3 - Engine Series 4000
+
Technical Project Guide Marine Application Part 4 - Engine Series 8000 (later on)
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Contents
CONTENTS Chapter
Title
Page
1 1.1 1.2 1.3
GENERAL Introduction Designations Special Documents Presented
1-1 1-1 1-2 1-3
2 2.1 2.2 2.3
DEFINITION OF APPLICATION GROUPS General Marine Main Propulsion and Auxiliary Propulsion Plants On-Board Electric Power Generation/Auxiliary Power
2-1 2-1 2-2 2-2
3 3.1 3.1.1 3.1.2 3.2 3.3 3.4
SPECIFICATION OF POWER AND REFERENCE CONDITION Definition of Terms ISO Standard Fuel-Stop Power (ICFN) ISO Standard Power Exceedable by 10 % (ICXN) Reference Conditions Load Profile Time Between Major Overhauls (TBO)
3-1 3-1 3-1 3-2 3-2 3-3 3-4
4 4.1 4.2
FLUIDS AND LUBRICANTS SPECIFICATION General MTU Approved Fuels
4-1 4-1 4-1
5
ENGINE PERFORMANCE DIAGRAM
5-1
6 6.1 6.1.1 6.1.2 6.1.3 6.2 6.2.1 6.2.2 6.2.3 6.2.4 6.3 6.3.1 6.3.2 6.3.3
PROPULSION, INTERACTION ENGINE WITH APPLICATION Propulsor Abbreviations Propulsive Devices (Overview) Shaft Line and Gearbox Losses Propeller Propeller Geometry Propeller Type Selection (FPP or CPP) Direction of Propeller Rotation Selection of Propeller Blade Number Propeller Curve Basics Theoretical Propeller Curve Estimating the Required Diesel Engine Power
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6-1 6-1 6-1 6-3 6-9 6-10 6-10 6-12 6-14 6-17 6-18 6-18 6-23 6-25
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Contents
CONTENTS Chapter 6.4 6.4.1 6.4.2 6.4.3 6.5 6.5.1 6.5.2 6.6 6.6.1 6.6.2 6.6.3 6.6.4 6.6.5 6.6.6 6.6.6.1 6.6.6.2 6.6.6.3 6.6.6.4 6.6.6.5 6.6.6.6 6.7 7 7.1 7.2 7.2.1 7.2.2 7.3 7.3.1 7.3.2 7.4 7.4.1 7.4.2 7.4.2.1 7.4.2.2 7.4.2.3 7.4.3 7.4.3.1 7.4.3.2 7.4.3.3
Title Propeller and Performance Diagram Driving Mode Fixed Pitch Propeller (FPP) Controllable Pitch Propeller (CPP) Waterjet and Performance Diagram Geometry and Design Point Estimation of Size and Shaft Speed Fuel Consumption General Assumptions Operating Profile Fuel Consumption at Design Condition Cruising Range Endurance at Sea Calculating Examples Example Data (Series 2000) Fuel consumption at design condition Fuel tank volume for a range of 500sm at 18kn Theoretical cruising range at 12kn and fuel tank volume of 5m3 Annual fuel consumption for an operating profile Correcting the lower heating value Generator Drive APPLICATION AND INSTALLATION GUIDELINES Foundation Engine/Gearbox Arrangements Engine with Flange-Mounted Gearbox (F-Drive) Engine with Free-Standing Gearbox, V Drive Inclusive Generator Set Arrangement Engine with Free-Standing Generator Engine with Flange-Mounted Generator System Interfaces and System Integration Flexible Connections Combustion Air and Cooling/Ventilation Air Supply Combustion-air intake from engine room Combustion-air intake directly from outside Cooling/ventilation air system Exhaust System Arrangements, support and connection for pipe and silencer Underwater discharge (with exhaust flap) Water-cooled exhaust system
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Page III
6-26 6-26 6-29 6-31 6-36 6-36 6-41 6-42 6-42 6-44 6-49 6-50 6-51 6-52 6-52 6-54 6-55 6-56 6-57 6-58 6-59 7-1 7-1 7-2 7-2 7-3 7-6 7-6 7-7 7-8 7-8 7-11 7-11 7-11 7-11 7-12 7-12 7-13 7-14
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Contents
CONTENTS Chapter 7.4.4 7.4.4.1 7.4.4.2 7.4.4.3 7.4.5 7.4.5.1 7.4.5.2 7.4.6 7.4.7 7.4.7.1 7.4.7.2 7.4.7.3 7.4.8 7.5 7.6 7.6.1 7.6.2 7.6.2.1 7.6.2.2 7.6.2.3 7.7 7.8 7.9 7.10 7.11
Title
Page
Cooling Water System Cooling water system with engine-mounted heat exchanger Cooling water system with separately-mounted heat exchanger Central cooling water system Fuel System General notes Design data Lube Oil System Starting System Electric starter motor Compressed-air starting, compressed-air starter motor Compressed-air starting, air-in-cylinder Electric Power Supply Safety System Emission Exhaust Gas Emission, General Information Acoustical Emission, General Information Airborne noise level Exhaust gas noise level Structure-borne noise level Mounting and Foundation Acoustic Enclosure/Acoustic Case Mechanical Power Transmission Auxiliary Power Take-Off Example Documents
7-15 7-15 7-16 7-17 7-18 7-19 7-19 7-22 7-23 7-23 7-24 7-25 7-28 7-29 7-30 7-30 7-32 7-32 7-34 7-35 7-42 7-43 7-44 7-47 7-48
8 8.1 8.2 8.2.1 8.2.2 8.2.3 8.3
STANDARD ACCEPTANCE TEST Factory Acceptance Test Acceptance Test According to a Classification Society Main Engines for Direct Propeller Drive: Main Engines for Indirect Propeller Drive Auxiliary Driving Engines and Engines Driving Electric Generators Example Documents
8-1 8-1 8-1 8-1 8-1 8-1 8-2
9 9.1 9.2 9.3 9.4 9.5 9.5.1 9.5.2
CONTROL, MONITORING AND DATA ACQUISITION (LOP) Standard Monitoring and Control Engine Series 2000/4000 Engine Governing and Control Unit ECU-MDEC Engine Monitoring Unit EMU-MDEC Separate Safety System Local Operating Panel LOP-MDEC Propulsion Plant Management System Version Manufacturer Specification Classification Society Regulation
9-1 9-1 9-2 9-2 9-2 9-3 9-3 9-4
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Contents
CONTENTS Chapter
Title
Page
10 10.1 10.2 10.3 10.3.1 10.3.2 10.3.3
MAINTENANCE CONCEPT / MAINTENANCE SCHEDULE Reason for Information Advantages of the New Maintenance Concept: New Maintenance Schedule: Cover Sheet Maintenance Schedule Matrix Task List
10-1 10-1 10-1 10-1 10-1 10-2 10-3
11
ASSEMBLING INSTRUCTIONS (LIFTING, TRANSPORTATION)
11-1
12
TRANSPORTATION, STORAGE, STARTING
12-1
13
PILOT INSTALLATION DESCRIPTION (PID)
13-1
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List of Figures
List of Figures Figure
Title
Figure 1.2.1:
Engine designations (sides, cylinders, direction of rotation)
1-2
Figure 1.3.1:
Structure of the MTU EXTRANET
1-3
Figure 3.3.1:
Typical Standard Load Profiles
3-3
Figure 3.4.1:
TBO definition of MTU
3-4
Figure 4.2.1:
Fuel specification
4-1
Figure 4.2.1:
Structure of the performance diagram
5-1
Figure 4.2.2:
Engine performance diagram
5-3
Figure 4.2.3:
Monohull
5-4
Figure 4.2.4:
Semi-planing boat hull = high speed monohull with medium displacement
5-4
Figure 4.2.5:
Multihulls = catamarans, trimarans,
5-5
Figure 4.2.6:
Semi-planing boat hull = high speed monohull with low displacement
5-5
Figure 6.1.1:
Scheme of a propulsive unit (side view)
6-1
Figure 6.2.1:
Scheme of propeller geometry (skew and rake)
6-10
Figure 6.2.2:
Propeller clearance
6-12
Figure 6.3.1:
Influence of change in resistance on effective power curve (example)
6-19
Figure 6.3.2:
From effective to delivered power curve (example)
6-20
Figure 6.3.3:
Effect of change in resistance on delivered power curve (example)
6-21
Figure 6.3.4:
Effect of different propeller pitches on delivered power (example)
6-22
Figure 6.4.1:
Change in delivered power due to weather, draught and fouling
6-26
Figure 6.4.2:
Diesel engine failure in a two shaft arrangement
6-27
Figure 6.4.3:
Choosing a design point for a fixed pitch propeller
6-29
Figure 6.4.4:
CPP characteristic in a typical diesel engine performance diagram
6-31
Figure 6.4.5:
Controllable pitch propeller design point
6-32
Figure 6.4.6:
Example: Single shaft operation with CPP
6-34
Figure 6.4.7:
Example: Constant speed generator in operation with CPP
6-35
Figure 6.5.1:
Waterjet
6-36
Figure 6.5.2:
Waterjet design point (Diagram has limited use for waterjet design)
6-37
Figure 6.5.3:
Platform with pump
6-38
Figure 6.5.4:
Waterjet performance diagram
6-39
Figure 6.5.5:
Estimating the size of a waterjet (inlet duct diameter)
6-41
Figure 6.5.6:
Estimating the design impeller speed of a waterjet
6-41
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List of Figures
List of Figures Figure
Title
Page
Figure 6.6.1:
Examples of operating profiles (freighter, fast ferry, OPV)
6-45
Figure 6.6.2:
Examples of operating profiles (freighter, fast ferry, OPV)
6-46
Figure 6.7.1:
Power definition
6-60
Figure 6.7.1:
Engine room arrangement, minimum distance
7-1
Figure 7.2.1:
Engine with flange-mounted gearbox
7-2
Figure 7.2.2:
Engine with free-standing gearbox
7-3
Figure 7.2.3:
Engine with free-standing gearbox and universal shaft, V drive arrangement
7-5
Figure 7.3.1:
Engine with free-standing generator
7-6
Figure 7.3.2:
Engine with flange-mounted generator
7-7
Figure 7.4.1:
Connection of rubber bellows
Figure 7.4.2:
Cooling water system with engine-mounted heat exchanger (Split-circuit cooling system) 7-15
Figure 7.4.3:
Cooling water system with separately-mounted heat exchanger (e.g. keel cooling) 7-16
Figure 7.4.4:
Central cooling water system
7-17
Figure 7.4.5:
Fuel System
7-18
Figure 7.4.6:
Evaluation value for max. fuel inlet temperature
7-20
Figure 7.4.7:
Lube oil system
7-22
Figure 7.4.8:
Starting system with pneumatic starter motor
7-25
Figure 7.4.9:
Starting system with air-in-cylinder starting
7-26
7-10
Figure 7.4.10: Electric power supply
7-28
Figure 7.6.1:
Limitation of NOx-emission (IMO)
Figure 7.6.2:
Test cycle for “Constant Speed Main Propulsion” application (including diesel electric drive and variable pitch propeller installation) 7-31
Figure 7.6.3:
Test cycle for “Propeller Law operated Main and Propeller Law operated Auxiliary Engines” application 7-31
Figure 7.6.4:
Test cycle for “Constant Speed Auxiliary Engine” application
7-31
Figure 7.6.5:
Test cycle for “Variable Speed, Variable Load Auxiliary Engine” application
7-31
Figure 7.6.6:
Engine surface noise analysis (example)
7-33
Figure 7.6.7:
Undamped exhaust gas noise analysis (example)
7-34
Figure 7.6.8:
Single resilient mounting system with shock
7-37
Figure 7.6.9:
Double resilient mounting system for extreme acoustic requirements
7-39
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List of Figures
List of Figures Figure
Title
Page
Figure 7.6.10: Examples for different “Quiet Systems”, structure-borne noise levels below the resilient mountings (e.g. diesel engine 20V 1163) 7-40 Figure 7.6.11: Structure borne noise analysis at engine feet, above rubber mounts (example) 7-41 Figure 7.9.1:
Combined diesel engine and diesel engine
7-44
Figure 7.9.2:
Combined diesel engine and diesel engine with separate gear compartment
7-44
Figure 7.9.3:
Combined diesel engine or gas turbine
7-45
Figure 7.9.4:
Combined diesel engine and gas turbine
7-45
Figure 7.10.1: Power take-off (PTO), gear driven
7-47
Figure 9.5.1:
Propulsion Plant Management System version in accordance with manufacturer specification 9-3
Figure 9.5.2:
Propulsion Plant Management System version in compliance with classification society regulations 9-4
Figure 10.3.1: Example of a maintenance schedule matrix
10-2
Figure 10.3.2: Example task list
10-4
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1
1 1.1
General
GENERAL Introduction MTU Friedrichshafen in Germany and Detroit Diesel Corporation in the USA, two DaimlerChrysler Group companies, have combined their off-highway operations. With product ranges of MTU and DDC plus Mercedes-Benz engines under one roof, a worldleading supplier of engines and systems for the marine, rail, power generation, heavy-duty military and commercial-vehicle as well as agricultural and construction-industry machinery sectors has been created. All marine engines are under the brand “MTU”. Especially within the shipping sector the company has established a long and successful partnership with hundred thousands of engines in operation around the globe on all seas. Based on its innovative capabilities, its reliability and system competence, MTU disposes of unique drive system know how and offers a large range of products of excellent quality. MTU develops, manufactures and sells diesel engines in the 200 to 9000 kW power range (for more information refer to publication “SALES PROGRAM MARINE”). This publication has been compiled as a source of information only. It contains generally applicable notes for planning and installation of marine propulsion plants and electric power plants. Non-standard design requirements (i.e. applicable to the design of individual components or entire systems) such as may be specified by the operator or by classification societies are not taken into consideration in the scope of this publication. Such requirements necessitate clarification on case-to-case basis. Project-related or contract-related specifications take precedence over the general information appearing in this publication, because the project-specific or contract-specific data are of course applicable to the particular application and the overall propulsion concept.
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1.2
General
Designations The DIN 6265 respectively ISO 1204 designations are used to identify the sides and cylinders of MTU engines. Details are explained in Figure 1.2.1.
Figure 1.2.1:
TPG-General.doc Rev. 1.0
Engine designations (sides, cylinders, direction of rotation)
Driving end
= KS (Kupplungsseite)
Free end
= KGS (Kupplungsgegenseite)
Left-bank cylinders
= A1, A2, A3, ..., A7, A8
Right-bank cylinders
= B1, B2, B3, ..., B7, B8
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1.3
General
Special Documents Presented Specific information and documents are found in the MTU EXTRANET. The structure of the EXTRANET with its essential components is represented in the following diagram.
Figure 1.3.1:
Structure of the MTU EXTRANET Back to Contents
Back to Start of Chapter
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3
2 2.1
Specification of Power and Reference Condition
DEFINITION OF APPLICATION GROUPS General In addition to general application by usage, e.g. marine vessel, the particular application must be taken into account for selecting the correct engine. The choice of the application group determines the maximum possible engine power and the anticipated time between major overhauls (TBO). Load varies during operation, with the result that the TBO is dependent on the actual load profile and varies from different applications. For an optimum selection of the engine taking into account the maximum power available the following information should be obtained from the operator: •
Application, e.g. yacht, patrol boat, ferry, fishing vessel, freighter etc.
•
Load profile (engine power versus operating time)
•
Anticipated operating hours per year
•
Preferred time between overhauls (TBO, for special cases only)
The terms “load profile” and “TBO” and the relationship between them are explained in detail in chapter –3
Specification of Power and Reference Condition- and
– 10
Maintenance Concept / Maintenance Schedule-.
If no specific load profile information is available from the operator, the selection of the engine is performed on the basis of the standard load profile determined by MTU by means of typical application. The MTU Sales Program distinguishes for the marine application propulsion engines and marine auxiliary engines and engines for the on-board supply of electricity. The following application groups are subdivided into in detail.
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2.2
Specification of Power and Reference Condition
Marine Main Propulsion and Auxiliary Propulsion Plants 1A
1B
Vessels for heavy-duty service with unlimited operating range and/or unrestricted continuous operation Average load
: 70 – 90 % of rated power
Annual usage
: unlimited
Examples
: Freighters, Tug Boats, Fishing Vessels, Ferries, Sailing Yachts, Displacement Yachts with high load profile and/or annual usage
Vessels for medium-duty service with high load factors Average load
: 60 to 80 % of rated power
Annual usage
: up to 5000 hours (as a guideline)
Examples
: Commercial Vessels, including Fast Ferries, Crew Boats, Offshore Supply & Service Vessels, Coastal Freighters, Multipurpose Vessels, Patrol Boats, Displacement Yachts, fan drive for Surface Effect Ships
1DS Vessels for light-duty service with low load factors Average load
: Less than 60 % of rated power
Annual usage
: Up to 3000 hours (as a guideline)
(Series 2000 & lower power engines approx. 1000 hours) Examples
: High speed Yachts, Fast Patrol Boats, FireFighting Vessels, Fishing Trawlers, Corvettes, Frigates
Significant deviations from the above application groups should be discussed with the responsible application engineering group.
2.3
On-Board Electric Power Generation/Auxiliary Power 3A
Electric power generation, continuous duty (no time restriction), e.g. dieselelectric drive, diesel-hydraulic drive or drive for fire fighting pumps
3C
Electric power generation for onboard standby power generation, e.g. emergency power supply or drive for emergency fire fighting pumps
Back to Start of Chapter
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3
3 3.1
Specification of Power and Reference Condition
SPECIFICATION OF POWER AND REFERENCE CONDITION Definition of Terms The available power for a specific engine type and application group is listed in the Sales Program.
3.1.1 ISO Standard Fuel-Stop Power (ICFN) The rated power of marine main propulsion engines of application group 1A, 1B and 1DS is stated as ISO standard fuel-stop power, ICFN, in accordance with DIN ISO 3046. Measurement unit is kW. I = ISO power C = Continuous power F = Fuel stop power N = Net brake power The fuel-stop power rating represents the power that an engine can produce unlimited during a period of time appropriate to the application, while operating at an associated speed and under defined ambient conditions (reference conditions), assuming performance of the maintenance as specified in the manufacturer’s maintenance schedule. Power specifications always express net brake power, i.e. power required for on-engine auxiliaries such as engine oil pump, coolant pump and raw water pump is already deducted. The figure therefore expresses the power available at the engine output flange. The engines of application group 1A and 1B can demonstrate 10 % overload in excess of rated fuel-stop power for the purposes of performance approval by classification societies. Fuel stop power of the engines in application group 1DS cannot generally be classified. Some classification societies accept the certification of engines of application group 1DS for special service vessels with specific load profiles. In case of such a request, the respective application engineering group should be contacted. Before delivery, all engines will be factory tested on the dynamometer at standard ISO reference conditions (intake air and raw water temperature 25°C). Acceptance test procedures at MTU: • MTU works acceptance test • Acceptance test in accordance with classification society regulations under supervision of the customer As a rule, marine main propulsion engines are supplied with power limited to fuel-stop power as specified in the Sales Program.
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Specification of Power and Reference Condition
3.1.2 ISO Standard Power Exceedable by 10 % (ICXN) The rated power of marine onboard power generation of application group 3A and 3C is stated as ISO standard power exceedable by 10 %, ICXN, in accordance with DIN ISO 3046. Measurement unit is kW. I = ISO power C = Continuous power X = Service standard power, exceedable by 10 % N = Net brake power
3.2
Reference Conditions The reference conditions define all ambient factors of relevance for determining engine power. The reference conditions are specified in the Sales Program and on the applicable engine performance diagram. ISO 3046-1 standard reference conditions: Total barometric pressure
: 1000 mbar or (hPa)
Air temperature
: 25
°C (298 K)
Relative humidity
: 30
%
Charge air coolant temperature
: 25
°C (298 K)
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3.3
Specification of Power and Reference Condition
Load Profile The load profile is a projection of the engine operating routine. The following standard load profiles have been established in the past, based on accumulated field experience with specific vessels and a huge number of recorded load profiles. Standard Load Profile Application Group
applied power in % of rated power
operating time in %
100
10
1A
80
50
(all engines except 4000 M60R)
60
20
< 15
20
100
20
90
70
< 15
10
1B
100
75
up to and incl. Series 4000
< 15
25
100
3
85
82
< 15
15
100
10
70
70
< 10
20
1A for V4000M60R only
1B above Series 4000
1DS
Figure 3.3.1:
Typical Standard Load Profiles
If there is a significant difference between the actual and standard load profiles, MTU calculates the TBO on the basis of the load profile submitted by the customer. All MTU engines can be operated at fuel-stop power as long as required by the customer. Of course, extensive operation at fuel stop power (higher load profile) will shorten the time between maintenance intervals.
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3
3.4
Specification of Power and Reference Condition
Time Between Major Overhauls (TBO)
Failure rate
Up to now, the TBO for diesel engines is not specified in any international standard. Therefore each engine manufacturer uses his own definition for TBO.
TBO
Early failures 1 1
Figure 3.4.1:
MTU
Maintenance Echelon W6
Random failures
W earout failures
Probable start-up failures
Operating tim e
TBO definition of MTU
According to MTU, the TBO is defined to be the time span in which operation without major failure is ensured, i.e. it precludes wear-related damage requiring a major overhaul or engine replacement. This time span is theoretically reached, if a probability of wear-out failures exceeds 1% (socalled B1 definition). This means that an MTU engine can still provide full and unlimited service until the last operating hour before the scheduled overhaul. The major criterion for a ship is availability and thus the reliability of the propulsion. Based on this, MTU decided to limit the statistical wear-out failure rate to 1 % only.
TBO definition from other engine manufacturers In contrast to MTU’s TBO definition, some other manufacturers define a scheduled TBO at a wear-out failure rate of 10% or up to 50% (B10 or B50 definition). This means, that statistically up to 50% of all engines do not reach the pre-defined TBO without major failure.
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Specification of Power and Reference Condition
Load Profile Recorder Most engines in the MTU Sales Program do include a load profile recorder as an integral part of the Electronic Engine Management System. This device continuously records the operating time spent at certain power levels and speeds, together with several other important engine parameters. The load profile could be downloaded from the Electronic Engine Management System and analysed. In case of significant deviations between the recorded load profile and the assumed load profile, the TBO could be revised. The finally applicable TBO will also take into account the actual engine condition as a result of installation conditions, quality of fluids and lubricants and service.
Back to Contents
Back to Start of Chapter
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4 4.1
Fluids and Lubricants Specification
FLUIDS AND LUBRICANTS SPECIFICATION General The fluids and lubricants used in an engine are among the factors influencing serviceability, reliability and general operability of the propulsion plant. Only fluids and lubricants approved by MTU may be used with MTU products. MTU issues a list of approved fluids and lubricants, for engine operation and engine preservation i.e. • • • •
lubricants (oils, greases and special-purpose lubricant substances) coolants (corrosion-inhibiting agents, anti-freeze agents) fuels preserving agents (corrosion-inhibiting oils for use in and on the engine)
The MTU approved fluids and lubricants as well as the requirements which they must satisfy are listed in the currently applicable MTU Fluids and Lubricants Specification. MTU Fluids and Lubricants Specification (A001061/..) is available. An operator wishing to use a fluid or lubricant that is not included in the Fluids and Lubricants Specification must consult MTU.
4.2
MTU Approved Fuels EN 590 Density at 15°C
kg/m3
Lower calorific value
kJ/kg
Figure 4.2.1:
MGO/MDO according ISO 8217 DM
DMA
DMB
DMC
880-890
900
920
Fuel specification
( under preparation )
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5
5
Engine Performance Diagram
ENGINE PERFORMANCE DIAGRAM The engine performance diagram serves as the basis for a number of calculations, but one of its most important functions is to indicate the speed and power limits that must be observed for propeller and waterjet design. Engine power [kW]
Speed band of constant power Nominal power = 100% Limit of MCR ATL switching border line
II UMBL
Min. engine Speed (lowidle) Power surplus (acceleration reserve)
II Nominal speed = 100%
I
Propeller curve = power demand (P ~n³) Engine speed [rpm]
Figure 4.2.1: I –II
: Status, sequential turbocharging
II UMBL
: The engine operating values can be further optimized by employment of some blowing over facilities within the ATL-connection (ATL = tubocharger). After connection of the second ATL, air charge is blown over to the exhaust line controlled by the engine electronics in order to increase the mass flow rate through the turbine. In combination with the improved situation of the working line with reference to the compressor efficiency a higher loadingpressure and consequently an improvement of the engine operating values is obtained.
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Structure of the performance diagram
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Engine Performance Diagram
Base for the layout of the performance diagram: • Application group (1A, 1B, 1DS) • Reference conditions • Definition of power rating and fuel consumption • Time between overhauls/operating load profile The engine performance diagram shows engine power plotted against engine speed. It also includes the specific fuel consumption curves and operating-speed range limits, along with all other boundary conditions. Figure 4.2.2 shows a representative engine power diagram.
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Figure 4.2.2:
TPG-General.doc Rev. 1.0
Engine Performance Diagram
Engine performance diagram
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Engine Performance Diagram
There are different power/speed demand curves depending on difference hull shapes:
Figure 4.2.3:
Monohull
Figure 4.2.4:
Semi-planing boat hull = high speed monohull with medium displacement
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Figure 4.2.5:
Multihulls = catamarans, trimarans,
Figure 4.2.6:
Semi-planing boat hull = high speed monohull with low displacement Back to Contents
Back to Start of Chapter
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6 PROPULSION, INTERACTION ENGINE WITH APPLICATION 6.1 Propulsor 6.1.1 Abbreviations The following abbreviations will be used in section 6. In the majority (marked with an asterisk) they are according to recommendations of the ITTC Symbols and Terminology List, Draft Version1999 (International Towing Tank Conference).
PS
PD
Propeller
Figure 6.1.1:
PB
Gearbox
Diesel Engine
Scheme of a propulsive unit (side view)
Symbol
Name
Definition or Explanation
SI Unit
ITTC B D
*
Hu
m3/h
Propeller diameter
M
Lower heating value or lower caloric value
Lower heating value of fuel (preferred value 42800 kJ/kg)
kJ/kg
PB
*
Brake power
Power at output flange of the diesel engine, power delivered by primer mover.
W
PD
*
Delivered power or propeller power, propeller load
Power at propeller flange.
W
PE
*
Effective power or resistance power
Power for towing a ship.
W
PS
*
Shaft power
Power measured on the shaft. Power available at the output flange of a gearbox. If no gearbox fitted: PS = PB
W
PS
Generator apparent power
W
Pp
Generator active power
W
RT
*
Total resistance
T
*
Propeller thrust or waterjet thrust
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Fuel consumption
Total resistance of a towed ship.
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Symbol
Name
Definition or Explanation
be
Specific fuel consumption
f
Electrical power supply frequency
n
Shaft speed, rate of revolution
p
Number of generator pole pairs
v
Ship speed
(see remark 1)
Propulsive efficiency
PE / PD
*
ηD ηGen
*
ηH
within MTU often used as SFC ( alternative dimension g/kWh)
SI Unit kg/kWh (g/kWh) Hz
(diesel engine, gearbox, propulsor) alias rpm in several propulsor applications
1/s (rpm) --m/s (knot) ---
Generator efficiency
---
Hull efficiency
---
Mechanical efficiency
ηm
Propulsion, Interaction Engine with Application
PD / PB ,represents the losses between diesel engine and propeller flange.
---
η0
*
Propeller open water efficiency
---
ηR
*
Relative rotative efficiency
---
Specific density of fuel
ρfuel
(preferred value 830 kg/m3)
kg/m3
Remark 1: While the SI-Unit of velocity is meter/second the traditional unit knots is widely used and this situation will not change in the near future. kn
knot (1sm/h or 1852m/3600s = 0.5144 m/s)
sm
sea mile ( = 1852 m)
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(alias nm = nautical mile)
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6.1.2 Propulsive Devices (Overview) The duty of a propulsive unit is to convert the power of the diesel engine into propulsive thrust. A propulsive device can be a:
Type Fixed Pitch Propeller (FPP)
General Characteristics Ease of manufacture Small hub size Blade root dictates boss length Design for single condition (design point) Absorbed power varies with propeller speed No restriction on blade area or shape Gearbox: reversing gear needed
Controllable Pitch Propeller (CPP)
Constant or variable speed operation Blade root is restricted by palm dimensions Mechanical complexity Restriction on blade area to maintain reversibility Can accommodate multiple operating conditions Increased manoeuvrability Gearbox: if fully reversible no reversing gear needed
Waterjet
Good directional control of thrust Increased mechanical complexity Avoids need for separate rudder Increased manoeuvrability Diesel engine load independent of wind and sea state High speed range (approx.>20 kn) Gearbox: no reversing gear needed, but usually used to allow back flushing of water (reverse mode)
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Type Rudderpropeller
Propulsion, Interaction Engine with Application
General Characteristics Good directional control of thrust Increased mechanical complexity Avoids need for rudder Increased manoeuvrability Can employ ducted or non ducted FPP or CPP types Low speed range (approx.<20 kn) Gearbox: not required for standard arrangements
Cycloidal Propeller
Good directional control of thrust Increased mechanical complexity Avoids need for rudder Increased manoeuvrability Low speed range (approx.<20 kn) Gearbox: not required for standard arrangements
Twin-Propeller
Good directional control of thrust Increased mechanical complexity Avoids need for rudder Increased manoeuvrability Propeller coupled mechanically Same direction of rotation Low speed range (approx.<24 kn) Gearbox: not required for standard arrangements
Podded Propulsion
Good directional control of thrust Avoids need for rudder Increased manoeuvrability Electric motor drives propeller Gearbox: not required
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Type
Propulsion, Interaction Engine with Application
Typical Arrangements
Fixed Pitch Propeller (FPP)
Controllable Pitch Propeller (CPP)
Waterjet
Rudderpropeller
Cycloidal Propeller
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Type
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Typical Arrangements
Twin-Propeller
Podded Propulsion
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Type Fixed Pitch Propeller (FPP)
Controllable Pitch Propeller (CPP)
Waterjet
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Manoeuvring Characteristics Power demand: fixed relation between ship speed and diesel engine power. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: reversible gearbox. Control: not applicable. Gearbox: free standing, flange mounted, V-drive arrangement. Rudder: needed. Power demand: every possible pitch has its own fixed relation to the effective power curve. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed or propeller pitch. Astern: reversible gearbox or fully reversible propeller. Control: hydraulic power pack arranged in shaft line or at the gearbox. Gearbox: free standing, flange mounted. Rudder: needed. Power demand: fixed relation between shaft speed and diesel engine power. Small dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: reversing bucket (optional). Control: hydraulic power pack for steering and reversing bucket. Gearbox: free standing, flange mounted. Rudder: if no steering equipment at waterjet.
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Type Rudderpropeller
Cycloidal Propeller
Twin-Propeller
Podded Propulsion
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Manoeuvring Characteristics Power demand: fixed relation between ship speed and diesel engine power. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: turning the propeller pod. Control: hydraulic power pack for steering. Gearbox: standard. Rudder: no need. Power demand: every possible blade pitch has its own fixed relation to the effective power curve. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed or blade pitch. Astern: control of thrust direction via blade pitch. Control: hydraulic power pack. Gearbox: standard. Rudder: no need. Power demand: fixed relation between ship speed and diesel engine power. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: turning the propeller pod. Control: hydraulic power pack for steering. Gearbox: standard. Rudder: no need.
Power demand: full electric propulsion, fixed relation between ship speed and electric motor. Clear dependence on hull resistance. Ship speed: adjusting motor speed (electrical). Astern: turning the pod or reversing the motor. Control: hydraulic power pack for steering. Gearbox: no need. Rudder: no need.
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Shaft Line and Gearbox Losses The brake power (PB) of the diesel engine will be transferred via a shaft line to the propeller flange. All power consumers in the shaft line will be counted as mechanical losses (ηm). The main loss will occur in the gearbox depending on how many gears and clutches are used and how many pumps are attached, where at the pumps will generate the main part of the losses.
ηm =
PD in (---) PB
(E- 6.1.1) PB = diesel engine brake Power PD = delivered Power ηm = mechanical efficiency
At the design point the following approximations can be used: ηm = 0.98
non reversible gearbox
ηm = 0.97
reversible gearbox
Information about the losses in the gearbox must be provided by the manufacturer. The diesel engine has to deal with two different kinds of mechanical losses: 1. Static friction loss (no oil film yet) 2. Dynamic friction loss (built up oil film) The dynamic friction losses in the shaft line bearings (<1%) can be neglected. If no gearbox is used, take an approximation of ηm = 0.99%. If the propeller shaft starts turning, the static friction has to be overcome (initial break-away torque) until lubrication has been established and dynamic friction only is in effect.
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6.2 Propeller 6.2.1 Propeller Geometry To understand the hydrodynamic action of a propeller it is essential to have a thorough understanding of basic propeller geometry and the corresponding definitions. Figure 6.2.1 shows what is meant by rake and skew of a propeller. The use of skew has been shown to be effective in reducing vibratory forces, hull pressure induced vibration and retarding cavitation development. With rake the stress in the blade can be controlled and slightly thinner blade sections can be used, which can be advantageous from blade hydrodynamic considerations.
Rotation
Rake
Skew
Hub
Diameter
Figure 6.2.1:
Scheme of propeller geometry (skew and rake)
Every propeller needs a hub to fix the blades and to place the control mechanism (CPP) for the blades. This results in different hub sizes for a FPP and a CPP (propeller) and is a characteristic difference between these two types. The hub size of a CPP is 10 to 15% larger (related to the diameter). See the figures in the overview section (6.1.2) also. Another difference is the blade area ratio (A/A0). Blade area ratio is simply the blade area, a defined form of the blade outline projection, divided by the propeller disc area (A0). As a controllable pitch propeller is usually fully reversible in the sense that its blades can pass through zero pitch condition care has to be taken that the blades do not interfere with each other. With equal number of blades a CPP can only realize a somewhat smaller area ratio than a FPP.
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The expression (P/D) is the commonly used pitch ratio. Alternatively the pitch angle θ can be given. With
D = 2R and x =
r (dimensionless radius) R
the characteristic pitch angle is defined at a propeller ratio of x=0.7. Unfortunately there are several pitch definitions and the distinction between them is of considerable importance to avoid analytical mistakes: 1. nose tail pitch 2. face pitch The nose–tail pitch line is today the most commonly used and referenced line. The face pitch line is basically a tangent to the section of the pressure side surface and used in older model test series (e.g. the Wageningen B Series). Although the difference is not big it can be the reason for using different values for the same propeller. The following equation can be used to convert the pitch from P/D to θ or vice versa.
P Θ = arc tan −1 D xπ
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6.2.2 Propeller Type Selection (FPP or CPP) The selection of a propeller for a particular application usually is a result of the consideration of different factors. These factors can be determined in pursuit of maximum efficiency with respect to:
• noise limitation • ease of manoeuvrability • cost of installation and so on. Each vessel has to be considered with regard to its own special application. The choice between a fixed pitch (FPP) and a controllable pitch propeller (CPP) has been a long contested debate between the proponents of the various systems. Controllable pitch propellers have gained complete dominance in Ro-Ro vessels, ferry and tug markets with vessels of over 1500 kW propulsion power with an operational profile that can be satisfied by a CPP better than by a two speed gearbox. For all other purposes the simpler fixed pitch propeller appears to be a satisfactory solution. Comparing the reliability between the mechanical complex CPP and the FPP shows, that the CPP has achieved the status of being a reliable component. The CPP has the advantage of permitting constant speed operation of the propeller. Although this leads to a loss in efficiency, it does readily allow the use of shaft driven generators, if this is a demand in the operational profile of the ship. During the last years the electric drive with podded propeller has been arising on the market. Without the need of a gearbox and controllability of the electric motor a fixed pitch propeller seems to be the best choice. But it must not be forgotten to compare the economical aspects of an extended motor control with the cost of a CPP.
Rudder
a
Propeller Clearance a ≥ 0.25D b ≥ 0.20D
D
b
Figure 6.2.2:
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Propeller clearance
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To determine the propeller diameter (D) for a certain delivered power (PD) at a propeller speed (n) and a ship speed (v) is a complex routine. For the Wageningen B-Series propellers there are some calculation procedures available, which can be found in the literature with all necessary assumptions that have to be made. The size of a propeller cannot only be calculated theoretically, but must also be adapted to the ship. The ship must provide the necessary space for the propeller including a sufficient clearance between propeller and hull (Figure 6.2.2). Due to hydrodynamic effects and/or cavitation the ship hull and the rudder can be mechanically excited, which can cause heavy vibrations at the stern or the rudder with the possibility of mechanical failures. The values shown in Figure 6.2.2 are only a design proposal. For more detailed information see the recommendations of a classification society. A few words to the effect of thrust breakdown. The power density of a propeller can only be increased to a certain limit, which depends on the propeller parameters and especially on the blade area ratio. Obviously the cavitation occurs first at the tip section of a blade and extends downward with higher power consumption. It is a matter of definition when these effects are called “thrust breakdown”, e.g. if the cavitation exceeds below the 0.5 radius.
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6.2.3 Direction of Propeller Rotation The direction of rotation can have consequences for manoeuvring and efficiency considerations. Although the given explanations in literature are not really convincing the following recommendations can be given: Single shaft: (looking from aft at propeller)
FPP (fixed pitch propeller) Direction of rotation:
clockwise
CPP (controllable pitch propeller) Direction of rotation:
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counter clockwise
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Twin shaft: (looking from aft at propeller)
FPP (fixed pitch propeller) Port side:
counter clockwise
Starboard:
clockwise
Starboard:
counter clockwise
CPP (controllable pitch propeller) Port side:
clockwise
For those who are still eager to hear a few words about the reasons for doing so, here are some explanations from literature. Propeller efficiency: It has been found that the rotation present in the wake field, due to the flow around the ship, at the propeller disc can lead to a gain in propeller efficiency when the direction of rotation of the propeller is opposite to the direction of rotation in the wake field. Manoeuvring (single screw): For a single screw ship the influence on manoeuvring is entirely determined by the “paddle wheel effect”. When the ship is stationary and the propeller is started, the propeller will move the afterbody of the ship in the direction of rotation. Thus with a TPG-General.doc Rev. 1.0
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fixed pitch propeller, this direction of initial motion will change with the direction of rotation, i.e. is ahead or astern thrust. In the case of a controllable pitch propeller the motion will tend to be unidirectional because only the pitch changes from the ahead to the astern position. The direction of rotation will not change. In the astern thrust position FPP and CPP will have the same direction of rotation and assuming that starboard is the main docking side there is an advantage to push off from the quay with astern thrust. Manoeuvring (twin screw): In addition to the paddle wheel effect other forces due to the pressure differential on the hull and shaft eccentricity come into effect. The pressure differential, due to reverse thrusts of the propellers on either side of the hull gives a lateral force and turning moment. From the manoeuvrability point of view it can be deduced from test results that the fixed pitch propellers are best when outward turning. For the controllable pitch propeller no such clear-cut conclusion exists. Although these effects are small, the design should follow the given recommendations but if the rules are not kept no great disadvantage arises.
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6.2.4 Selection of Propeller Blade Number Blade numbers generally range from two to seven. For merchant ships four, five or six blades are favoured, although many tugs and fishing vessels frequently use three bladed designs. In naval applications where the generated noise become important blade numbers of five and above predominate. The number of blades shall be primarily determined by the need to avoid harmful resonant frequencies of the ship structure and torsional machinery vibration frequencies. As blade number increases cavitation problems at the blade root can be enhanced, since the blade clearance becomes less. It is also found that propeller efficiency and optimum diameter increase as the number of blades decreases and to some extent, the propeller speed (n) will dependent on the blade number.
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6.3 Propeller Curve 6.3.1 Basics When a ship is being towed and is not fitted with a propeller, the required force is called resistance (R) and the necessary power to tow the ship at a certain speed (v) is: PE = R T ⋅ v
in (kW)
(E- 6.3.1) PE = effective Power RT = total resistance v = ship speed
Basis for the design of a propulsive device is the effective power (PE) curve for a ship, showing the relation between effective power and ship speed (v). The effective power curve will be evaluated by a test facility or estimated with respect to a defined condition, i.e. usually the trial condition:
• new ship, clean hull • sea state 0-1 (calm water), wind Beaufort 2-3 • load condition (defined, e.g. full load) • no current The load of the propulsive device to match the effective power is called delivered power (PD) and the relation between the effective and delivered power is called the propulsive efficiency (ηD).
ηD =
PE PD
in (---)
(E- 6.3.2) ηD = propulsive efficiency PE = effective Power PD = delivered Power
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The propulsive efficiency is the product of:
•
Propulsive unit efficiency in open water (η0) depending on type, size, speed, e.g. (at design point approx. η0 = 0.60 – 0.75).
•
Hull efficiency (ηH) depending on wake fraction and thrust deduction fraction (at design point approx. 0.90 – 1.10).
•
Relative rotational efficiency (ηR) depending on the propeller efficiency behind the ship and the propeller open water efficiency (at design point approx. 0.95 – 1.02).
ηD = η O ⋅ ηH ⋅ ηR
in (---)
(E- 6.3.3)
The effective power varies not only with ship speed (v). Environmental conditions (wind, sea state), hull roughness (clean, fouling) and actual load condition of the ship have to be taken into consideration (Figure 6.3.1).
Effective Power PE
effective pow er curve (in service)
pow er difference at const. Speed (v) ship speed difference at const. Pow er (PE)
effective pow er curve (clean hull)
Ship Speed (v)
Figure 6.3.1:
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Influence of change in resistance on effective power curve (example)
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Effective Power (PE)
Effective Power Curve
Ship Speed (v)
Propeller Design
Ship Speed (v)
Figure 6.3.2:
As Required
Delivered Power (P D )
Delivered Power (P D )
The result of the propeller design can be presented in a bunch of diagrams.
Propeller Speed (n)
user defined
As Required
From effective to delivered power curve (example)
On the basis of a defined effective power curve a propeller will be designed. The relation between delivered power (PD) and ship speed (v) or propeller speed (n) can be shown in single diagrams or a diagram using both ordinates. Figure 6.3.2. shows some examples. The diagram with the propeller speed (n) as abscissa has the advantage that the performance diagram of the diesel engine can be plotted in also.
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Every change in the effective power curve will be seen in the propeller curve also. The example in Figure 6.3.3 shows that due to the cubic characteristic of the propeller curve small changes can have great effects.
Delivered Power PD
propeller curve (in service)
pow er difference at const. Propeller Speed (n) propeller speed difference at const. Pow er (PD)
propeller curve (clean hull)
Propeller Speed (n)
Figure 6.3.3:
Effect of change in resistance on delivered power curve (example)
Although the curves in Figure 6.3.1 and Figure 6.3.3 are similar in shape they are different. The effective and the delivered power will be related by the propulsive efficiency (ηD). This means that the propeller curve is only valid for the designed propeller. Changing the geometry of the propeller (e.g. diameter, area ratio, pitch or the number of blades) leads to a new power-speed relation, i.e. a new propeller curve. If the effective power curve changes, e.g. from clean hull and fair weather to fouled hull and heavy weather the propeller curve will also change. That leads to the conclusion: A change in the propeller curve can be initiated by the ship (effective power) or by a modification of the propeller.
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FPP: The propeller curve has a fixed relation to the effective power curve and will be influenced by the ship (effective power) only. CPP: Every possible pitch has its own fixed relation to the effective power curve. This leads to a bunch of propeller curves (Figure 6.3.4). The propeller curve will be influenced by the ship (effective power) and the propeller pitch.
CPP (Controllable Pitch Propeller)
Delivered Power PD
design pitch
constant ship speed
pitch increases propeller curves = lines of constant pitch
Propeller Speed (n)
Figure 6.3.4:
Effect of different propeller pitches on delivered power (example)
This different behaviour will have distinct consequences on the design of the chosen propeller type.
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6.3.2
Propulsion, Interaction Engine with Application
Theoretical Propeller Curve Diameter (D), delivered power (PD) and shaft speed (n) of the propeller can be calculated by the propeller manufacturer when the effective power curve is given and the design speed (v) and the installed brake power (PB) have been chosen. Power and propeller speed (n) have to match the installed power of the diesel engine. If only the design point of the propeller or the diesel engine is known, a simple approximation can be done by a theoretical propeller curve. PD design PD = 3 n design P
PB design PB = 3 n design
⋅ n prop 3
3 ⋅ n
PD = delivered power nprop = propeller speed fixed propeller geometry
PB = diesel engine brake power n = diesel engine speed fixed propeller geometry
Diesel engine and propeller have a fixed relation via the propeller shaft and therefore the equation can be used for PB and PD as well. There will be differences to the real curve, depending on the hull form (see chapter 5 also) as the decisive factor, and taking into account that the propeller geometry is fixed. That means the approximation of a controllable pitch propeller is only valid for the design pitch. There is another restriction for the lower speed range. Below a certain speed (v) the wind forces can become dominant and the delivered power does not decrease any more.
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Something to remember: Cubical propeller curve, why n3 ? •
V = c ⋅ A = c ⋅ π ⋅ D2 4 c = π ⋅ n ⋅D
V = volume flow A =propeller disc area c = flow speed D = propeller diameter (constant for a given design)
This leads to : •
V ~ n ⋅ D3 ∆p = ρ ⋅ c 2 2 •
P = ∆p ⋅ V
Bernoulli equation (c1=0) p = pressure P = power
The result : P ~ n3 ⋅ D 5 or P ~ c3 ⋅ D2
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theoretical propeller curve power is proportional to n3 (propeller speed) power is proportional to v3 (ship speed)
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6.3.3 Estimating the Required Diesel Engine Power In some cases the required total diesel engine brake power (PB) for a ship has to be estimated in a very early stage of a project and only estimations of the effective power (PE) or the total Resistance (RT) are available. With Equation (E- 6.1.1), (E- 6.3.1) and (E- 6.3.2) a rough estimation for the required total diesel engine brake power (PB) at ship speed (v) can be done.
PB =
R T ⋅ v ⋅ 0.5144 ηD ⋅ η m
in (kW)
(E- 6.3.4)
or PB =
PE ηD ⋅ η m
in (kW)
(E- 6.3.5) PB = total diesel engine brake power in kW PE = effective Power in kW RT = total resistance at ship speed (v) in kN v = ship speed in knot (0.5144 used to convert knot to m/s) ηD = propulsive efficiency ηm = mechanical efficiency
At the design point the following approximation can be used for the efficiencies:
ηm = 0.97 ηD = 0.60 The result is the total diesel engine break power (PB) for the ship. This value must be distributed onto the desired number of diesel engines.
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6.4 Propeller and Performance Diagram 6.4.1 Driving Mode Power (PD) and propeller speed (n) have to match the installed power for the propulsion (PB). Only the sea trials show whether estimations are correct or not. At this stage of evaluation a diesel engine has been selected and a design point inside the performance diagram of the diesel engine has to be chosen. In addition to the hydrodynamic aspects (see Figure 6.3.2, Propeller Curve), manufacturing tolerances have to be taken into account. Manufacturing tolerance in pitch, surface and profile influence the power absorption of the propeller.
Brake Power PB in ( % ) Rated Power
Hull resistance can vary due to inevitable differences in load and shape.
100% = rated pow er 100% = rated speed
120
3
110 4
100
C B
2
A
5
MCR curve 1
propeller curve
1
90 80 MCR curve 2
70 60 80
85
90
95
100
105
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.1:
Change in delivered power due to weather, draught and fouling
Hydrodynamical and geometrical aspects (Figure 6.4.1) can shift the propeller curve (A) to the left side of the performance diagram (C). Certain models of diesel engines are more sensitive to this shifting than others. As a consequence, the ship may not be able to operate at full speed when the hull has fouled, the weather deteriorates or the draught has increased.
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In Figure 6.4.1 two diesel engines (MCR curves 1 and 2) from various manufacturers with different performance limits are shown. A change in the propeller curve from (A) to (C) leads to the following behaviour: A
The diesel engine can run with full speed (n). No limitation arises (point 1). But the propeller does not absorb the maximum available power.
B
The diesel engine can run with full speed (n) and reach its full power. No limitation arises (point 2).
C
Due to the load limits (MTU: fuel stop power) both diesel engines are not able to provide the required power for full speed (n) at point (3). In this case the diesel engines reduce their speed (n) in order to find a new operation point within the performance limits. For the diesel engine with MCR curve 1 this is point (4) and for the other diesel engine point (5). The differences between the two operating points (4) and (5) are the magnitude of reduction in ship speed (v) which can be considerably high.
Brake Power PB in (%) Total Rated Power
A similar behaviour is experienced in a two-shaft arrangement which has been switched over in a single shaft mode. Figure 6.4.2 shows the arrangement with diesel engines of the same type one per shaft. The output power has been added over the speed range (MCR curve 1) and the propeller curve running through point 1. Each diesel engine takes half the load of the required brake power (PB). 120 100 80
MCR curve 1 (2 diesel engines, one per shaft)
fixedpitch pitchpropeller fixed propeller
1
100% = rated pow er 100% 100%==rated ratedspeed pow er 100% t d d
60
tw o shaft propeller curve
single shaft propeller curve
40 MCR curve 2 (single shaft) 1 diesel engine
2
20 0 20
30
40
50
60
70
80
90
100
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.2:
Diesel engine failure in a two shaft arrangement
MCR curve 2 shows the available brake power (PB) of one diesel engine. If one diesel engine is shut down, the effective power of the ship relates to one propeller instead of two with the consequence of a new propeller curve (single shaft propeller curve). TPG-General.doc Rev. 1.0
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The running diesel engine has to find a new operating point on the single shaft propeller curve within its performance limits. In this example, point (2) is the new operating point for the diesel engine. The point marks also the maximum available brake power (PB) (and speed (n)) in the single shaft mode for this ship. In case that the diesel engine finds no operating point it will stall. This will also point out that with the chosen diesel engines the ship cannot be run in single shaft mode. In this case a CPP has to be selected. These are some reasons why the design point of the diesel engine should be carefully specified with respect to the load limits and the kind of propeller (FPP, CPP) that is to be used.
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6.4.2 Fixed Pitch Propeller (FPP) The design of a propulsion system with a fixed pitch propeller is absolutely critical to the performance of the ship. The brake power (PB) curve should pass through the maximum continuous rating of the diesel engine. But due to geometrical tolerances and deteriorated hydrodynamics, the propeller curve can be higher than predicted. This situation will be overcome by designing the propeller a few revolutions faster for the new ship. Dependent on the type of diesel engine two different approaches are possible.
Brake Power PB in ( % ) Rated Power
120
fixed pitch propeller
C
100% = rated pow er 100% = rated speed
110
4
100
propeller curve
design margin 3
B 2
A
MCR curve 1
90
design margin
80
70 80
85
90
95
100
105
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.3:
Choosing a design point for a fixed pitch propeller
MTU Procedure (wide lug-down range diesel characteristic): Point 2: Preferred/recommended design point for the propeller. The characteristic of a MTU diesel engine is the wide lug-down range above a certain speed (n) (fuel stop power). This range can be used as a design margin. In poor weather conditions or at increased hull resistance the propeller curve will move to the left. This means, at trial condition the diesel engine should work at the rightmost point of the MCR curve (point 2, trial effective power curve = propeller curve B), i.e. the design point for the propeller. With growing lifetime the propeller curve will move to the left (e.g. point 3, propeller curve C).
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The design allows the propeller to run at 100% rated power (PB) as long as the propeller curve does not pass point 4 (lugging point). The maximum ship speed (v) will decrease slowly with the left shifting of the propeller curve towards point 3. Standard procedure (usable for all type of diesel engines): Point 1: Preferred/recommended design point for the propeller. In the design point the propeller runs at 100% rated speed (n) and small amount (design margin) below 100% rated power. In this case at trial condition the diesel engine is effectively working at a derated condition (point 1, trial effective power curve = propeller curve A). In poorer weather or with growing lifetime the propeller curve will move to the left and the maximum power will be used (point 2, propeller curve B). The design allows the propeller to run at 100% rpm (rated speed) as long as the propeller curve does not pass point 2. The ship speed (v) will increase with the shifting of the propeller curve and reaches its maximum at point 2. Using this procedure the designer has to consider that it may be not possible to demonstrate the full speed (v) capability of the ship at trial conditions, because the speed (n) of the diesel engine is limited to 100% rated speed. The difference between 100% rated power and design power is called "sea margin" (= design margin). If there are no specific demands, a design margin of approx. 6 to 10% shall be used. The rated power will be met by propeller curve A at 102 to 103.5% rated speed but this is only theoretical. Summary: Both procedures or a mixture can be used for choosing the design point of a fixed pitch propeller and a flat rated diesel engine. If the application demands no specific propeller design point, the MTU recommendation shall be used (point 2 = primary design point for the propeller). No matter what design point is chosen the propeller curve runs on a fixed curve through the performance range of the diesel engine. So, a few additional aspects shall not be forgotten: If the delivered power curve through the design point does not pass through the region of minimum fuel consumption, no change will be possible afterwards. If the power curve comes too close to the diesel engine surge limits, the curve cannot be moved away from this region with the result of a blocked operation range.
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6.4.3 Controllable Pitch Propeller (CPP) The controllable pitch propeller can be seen as an extension to the fixed pitch propeller. Each pitch results in a new propeller curve. A typical example is shown in Figure 6.4.4 where the controllable pitch propeller characteristic is superimposed on a diesel engine characteristic.
Brake Power PB in ( % ) Rated Power
design pitch
100 80
controllable pitch propeller 100% = rated pow er 100% = rated speed
constant ship speed
60 MCR curve
40 20
pitch increases propeller curves = lines of constant pitch
0 20
40
60
80
100
Propeller rpm in ( % ) Rated Speed
Figure 6.4.4:
CPP characteristic in a typical diesel engine performance diagram
Every change in the pitch of the propeller changes the relation between propeller speed (n) and brake power (PB) for the ship. Due to possible later adjustment of the propeller pitch there are no restrictions for the design point within the diesel engines performance diagram. The point at 100% brake power (PB) and speed (n) should be chosen (Figure 6.4.5). The available pitch range is not fixed. It is a part of the customer’s specification for the propeller. On the manufacturer’s side it is limited by the size of the hub and the maximum blade forces. Generally the available pitch range will be related to the design pitch and be given in degrees. The range above the design pitch is very small because there is no general need, except in special applications.
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Brake Power PB in ( % ) Rated Power
6
110 100
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controllable pitch propeller propeller curve (design pitch)
100% = rated pow er 100% = rated speed
design point
MCR curve
90 80 70 60 80
85
90
95
100
105
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.5: Controllable pitch propeller design point The performance of a CPP at design pitch can be calculated like a FPP. When off design performance is needed use should not be made of fixed pitch characteristics beyond 5° from design pitch because the effect of section distortion affects the calculation considerably. The controllable pitch gives a lot of options: If the delivered power curve through the design point (design pitch) does not pass through the minimum fuel consumption region, it is possible to adjust the pitch at partial load conditions. If the power curve comes too close to the diesel engine MCR limit, the operating curve can be moved away from this region. If the ship during trials is not able to achieve the design brake power (PB) the design pitch can be corrected or when the ship resistance increases with service life, the design brake power (PB) and speed (n) will stay available. A CPP can be chosen with a fully reversible position and the ship can move astern without the need of a reversing gearbox. The stopping distance will be significantly lower than with a FPP. Generally the manoeuvring characteristics are better. A CPP can be chosen with a feathering position (minimum resistance), if a single shaft mode is part of the operational profile.
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But you have to pay for the advantages: The controllable pitch propeller is more expensive than a FPP. If the propeller will be set out of the design pitch the efficiency decreases. Additional space inside the ship has to be provided for the propeller control unit. Due to its internal mechanism the propeller has a bigger hub than a FPP (approx. 50%), this can lead to a somewhat higher diameter. If the propeller is fully reversible, care has to be taken that the blades will not interfere with each other when passing zero pitch. The upper blade area ratio will be limited. There is an additional aspect that should be mentioned. If the diesel engine has a very slender performance diagram, the design propeller curve will not lie inside the diagram for the lower power range. This type of diesel engine can be used only with a propeller controlled by a pitch – RPM relationship, frequently called “combinator diagram “. Only in the last third of the power range the propeller can run at design pitch. Another reason is the access to the region of minimum fuel consumption. In doing so the propeller can come very close to the diesel engine surge limits. A programmed “combinator diagram” could give the best overall performance as well. With an MTU diesel engine the propeller can run in “combinator mode”, however, this is not necessary due to the wide performance range of the diesel engine. Another application is a constant speed generator attached to the gearbox. The diesel engine runs at constant speed (n) feeding the generator and the ship speed (v) will be controlled by the propeller pitch. This is a standard design for merchant ships running most of their service time at high power rates.
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An example is supposed to clarify this behaviour. Figure 6.4.6 is similar to Figure 6.4.2 and shows what happens when in a two-shaft arrangement the diesel engines are switched over in single shaft mode. MCR curve 2 shows the available brake power (PB) of one diesel engine. The running diesel engine has to find a new operating point on the single shaft propeller curve within its performance limits. In this example, point (2) is the new operating point for the diesel engine. This point marks also the maximum available brake power (PB) and speed (n) in single shaft mode at design pitch for this ship. In order to use the installed break power of the running diesel engine the propeller pitch has to be reduced (point 3). On this propeller curve, full power of the diesel engine and maximum ship speed (v) in single shaft mode are attainable.
Brake Power PB in (%) Total Rated Power
120 MCR curve 1 (2 diesel engines, one per shaft)
CPP 100
100% = rated pow er 100% = rated speed
tw o shaft propeller curve design pitch
80
single shaft propeller curve design pitch
60
MCR curve 2 (single shaft) 1 diesel engine
40
1
3
2
20
single shaft propeller curve reduced pitch
0 20
30
40
50
60
70
80
90
100
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.6:
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Example: Single shaft operation with CPP
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In the next example (Figure 6.4.7) the pitch of a CPP will be controlled by combinator. A constant speed generator is attached to the gearbox and shall run above 50% diesel engine load. In the lower power range the propeller shall run on design pitch. The thick line in the performance diagram shows the power-speed-pitch relation of the propeller.
Brake Power PB in ( % ) Rated Power
In the lower power range until point 3 the CPP runs at design pitch. Between point 3 and point 2 the diesel engine speed will be raised with decreasing propeller pitch. The ship speed will not change significantly. At point 2 the operating speed (n) for the attached generator has been reached. Between point 2 and point 1 the diesel engine runs at constant speed (n) feeding the propeller and the generator. The ship speed (v) will be controlled by the propeller pitch.
100 80
constant ship speed
CPP
1
design pitch
100% = rated pow er 100% = rated speed
Generator operating range
MCR curve
60 pitch increases
40
2 3
20 propeller curves = lines of constant pitch
0 40
60
80
100
120
Propeller rpm in ( % ) Rated Speed
Figure 6.4.7:
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Example: Constant speed generator in operation with CPP
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6.5 Waterjet and Performance Diagram 6.5.1 Geometry and Design Point The main application for a waterjet is in the higher speed range, let’s say above 20 kn. The propulsive efficiency of a waterjet decreases considerably with speed (v) reduction. Below 20 to 24 kn a propeller should be preferred. A waterjet is like a propeller a hydrodynamical propulsive device but is arranged inside the ship and behaves more like a pump than as a propeller. Pump
Nozzle
Inlet Shaft
Height above water line
Cross section Stator
Impeller
Inlet duct
Ship hull
V = Ship speed
7
8 10
Effective inlet velocity
11
9
5
6
1
4
1. 2. 3. 4. 5. 6.
Inlet duct Impeller Stator bowl Nozzle Shaft Sealing box
Figure 6.5.1:
TPG-General.doc Rev. 1.0
3
2
7. Thrust bearing 8. Steering deflector 9. Hydraulic steering cylinder 10. Hydraulic bucket cylinder 11. Inspection opening
Waterjet
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The main differences between a waterjet and a propeller are: The propeller is very sensitive to the velocity and direction of the local incoming flow. It senses the ship in its hydrodynamical situation (sea state, wind, draught, etc.), so does the diesel engine. The waterjet works more like a pump as long as there is any water in the intake duct and turns the brake power (PB) into thrust. There is only a minor feed back from ship. For this reasons the diesel engine has minor load cycles when it is connected to a waterjet.
120
Waterjet 100% = rated pow er 100% = rated speed
Brake Power PB in ( % ) Rated Power
100
propeller curve
design points 2
1
80
60 MCR curve
40
20
constant fuel consumption
0 30
50
70
90
110
Impeller Speed in ( % ) Rated Speed
Figure 6.5.2:
Waterjet design point (Diagram has limited use for waterjet design)
Due to the insensibility to the ship resistance (effective power curve) there are no restrictions for a design point within the diesel engine performance diagram. But the waterjet is like the propeller a mechanical device and manufacturing tolerances have also to be taken into account.
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This relation can lead to the fact that at 100% shaft speed (n) the waterjet cannot absorb the diesel engines brake power (PB). Therefore a design point at brake power and approx. 1 - 2% below 100% diesel engine shaft speed (n) (design margin) shall be chosen (Figure 6.5.2, design point 1). If the propeller curve shifts to the left the ship speed (v) will decrease but no change will be seen in Figure 6.5.2 because the waterjet is still running with its demanded speed (n) and brake power (PB). That is the reason why this diagram has a limited use for choosing a waterjet design point. It will only give an impression about the relation between the propeller curve, the lines of constant fuel consumption, the design margin and the margin to the diesel engine MCR limit curve. This relations will remain independent of the ship load as before. With this behaviour in mind design point 2 (Figure 6.5.2) can be chosen also. The leftmost design shaft speed (n) should be 1.5% above the speed (n) of the lugging point. The advantage is a less fuel consumption but the margin to the MCR curve (acceleration reserve) decreases. Because this behaviour is very fundamental a further example shall be given.
Figure 6.5.3:
Platform with pump
Imagine a platform on wheels with a water tank and a pump on its loading area (Figure 6.5.3 ). The water will be ejected horizontally in the air opposite to the direction of motion. The platform will start to move on the ground and no matter how fast the platform will move, the pump will always eject the same amount of water using the same power. This is true also if an obstacle stops the platform. The pump will not be affected by the behaviour of the platform. In other words the generated thrust depends only on the amount of ejected water. Although this is simplified, it shows the fundamental difference between a propeller and a waterjet. Let us take a step ahead. Even if there are two separated pumps on the loading area, they will not interfere which each other, independent whether they are or not of equal size or running at different power pumping different amounts of water.
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For this reasons another diagram has to be used which shows more consideration to the behaviour of a waterjet (Figure 6.5.4).
140
Waterjet
fuel stop pow er
Thrust in ( % ) Rated Thrust
120 design point
100 80 60 cavitation inception limit
constant brake pow er
40 20
propeller curve
0 0
20
40
60
80
100
Ship Speed in ( % ) Rated Speed
Figure 6.5.4:
Waterjet performance diagram
The figure shows the design propeller curve together with the waterjet performance diagram and instead of effective power the thrust is used. Because the ship speed (v) and the engine speed (n) of the diesel are not related to each other the performance diagram of the diesel engine can not be represented in the figure. A few words to the shown cavitation inception line: These lines are specific to the chosen waterjet and should not be compared between different manufacturers. For instance, KaMeWa divides its diagrams by two lines into three zones, showing different stages of cavitation. Generally these lines shall no be taken as absolute limits but as design guidelines. If the propeller curve shifts to the left the ship speed (v) will decrease and the distance to the cavitation inception limit will be reduced. The reason for this behaviour is that the stagnation pressure in the inlet duct goes down and the waterjet starts to suck the water through the duct. The thrust of a waterjet is the product of water mass flow and the speed of the ejected water. That means that a certain thrust can be generated by a smaller or a bigger waterjet. In the smaller one the speed of water is higher i.e. the distance between the design point and the cavitation inception line is smaller also. If there is limited space for installation or the operation time of the waterjet is short the designer will probably choose a small waterjet with a lesser distance to the cavitation area.
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The risk of getting air into the inlet duct of the waterjet depends on the specific arrangement in the ship and on the sea state. In this case the control system has to protect the diesel engine from any overspeed and due to the low inertial mass of the shaft line it is more demanding than for a propeller. The matching MTU control system has been adapted for this task.
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6.5.2 Estimation of Size and Shaft Speed The design shaft speed (n) of the waterjet depends on type, size and application and will be provided by the manufacturer. If the installed brake power (PB) and the ship design speed (n) are known Figure 6.5.5 and Figure 6.5.6 can be used for a quick look. 0.5
Ship Speed in (kn)
50
1.0
1.2
1.4 m (size inlet duct)
40 2.0
30 2.4
20
10 0
5000
10000
15000
20000
Brake Power in (kW)
Figure 6.5.5:
Estimating the size of a waterjet (inlet duct diameter)
Water Jet Speed in (min-1)
1000
Brake Pow er 500 kW 1000 kW 2000 kW 5000 kW 10000 kW 20000 kW
800 600 400
20000 kW
200 500 kW
0 0,5
1,0
1,5
2,0
2,5
Inlet Duct in (m)
Figure 6.5.6:
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Estimating the design impeller speed of a waterjet
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6.6 Fuel Consumption 6.6.1 General Assumptions The calculation of the fuel consumption for the diesel engines depends on a lot of assumptions. If the fuel calculation for a designed ship will be done by different people you will get different results, if you do not have a good specification. Nevertheless the size of the fuel storage tanks is an important impact on the ship design. The following values are required for calculation of the fuel consumption: (ref to chapter 6.6.6 for more detailed information) 1
Status and displacement of the ship (e.g. new ship, clean hull, full load)
2
Weather condition and sea state (e.g. wind Beaufort 2, sea state 2-3).
3
Ambient condition
4
Speed-power (ship speed (v) - brake power (PB)) diagram for assumed displacement, weather condition and sea state.
5
Propulsion plant and design condition (e.g. total installed brake power (PB) for propulsion, ship speed (v), propeller shaft speed (n), number of diesel engines per shaft).
6
Performance diagram of the diesel engine including the lines of specific fuel consumption for the required lower heating value (Hu), otherwise the values have to be corrected.
7
Lower heating value of fuel (e.g. Hu = 42800 kJ/kg for diesel oil).
8
Fuel density (e.g. ρfuel=830 kg/m3).
9
Gear ratio if a gearbox is used (for the relation between propeller shaft speed and diesel engine speed).
10
Fuel consumption of the diesel generator set running with a defined percentage of the installed mechanical power (e.g. all sets at 33%).
11
Usable volume of the fuel storage tank (e.g. 95%).
12
Operating profile (e.g. cruising speed (v) or speed profile).
It is obvious that an incomplete specification of these values can lead to calculation differences.
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The standard questions that arise in connection with fuel consumption are: 1.
Fuel consumption at design condition.
2.
The ship should run XXX sm on YY kn e.g. 1000sm on 12kn. The required fuel volume can be a design value for the necessary fuel storage volume.
3.
How long can the ship stay at sea for a given operating profile or the ship shall stay ZZ days at sea with a given mission profile. The required fuel volume can be a design value for the necessary fuel storage volume.
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6.6.2 Operating Profile The time between leaving and entering a port can be divided into several portions of time at constant speed ranges. Such list of time periods and speed ranges is called operating profile. Each ship has a characteristic operating profile which is determined by the owner to meet the commercial needs of the particular service. The result is a wide difference between the operating profiles of various ship types, e.g. a freighter, a fast ferry and a OPV, and one of the reasons why the design basis for a particular vessel must be chosen with care. Nevertheless an operating profile can change throughout the life of a ship, depending on a variety of circumstances. The operating profiles shown in Figure 6.6.1 and Figure 6.6.2 are very raw and shall only give an impression how such profiles can look like. Both operating profiles are equal. They are shown in different style for those who are not familiar with one of the presentations.
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Speed in (%) Rated Speed
Example:
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Freighter: Leaving the port and then running continuously at design speed.
100 80 60 40 20
Freighter
0 0
20
40
60
80
100
Time in (%) Operating Time
Speed in (%) Rated Speed
Example:
Ferry: Nearly the same as a freighter but when operating between islands there are often speed restrictions.
100 80 60 40 20
Fast Ferry
0 0
20
40
60
80
100
Time in (%) Operating Time
Speed in (%) Rated Speed
Example:
OPV: The shown tasks are at loitering speed (maybe embargo control), cruising speed (cruising in formation) and fast manoeuvring.
100 80 60 40 20
Offshore Patrol Vessel
0 0
20
40
60
80
100
Time in (%) Operating Time
Figure 6.6.1:
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Examples of operating profiles (freighter, fast ferry, OPV)
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Speed in (%) Rated Speed
Example:
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Freighter: Leaving the port and then running continuously at design speed.
100 Freighter
80 60 40 20 0
10
5
10
75
Time in (%) Operating Time
Time in (%) Operating Time
Example:
Ferry: Nearly the same as a freighter but when operating between islands there are often speed restrictions.
60
Fast Ferry 40
20
0 0 - 25
25 - 50
50 - 70
70 - 85
85 - 100
Speed Range in (%) Rated Speed
Time in (%) Operating Time
Example:
OPV: The shown tasks are at loitering speed (maybe embargo control), cruising speed (cruising in formation) and fast manoeuvring.
60
Offshore Patrol Vessel 40
20
0 0 - 25 25 - 40 40 - 70 70 - 85 85 - 95
>95
Speed Range in (%) Rated Speed
Figure 6.6.2:
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Examples of operating profiles (freighter, fast ferry, OPV)
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The owner should specify the operating profile, the operating hours per year and the number of missions per year. A mission is the time period needed to run one operating profile. In the design phase this specification can be used to calculate the fuel consumption for different propulsion alternatives, the TBO and as a first guess for the life cycle cost. Example of a user defined operating profile for a ship in tabulated form: Operating Profile (Ship) Ship Speed (kn) Time Period (%) 0–9
15
9 - 15
35
15 - 21
40
21 – max.
10
Generally, speed ranges will be shown in a operating profile, but for the calculation of the fuel consumption precise speed values have to be given, otherwise the results are not comparable. From that follows the brake power of the diesel engine e.g. at the upper bound of the given speed ranges. Example: Owner defined operating profile for a diesel engine:
Brake Power (%)
Time Period (%)
3
15
18
35
74
40
100
10
100
Brake Power in (%)
Operating Profile (Diesel Engine)
80 60 40 20 0 0
20
40
60
80
100
Time in (%) Operating Time
On the basis of such a operating profile the available TBO for the chosen diesel engine rating can be calculated.
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Alternatively, if the owner has not the experience to prepare a operating profile, the fuel consumption can be calculated on the basis of the standard load profile of the chosen diesel engine rating (e.g. 1A ,1B or 1DS). More information about “load profile” and TBO see chapter 2 and 3. Example: 1DS diesel engine rating (TBO 9000h)
Brake Power (%)
Time Period (%)
10
20
70
70
100
10
100
Brake Power in (%)
Operating Profile (Diesel Engine)
80 60 40 20 0 0
20
40
60
80
100
Time in (%) Operating Time
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6.6.3 Fuel Consumption at Design Condition With the provided information (see section 6.6.1) the fuel consumption at a given brake power (PB) and diesel engine speed (n) can be calculated. If no tolerances are given in the fuel consumption diagram, a margin of 5% has to be added to the calculated value.
B=
PB ⋅ be ρfuel
in (m3/h)
(E- 6.6.1) be = specific fuel consumption (kg/kWh) B = fuel consumption (m3/h) PB = diesel engine brake power (kW) ρfuel = fuel density (kg/m3)
Additional consumers, e.g. gensets have to be added to calculate the entire fuel consumption. If only the electrical power in kW is known for the genset use an estimation for the generator efficiency (e.g. 95%). B = B propulsion + B gensets + B auxiliary
in (m3/h)
(E- 6.6.2)
B = fuel consumption (m3/h)
The equation can be used for any other brake power (PB) and speed (n) in the performance diagram. If the consumption has to be calculated for the time periods of a operating profile the following equation can be used.
B=
(P
B1
⋅ b e 1 ⋅ t 1 + ....... + PB n ⋅ b e n ⋅ t n
)
100 ⋅ ρ fuel
in (m3/h)
(E- 6.6.3)
be = specific fuel consumption (kg/kWh) t1 = first period of time in a operating profile (%) tn = last period of time in a operating profile (%) B = fuel consumption (m3/h) PB = diesel engine brake power (kW) ρfuel = fuel density (kg/m3)
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6.6.4 Cruising Range To calculate the theoretical cruising range for a given fuel volume the following equation can be used.
scr =
Vfuel ⋅ v cr B
(E- 6.6.4)
in (sm) scr = theoretical cruising range (sm) vcr = constant cruising speed (kn) B = entire fuel consumption (m3/h) Vfuel= available fuel volume (m3)
If the fuel consumption for a given theoretical cruising range shall be used as a design value for the necessary fuel storage volume, use the following equations.
t cr =
s cr v cr
in (h)
(E- 6.6.5) scr = theoretical cruising range (sm) tcr = theoretical cruising time (h) vcr = constant cruising speed (kn)
B = B propulsion + B gensets + B auxiliary
in (m3/h)
(E- 6.6.6)
B = entire fuel consumption at vcr (m3/h)
Vfuel = B ⋅ t cr
in (m3)
(E- 6.6.7) tcr = theoretical cruising time (h) B = entire fuel consumption (m3/h) Vfuel= necessary fuel volume for cruising range (m3)
The fuel tank capacity has to be assumed 5% larger, because the usable volume of a tank will be only approx. 95%.
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6.6.5 Endurance at Sea This question is the same as under section 6.6.4 extended by an operating profile. To calculate the endurance time at sea for a given fuel volume and operating profile the following equation can be used.
t end =
PB 1
100 ⋅ Vfuel ⋅ ρ fuel in (h) ⋅ b e 1 ⋅ t 1 + ....... + PB n ⋅ b e n ⋅ t n
(E- 6.6.8)
be = specific fuel consumption (kg/kWh) tend = theoretical endurance for an operating profile (h) t1 = first period of time in an operating profile (%) tn = last period of time in an operating profile (%) PB = diesel engine brake power (kW) Vfuel= available fuel volume (m3) ρfuel = fuel density (kg/m3)
The background is to calculate how long the ship can stay in duty without replenishing or going back to the harbour and with enough fuel left in the storage tanks for reserve.
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6.6.6 Calculating Examples 6.6.6.1 Example Data (Series 2000) Basing on some exemplary data the fuel consumption shall be calculated. The available data are: S t e p
Call for
Exemplary Data
1 Status of the ship
new ship, clean hull, full load
2 Weather condition and sea state
wind Beaufort 2-3, sea state 0-1, no current (trial condition)
3 Ambient condition
Intake air = 45°C, Raw water = 32°C
ship for the chosen displacement, weather condition and sea state as diagram or in tabulated form
1400
Brake Power PB per Ship in (kW)
1200
Annotation: The ship speed (v) – brake power (PB) data can be represented in a lot of different diagrams. The one shown is only one representation of that bunch.
750
Design Point: PB...: 990 (kW) v.....: 27.5 (kn)
⇒ 650
1000
550
⇐ 800
450 Shaft Speed
600
350
400
250
Propeller Shaft Speed in (rpm)
4 Speed (v) – brake power (PB) data of the
⇑ 200
150 Brake Pow er
0
50
6
10
14
18
22
26
30
Ship Speed in (kn)
In tabulated form:
5 Propulsion plant and design condition
TPG-General.doc Rev. 1.0
Ship Speed (v) (kn)
Propeller Speed (nprop) (rpm)
Ship Brake Power (PB) (kW)
10
270
85
24
590
690
>27.5
670
990
Ship design condition: PB = 990 kW per ship, v = 27.5 kn, propeller shaft speed n = 670 rpm The ship is powered by a single diesel engine (design point: PB=1007 kW, n=2300 rpm, 1.5% power reduction due to ambient condition).
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S t e p
Propulsion, Interaction Engine with Application
Call for
Exemplary Data
6 Performance diagram of the diesel engine including the lines of specific fuel consumption
kW 1100 218 1000
900
800
Annotation: The diagram must be referenced to the chosen design conditions. Application group: e.g. 1DS Reference condition: ambient condition and typical intake/exhaust losses. Specific fuel consumption: Lower heating value Hu = 42800 kJ/kg
206
700
202 210
600
500
206 400
210 220
198
300
240 200
202 206 210
100
220
280 240 280 II
I
0 500
800
1000
1200
1400
1600
1800
2000
2200
2400
Power reduction: subtract 1.5% for ambient condition Specific fuel consumption: add 1.5% for ambient condition and 5% for tolerance
7 Lower heating value of fuel
Hu = 42800 kJ/kg
8 Fuel density
ρfuel= 830 kg/m3
9 Gearbox ratio
i = 3.473 = ndiesel / npropeller (e.g. ZF 1960)
10 Fuel consumption of the diesel generator
2 gensets (diesel engine e.g. 6R183T52), generated electric power P = 245kW, n = 1800rpm, be = 0.225 kg/kWh at 50% power, ηGen= 0.942 (includes 2% increased fuel consumption due to ambient condition and 5% tolerance)
11 Usable volume of the fuel storage tank
95%
12 Operating profile
Fuel Tank capacity: 5 m3 No user defined service time. =>Estimated annual usage: 500h =>MTU load profile (1DS) will be used.
sets (one genset running at 50% power)
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Ship Speed (v) (kn)
Time Period (t) (%)
10
20
24
70
27.5
10
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Propulsion, Interaction Engine with Application
The following examples show some applications on fuel consumption calculation: 6.6.6.2 6.6.6.3 6.6.6.4 6.6.6.5 6.6.6.6
Fuel consumption at design condition Fuel tank volume for a range of 500sm at 18kn Theoretical cruising range at 12kn and a fuel tank volume of 5m3 Annual fuel consumption for an operating profile Correcting the lower heating value
6.6.6.2 Fuel consumption at design condition Main diesel engine: Use equation (E- 6.6.1) PB = 990 kW
(table row step 5)
be = 0.218 kg/kWh
(table row step 6)
add 1.5% for ambient condition and 5% for tolerance be = 0.218 kg/kWh + 1.5% + 5% = 0.232 kg/kWh ρfuel = 830 kg/m3
Bpropulsion =
990 ⋅ 0.224 = 0.277 830
(table row step 8)
(m3/h) per main diesel engine
Genset diesel engine: Use equation (E- 6.6.1) Pmechnical = Pelectrical /ηGen = 125 kW/0.942 Pmechnical = 133kW
(table row step 10)
be = 0.225 kg/kWh
(table row step 10)
(value includes tolerance and ambient condition) ρfuel = 830 kg/m3
B genset =
133 ⋅ 0.225 = 0.0361 830
(table row step 8)
(m3/h) per genset diesel engine
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.277 + 1 ⋅ 0.0361 = 0.313
TPG-General.doc Rev. 1.0
(m3/h)
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Propulsion, Interaction Engine with Application
6.6.6.3 Fuel tank volume for a range of 500sm at 18kn scr = 500 sm vcr = 18 kn PB = 390 kW per ship and diesel engine
(table row step 4)
npropeller = 470 rpm (propeller shaft speed)
(table row step 4)
ndiesel = 1632 rpm (main diesel engine speed)
(table row step 9)
be = 0.202 kg/kWh + 1.5% + 5% = 0.215 kg/kWh
(table row step 6)
The fuel consumption can be calculated as in example (1). Bpropulsion =
390 ⋅ 0.215 = 0.101 830
B genset = 0.0361
(m3/h) per main diesel engine
(m3/h) per genset diesel engine
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.101 + 1 ⋅ 0.0361 = 0.137
(m3/h)
Theoretical cruising time: Use equation (E- 6.6.5)
t cr =
500 = 27 .8 18
(h)
Fuel volume for the cruising range: Use equation (E- 6.6.7) Vfuel = 0.137 ⋅ 27.8 = 3.8
(m3)
Required fuel tank volume:
Vtan k =
TPG-General.doc Rev. 1.0
3 .8 = 4 .0 0.95
(m3)
(table row step 11)
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Propulsion, Interaction Engine with Application
6.6.6.4 Theoretical cruising range at 12kn and fuel tank volume of 5m3 Vtank = 5 m3 Vfuel = Vtank ⋅ 0.95 = 4.75 m3
(table row step11)
vcr = 12 kn PB = 145 kW per ship and diesel engine
(table row step 4)
npropeller = 330 rpm (propeller shaft speed)
(table row step 4)
ndiesel = 1146 rpm (main diesel engine speed)
(table row step 9)
be = 0.208 kg/kWh + 1.5% + 5% = 0.222 kg/kWh
(table row step 6)
The fuel consumption can be calculated as in example (1). Bpropulsion =
145 ⋅ 0.222 = 0.039 830
B genset = 0.0361
(m3/h) per main diesel engine
(m3/h) per genset diesel engine
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.039 + 1 ⋅ 0.0361 = 0.075
(m3/h)
Theoretical cruising range: Use equation (E- 6.6.4)
scr =
TPG-General.doc Rev. 1.0
4.75 ⋅ 12 = 760 0.075
(sm)
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Propulsion, Interaction Engine with Application
6.6.6.5 Annual fuel consumption for an operating profile Operating profile: (table row step 12) Ship Speed (v) (kn)
Time Period (t) (%)
10
20
24
70
27.5
10
Data per ship: (table row step 4 and 9) Ship Speed (v) Propeller Speed (kn) (rpm)
Ship Brake Power (kW)
Diesel Speed (rpm)
10
270
85
938
24
590
690
2049
27.5
670
990
2300
Data per diesel engine: (table row step 4) Ship Speed (v) (kn)
Diesel Speed (n) (rpm)
Diesel Power (PB) (kW)
be (raw) (kg/kWh)
be (corrected) (kg/kWh)
10
938
85
220
0.234
24
2049
690
203
0.216
27.5
2300
990
218
0.232
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Fuel consumption: Use equation (E- 6.6.3) B=
(P
B1
⋅ b e 1 ⋅ t 1 + ....... + PB n ⋅ b e n ⋅ t n 100 ⋅ ρ fuel
)
in (m3/h)
Ship Speed (v) (kn)
Ship Brake Power PB (kW)
be (kg/kWh)
Time Period (t) (%)
B (m3/h)
10
85
0.234
20
0.0048
24
690
0.216
70
0.1257
27.5
990
0.232
10
0.0277
Sum
0.1582
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.1582 + 1 ⋅ 0.0361 = 0.1943
(m3/h)
The annual fuel consumption based on an estimated usage of 500 h: Use equation (E- 6.6.7) Vfuel = 0.1943 ⋅ 500 = 97.2
(table row step 12)
(m3)
6.6.6.6 Correcting the lower heating value If the lower heating value of the given specific fuel does not match the required value the data have to be corrected. Use the following procedure:
be, required = be, given
TPG-General.doc Rev. 1.0
Hu, required Hu, given
in (kg/kWh)
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6.7
Propulsion, Interaction Engine with Application
Generator Drive Electrical power supplies on ships is a question of three-phase mains. Following rules are to be considered at the design/dimensioning of the diesel engines for the generator drive: Diesel Engine Speed (n):
n=
f ⋅ 60 p
in (rpm)
(E- 6.7.1) f = shipboard power supply frequency in Hz n = diesel engine speed in rpm p = number of pole pair
Example: Shipboard power supply frequency
f = 60 Hz
Generator
p = 4 pole = 2 pole pair
n=
60 ⋅ 60 = 1800 4
(rpm)
Diesel Engine Brake Power (PB): P = B
Pp ⋅ cos ϕ η Gen
in (kW)
(E- 6.7.2) PB = engine brake power in kW PS = generator apparent power in kVA cos ϕ = generator power factor (e.g. 0.8) ηGen = generator efficiency (0.94; above 1800 kW 0.95)
Pp = Ps ⋅ cos ϕ
in (kW)
(E- 6.7.3) Pp = generator active power in kW PS = generator apparent power in kVA cos ϕ = generator power factor (e.g. 0.8)
Pp P = B η Gen
in (kW)
(E- 6.7.4) Pp = generator active power in kW PB = engine brake power in kW ηGen = generator efficiency (0.94; above 1800 kW 0.95)
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Figure 6.7.1:
Propulsion, Interaction Engine with Application
Power definition
Example: Necessary electrical shipboard power is PSBP = 1600 kW For instance: Power partition onto two genset
: z=2
Load of the genset each 85%
: x = 0.85
Max. electrical power per genset: Pp =
PSBP 1600 = = 941 z ⋅ x 2 ⋅ 0.85
(kW)
Necessary diesel engine power per genset: Use Equation (E- 6.7.4)
η= 0,94 PB =
Pp η
=
941 = 1001 0.94
(kW)
Generator apparent power: Use Equation (E- 6.7.2) PS =
PB ⋅ η 1001 ⋅ 0.94 = = 1176 cos ϕ 0 .8
(kVA)
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7
Application and Installation Guidelines
APPLICATION AND INSTALLATION GUIDELINES During the arrangement of the engines in the engine room specific distance between the engines or to the bulkhead/shell must be kept for the service of the engines and for maintenance operations.
Figure 6.7.1:
7.1
Engine room arrangement, minimum distance
Foundation ( under preparation )
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7.2
Application and Installation Guidelines
Engine/Gearbox Arrangements A general distinction is made between certain basic drive arrangements, i.e. the way in which engine and drive line disposed in the vessel.
7.2.1 Engine with Flange-Mounted Gearbox (F-Drive) This arrangement is shown in Figure 7.2.1. Engine with torsionally resilient coupling and gearbox form a single unit. The gearbox is connected to the engine by means of a bell housing, which also accommodates the coupling.
Figure 7.2.1:
Engine with flange-mounted gearbox
1 Engine 2 Torsionally resilient coupling 3 Gearbox This drive arrangement with flange-mounted gearbox is possible only with some specific engines. The advantages inherent to this arrangement are as follows:
• The flange-mounted configuration is the most compact of all drive arrangements. Another advantage in addition to compactness is the comparatively low overall weight of the propulsion plant.
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Application and Installation Guidelines
• Time-saving alignment of the propulsion unit in the vessel, because only one operation is necessary, namely aligning the propulsion plant with the propeller shaft. The engine and gearbox are already aligned and do not have to be realigned unless they have been separated for repair or servicing and the gearbox has to be re-mated to the engine. As a rule, a foundation with a total of only four supports suffices for this plant. Of these supports two are required for the engine mounts and two for the gearbox mounts.
7.2.2 Engine with Free-Standing Gearbox, V Drive Inclusive Engine with free-standing gearbox (D-Drive): For this arrangement, shown in Figure 7.2.2 , with free-standing gearbox, the engine combined with torsionally resilient coupling forms one unit, the free-standing gearbox being another.
Figure 7.2.2: 1 2 3 4
Engine Torsionally resilient coupling Coupling to compensate relative displacement (offset compensating coupling) Gearbox
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Application and Installation Guidelines
The points of relevance as regards this arrangement are as follows:
• An arrangement with engine and free-standing gearbox is preferable when a flangemounted gearbox is either not desirable or, due to the engine size, is not possible for technical reasons. • One advantage of the arrangement with separate engine and gearbox is the leeway it affords for enhanced requirements regarding structure-borne noise and/or resistance to shock loading. • Given the dimensions and weights of the subassemblies - engine and gearbox being subassemblies in this case - installation and removal can be less complex than in the case of the engine with flange-mounted gearbox, because the subassemblies are handled separately. • If the specification calls for a controllable-pitch propeller (CPP), the O.D. box for pitch control can be mounted on the gearbox output shaft in immediate proximity to the gearbox. • An engine with free-standing gearbox is heavier and requires slightly more space than the configuration with flange-mounted gearbox.
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Engine with free-standing gearbox and universal shaft, V drive arrangement: This arrangement is shown in Figure 7.2.3. The ,,V drive“, as it is sometimes named, consists of the engine and engine-mounted bearing housing and a separate gearbox. The bearing housing accommodates the torsionally resilient coupling. Engine power is transmitted from the coupling to the gearbox by a universal shaft.
Figure 7.2.3: 1 2 3 4
Engine with free-standing gearbox and universal shaft, V drive arrangement
Engine Torsionally resilient coupling with engine-mounted bearing housing Universal shaft Gearbox
This engine and gearbox configuration permits the propulsion plant to be installed either at the stern or near the stern of the vessel, if this arrangement is preferable with respect to hull design.
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Application and Installation Guidelines
7.3 Generator Set Arrangement 7.3.1 Engine with Free-Standing Generator
Figure 7.3.1: 1 2 3 4
Engine Generator Base frame Resilient elements
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Application and Installation Guidelines
7.3.2 Engine with Flange-Mounted Generator
Figure 7.3.2: 1 2 3 4 5
Engine Generator Intermediate mass Resilient elements, upper Resilient elements
TPG-General.doc Rev. 1.0
Engine with flange-mounted generator
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Application and Installation Guidelines
7.4 System Interfaces and System Integration 7.4.1 Flexible Connections All pipes from and to the propulsion unit must be fitted with flexible connecting elements. These flexible connecting elements are usually included in the MTU scope of supply and their purpose is to compensate for relative motions between the propulsion plant and the on-board piping systems. If the hoses, bellows or rubber sleeves are not supplied by MTU, they must satisfy the minimum requirements for plant operation. If doubt arises, customers should consult MTU to ascertain the displacements occurring at the interfaces due to movements of the resilient mounts and thermally induced expansion. The invariable rule is that all flexible connecting elements must be connected directly with the on-engine or on-gearbox interfaces. Notes on installation The installation characteristics such as
• • • •
dimensions, permissible operating-pressure range, minimum bending radius and resistance to medium
for the hoses, bellows and rubber sleeves are stated in the corresponding installation drawing. The part numbers are stated in the system schematics, for example for the fuel and coolant systems. If welding is performed on the on-board piping system, it is important to ensure that no hoses, rubber bellows or rubber sleeves are installed in the line, as they could be damaged by the welding operations. If already installed, these elements must be removed for the duration of the welding operations and stored where they are safe from damage such as could be caused by weld spatter, e.g. General notes on system routing
• Hoses must be installed such that they are not subjected to tensile or compressive loads in operation. • Hoses should follow the contour of the foundation as closely as allowed by the specified minimum bending radii. • Multiple hoses should always be routed together and kept parallel. • Suitable fittings (e.g. pipe elbows) can be used to avoid additional stresses and strains on the hoses.
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Application and Installation Guidelines
• When installing hoses, care must be taken to ensure that the hoses are not twisted. • For a curved run, the length of the hose must be such that the curve does not commence less than approx. 1.5*d from the fitting. • Flexible connecting elements should be arranged and/or secured in such a way as to prevent exposure to external mechanical influences, for example rubbing. • The attachments use to secure hoses must be of correct size for the hose diameters. • Hose attachments should not be used at points where they would impede the natural freedom of motion of the hose. • High ambient temperatures significantly reduce the durability of flexible connecting elements and may even lead to the failure of the component. Always ensure adequate clearance from components that radiate heat, or provide suitable heat shielding. These notes on routing hoses, of course, apply by analogy to all other flexible connecting elements. MTU propulsion plants are designed normally such that all small-diameter interfaces (< DN 50) connect by means of hoses, while rubber bellows are used for all large-diameter interfaces (DN 50 or larger). This of course does not apply to the exhaust system, for which steel bellows are required, and for the air intake system, which employs hose connectors (sleeve-type connection). Rubber sleeves are used for connections < DN 50 only in exceptional circumstances and at locations where displacement is slight, e.g. at the gearbox with rigid mount. Hose connections The hoses are fitted with sealing cones (60°) and union nuts and can therefore be secured directly to the corresponding interfaces on the engine, gearbox or accessory. The requisite dimensions are stated in the applicable installation drawing. Bellows connections Both rubber (e.g. raw water) and steel bellows (e.g. exhaust) are used for the plant interfaces, but only the rubber bellows are discussed here. The use of rubber bellows on engines is usually restricted to the lines of diameter in excess of DN 40 of the raw water system, so only this application is discussed here. The interface on the engine, gearbox or accessory is of a design such that the rubber bellows can be secured directly by means of screw fasteners. Connection to the on-board piping system is performed by means of a welding neck to DIN 86037 and the corresponding securing flange to DIN 2642, both of which are included in the standard scope of supply. To avoid excessive strain on the rubber bellows, care must be taken to ensure that the installation length is as specified in the installation drawing. The rubber bellows are usually installed without axial preload. Note, however, that preload may be specified for a rubber bellows for a special application in which non-standard displacements are anticipated. TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
The binding connection and installation dimensions for the rubber bellows are stated in the project- or contract-specific installation drawings. Figure 7.4.1 shows the connection in diagram form. Note that the pipe material used as standard is copper-nickel alloy.
Figure 7.4.1: 1 2 3 A D L
Rubber bellows Welding neck Pipe (not MTU scope of supply) Interface to engine, gearbox or accessory Pipe outside diameter Installation dimension
TPG-General.doc Rev. 1.0
Connection of rubber bellows
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Application and Installation Guidelines
7.4.2 Combustion Air and Cooling/Ventilation Air Supply 7.4.2.1 Combustion-air intake from engine room 7.4.2.2 Combustion-air intake directly from outside 7.4.2.3 Cooling/ventilation air system
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Application and Installation Guidelines
7.4.3 Exhaust System 7.4.3.1 Arrangements, support and connection for pipe and silencer
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Application and Installation Guidelines
7.4.3.2 Underwater discharge (with exhaust flap)
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Application and Installation Guidelines
7.4.3.3 Water-cooled exhaust system
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Application and Installation Guidelines
7.4.4 Cooling Water System 7.4.4.1 Cooling water system with engine-mounted heat exchanger
Figure 7.4.2:
Cooling water system with engine-mounted heat exchanger (Split-circuit cooling system)
1 Engine coolant pump 2 Lube oil heat exchanger 3 Intercooler 4 Coolant heat exchanger 5 Preheating unit, complete, not standard scope of supply 6 Expansion tank, engine coolant, shipyard supply 7 Gearbox 8 Gearbox oil heat exchanger 9 Ship heating, shipyard supply 10 Connecting point, flexible connecting element 11 Flow restrictor 12 Sea water pump 13 Sea water filter, shipyard supply 14 Fuel oil heat exchanger Split-circuit cooling system using heat exchanger with titanium plates. Benefits: • Keeps engine coolant, oil and intake air at optimum temperature under all operating conditions. • Higher temperature during idle or low-load operation. • No seawater in the engine. TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
7.4.4.2 Cooling water system with separately-mounted heat exchanger (including keel cooling)
Figure 7.4.3:
Cooling water system with separately-mounted heat exchanger (e.g. keel cooling)
1 Engine coolant pump 2 Lube oil heat exchanger 3 Intercooler 4 Coolant heat exchanger (Shell cooler/Case cooler), shipyard supply 5 Preheating unit, complete, not standard scope of supply 6 Expansion tank, engine coolant, shipyard supply 7 Gearbox 8 Gearbox oil heat exchanger 9 Ship heating, shipyard supply 10 Connecting point, flexible connecting element 11 Flow restrictor Cooling system for low power and ships operating in the flat water. Advantages: No sea water in pipelines, valves, pumps and heat exchanger in the ship. Low-cost materials for above-mentioned components. Less prone to interference through corrosion.
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Application and Installation Guidelines
7.4.4.3 Central cooling water system
Figure 7.4.4:
1 Engine coolant pump 2 Lube oil heat exchanger
9 Ship heating, shipyard supply 10 Flexible connecting element
3 Intercooler 4 Coolant heat exchanger 5 Preheating unit, complete, not standard scope of supply 6 Expansion tank, engine coolant, shipyard supply 7 Gearbox 8 Gearbox oil heat exchanger
11 Flow restrictor ② 12 Sea water pump, shipyard supply 13 Sea water filter, shipyard supply
TPG-General.doc Rev. 1.0
Central cooling water system
15 Sea water stand-by pump, shipyard supply 16 Harbour sea water pump, shipyard supply
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Application and Installation Guidelines
7.4.5 Fuel System The standard scope of supply requires the shipyard to connect the fuel feed and return lines for the engine. The standard scope of supply includes flexible connectors and a fuel prefilter for connecting the fuel supply line to the engine.
Figure 7.4.5: 1 2 3 4 5 6
Fuel System
Fuel prefilter with water separator Service tank, shipyard supply Fuel transfer pump, shipyard supply Fuel coarse filter or (water) separator, shipyard supply Flexible connecting element Fuel heat exchanger, not standard scope of supply
An engine with a safety-enhanced fuel system (comprising jacketed high-pressure fuel lines and an on-engine tank for leak-off fuel) requires an additional line to carry off an overflow. When routing this overflow, bear in mind that the leak-off fuel is not under pressure, i.e. it must return to the on-board collecting tank or the fuel tank via a line routed on a declining plane and venting to atmosphere. Only fuels listed in the Fluids and Lubricants Specification are approved for use in MTU diesel engines. TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
7.4.5.1 General notes
• The supply pipe must be connected to the on-engine interface by means of a flexible connector. See Chapter 8.4.1, Flexible connections. • If, as maybe the case in exceptional circumstances, the flexible connector (hose) is not supplied by MTU, it must satisfy the requirements laid down in Chapter 8.4.1. • We recommend the use of steel piping (e.g. St 35). The engineering guidelines apply with regard to wall thickness of piping. • Pipe runs should be kept as short as possible and a measuring connection must be provided immediately in front of the on-engine interface to permit system checking, e.g. for commencement. • If an auxiliary diesel engine receives its fuel supply via a bypass incorporated in the fuel supply system of the main diesel engine, this design feature must be taken into account when calculating the cross-section of the lines. Failure to take this factor into account may result in the auxiliary diesel receiving insufficient fuel when the main diesel engine is in operation, with the danger of engine malfunction as a result.
7.4.5.2 Design data Compliance with the limits defined for the system interface is essential in order to ensure compliance with the limits for engine operation. Data such as required for design/dimensioning of the fuel system
• Fuel volume flows, feed an return • Pressure limitations at on-engine interface, min./max. • Temperature limitations for supply, min./max. • Fuel temperature increase before/after engine • Heat to be removed from return fuel is specified in the data sheet for the project or contract. The needs of the engine must be taken into account with regard to the arrangement of the fuel tanks in the vessel and the dimensioning of the tanks. As general rule, the fuel supply system should incorporate at least one supply tank, plus a service tank for the engine or the engines. The location of the service tank has an effect on the efficiency of heat exchange and the routing of the fuel lines from and to the engine. In order to avoid malfunctions, it is important to observe the following points:
• The service tank must be of a size such that the temperature in the tank caused by return fuel mixing with residual fuel in the tank always remains below a permissible maximum.
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Application and Installation Guidelines
The equations below can be used to calculate the requisite volume of the service tank (size of service tank).
Vtank = Vtank = t = = be PB = Vreturn = W =
t ⋅ (0.04 ⋅ be ⋅ PB + Vreturn ⋅ 2 .1) w
m3
Total volume of service tank in m3 Time to replenish of the service tank in h Specific fuel consumption at fuel stop power in kg/kWh Fuel stop power in kW Fuel return flow from engine at fuel stop power in litre/min Evaluation value for max. fuel inlet temperature (Figure 7.4.6)
70
Evaluation value W.
60 50 40 30 20 10 0 25
30
35
40
45
50
55
60
65
70
Max. fuel inlet temperature T in °C
Figure 7.4.6:
Evaluation value for max. fuel inlet temperature
The calculation of the total volume of the service tank is taken with regard to a maximal permissible level of 85 % and of a remaining level of 10 %.
• If the available service tank volume is less than the calculated volume and the engine has return fuel, the temperature of the fuel in the service tank exceeds the permissible limit for the fuel supply to the engine and a fuel heat exchanger must be installed in the return fuel line from the engine. • The fuel supply from the service tank to the engine must be • such that no sludge seasoned on the bottom of the service tank or water precipitated from the fuel is drawn into the supply line to the engine. This is achieved by locating the supply pipe at an adequate height above the bottom of the service tank (at least 100 mm clearance from the bottom of the tank). TPG-General.doc Rev. 1.0
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• If the service tank is on a level higher than that of the fuel delivery pump (overhead tank, header tank) the return line carrying excess fuel from the engine must be routed above the maximum level of fuel in the service tank. This precaution is adopted in order to prevent fuel flooding the engine while it is at a standstill, because it is not possible to guarantee that the non-return valves in the delivery line always remain absolutely leak tight. • If the service tank is on a level lower than that of the fuel delivery pump (low level tank, bottom tank), the return line carrying excess fuel from the engine must be routed below the minimum level of the fuel in the service tank. This precaution is adopted in order to prevent air entering the fuel system and the fuel delivery pump when the engine is at a standstill. • The min./max. pressures at the on-engine interfaces must be as specified in the data sheet. If the plant incorporates a bottom tank and/or a relatively long fuel supply line, a booster pump must be installed in order to prevent an impermissibly high intake depression before the engine. • A water drain valve and sludge drain valve must be provided at the lowest point of the service tank. The tank must be provided with adequate breather facilities, which in turn must afford adequate protection against the ingress of water.
( under preparation )
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Application and Installation Guidelines
7.4.6 Lube Oil System
Figure 7.4.7:
Lube oil system
1 2 3 4 5 6 7 8
Lube oil pump Lube oil heat exchanger Drain plug on oil pan Oil dipstick Lube oil hand pump 3-way cock, lube oil, shipyard supply Gearbox Automatic lube oil level monitoring and replenishment system, not standard scope of supply (according to classification societies for watch-free operation) 9 Lube oil tank, shipyard supply 10 Flexible connecting element
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Application and Installation Guidelines
7.4.7 Starting System The engines may employ one of three different methods of starting. There are principally two types of starting systems which differ by the way in which the energy, required to start the engine is stored: -
Electric starting with battery-powered starter motor
-
Compressed air starting, by means of
• pneumatic starter motor, operating pressure range from 1 x 106 to 3 x 106 Pa (10 to 30 bar) • air-in-cylinder, operating pressure range from 2 x 106 to 4 x 106 Pa (20 to 40 bar) The regulations to which the plant is subject govern the choice of the starting system, i.e. electric or pneumatic. Unless otherwise specified by the customer, the engines are supplied with electric starting Systems by default (series 2000 and 4000), because the electric system is more straightforward and involves fewer system components. In terms of reliability, there is a difference between the systems - all three are thoroughly satisfactory. Compressed air starting is preferable on vessels with a central compressed air supply system, because under these circumstances there is no need to provide an additional supply system and so there is a weight advantage when compared with the electric starter. The starting procedure is controlled and monitored by a control system included in the standard scope of supply. The control unit incorporates both the controller logic circuits and all requisite control elements. 7.4.7.1 Electric starter motor The starter motor (some engine models have two starter) mounted on the engine requires a 24 VDC supply. Starter motors with other voltage ratings are available on request for special applications. Design data such as
• nominal power • current consumption and • requisite storage-battery capacity required for the design of the starting system are part of the data sheet of the project or contract. The starter batteries are usually recharged by means of an alternator which is usually included in the engine scope of supply.
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Application and Installation Guidelines
The battery does not usually form part of the MTU scope of supply. The following points require consideration:
• The position of the battery in the engine room must be such as to permit easy access for maintenance. • The battery must be protected against moisture, mechanical damage and extreme temperature. • The battery must be as close as possible to the engine or, more precisely, to the starter motor, so that the electric cables are as short as possible. • In order to avoid corrosion in the vicinity of the battery, it must be well, ventilated because it is not always possible to prevent acid vapor escaping from the battery cells. There are no design-related restrictions on the choice of battery type, e.g. lead-acid or nickel-cadmium battery. Note, however, that the ambient conditions must be taken into account in this respect. The engine documentation and the special documentation for the electronic accessories contain information that must be taken into account with regard to the electric wiring of the starting system and the calculation of the cross-section of the conductors to suit the cable lengths and currents carried.
7.4.7.2 Compressed-air starting, compressed-air starter motor If the engine is equipped with a pneumatic starter motor, the compressed air supply connects to the starter motor mounted on the diesel engine. The starting air supply valve mounted on the starter motor is electrically actuated with provision for emergency manual actuation. The system components required for the starting system (flexible connecting element, air filter and pressure reducing valve from 4 x 106 to 1 x 106 Pa) are usually part of the MTU scope of supply. Figure 7.4.8 is a schematic view of the compressed air starting system with pneumatic starter motor as of the on-engine interface. The incorporation of a pressure reducing valve makes it feasible to dimension the compressed air storage tanks for a pressure considerably higher than the operating pressure of the starter motor, with the result that the size of the tanks can be minimized (by a factor of between 6 and 8).
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Figure 7.4.8:
Application and Installation Guidelines
Starting system with pneumatic starter motor
1 Compressed air starter
6 Safety valve ②
2 Lubricator (optional) ②
7 Pressure gauge ②
3 Air filter ②
8 Flexible connecting element
4 Pressure reducing globe valve ②
9 Pneumatic starter motor
5 Starting air receiver ②
② Shipyard
7.4.7.3 Compressed-air starting, air-in-cylinder If the engine is equipped for air-in-cylinder starting, it features an interface at which compressed air from the starting valve must be made available. The starting valve is electrically actuated but is also designed for emergency manual operation. It usually forms part of the MTU scope of supply and is supplied with, but not mounted on, the engine. Figure 7.4.9 is a schematic view of the air-in-cylinder starting system as of the on-engine interface. The compressed air tanks used to store the starting air can be supplied by MTU or by the shipyard. If they are not supplied by MTU, the tanks must be dimensioned by the shipyard as to contain an air supply adequate for the number of engine starts specified by the applicable regulations. TPG-General.doc Rev. 1.0
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Figure 7.4.9:
Application and Installation Guidelines
Starting system with air-in-cylinder starting
1 Starting air distributor 2 Starting valve 3 Starting air receiver ② 4 Flexible connecting element 5 Safety valve ② 6 Pressure gauge ② ② Shipyard
Design data Data such as
• min./max. starting air pressures for engine • average air consumption per start • regulation number of engine starts are specified in the data sheet for the project or contract. Unless the number of engine starts is specified elsewhere, we recommend dimensioning the compressed air tanks such that at least six starts are possible without recharging the tanks. In twin-engine or multiple-engine configurations, the engines housed in a single engine room can be supplied from a common compressed air storage system. TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
The equations below can be used to calculate the requisite volume of the compressed air storage system (size of compressed air tank or tanks).
V =
V s Vn1 ∆p p1 p2 pmax pmin pn
= = = = = = = = = =
s × Vn1 × p n ∆ p
m3
Volume of compressed air tank in m3 Number of engine starts Air consumption per start (at normal pressure pn) in m3 Pressure differential in compressed air tank in Pa p1 - p2 or pmax - pmin Pressure in air tank before engine start in Pa Pressure in air tank after engine start in Pa Max. permissible starting air pressure in Pa Min. permissible starting air pressure in Pa Normal pressure = 1,013 x 105 Pa
The starting air supply valve should be located in the engine room and as close as possible to the engine, and in such a way that it is protected against damage and moisture. The supply pipe must be connected to the on-engine interface by means of a flexible connector. We recommend the use of steel piping (e.g. St 35 according to DIN 2391). Pipe runs should be kept as short as possible and a measuring adapter (Ml8xl,5) must be provided immediately in front of the on-engine interface to permit system checking, e.g. for commencement.
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Application and Installation Guidelines
7.4.8 Electric Power Supply
Figure 7.4.10: Electric power supply
( under preparation )
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7.5
Application and Installation Guidelines
Safety System ( under preparation )
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Application and Installation Guidelines
7.6 Emission 7.6.1 Exhaust Gas Emission, General Information The MTU standard reduction of exhaust gas emissions for navy applications are in accordance with International Maritime Organization (IMO)
Limitation of NOx-Emission 18
NOx in g/kWh
16 14 12 10 8 6 4 2 0 0
200
400
600
800
1000 1200 1400 1600 1800 2000 2200 -1
Engine rates speed in min
Figure 7.6.1:
Limitation of NOx-emission (IMO)
The IMO NOx emission limit depends on the rated engine speed: n < 130 min-1
NOx = 17 g/kWh
n = 130 to < 2000 min-1
NOx = 45 x n-0,2 g/kWh
n ≥ 2000 min-1
NOx = 9,8 g/kWh
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Application and Installation Guidelines
The test procedure and measurement methods shall be in accordance with the NOx Technical Code, taking into consideration the Test Cycles and Weighting Factors: Speed (%)
100
100
100
100
Test cycle type E2 Power (%)
100
75
50
25
0.2
0.5
0.15
0.15
Weighting Factor Figure 7.6.2:
Test cycle for “Constant Speed Main Propulsion” application (including diesel electric drive and variable pitch propeller installation)
Speed (%)
100
91
80
63
Test cycle type E3 Power (%)
100
75
50
25
0.2
0.5
0.15
0.15
Weighting Factor Figure 7.6.3:
Test cycle for “Propeller Law operated Main and Propeller Law operated Auxiliary Engines” application
Speed (%)
100
100
100
100
100
Test cycle type D2 Power (%)
100
75
50
25
10
0.05
0.25
0.3
0.3
0.1
Weighting Factor Figure 7.6.4:
Test cycle for “Constant Speed Auxiliary Engine” application
Speed Test cycle type C1 Torque (%) Figure 7.6.5:
Rated 100
75
50
Intermediate
Idle
10
100
75
50
0
Weighting Factor 0.15 0.15 0.15 0.1
0.1
0.1
0.1 0.15
Test cycle for “Variable Speed, Variable Load Auxiliary Engine” application
( under preparation )
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Application and Installation Guidelines
7.6.2 Acoustical Emission, General Information Low noise on board of yachts, passenger vessels and on naval ships is an important demand. Noise spectra, i.e. frequency analyses for operating noises distinguishing between
• air-borne noise as - engine free-field noise - undamped exhaust noise - undamped air intake noise • structure-borne noise have been performed for all engines listed in the current Sales Program. The results of these analyses are available on request for projects and contracts. Note that these analyses do not take into account the air intake noise. In the noise spectra the information relating to noise pressure level and level of oscillation velocity is valid only for to the rated engine power and engine speed as stated, and thus merely informative for other power/speed combinations. 7.6.2.1 Airborne noise level A noise spectrum of the engine operating noise emitted to the environment (free-field) is available for each engine in the Sales Program. These spectra are available on request for projector contract-specific purposes. The figures in the noise spectrum are in dB(A) and comply with ISO standards. The datum level is 2*10-5 Pa and the noise pressures are measured at a distance of 1 m, unless otherwise stated in the diagram.
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Figure 7.6.6:
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Application and Installation Guidelines
Engine surface noise analysis (example)
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Application and Installation Guidelines
7.6.2.2 Exhaust gas noise level
Figure 7.6.7:
TPG-General.doc Rev. 1.0
Undamped exhaust gas noise analysis (example)
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Application and Installation Guidelines
7.6.2.3 Structure-borne noise level (e.g.: single-(standard), single-(shock resistance), double-resilient mounting) Depending on different requirements, we offer additionally to our standard design four different “Quiet Systems”. All options are based on proven design. Standard single resilient mounting system: (Standard) Standard single resilient mounting system for ships without any special shock or acoustic requirements, e.g. working ships and fast ferries. Technical Features: -
Standard acoustic, no shock requirements
-
Single resilient mounting system
-
Standard coupling system for torsional vibration and misalignment
Single resilient mounting system with shock: (Option 1) Single resilient mounting system for applications with shock requirements for ships, such as OPV´s and Corvettes. Technical Features:
TPG-General.doc Rev. 1.0
-
Shock requirements according to BV 043/85; STANAG 4142 combined with moderate acoustic requirements
-
Special single resilient mounting system
-
Resilient coupling system for increased shock and structure-borne noise attenuation
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Application and Installation Guidelines
Typical Arrangement 1
2
1 Engine 2 Gearbox 3 Ship foundation 4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements 4
3
Engine with flange-mounted gearbox 1 Engine 2
1
5
6
2 Gearbox 3 Ship foundation
3
4
Engine with free-standing gearbox
4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements 5 Standard coupling system for torsional vibration and misalignment, optional with resilient coupling system for increased shock and structure-borne noise attenuation 6 Noise case (optional)
1
2
1 Engine 2 Generator 3 Ship foundation 4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements
3
4
Engine with flange-mounted generator
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Application and Installation Guidelines
Typical Arrangement 1 Engine 2
1
5
6
2 Generator 3 Ship foundation
3
4
Engine with free-standing generator
Figure 7.6.8:
4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements 5 Standard coupling system for torsional vibration and misalignment, optional with resilient coupling system for increased shock and structure-borne noise attenuation 6 Noise case (optional)
Single resilient mounting system with shock
Standard double resilient mounting system: (Option 2) Double resilient mounting system improves the acoustic behaviour for ASW ships, comfortable pleasure crafts and casino ships. Technical Features: -
Higher acoustic demands, shock requirements according to BV 043/85; STANAG 4142, weight critical application
-
Double resilient mounting system consist of: Rubber elements shock proved, with shock buffers Light/stiff base frame with 30% of engine weight as intermediate mass
-
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Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
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Application and Installation Guidelines
Double resilient mounting system for low noise: (Option 3) Double resilient mounting system to achieve low noise levels onboard of yachts, passenger vessels and most naval applications. Technical Features: -
High acoustic demands, shock requirements according to BV 043/85; STANAG 4142
-
Double resilient mounting system consist of: Rubber elements shock proved, with shock buffers Polymeric concrete/steel base frame with 50% of engine weight as intermediate mass
-
Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
-
Noise enclosure
Double resilient mounting system for extreme acoustic requirements: (Option 4) Double resilient mounting system for extreme acoustic requirements for ASW ships and research vessels. Technical Features: -
Extreme acoustic demands, shock requirements according to BV 043/85; STANAG 4142
-
Double resilient mounting system consisting of: Rubber elements shock proved, with shock buffers Polymeric concrete/steel combination base frame with 70% of engine weight as intermediate mass Double stage steel springs with silicon damping filling
TPG-General.doc Rev. 1.0
-
Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
-
Noise enclosure
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Application and Installation Guidelines
Typical Arrangement 2
5
1 Engine
6
1
2 Gearbox 3 Ship foundation 4 Resilient elements, double resilient mounting system, with shock requirements
3
7
5 Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
4
Engine with free-standing gearbox
6 Noise enclosure 7 Intermediate mass
2
1
5
1 Engine
6
2 Generator 3 Ship foundation 4 Resilient elements, double resilient mounting system, with shock requirements
3
4
5 Coupling system for torsional vibration, misalignment and increased shock attenuation
7
Engine with free-standing generator
6 Noise enclosure 7 Intermediate mass
Figure 7.6.9:
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Double resilient mounting system for extreme acoustic requirements
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Application and Installation Guidelines
90
Lv in dB re 5x10
-8
m/s
80 70 Standard Option 1 Option 2 Option 3 Option 4
60 50 40 30 20 10 0 31,5
63
125
250
500 1000 2000 4000 8000
Frequency in Hz
Figure 7.6.10: Examples for different “Quiet Systems”, structure-borne noise levels below the resilient mountings (e.g. diesel engine 20V 1163)
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Application and Installation Guidelines
Figure 7.6.11: Structure borne noise analysis at engine feet, above rubber mounts (example)
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7.7
Mounting and Foundation
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7.8
Acoustic Enclosure/Acoustic Case
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7.9
Application and Installation Guidelines
Mechanical Power Transmission There are different possibilities and combinations for the mechanical power transmission with internationally system-specific terms established. In the following one the most customary denotation is used: CODAD = COMBINED DIESEL ENGINE AND DIESEL ENGINE This kind of power plants offers e.g. the possibilities to transmit the power to on one shaft optionally from one or several diesel engines.
2 3 1
2
2 3 2
1
Figure 7.9.1:
Combined diesel engine and diesel engine 2 3
1
2
2 3 2
1
Figure 7.9.2:
Combined diesel engine and diesel engine with separate gear compartment
1 Controllable pitch propeller (CPP) 2 Diesel engine 3 Gearbox TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
CODOG = COMBINED DIESEL ENGINE OR GAS TURBINE This kind of power plant offers the possibilities to transmit the power to a shaft optionally only with a diesel engine or only from a gas turbine. 3
4 1
2
2
3
4
1
Figure 7.9.3:
Combined diesel engine or gas turbine
CODAG = COMBINED DIESEL ENGINE AND GAS TURBINE This kind of power plants offers the possibilities to transmit the power to both shafts optionally only from one diesel engine, or to transmit the power to one shaft separately from one diesel engine, or to transmit the power to one or two shafts only from the gas turbine, or to transmit the power onto both shafts together from all driving engines .
3 1
2
3
2
4
3
1
Figure 7.9.4: 1 2 3 4
Controllable pitch propeller (CPP) Diesel engine Gearbox (distribution gear/multi-staged gear) Gas turbine
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Combined diesel engine and gas turbine
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Application and Installation Guidelines
Further denotation for combinations of mechanical power transmission is used as follows: COGAG
= COMBINED GAS TURBINE AND GAS TURBINE
COGOG
= COMBINED GAS TURBINE OR GAS TURBINE
CODLAG
= COMBINED DIESEL-ELECTRIC AND GAS TURBINE
CODLAGL = COMBINED DIESEL-ELECTRIC AND GAS TURBINE-ELECTRIC
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7.10
Application and Installation Guidelines
Auxiliary Power Take-Off
Figure 7.10.1: Power take-off (PTO), gear driven
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7.11
Example Documents
Back to Start of Chapter
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Back to Contents
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8
8 8.1
Standard Acceptance Test
STANDARD ACCEPTANCE TEST Factory Acceptance Test In general, engines are to be subject to a test bed trial under the supervision of the scope stated below.
8.2
Acceptance Test According to a Classification Society (e.g. Germanischer Lloyd).
8.2.1 Main Engines for Direct Propeller Drive: • 100 % power (rated power) at rated speed n0: 60 minutes • 100 % power at n = 1,032 · n0: 45 minutes • 90 %, 75 %, 50 % and 25 % power in accordance with the nominal propeller curve. In each case the measurements shall not be carried out until the steady operating condition has been achieved. • Starting and reversing manoeuvres • Test of governor and independent overspeed protection device • Test of engine shutdown devices
8.2.2 Main Engines for Indirect Propeller Drive The test is to be performed at rated speed with a constant governor setting under conditions of:
• 100 % power (rated power): 60 minutes • 110 % power: 45 minutes • 75 %, 50 % and 25 % power and idle run. In each case the measurements shall not be carried out until the steady operating condition has been achieved. • Start-up tests
8.2.3 Auxiliary Driving Engines and Engines Driving Electric Generators Tests to be performed in accordance with 9.2.2. The manufacturer's test bed reports are acceptable for auxiliary driving engines rated at ≤ 100 kW.
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8.3
Example Documents
Back to Start of Chapter
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9
9
Control, Monitoring and Data Acquisition (LOP)
CONTROL, MONITORING AND DATA ACQUISITION (LOP) MTU engines for marine applications are provided with an Electronic Control System matched to special marine requirements. The high functional efficiency and simple system design with plug connectors and pre-fabricated system cables for engine installation make incorporation into ships an easy operation. This system ensures optimised engine functioning under all operating conditions. Economical engine operation with low fuel consumption and minimum exhaust emission over the complete load range is guaranteed by the MDEC system. Important Information ! All descriptions herein have reference to the following Standard Diesel Engine Series:
• 2000 M60 / M70 / M80 / M90 / M91 • 4000 M60 / M70 / M80 / M90 The project guide describes the Propulsion Remote Control System RCS-5 for Fixed Pitch Propeller FPP. For applications with Controllable Pitch Propeller CPP, Waterjet WJ or Voith Schneider VS please ask TZPV for assistance. This systems are also available as standard applications. Furthermore MTU Electronic offers on request, after technical clarification, RCS-5 versions for combined propulsion plants e.g. CODAD, CODAG, CODOG etc., in combination with current propeller systems.
9.1
Standard Monitoring and Control Engine Series 2000/4000 Complete monitoring and control, ready for installation and operation, for Non-Classified and Classified automation and single- to four-engine plant with or without gearbox consisting of:
• Monitoring and Control System for the propulsion plant within the Engine Room (FPP, WJ or CPP). • Monitoring and Control System MCS-5 Type 1 for the propulsion plant within the Control Stands. • Monitoring and Control System MCS-5 Type 1 for the shipboard equipment (auxiliary systems in engine room and general ship area). • Remote Control System RCS-5 for the propulsion plant (FPP) within the Control Stands. The meaning of MDEC: MTU Diesel Engine Control. The MDEC System satisfies the following units: • ECU = Engine Control Unit Mounted on engine • EMU = Engine Monitoring Unit Mounted on engine if classification is required • LOP = Local Operating Panel Loose supplied for Engine Room installation
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9.2
Control, Monitoring and Data Acquisition (LOP)
Engine Governing and Control Unit ECU-MDEC Engine governing and control unit ECU-MDEC with integrated safety system, load profile recorder and data modules (for engine and plant specific parameter), for engine speed control in response to rated value setting with fuel injection and speed limitation as a function of engine status and operating conditions as well as MTU sequential turbo charging. Set of sensors including on-engine cabling.
9.3
Engine Monitoring Unit EMU-MDEC Separate Safety System Engine Monitoring Unit EMU-MDEC is used to cover the additional requirements and scope of redundant measuring points specified for classified marine plants. In such cases, EMUMDEC also represents the second, independent safety system, which protects the engine from states assumed to be a risk to continued operation.
9.4
Local Operating Panel LOP-MDEC Local operating panel LOP-MDEC in sheet-metal housing, for ship-side installation in the engine room, comprising the following components and functions: -
-
Interface for ECU-MDEC, gearbox GCU, Shipside Monitoring System and Remote Control. Automatic start/stop and emergency stop sequencing control.
-
LCD display (standard language English, switch-over to other language on request) with selector keyboard for monitoring data of engine and gearbox sensors and status display of turbochargers. System-integrated alarm unit with visual individual alarm and output for visual and audio alarm.
-
Combined control and display elements for engine and gearbox: Ready for operation, Local control, Engine Start/Stop/Emergency Stop, Gearbox clutch control, Engine speed increase/decrease, Lamp test, Alarm acknowledgement and illumination dim control.
Set of connecting cables (10 m each with plug connectors at both ends) for connecting the individual electronic components. Flashing light and horn for alarm in engine room.
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Control, Monitoring and Data Acquisition (LOP)
9.5 Propulsion Plant Management System Version 9.5.1 Manufacturer Specification In accordance with manufacturer specification. (Not classifiable)
Figure 9.5.1:
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Propulsion Plant Management System version in accordance with manufacturer specification
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Control, Monitoring and Data Acquisition (LOP)
9.5.2 Classification Society Regulation Version in compliance with Classification society regulations (GL, ABS, BV, CCS, DNV, KR, LRS, NK, RINA type test approval).
Figure 9.5.2:
Propulsion Plant Management System version in compliance with classification society regulations
Back to Contents
Back to Start of Chapter
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10 10.1
MAINTENANCE CONCEPT / MAINTENANCE SCHEDULE Reason for Information MTU has revised the engine maintenance concept. The former combination of several maintenance tasks in maintenance echelons (W1 to W6) is now obsolete. It is replaced by a concept of maximum service time periods for single components (items) until their next scheduled maintenance is due. The preventive maintenance principle remains effective with the new maintenance concept. The Maintenance Schedules for all MTU engine series and applications, with effect from Sales Program 2003, will be converted to the new concept this year. The current maintenance schedules may continue to be used for engines already in service, they will not, however, be subjected to any up-dating or amendment procedures.
10.2
Advantages of the New Maintenance Concept: Technical: -
Individual maintenance tasks per operating period interval resulting in reduced down time per maintenance operation.
-
Utilisation of the maximum service life of the single components.
-
Reduced life cycle costs.
Data Processing:
10.3
-
Central administration of the individual tasks in a data bank.
-
Common designation of identical maintenance tasks irrespective of engine series.
-
Efficient translation and availability in 5 languages.
New Maintenance Schedule: The new maintenance schedule is divided into three sections.
10.3.1 Cover Sheet The cover sheet provides the following information: -
Engine series/production model, application group, load profile.
-
Order No. (only with order-specific maintenance schedules).
-
Maintenance schedule and version numbers.
-
General information with respect to the maintenance concept.
-
Cross-reference to other applicable documentation (Fluids and Lubricants Specification).
-
Maintenance tasks that are not included in the maintenance schedule matrix as their maintenance intervals are strictly related to the individual operating conditions (fuel prefilter, battery).
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10.3.2 Maintenance Schedule Matrix
Engine oil
Engine operation
Engine oil filter
Centrifugal oil filter
Fuel duplex filter
Valve gear
Air filter
Fuel injectors
Fuel injection pumps
Combustion chambers
Belt drive
Component maintenance
Extended component maintenance
The maintenance schedule matrix provides an overview of the minimum scope of maintenance tasks.
Maint. Level
W1
W1
W2
W2
W3
W3
W4
W4
W4
W4
W4
W5
W6
Time limit,
-
-
2
-
2
-
3
-
-
-
2
18
18
Operating ho rs Daily
X
X
500
X
X
X
1000
X
X
X
1500
X
X
X
2000
X
X
X
2500
X
X
X
3000
X
X
X
3500
X
X
X
4000
X
X
X
X
X
X
X
X
X
X
X
X
Figure 10.3.1: Example of a maintenance schedule matrix -
The matrix headings contain the individual maintenance items. The item content is described in the task list (see below).
-
In comparison to the previous maintenance concept, the “Maintenance Levels” listed in the 2nd line have a new meaning. They indicate the qualifications (scope of training) required for the maintenance personnel and the scope of tools required; these are combined in tool kits.
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11 Assembling Instructions (Lifting, Transportation)
-
In addition to the operating hours limits, some maintenance tasks are subject to a time restriction, “Time limit in years”. This is indicated in the 3rd line. As a matter of principle the limit value (operating hours or years) that first becomes effective is to be used.
-
The 1st column of the matrix indicates the “Operating hours” at which a maintenance operation is to be executed. The associated tasks are indicated by an “x” in the appropriate line. The maintenance schedule matrix normally ends with the “Extended component maintenance”. Thereafter, the maintenance tasks are to continue in accordance with the related intervals (see task list), i.e. as a matter of principle, maintenance is to be carried out at the intervals indicated and not recommenced at the beginning of the matrix. If required (on request) a maintenance schedule with an extended matrix can be provided.
10.3.3 Task List The task list describes the maintenance tasks listed as positions in the matrix. Maint. Interval Item Level (hours/years)
W1
-/-
W1 W2
-/-/2
W2
500/-
W3 W3 W4
500/500/2 2000/3
W4
2000/2
W4 W4 W4
3000/3000/4000/-
TPG-General.doc Rev. 1.0
Maintenance tasks
Check general conditions of engine and verify that there are no leaks. Check drain lines of intercooler. Check service indicator of air filter. Check relief bores of water pump(s). Engine operation Check for abnormal running noises, exhaust gas colour, vibration. Drain off water and contamination at drain cock of fuel prefilter (if fitted). Check service indicator of fuel prefilter (if fitted). Engine oil Check level. Engine oil filter Replace. Or replace when changing engine oil. Check thickness of oil residue layer, clean and Centrifugal oil filter change sleeve. Valve gear Check valve clearance. Fuel duplex filter Replace filters. Air filter Fit new air filter(s). Check belt condition and tension, replace if Belt drive necessary. Combustion chambers Inspect cylinder chambers using endoscope. Fuel injectors Fit new fuel injectors. Fuel injection pumps Fit new fuel injector pumps.
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11 Assembling Instructions (Lifting, Transportation) Maint. Interval Item Level (hours/years)
W5
4000/18
Maintenance tasks
Component maintenance
Before starting maintenance work, drain coolant and flush cooling systems. Check rocker arms, valve bridges, pushrods and ball joints for wear. Check wear pattern of cylinder-liner running surfaces. Replace turbocharger. Check vibration damper. Clean air ducting. Clean intercooler and check it for leaks.
Figure 10.3.2: Example task list
-
The “Maintenance level” serves only as an orientation for the qualifications required for the maintenance personnel and the tool kits required.
-
The “Interval” defines the maximum permissible operational period between the individual maintenance tasks for each component/item in operating hours/years referenced to the specified load profile (see cover sheet). The time intervals are based on the average results of operational experience and, therefore, are guideline values only. In the case of arduous operating conditions, modifications may be necessary.
-
The “Item” matches the data given in the headings of the maintenance schedule matrix.
-
The “Maintenance tasks” column lists the individual maintenance tasks per item. Detailed task descriptions are contained in the engine-related Operation Manual.
Note: Change intervals for fluids and lubricants are no longer included in the maintenance schedule. These are defined in the MTU Fluids and Lubricants Specification A001061. Reason: -
The oil service life is influenced by the quality of the oil, oil filtration, operational conditions and the fuel used. In individual applications, oil service life may be optimized by regular laboratory analyses.
-
The coolant service life depends on the type of coolant additive(s) used.
With the new maintenance schedule concept it is still possible for tasks to be combined in individual blocks in accordance with the customer's wishes. It is, however, mandatory to ensure that the maximum permissible maintenance intervals for each position are not exceeded. Reduction of the intervals is, as a matter of principle, possible. However, this can have a negative effect on overall maintenance costs. Back to Start of Chapter TPG-General.doc Rev. 1.0
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11 Assembling Instructions (Lifting, Transportation)
11
ASSEMBLING INSTRUCTIONS (LIFTING, TRANSPORTATION)
Back to Start of Chapter
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12 Transportation, Storage, Starting
12
TRANSPORTATION, STORAGE, STARTING
Back to Start of Chapter
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13 Pilot Installation Description (PID)
13
PILOT INSTALLATION DESCRIPTION (PID)
Back to Start of Chapter
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MTU Friedrichshafen GmbH Ship Systems Technology Commercial D-88040 Friedrichshafen Germany Phone +49 7541 90 - 0 www.mtu-friedrichshafen.com Assistance: MTG Marinetechnik GmbH D-22041 Hamburg Germany MTG Ref.: 679/335/2100 - 001 Phone +49 40 65 803 - 0 www.mtg-marinetechnik.de
Technical Project Guide Marine Application Part 1 - General June 2003 Revision 1.0
The illustrations herein are presented with kind permission of the companies listed below. Rolls-Royce AB www.rolls-royce.com S-681 29 Kristinehamn Sweden Schottel GmbH & Co. KG www.schottel.de D-56322 Spay/Rhein Germany Voith Schiffstechnik GmbH & Co. KG www.voith-schiffstechnik.de D-89522 Heidenheim Germany ZF Marine GmbH www.zf-marine.com D-88039 Friedrichshafen Germany
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User Information
USER INFORMATION This –Technical Project Guide- is supposed to give the user general references for the planning, design and the arrangement of propulsion plants and on-board power generation plants. Precise information on the different diesel engine series are to be taken from the specific engine parts. Following engine parts are planned/available:
Technical Projekt Guide Marine Application Part 1 - General
TPG-General.doc Rev. 1.0
+
Technical Project Guide Marine Application Part 2 - Engine Series 2000
+
Technical Project Guide Marine Application Part 3 - Engine Series 4000
+
Technical Project Guide Marine Application Part 4 - Engine Series 8000 (later on)
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Contents
CONTENTS Chapter
Title
Page
1 1.1 1.2 1.3
GENERAL Introduction Designations Special Documents Presented
1-1 1-1 1-2 1-3
2 2.1 2.2 2.3
DEFINITION OF APPLICATION GROUPS General Marine Main Propulsion and Auxiliary Propulsion Plants On-Board Electric Power Generation/Auxiliary Power
2-1 2-1 2-2 2-2
3 3.1 3.1.1 3.1.2 3.2 3.3 3.4
SPECIFICATION OF POWER AND REFERENCE CONDITION Definition of Terms ISO Standard Fuel-Stop Power (ICFN) ISO Standard Power Exceedable by 10 % (ICXN) Reference Conditions Load Profile Time Between Major Overhauls (TBO)
3-1 3-1 3-1 3-2 3-2 3-3 3-4
4 4.1 4.2
FLUIDS AND LUBRICANTS SPECIFICATION General MTU Approved Fuels
4-1 4-1 4-1
5
ENGINE PERFORMANCE DIAGRAM
5-1
6 6.1 6.1.1 6.1.2 6.1.3 6.2 6.2.1 6.2.2 6.2.3 6.2.4 6.3 6.3.1 6.3.2 6.3.3
PROPULSION, INTERACTION ENGINE WITH APPLICATION Propulsor Abbreviations Propulsive Devices (Overview) Shaft Line and Gearbox Losses Propeller Propeller Geometry Propeller Type Selection (FPP or CPP) Direction of Propeller Rotation Selection of Propeller Blade Number Propeller Curve Basics Theoretical Propeller Curve Estimating the Required Diesel Engine Power
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6-1 6-1 6-1 6-3 6-9 6-10 6-10 6-12 6-14 6-17 6-18 6-18 6-23 6-25
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Contents
CONTENTS Chapter 6.4 6.4.1 6.4.2 6.4.3 6.5 6.5.1 6.5.2 6.6 6.6.1 6.6.2 6.6.3 6.6.4 6.6.5 6.6.6 6.6.6.1 6.6.6.2 6.6.6.3 6.6.6.4 6.6.6.5 6.6.6.6 6.7 7 7.1 7.2 7.2.1 7.2.2 7.3 7.3.1 7.3.2 7.4 7.4.1 7.4.2 7.4.2.1 7.4.2.2 7.4.2.3 7.4.3 7.4.3.1 7.4.3.2 7.4.3.3
Title Propeller and Performance Diagram Driving Mode Fixed Pitch Propeller (FPP) Controllable Pitch Propeller (CPP) Waterjet and Performance Diagram Geometry and Design Point Estimation of Size and Shaft Speed Fuel Consumption General Assumptions Operating Profile Fuel Consumption at Design Condition Cruising Range Endurance at Sea Calculating Examples Example Data (Series 2000) Fuel consumption at design condition Fuel tank volume for a range of 500sm at 18kn Theoretical cruising range at 12kn and fuel tank volume of 5m3 Annual fuel consumption for an operating profile Correcting the lower heating value Generator Drive APPLICATION AND INSTALLATION GUIDELINES Foundation Engine/Gearbox Arrangements Engine with Flange-Mounted Gearbox (F-Drive) Engine with Free-Standing Gearbox, V Drive Inclusive Generator Set Arrangement Engine with Free-Standing Generator Engine with Flange-Mounted Generator System Interfaces and System Integration Flexible Connections Combustion Air and Cooling/Ventilation Air Supply Combustion-air intake from engine room Combustion-air intake directly from outside Cooling/ventilation air system Exhaust System Arrangements, support and connection for pipe and silencer Underwater discharge (with exhaust flap) Water-cooled exhaust system
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Page III
6-26 6-26 6-29 6-31 6-36 6-36 6-41 6-42 6-42 6-44 6-49 6-50 6-51 6-52 6-52 6-54 6-55 6-56 6-57 6-58 6-59 7-1 7-1 7-2 7-2 7-3 7-6 7-6 7-7 7-8 7-8 7-11 7-11 7-11 7-11 7-12 7-12 7-13 7-14
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Contents
CONTENTS Chapter 7.4.4 7.4.4.1 7.4.4.2 7.4.4.3 7.4.5 7.4.5.1 7.4.5.2 7.4.6 7.4.7 7.4.7.1 7.4.7.2 7.4.7.3 7.4.8 7.5 7.6 7.6.1 7.6.2 7.6.2.1 7.6.2.2 7.6.2.3 7.7 7.8 7.9 7.10 7.11
Title
Page
Cooling Water System Cooling water system with engine-mounted heat exchanger Cooling water system with separately-mounted heat exchanger Central cooling water system Fuel System General notes Design data Lube Oil System Starting System Electric starter motor Compressed-air starting, compressed-air starter motor Compressed-air starting, air-in-cylinder Electric Power Supply Safety System Emission Exhaust Gas Emission, General Information Acoustical Emission, General Information Airborne noise level Exhaust gas noise level Structure-borne noise level Mounting and Foundation Acoustic Enclosure/Acoustic Case Mechanical Power Transmission Auxiliary Power Take-Off Example Documents
7-15 7-15 7-16 7-17 7-18 7-19 7-19 7-22 7-23 7-23 7-24 7-25 7-28 7-29 7-30 7-30 7-32 7-32 7-34 7-35 7-42 7-43 7-44 7-47 7-48
8 8.1 8.2 8.2.1 8.2.2 8.2.3 8.3
STANDARD ACCEPTANCE TEST Factory Acceptance Test Acceptance Test According to a Classification Society Main Engines for Direct Propeller Drive: Main Engines for Indirect Propeller Drive Auxiliary Driving Engines and Engines Driving Electric Generators Example Documents
8-1 8-1 8-1 8-1 8-1 8-1 8-2
9 9.1 9.2 9.3 9.4 9.5 9.5.1 9.5.2
CONTROL, MONITORING AND DATA ACQUISITION (LOP) Standard Monitoring and Control Engine Series 2000/4000 Engine Governing and Control Unit ECU-MDEC Engine Monitoring Unit EMU-MDEC Separate Safety System Local Operating Panel LOP-MDEC Propulsion Plant Management System Version Manufacturer Specification Classification Society Regulation
9-1 9-1 9-2 9-2 9-2 9-3 9-3 9-4
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Contents
CONTENTS Chapter
Title
Page
10 10.1 10.2 10.3 10.3.1 10.3.2 10.3.3
MAINTENANCE CONCEPT / MAINTENANCE SCHEDULE Reason for Information Advantages of the New Maintenance Concept: New Maintenance Schedule: Cover Sheet Maintenance Schedule Matrix Task List
10-1 10-1 10-1 10-1 10-1 10-2 10-3
11
ASSEMBLING INSTRUCTIONS (LIFTING, TRANSPORTATION)
11-1
12
TRANSPORTATION, STORAGE, STARTING
12-1
13
PILOT INSTALLATION DESCRIPTION (PID)
13-1
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List of Figures
List of Figures Figure
Title
Figure 1.2.1:
Engine designations (sides, cylinders, direction of rotation)
1-2
Figure 1.3.1:
Structure of the MTU EXTRANET
1-3
Figure 3.3.1:
Typical Standard Load Profiles
3-3
Figure 3.4.1:
TBO definition of MTU
3-4
Figure 4.2.1:
Fuel specification
4-1
Figure 4.2.1:
Structure of the performance diagram
5-1
Figure 4.2.2:
Engine performance diagram
5-3
Figure 4.2.3:
Monohull
5-4
Figure 4.2.4:
Semi-planing boat hull = high speed monohull with medium displacement
5-4
Figure 4.2.5:
Multihulls = catamarans, trimarans,
5-5
Figure 4.2.6:
Semi-planing boat hull = high speed monohull with low displacement
5-5
Figure 6.1.1:
Scheme of a propulsive unit (side view)
6-1
Figure 6.2.1:
Scheme of propeller geometry (skew and rake)
6-10
Figure 6.2.2:
Propeller clearance
6-12
Figure 6.3.1:
Influence of change in resistance on effective power curve (example)
6-19
Figure 6.3.2:
From effective to delivered power curve (example)
6-20
Figure 6.3.3:
Effect of change in resistance on delivered power curve (example)
6-21
Figure 6.3.4:
Effect of different propeller pitches on delivered power (example)
6-22
Figure 6.4.1:
Change in delivered power due to weather, draught and fouling
6-26
Figure 6.4.2:
Diesel engine failure in a two shaft arrangement
6-27
Figure 6.4.3:
Choosing a design point for a fixed pitch propeller
6-29
Figure 6.4.4:
CPP characteristic in a typical diesel engine performance diagram
6-31
Figure 6.4.5:
Controllable pitch propeller design point
6-32
Figure 6.4.6:
Example: Single shaft operation with CPP
6-34
Figure 6.4.7:
Example: Constant speed generator in operation with CPP
6-35
Figure 6.5.1:
Waterjet
6-36
Figure 6.5.2:
Waterjet design point (Diagram has limited use for waterjet design)
6-37
Figure 6.5.3:
Platform with pump
6-38
Figure 6.5.4:
Waterjet performance diagram
6-39
Figure 6.5.5:
Estimating the size of a waterjet (inlet duct diameter)
6-41
Figure 6.5.6:
Estimating the design impeller speed of a waterjet
6-41
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List of Figures
List of Figures Figure
Title
Page
Figure 6.6.1:
Examples of operating profiles (freighter, fast ferry, OPV)
6-45
Figure 6.6.2:
Examples of operating profiles (freighter, fast ferry, OPV)
6-46
Figure 6.7.1:
Power definition
6-60
Figure 6.7.1:
Engine room arrangement, minimum distance
7-1
Figure 7.2.1:
Engine with flange-mounted gearbox
7-2
Figure 7.2.2:
Engine with free-standing gearbox
7-3
Figure 7.2.3:
Engine with free-standing gearbox and universal shaft, V drive arrangement
7-5
Figure 7.3.1:
Engine with free-standing generator
7-6
Figure 7.3.2:
Engine with flange-mounted generator
7-7
Figure 7.4.1:
Connection of rubber bellows
Figure 7.4.2:
Cooling water system with engine-mounted heat exchanger (Split-circuit cooling system) 7-15
Figure 7.4.3:
Cooling water system with separately-mounted heat exchanger (e.g. keel cooling) 7-16
Figure 7.4.4:
Central cooling water system
7-17
Figure 7.4.5:
Fuel System
7-18
Figure 7.4.6:
Evaluation value for max. fuel inlet temperature
7-20
Figure 7.4.7:
Lube oil system
7-22
Figure 7.4.8:
Starting system with pneumatic starter motor
7-25
Figure 7.4.9:
Starting system with air-in-cylinder starting
7-26
7-10
Figure 7.4.10: Electric power supply
7-28
Figure 7.6.1:
Limitation of NOx-emission (IMO)
Figure 7.6.2:
Test cycle for “Constant Speed Main Propulsion” application (including diesel electric drive and variable pitch propeller installation) 7-31
Figure 7.6.3:
Test cycle for “Propeller Law operated Main and Propeller Law operated Auxiliary Engines” application 7-31
Figure 7.6.4:
Test cycle for “Constant Speed Auxiliary Engine” application
7-31
Figure 7.6.5:
Test cycle for “Variable Speed, Variable Load Auxiliary Engine” application
7-31
Figure 7.6.6:
Engine surface noise analysis (example)
7-33
Figure 7.6.7:
Undamped exhaust gas noise analysis (example)
7-34
Figure 7.6.8:
Single resilient mounting system with shock
7-37
Figure 7.6.9:
Double resilient mounting system for extreme acoustic requirements
7-39
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List of Figures
List of Figures Figure
Title
Page
Figure 7.6.10: Examples for different “Quiet Systems”, structure-borne noise levels below the resilient mountings (e.g. diesel engine 20V 1163) 7-40 Figure 7.6.11: Structure borne noise analysis at engine feet, above rubber mounts (example) 7-41 Figure 7.9.1:
Combined diesel engine and diesel engine
7-44
Figure 7.9.2:
Combined diesel engine and diesel engine with separate gear compartment
7-44
Figure 7.9.3:
Combined diesel engine or gas turbine
7-45
Figure 7.9.4:
Combined diesel engine and gas turbine
7-45
Figure 7.10.1: Power take-off (PTO), gear driven
7-47
Figure 9.5.1:
Propulsion Plant Management System version in accordance with manufacturer specification 9-3
Figure 9.5.2:
Propulsion Plant Management System version in compliance with classification society regulations 9-4
Figure 10.3.1: Example of a maintenance schedule matrix
10-2
Figure 10.3.2: Example task list
10-4
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1
1 1.1
General
GENERAL Introduction MTU Friedrichshafen in Germany and Detroit Diesel Corporation in the USA, two DaimlerChrysler Group companies, have combined their off-highway operations. With product ranges of MTU and DDC plus Mercedes-Benz engines under one roof, a worldleading supplier of engines and systems for the marine, rail, power generation, heavy-duty military and commercial-vehicle as well as agricultural and construction-industry machinery sectors has been created. All marine engines are under the brand “MTU”. Especially within the shipping sector the company has established a long and successful partnership with hundred thousands of engines in operation around the globe on all seas. Based on its innovative capabilities, its reliability and system competence, MTU disposes of unique drive system know how and offers a large range of products of excellent quality. MTU develops, manufactures and sells diesel engines in the 200 to 9000 kW power range (for more information refer to publication “SALES PROGRAM MARINE”). This publication has been compiled as a source of information only. It contains generally applicable notes for planning and installation of marine propulsion plants and electric power plants. Non-standard design requirements (i.e. applicable to the design of individual components or entire systems) such as may be specified by the operator or by classification societies are not taken into consideration in the scope of this publication. Such requirements necessitate clarification on case-to-case basis. Project-related or contract-related specifications take precedence over the general information appearing in this publication, because the project-specific or contract-specific data are of course applicable to the particular application and the overall propulsion concept.
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1
1.2
General
Designations The DIN 6265 respectively ISO 1204 designations are used to identify the sides and cylinders of MTU engines. Details are explained in Figure 1.2.1.
Figure 1.2.1:
TPG-General.doc Rev. 1.0
Engine designations (sides, cylinders, direction of rotation)
Driving end
= KS (Kupplungsseite)
Free end
= KGS (Kupplungsgegenseite)
Left-bank cylinders
= A1, A2, A3, ..., A7, A8
Right-bank cylinders
= B1, B2, B3, ..., B7, B8
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1
1.3
General
Special Documents Presented Specific information and documents are found in the MTU EXTRANET. The structure of the EXTRANET with its essential components is represented in the following diagram.
Figure 1.3.1:
Structure of the MTU EXTRANET Back to Contents
Back to Start of Chapter
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3
2 2.1
Specification of Power and Reference Condition
DEFINITION OF APPLICATION GROUPS General In addition to general application by usage, e.g. marine vessel, the particular application must be taken into account for selecting the correct engine. The choice of the application group determines the maximum possible engine power and the anticipated time between major overhauls (TBO). Load varies during operation, with the result that the TBO is dependent on the actual load profile and varies from different applications. For an optimum selection of the engine taking into account the maximum power available the following information should be obtained from the operator: •
Application, e.g. yacht, patrol boat, ferry, fishing vessel, freighter etc.
•
Load profile (engine power versus operating time)
•
Anticipated operating hours per year
•
Preferred time between overhauls (TBO, for special cases only)
The terms “load profile” and “TBO” and the relationship between them are explained in detail in chapter –3
Specification of Power and Reference Condition- and
– 10
Maintenance Concept / Maintenance Schedule-.
If no specific load profile information is available from the operator, the selection of the engine is performed on the basis of the standard load profile determined by MTU by means of typical application. The MTU Sales Program distinguishes for the marine application propulsion engines and marine auxiliary engines and engines for the on-board supply of electricity. The following application groups are subdivided into in detail.
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3
2.2
Specification of Power and Reference Condition
Marine Main Propulsion and Auxiliary Propulsion Plants 1A
1B
Vessels for heavy-duty service with unlimited operating range and/or unrestricted continuous operation Average load
: 70 – 90 % of rated power
Annual usage
: unlimited
Examples
: Freighters, Tug Boats, Fishing Vessels, Ferries, Sailing Yachts, Displacement Yachts with high load profile and/or annual usage
Vessels for medium-duty service with high load factors Average load
: 60 to 80 % of rated power
Annual usage
: up to 5000 hours (as a guideline)
Examples
: Commercial Vessels, including Fast Ferries, Crew Boats, Offshore Supply & Service Vessels, Coastal Freighters, Multipurpose Vessels, Patrol Boats, Displacement Yachts, fan drive for Surface Effect Ships
1DS Vessels for light-duty service with low load factors Average load
: Less than 60 % of rated power
Annual usage
: Up to 3000 hours (as a guideline)
(Series 2000 & lower power engines approx. 1000 hours) Examples
: High speed Yachts, Fast Patrol Boats, FireFighting Vessels, Fishing Trawlers, Corvettes, Frigates
Significant deviations from the above application groups should be discussed with the responsible application engineering group.
2.3
On-Board Electric Power Generation/Auxiliary Power 3A
Electric power generation, continuous duty (no time restriction), e.g. dieselelectric drive, diesel-hydraulic drive or drive for fire fighting pumps
3C
Electric power generation for onboard standby power generation, e.g. emergency power supply or drive for emergency fire fighting pumps
Back to Start of Chapter
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3
3 3.1
Specification of Power and Reference Condition
SPECIFICATION OF POWER AND REFERENCE CONDITION Definition of Terms The available power for a specific engine type and application group is listed in the Sales Program.
3.1.1 ISO Standard Fuel-Stop Power (ICFN) The rated power of marine main propulsion engines of application group 1A, 1B and 1DS is stated as ISO standard fuel-stop power, ICFN, in accordance with DIN ISO 3046. Measurement unit is kW. I = ISO power C = Continuous power F = Fuel stop power N = Net brake power The fuel-stop power rating represents the power that an engine can produce unlimited during a period of time appropriate to the application, while operating at an associated speed and under defined ambient conditions (reference conditions), assuming performance of the maintenance as specified in the manufacturer’s maintenance schedule. Power specifications always express net brake power, i.e. power required for on-engine auxiliaries such as engine oil pump, coolant pump and raw water pump is already deducted. The figure therefore expresses the power available at the engine output flange. The engines of application group 1A and 1B can demonstrate 10 % overload in excess of rated fuel-stop power for the purposes of performance approval by classification societies. Fuel stop power of the engines in application group 1DS cannot generally be classified. Some classification societies accept the certification of engines of application group 1DS for special service vessels with specific load profiles. In case of such a request, the respective application engineering group should be contacted. Before delivery, all engines will be factory tested on the dynamometer at standard ISO reference conditions (intake air and raw water temperature 25°C). Acceptance test procedures at MTU: • MTU works acceptance test • Acceptance test in accordance with classification society regulations under supervision of the customer As a rule, marine main propulsion engines are supplied with power limited to fuel-stop power as specified in the Sales Program.
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3
Specification of Power and Reference Condition
3.1.2 ISO Standard Power Exceedable by 10 % (ICXN) The rated power of marine onboard power generation of application group 3A and 3C is stated as ISO standard power exceedable by 10 %, ICXN, in accordance with DIN ISO 3046. Measurement unit is kW. I = ISO power C = Continuous power X = Service standard power, exceedable by 10 % N = Net brake power
3.2
Reference Conditions The reference conditions define all ambient factors of relevance for determining engine power. The reference conditions are specified in the Sales Program and on the applicable engine performance diagram. ISO 3046-1 standard reference conditions: Total barometric pressure
: 1000 mbar or (hPa)
Air temperature
: 25
°C (298 K)
Relative humidity
: 30
%
Charge air coolant temperature
: 25
°C (298 K)
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3
3.3
Specification of Power and Reference Condition
Load Profile The load profile is a projection of the engine operating routine. The following standard load profiles have been established in the past, based on accumulated field experience with specific vessels and a huge number of recorded load profiles. Standard Load Profile Application Group
applied power in % of rated power
operating time in %
100
10
1A
80
50
(all engines except 4000 M60R)
60
20
< 15
20
100
20
90
70
< 15
10
1B
100
75
up to and incl. Series 4000
< 15
25
100
3
85
82
< 15
15
100
10
70
70
< 10
20
1A for V4000M60R only
1B above Series 4000
1DS
Figure 3.3.1:
Typical Standard Load Profiles
If there is a significant difference between the actual and standard load profiles, MTU calculates the TBO on the basis of the load profile submitted by the customer. All MTU engines can be operated at fuel-stop power as long as required by the customer. Of course, extensive operation at fuel stop power (higher load profile) will shorten the time between maintenance intervals.
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3.4
Specification of Power and Reference Condition
Time Between Major Overhauls (TBO)
Failure rate
Up to now, the TBO for diesel engines is not specified in any international standard. Therefore each engine manufacturer uses his own definition for TBO.
TBO
Early failures 1 1
Figure 3.4.1:
MTU
Maintenance Echelon W6
Random failures
W earout failures
Probable start-up failures
Operating tim e
TBO definition of MTU
According to MTU, the TBO is defined to be the time span in which operation without major failure is ensured, i.e. it precludes wear-related damage requiring a major overhaul or engine replacement. This time span is theoretically reached, if a probability of wear-out failures exceeds 1% (socalled B1 definition). This means that an MTU engine can still provide full and unlimited service until the last operating hour before the scheduled overhaul. The major criterion for a ship is availability and thus the reliability of the propulsion. Based on this, MTU decided to limit the statistical wear-out failure rate to 1 % only.
TBO definition from other engine manufacturers In contrast to MTU’s TBO definition, some other manufacturers define a scheduled TBO at a wear-out failure rate of 10% or up to 50% (B10 or B50 definition). This means, that statistically up to 50% of all engines do not reach the pre-defined TBO without major failure.
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Specification of Power and Reference Condition
Load Profile Recorder Most engines in the MTU Sales Program do include a load profile recorder as an integral part of the Electronic Engine Management System. This device continuously records the operating time spent at certain power levels and speeds, together with several other important engine parameters. The load profile could be downloaded from the Electronic Engine Management System and analysed. In case of significant deviations between the recorded load profile and the assumed load profile, the TBO could be revised. The finally applicable TBO will also take into account the actual engine condition as a result of installation conditions, quality of fluids and lubricants and service.
Back to Contents
Back to Start of Chapter
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4 4.1
Fluids and Lubricants Specification
FLUIDS AND LUBRICANTS SPECIFICATION General The fluids and lubricants used in an engine are among the factors influencing serviceability, reliability and general operability of the propulsion plant. Only fluids and lubricants approved by MTU may be used with MTU products. MTU issues a list of approved fluids and lubricants, for engine operation and engine preservation i.e. • • • •
lubricants (oils, greases and special-purpose lubricant substances) coolants (corrosion-inhibiting agents, anti-freeze agents) fuels preserving agents (corrosion-inhibiting oils for use in and on the engine)
The MTU approved fluids and lubricants as well as the requirements which they must satisfy are listed in the currently applicable MTU Fluids and Lubricants Specification. MTU Fluids and Lubricants Specification (A001061/..) is available. An operator wishing to use a fluid or lubricant that is not included in the Fluids and Lubricants Specification must consult MTU.
4.2
MTU Approved Fuels EN 590 Density at 15°C
kg/m3
Lower calorific value
kJ/kg
Figure 4.2.1:
MGO/MDO according ISO 8217 DM
DMA
DMB
DMC
880-890
900
920
Fuel specification
( under preparation )
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Engine Performance Diagram
ENGINE PERFORMANCE DIAGRAM The engine performance diagram serves as the basis for a number of calculations, but one of its most important functions is to indicate the speed and power limits that must be observed for propeller and waterjet design. Engine power [kW]
Speed band of constant power Nominal power = 100% Limit of MCR ATL switching border line
II UMBL
Min. engine Speed (lowidle) Power surplus (acceleration reserve)
II Nominal speed = 100%
I
Propeller curve = power demand (P ~n³) Engine speed [rpm]
Figure 4.2.1: I –II
: Status, sequential turbocharging
II UMBL
: The engine operating values can be further optimized by employment of some blowing over facilities within the ATL-connection (ATL = tubocharger). After connection of the second ATL, air charge is blown over to the exhaust line controlled by the engine electronics in order to increase the mass flow rate through the turbine. In combination with the improved situation of the working line with reference to the compressor efficiency a higher loadingpressure and consequently an improvement of the engine operating values is obtained.
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Structure of the performance diagram
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Engine Performance Diagram
Base for the layout of the performance diagram: • Application group (1A, 1B, 1DS) • Reference conditions • Definition of power rating and fuel consumption • Time between overhauls/operating load profile The engine performance diagram shows engine power plotted against engine speed. It also includes the specific fuel consumption curves and operating-speed range limits, along with all other boundary conditions. Figure 4.2.2 shows a representative engine power diagram.
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Figure 4.2.2:
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Engine performance diagram
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Engine Performance Diagram
There are different power/speed demand curves depending on difference hull shapes:
Figure 4.2.3:
Monohull
Figure 4.2.4:
Semi-planing boat hull = high speed monohull with medium displacement
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Figure 4.2.5:
Multihulls = catamarans, trimarans,
Figure 4.2.6:
Semi-planing boat hull = high speed monohull with low displacement Back to Contents
Back to Start of Chapter
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Propulsion, Interaction Engine with Application
6 PROPULSION, INTERACTION ENGINE WITH APPLICATION 6.1 Propulsor 6.1.1 Abbreviations The following abbreviations will be used in section 6. In the majority (marked with an asterisk) they are according to recommendations of the ITTC Symbols and Terminology List, Draft Version1999 (International Towing Tank Conference).
PS
PD
Propeller
Figure 6.1.1:
PB
Gearbox
Diesel Engine
Scheme of a propulsive unit (side view)
Symbol
Name
Definition or Explanation
SI Unit
ITTC B D
*
Hu
m3/h
Propeller diameter
M
Lower heating value or lower caloric value
Lower heating value of fuel (preferred value 42800 kJ/kg)
kJ/kg
PB
*
Brake power
Power at output flange of the diesel engine, power delivered by primer mover.
W
PD
*
Delivered power or propeller power, propeller load
Power at propeller flange.
W
PE
*
Effective power or resistance power
Power for towing a ship.
W
PS
*
Shaft power
Power measured on the shaft. Power available at the output flange of a gearbox. If no gearbox fitted: PS = PB
W
PS
Generator apparent power
W
Pp
Generator active power
W
RT
*
Total resistance
T
*
Propeller thrust or waterjet thrust
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Total resistance of a towed ship.
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Symbol
Name
Definition or Explanation
be
Specific fuel consumption
f
Electrical power supply frequency
n
Shaft speed, rate of revolution
p
Number of generator pole pairs
v
Ship speed
(see remark 1)
Propulsive efficiency
PE / PD
*
ηD ηGen
*
ηH
within MTU often used as SFC ( alternative dimension g/kWh)
SI Unit kg/kWh (g/kWh) Hz
(diesel engine, gearbox, propulsor) alias rpm in several propulsor applications
1/s (rpm) --m/s (knot) ---
Generator efficiency
---
Hull efficiency
---
Mechanical efficiency
ηm
Propulsion, Interaction Engine with Application
PD / PB ,represents the losses between diesel engine and propeller flange.
---
η0
*
Propeller open water efficiency
---
ηR
*
Relative rotative efficiency
---
Specific density of fuel
ρfuel
(preferred value 830 kg/m3)
kg/m3
Remark 1: While the SI-Unit of velocity is meter/second the traditional unit knots is widely used and this situation will not change in the near future. kn
knot (1sm/h or 1852m/3600s = 0.5144 m/s)
sm
sea mile ( = 1852 m)
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6.1.2 Propulsive Devices (Overview) The duty of a propulsive unit is to convert the power of the diesel engine into propulsive thrust. A propulsive device can be a:
Type Fixed Pitch Propeller (FPP)
General Characteristics Ease of manufacture Small hub size Blade root dictates boss length Design for single condition (design point) Absorbed power varies with propeller speed No restriction on blade area or shape Gearbox: reversing gear needed
Controllable Pitch Propeller (CPP)
Constant or variable speed operation Blade root is restricted by palm dimensions Mechanical complexity Restriction on blade area to maintain reversibility Can accommodate multiple operating conditions Increased manoeuvrability Gearbox: if fully reversible no reversing gear needed
Waterjet
Good directional control of thrust Increased mechanical complexity Avoids need for separate rudder Increased manoeuvrability Diesel engine load independent of wind and sea state High speed range (approx.>20 kn) Gearbox: no reversing gear needed, but usually used to allow back flushing of water (reverse mode)
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Type Rudderpropeller
Propulsion, Interaction Engine with Application
General Characteristics Good directional control of thrust Increased mechanical complexity Avoids need for rudder Increased manoeuvrability Can employ ducted or non ducted FPP or CPP types Low speed range (approx.<20 kn) Gearbox: not required for standard arrangements
Cycloidal Propeller
Good directional control of thrust Increased mechanical complexity Avoids need for rudder Increased manoeuvrability Low speed range (approx.<20 kn) Gearbox: not required for standard arrangements
Twin-Propeller
Good directional control of thrust Increased mechanical complexity Avoids need for rudder Increased manoeuvrability Propeller coupled mechanically Same direction of rotation Low speed range (approx.<24 kn) Gearbox: not required for standard arrangements
Podded Propulsion
Good directional control of thrust Avoids need for rudder Increased manoeuvrability Electric motor drives propeller Gearbox: not required
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Type
Propulsion, Interaction Engine with Application
Typical Arrangements
Fixed Pitch Propeller (FPP)
Controllable Pitch Propeller (CPP)
Waterjet
Rudderpropeller
Cycloidal Propeller
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Type
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Typical Arrangements
Twin-Propeller
Podded Propulsion
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Type Fixed Pitch Propeller (FPP)
Controllable Pitch Propeller (CPP)
Waterjet
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Manoeuvring Characteristics Power demand: fixed relation between ship speed and diesel engine power. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: reversible gearbox. Control: not applicable. Gearbox: free standing, flange mounted, V-drive arrangement. Rudder: needed. Power demand: every possible pitch has its own fixed relation to the effective power curve. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed or propeller pitch. Astern: reversible gearbox or fully reversible propeller. Control: hydraulic power pack arranged in shaft line or at the gearbox. Gearbox: free standing, flange mounted. Rudder: needed. Power demand: fixed relation between shaft speed and diesel engine power. Small dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: reversing bucket (optional). Control: hydraulic power pack for steering and reversing bucket. Gearbox: free standing, flange mounted. Rudder: if no steering equipment at waterjet.
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Type Rudderpropeller
Cycloidal Propeller
Twin-Propeller
Podded Propulsion
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Manoeuvring Characteristics Power demand: fixed relation between ship speed and diesel engine power. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: turning the propeller pod. Control: hydraulic power pack for steering. Gearbox: standard. Rudder: no need. Power demand: every possible blade pitch has its own fixed relation to the effective power curve. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed or blade pitch. Astern: control of thrust direction via blade pitch. Control: hydraulic power pack. Gearbox: standard. Rudder: no need. Power demand: fixed relation between ship speed and diesel engine power. Clear dependence on hull resistance. Ship speed: adjusting diesel engine speed. Astern: turning the propeller pod. Control: hydraulic power pack for steering. Gearbox: standard. Rudder: no need.
Power demand: full electric propulsion, fixed relation between ship speed and electric motor. Clear dependence on hull resistance. Ship speed: adjusting motor speed (electrical). Astern: turning the pod or reversing the motor. Control: hydraulic power pack for steering. Gearbox: no need. Rudder: no need.
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Shaft Line and Gearbox Losses The brake power (PB) of the diesel engine will be transferred via a shaft line to the propeller flange. All power consumers in the shaft line will be counted as mechanical losses (ηm). The main loss will occur in the gearbox depending on how many gears and clutches are used and how many pumps are attached, where at the pumps will generate the main part of the losses.
ηm =
PD in (---) PB
(E- 6.1.1) PB = diesel engine brake Power PD = delivered Power ηm = mechanical efficiency
At the design point the following approximations can be used: ηm = 0.98
non reversible gearbox
ηm = 0.97
reversible gearbox
Information about the losses in the gearbox must be provided by the manufacturer. The diesel engine has to deal with two different kinds of mechanical losses: 1. Static friction loss (no oil film yet) 2. Dynamic friction loss (built up oil film) The dynamic friction losses in the shaft line bearings (<1%) can be neglected. If no gearbox is used, take an approximation of ηm = 0.99%. If the propeller shaft starts turning, the static friction has to be overcome (initial break-away torque) until lubrication has been established and dynamic friction only is in effect.
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6.2 Propeller 6.2.1 Propeller Geometry To understand the hydrodynamic action of a propeller it is essential to have a thorough understanding of basic propeller geometry and the corresponding definitions. Figure 6.2.1 shows what is meant by rake and skew of a propeller. The use of skew has been shown to be effective in reducing vibratory forces, hull pressure induced vibration and retarding cavitation development. With rake the stress in the blade can be controlled and slightly thinner blade sections can be used, which can be advantageous from blade hydrodynamic considerations.
Rotation
Rake
Skew
Hub
Diameter
Figure 6.2.1:
Scheme of propeller geometry (skew and rake)
Every propeller needs a hub to fix the blades and to place the control mechanism (CPP) for the blades. This results in different hub sizes for a FPP and a CPP (propeller) and is a characteristic difference between these two types. The hub size of a CPP is 10 to 15% larger (related to the diameter). See the figures in the overview section (6.1.2) also. Another difference is the blade area ratio (A/A0). Blade area ratio is simply the blade area, a defined form of the blade outline projection, divided by the propeller disc area (A0). As a controllable pitch propeller is usually fully reversible in the sense that its blades can pass through zero pitch condition care has to be taken that the blades do not interfere with each other. With equal number of blades a CPP can only realize a somewhat smaller area ratio than a FPP.
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The expression (P/D) is the commonly used pitch ratio. Alternatively the pitch angle θ can be given. With
D = 2R and x =
r (dimensionless radius) R
the characteristic pitch angle is defined at a propeller ratio of x=0.7. Unfortunately there are several pitch definitions and the distinction between them is of considerable importance to avoid analytical mistakes: 1. nose tail pitch 2. face pitch The nose–tail pitch line is today the most commonly used and referenced line. The face pitch line is basically a tangent to the section of the pressure side surface and used in older model test series (e.g. the Wageningen B Series). Although the difference is not big it can be the reason for using different values for the same propeller. The following equation can be used to convert the pitch from P/D to θ or vice versa.
P Θ = arc tan −1 D xπ
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6.2.2 Propeller Type Selection (FPP or CPP) The selection of a propeller for a particular application usually is a result of the consideration of different factors. These factors can be determined in pursuit of maximum efficiency with respect to:
• noise limitation • ease of manoeuvrability • cost of installation and so on. Each vessel has to be considered with regard to its own special application. The choice between a fixed pitch (FPP) and a controllable pitch propeller (CPP) has been a long contested debate between the proponents of the various systems. Controllable pitch propellers have gained complete dominance in Ro-Ro vessels, ferry and tug markets with vessels of over 1500 kW propulsion power with an operational profile that can be satisfied by a CPP better than by a two speed gearbox. For all other purposes the simpler fixed pitch propeller appears to be a satisfactory solution. Comparing the reliability between the mechanical complex CPP and the FPP shows, that the CPP has achieved the status of being a reliable component. The CPP has the advantage of permitting constant speed operation of the propeller. Although this leads to a loss in efficiency, it does readily allow the use of shaft driven generators, if this is a demand in the operational profile of the ship. During the last years the electric drive with podded propeller has been arising on the market. Without the need of a gearbox and controllability of the electric motor a fixed pitch propeller seems to be the best choice. But it must not be forgotten to compare the economical aspects of an extended motor control with the cost of a CPP.
Rudder
a
Propeller Clearance a ≥ 0.25D b ≥ 0.20D
D
b
Figure 6.2.2:
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Propeller clearance
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To determine the propeller diameter (D) for a certain delivered power (PD) at a propeller speed (n) and a ship speed (v) is a complex routine. For the Wageningen B-Series propellers there are some calculation procedures available, which can be found in the literature with all necessary assumptions that have to be made. The size of a propeller cannot only be calculated theoretically, but must also be adapted to the ship. The ship must provide the necessary space for the propeller including a sufficient clearance between propeller and hull (Figure 6.2.2). Due to hydrodynamic effects and/or cavitation the ship hull and the rudder can be mechanically excited, which can cause heavy vibrations at the stern or the rudder with the possibility of mechanical failures. The values shown in Figure 6.2.2 are only a design proposal. For more detailed information see the recommendations of a classification society. A few words to the effect of thrust breakdown. The power density of a propeller can only be increased to a certain limit, which depends on the propeller parameters and especially on the blade area ratio. Obviously the cavitation occurs first at the tip section of a blade and extends downward with higher power consumption. It is a matter of definition when these effects are called “thrust breakdown”, e.g. if the cavitation exceeds below the 0.5 radius.
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6.2.3 Direction of Propeller Rotation The direction of rotation can have consequences for manoeuvring and efficiency considerations. Although the given explanations in literature are not really convincing the following recommendations can be given: Single shaft: (looking from aft at propeller)
FPP (fixed pitch propeller) Direction of rotation:
clockwise
CPP (controllable pitch propeller) Direction of rotation:
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counter clockwise
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Twin shaft: (looking from aft at propeller)
FPP (fixed pitch propeller) Port side:
counter clockwise
Starboard:
clockwise
Starboard:
counter clockwise
CPP (controllable pitch propeller) Port side:
clockwise
For those who are still eager to hear a few words about the reasons for doing so, here are some explanations from literature. Propeller efficiency: It has been found that the rotation present in the wake field, due to the flow around the ship, at the propeller disc can lead to a gain in propeller efficiency when the direction of rotation of the propeller is opposite to the direction of rotation in the wake field. Manoeuvring (single screw): For a single screw ship the influence on manoeuvring is entirely determined by the “paddle wheel effect”. When the ship is stationary and the propeller is started, the propeller will move the afterbody of the ship in the direction of rotation. Thus with a TPG-General.doc Rev. 1.0
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fixed pitch propeller, this direction of initial motion will change with the direction of rotation, i.e. is ahead or astern thrust. In the case of a controllable pitch propeller the motion will tend to be unidirectional because only the pitch changes from the ahead to the astern position. The direction of rotation will not change. In the astern thrust position FPP and CPP will have the same direction of rotation and assuming that starboard is the main docking side there is an advantage to push off from the quay with astern thrust. Manoeuvring (twin screw): In addition to the paddle wheel effect other forces due to the pressure differential on the hull and shaft eccentricity come into effect. The pressure differential, due to reverse thrusts of the propellers on either side of the hull gives a lateral force and turning moment. From the manoeuvrability point of view it can be deduced from test results that the fixed pitch propellers are best when outward turning. For the controllable pitch propeller no such clear-cut conclusion exists. Although these effects are small, the design should follow the given recommendations but if the rules are not kept no great disadvantage arises.
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6.2.4 Selection of Propeller Blade Number Blade numbers generally range from two to seven. For merchant ships four, five or six blades are favoured, although many tugs and fishing vessels frequently use three bladed designs. In naval applications where the generated noise become important blade numbers of five and above predominate. The number of blades shall be primarily determined by the need to avoid harmful resonant frequencies of the ship structure and torsional machinery vibration frequencies. As blade number increases cavitation problems at the blade root can be enhanced, since the blade clearance becomes less. It is also found that propeller efficiency and optimum diameter increase as the number of blades decreases and to some extent, the propeller speed (n) will dependent on the blade number.
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6.3 Propeller Curve 6.3.1 Basics When a ship is being towed and is not fitted with a propeller, the required force is called resistance (R) and the necessary power to tow the ship at a certain speed (v) is: PE = R T ⋅ v
in (kW)
(E- 6.3.1) PE = effective Power RT = total resistance v = ship speed
Basis for the design of a propulsive device is the effective power (PE) curve for a ship, showing the relation between effective power and ship speed (v). The effective power curve will be evaluated by a test facility or estimated with respect to a defined condition, i.e. usually the trial condition:
• new ship, clean hull • sea state 0-1 (calm water), wind Beaufort 2-3 • load condition (defined, e.g. full load) • no current The load of the propulsive device to match the effective power is called delivered power (PD) and the relation between the effective and delivered power is called the propulsive efficiency (ηD).
ηD =
PE PD
in (---)
(E- 6.3.2) ηD = propulsive efficiency PE = effective Power PD = delivered Power
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The propulsive efficiency is the product of:
•
Propulsive unit efficiency in open water (η0) depending on type, size, speed, e.g. (at design point approx. η0 = 0.60 – 0.75).
•
Hull efficiency (ηH) depending on wake fraction and thrust deduction fraction (at design point approx. 0.90 – 1.10).
•
Relative rotational efficiency (ηR) depending on the propeller efficiency behind the ship and the propeller open water efficiency (at design point approx. 0.95 – 1.02).
ηD = η O ⋅ ηH ⋅ ηR
in (---)
(E- 6.3.3)
The effective power varies not only with ship speed (v). Environmental conditions (wind, sea state), hull roughness (clean, fouling) and actual load condition of the ship have to be taken into consideration (Figure 6.3.1).
Effective Power PE
effective pow er curve (in service)
pow er difference at const. Speed (v) ship speed difference at const. Pow er (PE)
effective pow er curve (clean hull)
Ship Speed (v)
Figure 6.3.1:
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Influence of change in resistance on effective power curve (example)
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Effective Power (PE)
Effective Power Curve
Ship Speed (v)
Propeller Design
Ship Speed (v)
Figure 6.3.2:
As Required
Delivered Power (P D )
Delivered Power (P D )
The result of the propeller design can be presented in a bunch of diagrams.
Propeller Speed (n)
user defined
As Required
From effective to delivered power curve (example)
On the basis of a defined effective power curve a propeller will be designed. The relation between delivered power (PD) and ship speed (v) or propeller speed (n) can be shown in single diagrams or a diagram using both ordinates. Figure 6.3.2. shows some examples. The diagram with the propeller speed (n) as abscissa has the advantage that the performance diagram of the diesel engine can be plotted in also.
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Every change in the effective power curve will be seen in the propeller curve also. The example in Figure 6.3.3 shows that due to the cubic characteristic of the propeller curve small changes can have great effects.
Delivered Power PD
propeller curve (in service)
pow er difference at const. Propeller Speed (n) propeller speed difference at const. Pow er (PD)
propeller curve (clean hull)
Propeller Speed (n)
Figure 6.3.3:
Effect of change in resistance on delivered power curve (example)
Although the curves in Figure 6.3.1 and Figure 6.3.3 are similar in shape they are different. The effective and the delivered power will be related by the propulsive efficiency (ηD). This means that the propeller curve is only valid for the designed propeller. Changing the geometry of the propeller (e.g. diameter, area ratio, pitch or the number of blades) leads to a new power-speed relation, i.e. a new propeller curve. If the effective power curve changes, e.g. from clean hull and fair weather to fouled hull and heavy weather the propeller curve will also change. That leads to the conclusion: A change in the propeller curve can be initiated by the ship (effective power) or by a modification of the propeller.
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FPP: The propeller curve has a fixed relation to the effective power curve and will be influenced by the ship (effective power) only. CPP: Every possible pitch has its own fixed relation to the effective power curve. This leads to a bunch of propeller curves (Figure 6.3.4). The propeller curve will be influenced by the ship (effective power) and the propeller pitch.
CPP (Controllable Pitch Propeller)
Delivered Power PD
design pitch
constant ship speed
pitch increases propeller curves = lines of constant pitch
Propeller Speed (n)
Figure 6.3.4:
Effect of different propeller pitches on delivered power (example)
This different behaviour will have distinct consequences on the design of the chosen propeller type.
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6.3.2
Propulsion, Interaction Engine with Application
Theoretical Propeller Curve Diameter (D), delivered power (PD) and shaft speed (n) of the propeller can be calculated by the propeller manufacturer when the effective power curve is given and the design speed (v) and the installed brake power (PB) have been chosen. Power and propeller speed (n) have to match the installed power of the diesel engine. If only the design point of the propeller or the diesel engine is known, a simple approximation can be done by a theoretical propeller curve. PD design PD = 3 n design P
PB design PB = 3 n design
⋅ n prop 3
3 ⋅ n
PD = delivered power nprop = propeller speed fixed propeller geometry
PB = diesel engine brake power n = diesel engine speed fixed propeller geometry
Diesel engine and propeller have a fixed relation via the propeller shaft and therefore the equation can be used for PB and PD as well. There will be differences to the real curve, depending on the hull form (see chapter 5 also) as the decisive factor, and taking into account that the propeller geometry is fixed. That means the approximation of a controllable pitch propeller is only valid for the design pitch. There is another restriction for the lower speed range. Below a certain speed (v) the wind forces can become dominant and the delivered power does not decrease any more.
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Something to remember: Cubical propeller curve, why n3 ? •
V = c ⋅ A = c ⋅ π ⋅ D2 4 c = π ⋅ n ⋅D
V = volume flow A =propeller disc area c = flow speed D = propeller diameter (constant for a given design)
This leads to : •
V ~ n ⋅ D3 ∆p = ρ ⋅ c 2 2 •
P = ∆p ⋅ V
Bernoulli equation (c1=0) p = pressure P = power
The result : P ~ n3 ⋅ D 5 or P ~ c3 ⋅ D2
TPG-General.doc Rev. 1.0
theoretical propeller curve power is proportional to n3 (propeller speed) power is proportional to v3 (ship speed)
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6.3.3 Estimating the Required Diesel Engine Power In some cases the required total diesel engine brake power (PB) for a ship has to be estimated in a very early stage of a project and only estimations of the effective power (PE) or the total Resistance (RT) are available. With Equation (E- 6.1.1), (E- 6.3.1) and (E- 6.3.2) a rough estimation for the required total diesel engine brake power (PB) at ship speed (v) can be done.
PB =
R T ⋅ v ⋅ 0.5144 ηD ⋅ η m
in (kW)
(E- 6.3.4)
or PB =
PE ηD ⋅ η m
in (kW)
(E- 6.3.5) PB = total diesel engine brake power in kW PE = effective Power in kW RT = total resistance at ship speed (v) in kN v = ship speed in knot (0.5144 used to convert knot to m/s) ηD = propulsive efficiency ηm = mechanical efficiency
At the design point the following approximation can be used for the efficiencies:
ηm = 0.97 ηD = 0.60 The result is the total diesel engine break power (PB) for the ship. This value must be distributed onto the desired number of diesel engines.
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6.4 Propeller and Performance Diagram 6.4.1 Driving Mode Power (PD) and propeller speed (n) have to match the installed power for the propulsion (PB). Only the sea trials show whether estimations are correct or not. At this stage of evaluation a diesel engine has been selected and a design point inside the performance diagram of the diesel engine has to be chosen. In addition to the hydrodynamic aspects (see Figure 6.3.2, Propeller Curve), manufacturing tolerances have to be taken into account. Manufacturing tolerance in pitch, surface and profile influence the power absorption of the propeller.
Brake Power PB in ( % ) Rated Power
Hull resistance can vary due to inevitable differences in load and shape.
100% = rated pow er 100% = rated speed
120
3
110 4
100
C B
2
A
5
MCR curve 1
propeller curve
1
90 80 MCR curve 2
70 60 80
85
90
95
100
105
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.1:
Change in delivered power due to weather, draught and fouling
Hydrodynamical and geometrical aspects (Figure 6.4.1) can shift the propeller curve (A) to the left side of the performance diagram (C). Certain models of diesel engines are more sensitive to this shifting than others. As a consequence, the ship may not be able to operate at full speed when the hull has fouled, the weather deteriorates or the draught has increased.
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In Figure 6.4.1 two diesel engines (MCR curves 1 and 2) from various manufacturers with different performance limits are shown. A change in the propeller curve from (A) to (C) leads to the following behaviour: A
The diesel engine can run with full speed (n). No limitation arises (point 1). But the propeller does not absorb the maximum available power.
B
The diesel engine can run with full speed (n) and reach its full power. No limitation arises (point 2).
C
Due to the load limits (MTU: fuel stop power) both diesel engines are not able to provide the required power for full speed (n) at point (3). In this case the diesel engines reduce their speed (n) in order to find a new operation point within the performance limits. For the diesel engine with MCR curve 1 this is point (4) and for the other diesel engine point (5). The differences between the two operating points (4) and (5) are the magnitude of reduction in ship speed (v) which can be considerably high.
Brake Power PB in (%) Total Rated Power
A similar behaviour is experienced in a two-shaft arrangement which has been switched over in a single shaft mode. Figure 6.4.2 shows the arrangement with diesel engines of the same type one per shaft. The output power has been added over the speed range (MCR curve 1) and the propeller curve running through point 1. Each diesel engine takes half the load of the required brake power (PB). 120 100 80
MCR curve 1 (2 diesel engines, one per shaft)
fixedpitch pitchpropeller fixed propeller
1
100% = rated pow er 100% 100%==rated ratedspeed pow er 100% t d d
60
tw o shaft propeller curve
single shaft propeller curve
40 MCR curve 2 (single shaft) 1 diesel engine
2
20 0 20
30
40
50
60
70
80
90
100
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.2:
Diesel engine failure in a two shaft arrangement
MCR curve 2 shows the available brake power (PB) of one diesel engine. If one diesel engine is shut down, the effective power of the ship relates to one propeller instead of two with the consequence of a new propeller curve (single shaft propeller curve). TPG-General.doc Rev. 1.0
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The running diesel engine has to find a new operating point on the single shaft propeller curve within its performance limits. In this example, point (2) is the new operating point for the diesel engine. The point marks also the maximum available brake power (PB) (and speed (n)) in the single shaft mode for this ship. In case that the diesel engine finds no operating point it will stall. This will also point out that with the chosen diesel engines the ship cannot be run in single shaft mode. In this case a CPP has to be selected. These are some reasons why the design point of the diesel engine should be carefully specified with respect to the load limits and the kind of propeller (FPP, CPP) that is to be used.
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6.4.2 Fixed Pitch Propeller (FPP) The design of a propulsion system with a fixed pitch propeller is absolutely critical to the performance of the ship. The brake power (PB) curve should pass through the maximum continuous rating of the diesel engine. But due to geometrical tolerances and deteriorated hydrodynamics, the propeller curve can be higher than predicted. This situation will be overcome by designing the propeller a few revolutions faster for the new ship. Dependent on the type of diesel engine two different approaches are possible.
Brake Power PB in ( % ) Rated Power
120
fixed pitch propeller
C
100% = rated pow er 100% = rated speed
110
4
100
propeller curve
design margin 3
B 2
A
MCR curve 1
90
design margin
80
70 80
85
90
95
100
105
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.3:
Choosing a design point for a fixed pitch propeller
MTU Procedure (wide lug-down range diesel characteristic): Point 2: Preferred/recommended design point for the propeller. The characteristic of a MTU diesel engine is the wide lug-down range above a certain speed (n) (fuel stop power). This range can be used as a design margin. In poor weather conditions or at increased hull resistance the propeller curve will move to the left. This means, at trial condition the diesel engine should work at the rightmost point of the MCR curve (point 2, trial effective power curve = propeller curve B), i.e. the design point for the propeller. With growing lifetime the propeller curve will move to the left (e.g. point 3, propeller curve C).
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The design allows the propeller to run at 100% rated power (PB) as long as the propeller curve does not pass point 4 (lugging point). The maximum ship speed (v) will decrease slowly with the left shifting of the propeller curve towards point 3. Standard procedure (usable for all type of diesel engines): Point 1: Preferred/recommended design point for the propeller. In the design point the propeller runs at 100% rated speed (n) and small amount (design margin) below 100% rated power. In this case at trial condition the diesel engine is effectively working at a derated condition (point 1, trial effective power curve = propeller curve A). In poorer weather or with growing lifetime the propeller curve will move to the left and the maximum power will be used (point 2, propeller curve B). The design allows the propeller to run at 100% rpm (rated speed) as long as the propeller curve does not pass point 2. The ship speed (v) will increase with the shifting of the propeller curve and reaches its maximum at point 2. Using this procedure the designer has to consider that it may be not possible to demonstrate the full speed (v) capability of the ship at trial conditions, because the speed (n) of the diesel engine is limited to 100% rated speed. The difference between 100% rated power and design power is called "sea margin" (= design margin). If there are no specific demands, a design margin of approx. 6 to 10% shall be used. The rated power will be met by propeller curve A at 102 to 103.5% rated speed but this is only theoretical. Summary: Both procedures or a mixture can be used for choosing the design point of a fixed pitch propeller and a flat rated diesel engine. If the application demands no specific propeller design point, the MTU recommendation shall be used (point 2 = primary design point for the propeller). No matter what design point is chosen the propeller curve runs on a fixed curve through the performance range of the diesel engine. So, a few additional aspects shall not be forgotten: If the delivered power curve through the design point does not pass through the region of minimum fuel consumption, no change will be possible afterwards. If the power curve comes too close to the diesel engine surge limits, the curve cannot be moved away from this region with the result of a blocked operation range.
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6.4.3 Controllable Pitch Propeller (CPP) The controllable pitch propeller can be seen as an extension to the fixed pitch propeller. Each pitch results in a new propeller curve. A typical example is shown in Figure 6.4.4 where the controllable pitch propeller characteristic is superimposed on a diesel engine characteristic.
Brake Power PB in ( % ) Rated Power
design pitch
100 80
controllable pitch propeller 100% = rated pow er 100% = rated speed
constant ship speed
60 MCR curve
40 20
pitch increases propeller curves = lines of constant pitch
0 20
40
60
80
100
Propeller rpm in ( % ) Rated Speed
Figure 6.4.4:
CPP characteristic in a typical diesel engine performance diagram
Every change in the pitch of the propeller changes the relation between propeller speed (n) and brake power (PB) for the ship. Due to possible later adjustment of the propeller pitch there are no restrictions for the design point within the diesel engines performance diagram. The point at 100% brake power (PB) and speed (n) should be chosen (Figure 6.4.5). The available pitch range is not fixed. It is a part of the customer’s specification for the propeller. On the manufacturer’s side it is limited by the size of the hub and the maximum blade forces. Generally the available pitch range will be related to the design pitch and be given in degrees. The range above the design pitch is very small because there is no general need, except in special applications.
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Brake Power PB in ( % ) Rated Power
6
110 100
Propulsion, Interaction Engine with Application
controllable pitch propeller propeller curve (design pitch)
100% = rated pow er 100% = rated speed
design point
MCR curve
90 80 70 60 80
85
90
95
100
105
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.5: Controllable pitch propeller design point The performance of a CPP at design pitch can be calculated like a FPP. When off design performance is needed use should not be made of fixed pitch characteristics beyond 5° from design pitch because the effect of section distortion affects the calculation considerably. The controllable pitch gives a lot of options: If the delivered power curve through the design point (design pitch) does not pass through the minimum fuel consumption region, it is possible to adjust the pitch at partial load conditions. If the power curve comes too close to the diesel engine MCR limit, the operating curve can be moved away from this region. If the ship during trials is not able to achieve the design brake power (PB) the design pitch can be corrected or when the ship resistance increases with service life, the design brake power (PB) and speed (n) will stay available. A CPP can be chosen with a fully reversible position and the ship can move astern without the need of a reversing gearbox. The stopping distance will be significantly lower than with a FPP. Generally the manoeuvring characteristics are better. A CPP can be chosen with a feathering position (minimum resistance), if a single shaft mode is part of the operational profile.
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But you have to pay for the advantages: The controllable pitch propeller is more expensive than a FPP. If the propeller will be set out of the design pitch the efficiency decreases. Additional space inside the ship has to be provided for the propeller control unit. Due to its internal mechanism the propeller has a bigger hub than a FPP (approx. 50%), this can lead to a somewhat higher diameter. If the propeller is fully reversible, care has to be taken that the blades will not interfere with each other when passing zero pitch. The upper blade area ratio will be limited. There is an additional aspect that should be mentioned. If the diesel engine has a very slender performance diagram, the design propeller curve will not lie inside the diagram for the lower power range. This type of diesel engine can be used only with a propeller controlled by a pitch – RPM relationship, frequently called “combinator diagram “. Only in the last third of the power range the propeller can run at design pitch. Another reason is the access to the region of minimum fuel consumption. In doing so the propeller can come very close to the diesel engine surge limits. A programmed “combinator diagram” could give the best overall performance as well. With an MTU diesel engine the propeller can run in “combinator mode”, however, this is not necessary due to the wide performance range of the diesel engine. Another application is a constant speed generator attached to the gearbox. The diesel engine runs at constant speed (n) feeding the generator and the ship speed (v) will be controlled by the propeller pitch. This is a standard design for merchant ships running most of their service time at high power rates.
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An example is supposed to clarify this behaviour. Figure 6.4.6 is similar to Figure 6.4.2 and shows what happens when in a two-shaft arrangement the diesel engines are switched over in single shaft mode. MCR curve 2 shows the available brake power (PB) of one diesel engine. The running diesel engine has to find a new operating point on the single shaft propeller curve within its performance limits. In this example, point (2) is the new operating point for the diesel engine. This point marks also the maximum available brake power (PB) and speed (n) in single shaft mode at design pitch for this ship. In order to use the installed break power of the running diesel engine the propeller pitch has to be reduced (point 3). On this propeller curve, full power of the diesel engine and maximum ship speed (v) in single shaft mode are attainable.
Brake Power PB in (%) Total Rated Power
120 MCR curve 1 (2 diesel engines, one per shaft)
CPP 100
100% = rated pow er 100% = rated speed
tw o shaft propeller curve design pitch
80
single shaft propeller curve design pitch
60
MCR curve 2 (single shaft) 1 diesel engine
40
1
3
2
20
single shaft propeller curve reduced pitch
0 20
30
40
50
60
70
80
90
100
110
Propeller rpm in ( % ) Rated Speed
Figure 6.4.6:
TPG-General.doc Rev. 1.0
Example: Single shaft operation with CPP
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In the next example (Figure 6.4.7) the pitch of a CPP will be controlled by combinator. A constant speed generator is attached to the gearbox and shall run above 50% diesel engine load. In the lower power range the propeller shall run on design pitch. The thick line in the performance diagram shows the power-speed-pitch relation of the propeller.
Brake Power PB in ( % ) Rated Power
In the lower power range until point 3 the CPP runs at design pitch. Between point 3 and point 2 the diesel engine speed will be raised with decreasing propeller pitch. The ship speed will not change significantly. At point 2 the operating speed (n) for the attached generator has been reached. Between point 2 and point 1 the diesel engine runs at constant speed (n) feeding the propeller and the generator. The ship speed (v) will be controlled by the propeller pitch.
100 80
constant ship speed
CPP
1
design pitch
100% = rated pow er 100% = rated speed
Generator operating range
MCR curve
60 pitch increases
40
2 3
20 propeller curves = lines of constant pitch
0 40
60
80
100
120
Propeller rpm in ( % ) Rated Speed
Figure 6.4.7:
TPG-General.doc Rev. 1.0
Example: Constant speed generator in operation with CPP
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6.5 Waterjet and Performance Diagram 6.5.1 Geometry and Design Point The main application for a waterjet is in the higher speed range, let’s say above 20 kn. The propulsive efficiency of a waterjet decreases considerably with speed (v) reduction. Below 20 to 24 kn a propeller should be preferred. A waterjet is like a propeller a hydrodynamical propulsive device but is arranged inside the ship and behaves more like a pump than as a propeller. Pump
Nozzle
Inlet Shaft
Height above water line
Cross section Stator
Impeller
Inlet duct
Ship hull
V = Ship speed
7
8 10
Effective inlet velocity
11
9
5
6
1
4
1. 2. 3. 4. 5. 6.
Inlet duct Impeller Stator bowl Nozzle Shaft Sealing box
Figure 6.5.1:
TPG-General.doc Rev. 1.0
3
2
7. Thrust bearing 8. Steering deflector 9. Hydraulic steering cylinder 10. Hydraulic bucket cylinder 11. Inspection opening
Waterjet
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The main differences between a waterjet and a propeller are: The propeller is very sensitive to the velocity and direction of the local incoming flow. It senses the ship in its hydrodynamical situation (sea state, wind, draught, etc.), so does the diesel engine. The waterjet works more like a pump as long as there is any water in the intake duct and turns the brake power (PB) into thrust. There is only a minor feed back from ship. For this reasons the diesel engine has minor load cycles when it is connected to a waterjet.
120
Waterjet 100% = rated pow er 100% = rated speed
Brake Power PB in ( % ) Rated Power
100
propeller curve
design points 2
1
80
60 MCR curve
40
20
constant fuel consumption
0 30
50
70
90
110
Impeller Speed in ( % ) Rated Speed
Figure 6.5.2:
Waterjet design point (Diagram has limited use for waterjet design)
Due to the insensibility to the ship resistance (effective power curve) there are no restrictions for a design point within the diesel engine performance diagram. But the waterjet is like the propeller a mechanical device and manufacturing tolerances have also to be taken into account.
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This relation can lead to the fact that at 100% shaft speed (n) the waterjet cannot absorb the diesel engines brake power (PB). Therefore a design point at brake power and approx. 1 - 2% below 100% diesel engine shaft speed (n) (design margin) shall be chosen (Figure 6.5.2, design point 1). If the propeller curve shifts to the left the ship speed (v) will decrease but no change will be seen in Figure 6.5.2 because the waterjet is still running with its demanded speed (n) and brake power (PB). That is the reason why this diagram has a limited use for choosing a waterjet design point. It will only give an impression about the relation between the propeller curve, the lines of constant fuel consumption, the design margin and the margin to the diesel engine MCR limit curve. This relations will remain independent of the ship load as before. With this behaviour in mind design point 2 (Figure 6.5.2) can be chosen also. The leftmost design shaft speed (n) should be 1.5% above the speed (n) of the lugging point. The advantage is a less fuel consumption but the margin to the MCR curve (acceleration reserve) decreases. Because this behaviour is very fundamental a further example shall be given.
Figure 6.5.3:
Platform with pump
Imagine a platform on wheels with a water tank and a pump on its loading area (Figure 6.5.3 ). The water will be ejected horizontally in the air opposite to the direction of motion. The platform will start to move on the ground and no matter how fast the platform will move, the pump will always eject the same amount of water using the same power. This is true also if an obstacle stops the platform. The pump will not be affected by the behaviour of the platform. In other words the generated thrust depends only on the amount of ejected water. Although this is simplified, it shows the fundamental difference between a propeller and a waterjet. Let us take a step ahead. Even if there are two separated pumps on the loading area, they will not interfere which each other, independent whether they are or not of equal size or running at different power pumping different amounts of water.
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For this reasons another diagram has to be used which shows more consideration to the behaviour of a waterjet (Figure 6.5.4).
140
Waterjet
fuel stop pow er
Thrust in ( % ) Rated Thrust
120 design point
100 80 60 cavitation inception limit
constant brake pow er
40 20
propeller curve
0 0
20
40
60
80
100
Ship Speed in ( % ) Rated Speed
Figure 6.5.4:
Waterjet performance diagram
The figure shows the design propeller curve together with the waterjet performance diagram and instead of effective power the thrust is used. Because the ship speed (v) and the engine speed (n) of the diesel are not related to each other the performance diagram of the diesel engine can not be represented in the figure. A few words to the shown cavitation inception line: These lines are specific to the chosen waterjet and should not be compared between different manufacturers. For instance, KaMeWa divides its diagrams by two lines into three zones, showing different stages of cavitation. Generally these lines shall no be taken as absolute limits but as design guidelines. If the propeller curve shifts to the left the ship speed (v) will decrease and the distance to the cavitation inception limit will be reduced. The reason for this behaviour is that the stagnation pressure in the inlet duct goes down and the waterjet starts to suck the water through the duct. The thrust of a waterjet is the product of water mass flow and the speed of the ejected water. That means that a certain thrust can be generated by a smaller or a bigger waterjet. In the smaller one the speed of water is higher i.e. the distance between the design point and the cavitation inception line is smaller also. If there is limited space for installation or the operation time of the waterjet is short the designer will probably choose a small waterjet with a lesser distance to the cavitation area.
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The risk of getting air into the inlet duct of the waterjet depends on the specific arrangement in the ship and on the sea state. In this case the control system has to protect the diesel engine from any overspeed and due to the low inertial mass of the shaft line it is more demanding than for a propeller. The matching MTU control system has been adapted for this task.
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6.5.2 Estimation of Size and Shaft Speed The design shaft speed (n) of the waterjet depends on type, size and application and will be provided by the manufacturer. If the installed brake power (PB) and the ship design speed (n) are known Figure 6.5.5 and Figure 6.5.6 can be used for a quick look. 0.5
Ship Speed in (kn)
50
1.0
1.2
1.4 m (size inlet duct)
40 2.0
30 2.4
20
10 0
5000
10000
15000
20000
Brake Power in (kW)
Figure 6.5.5:
Estimating the size of a waterjet (inlet duct diameter)
Water Jet Speed in (min-1)
1000
Brake Pow er 500 kW 1000 kW 2000 kW 5000 kW 10000 kW 20000 kW
800 600 400
20000 kW
200 500 kW
0 0,5
1,0
1,5
2,0
2,5
Inlet Duct in (m)
Figure 6.5.6:
TPG-General.doc Rev. 1.0
Estimating the design impeller speed of a waterjet
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6.6 Fuel Consumption 6.6.1 General Assumptions The calculation of the fuel consumption for the diesel engines depends on a lot of assumptions. If the fuel calculation for a designed ship will be done by different people you will get different results, if you do not have a good specification. Nevertheless the size of the fuel storage tanks is an important impact on the ship design. The following values are required for calculation of the fuel consumption: (ref to chapter 6.6.6 for more detailed information) 1
Status and displacement of the ship (e.g. new ship, clean hull, full load)
2
Weather condition and sea state (e.g. wind Beaufort 2, sea state 2-3).
3
Ambient condition
4
Speed-power (ship speed (v) - brake power (PB)) diagram for assumed displacement, weather condition and sea state.
5
Propulsion plant and design condition (e.g. total installed brake power (PB) for propulsion, ship speed (v), propeller shaft speed (n), number of diesel engines per shaft).
6
Performance diagram of the diesel engine including the lines of specific fuel consumption for the required lower heating value (Hu), otherwise the values have to be corrected.
7
Lower heating value of fuel (e.g. Hu = 42800 kJ/kg for diesel oil).
8
Fuel density (e.g. ρfuel=830 kg/m3).
9
Gear ratio if a gearbox is used (for the relation between propeller shaft speed and diesel engine speed).
10
Fuel consumption of the diesel generator set running with a defined percentage of the installed mechanical power (e.g. all sets at 33%).
11
Usable volume of the fuel storage tank (e.g. 95%).
12
Operating profile (e.g. cruising speed (v) or speed profile).
It is obvious that an incomplete specification of these values can lead to calculation differences.
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The standard questions that arise in connection with fuel consumption are: 1.
Fuel consumption at design condition.
2.
The ship should run XXX sm on YY kn e.g. 1000sm on 12kn. The required fuel volume can be a design value for the necessary fuel storage volume.
3.
How long can the ship stay at sea for a given operating profile or the ship shall stay ZZ days at sea with a given mission profile. The required fuel volume can be a design value for the necessary fuel storage volume.
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6.6.2 Operating Profile The time between leaving and entering a port can be divided into several portions of time at constant speed ranges. Such list of time periods and speed ranges is called operating profile. Each ship has a characteristic operating profile which is determined by the owner to meet the commercial needs of the particular service. The result is a wide difference between the operating profiles of various ship types, e.g. a freighter, a fast ferry and a OPV, and one of the reasons why the design basis for a particular vessel must be chosen with care. Nevertheless an operating profile can change throughout the life of a ship, depending on a variety of circumstances. The operating profiles shown in Figure 6.6.1 and Figure 6.6.2 are very raw and shall only give an impression how such profiles can look like. Both operating profiles are equal. They are shown in different style for those who are not familiar with one of the presentations.
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Speed in (%) Rated Speed
Example:
Propulsion, Interaction Engine with Application
Freighter: Leaving the port and then running continuously at design speed.
100 80 60 40 20
Freighter
0 0
20
40
60
80
100
Time in (%) Operating Time
Speed in (%) Rated Speed
Example:
Ferry: Nearly the same as a freighter but when operating between islands there are often speed restrictions.
100 80 60 40 20
Fast Ferry
0 0
20
40
60
80
100
Time in (%) Operating Time
Speed in (%) Rated Speed
Example:
OPV: The shown tasks are at loitering speed (maybe embargo control), cruising speed (cruising in formation) and fast manoeuvring.
100 80 60 40 20
Offshore Patrol Vessel
0 0
20
40
60
80
100
Time in (%) Operating Time
Figure 6.6.1:
TPG-General.doc Rev. 1.0
Examples of operating profiles (freighter, fast ferry, OPV)
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Speed in (%) Rated Speed
Example:
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Freighter: Leaving the port and then running continuously at design speed.
100 Freighter
80 60 40 20 0
10
5
10
75
Time in (%) Operating Time
Time in (%) Operating Time
Example:
Ferry: Nearly the same as a freighter but when operating between islands there are often speed restrictions.
60
Fast Ferry 40
20
0 0 - 25
25 - 50
50 - 70
70 - 85
85 - 100
Speed Range in (%) Rated Speed
Time in (%) Operating Time
Example:
OPV: The shown tasks are at loitering speed (maybe embargo control), cruising speed (cruising in formation) and fast manoeuvring.
60
Offshore Patrol Vessel 40
20
0 0 - 25 25 - 40 40 - 70 70 - 85 85 - 95
>95
Speed Range in (%) Rated Speed
Figure 6.6.2:
TPG-General.doc Rev. 1.0
Examples of operating profiles (freighter, fast ferry, OPV)
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The owner should specify the operating profile, the operating hours per year and the number of missions per year. A mission is the time period needed to run one operating profile. In the design phase this specification can be used to calculate the fuel consumption for different propulsion alternatives, the TBO and as a first guess for the life cycle cost. Example of a user defined operating profile for a ship in tabulated form: Operating Profile (Ship) Ship Speed (kn) Time Period (%) 0–9
15
9 - 15
35
15 - 21
40
21 – max.
10
Generally, speed ranges will be shown in a operating profile, but for the calculation of the fuel consumption precise speed values have to be given, otherwise the results are not comparable. From that follows the brake power of the diesel engine e.g. at the upper bound of the given speed ranges. Example: Owner defined operating profile for a diesel engine:
Brake Power (%)
Time Period (%)
3
15
18
35
74
40
100
10
100
Brake Power in (%)
Operating Profile (Diesel Engine)
80 60 40 20 0 0
20
40
60
80
100
Time in (%) Operating Time
On the basis of such a operating profile the available TBO for the chosen diesel engine rating can be calculated.
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Alternatively, if the owner has not the experience to prepare a operating profile, the fuel consumption can be calculated on the basis of the standard load profile of the chosen diesel engine rating (e.g. 1A ,1B or 1DS). More information about “load profile” and TBO see chapter 2 and 3. Example: 1DS diesel engine rating (TBO 9000h)
Brake Power (%)
Time Period (%)
10
20
70
70
100
10
100
Brake Power in (%)
Operating Profile (Diesel Engine)
80 60 40 20 0 0
20
40
60
80
100
Time in (%) Operating Time
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6.6.3 Fuel Consumption at Design Condition With the provided information (see section 6.6.1) the fuel consumption at a given brake power (PB) and diesel engine speed (n) can be calculated. If no tolerances are given in the fuel consumption diagram, a margin of 5% has to be added to the calculated value.
B=
PB ⋅ be ρfuel
in (m3/h)
(E- 6.6.1) be = specific fuel consumption (kg/kWh) B = fuel consumption (m3/h) PB = diesel engine brake power (kW) ρfuel = fuel density (kg/m3)
Additional consumers, e.g. gensets have to be added to calculate the entire fuel consumption. If only the electrical power in kW is known for the genset use an estimation for the generator efficiency (e.g. 95%). B = B propulsion + B gensets + B auxiliary
in (m3/h)
(E- 6.6.2)
B = fuel consumption (m3/h)
The equation can be used for any other brake power (PB) and speed (n) in the performance diagram. If the consumption has to be calculated for the time periods of a operating profile the following equation can be used.
B=
(P
B1
⋅ b e 1 ⋅ t 1 + ....... + PB n ⋅ b e n ⋅ t n
)
100 ⋅ ρ fuel
in (m3/h)
(E- 6.6.3)
be = specific fuel consumption (kg/kWh) t1 = first period of time in a operating profile (%) tn = last period of time in a operating profile (%) B = fuel consumption (m3/h) PB = diesel engine brake power (kW) ρfuel = fuel density (kg/m3)
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6.6.4 Cruising Range To calculate the theoretical cruising range for a given fuel volume the following equation can be used.
scr =
Vfuel ⋅ v cr B
(E- 6.6.4)
in (sm) scr = theoretical cruising range (sm) vcr = constant cruising speed (kn) B = entire fuel consumption (m3/h) Vfuel= available fuel volume (m3)
If the fuel consumption for a given theoretical cruising range shall be used as a design value for the necessary fuel storage volume, use the following equations.
t cr =
s cr v cr
in (h)
(E- 6.6.5) scr = theoretical cruising range (sm) tcr = theoretical cruising time (h) vcr = constant cruising speed (kn)
B = B propulsion + B gensets + B auxiliary
in (m3/h)
(E- 6.6.6)
B = entire fuel consumption at vcr (m3/h)
Vfuel = B ⋅ t cr
in (m3)
(E- 6.6.7) tcr = theoretical cruising time (h) B = entire fuel consumption (m3/h) Vfuel= necessary fuel volume for cruising range (m3)
The fuel tank capacity has to be assumed 5% larger, because the usable volume of a tank will be only approx. 95%.
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6.6.5 Endurance at Sea This question is the same as under section 6.6.4 extended by an operating profile. To calculate the endurance time at sea for a given fuel volume and operating profile the following equation can be used.
t end =
PB 1
100 ⋅ Vfuel ⋅ ρ fuel in (h) ⋅ b e 1 ⋅ t 1 + ....... + PB n ⋅ b e n ⋅ t n
(E- 6.6.8)
be = specific fuel consumption (kg/kWh) tend = theoretical endurance for an operating profile (h) t1 = first period of time in an operating profile (%) tn = last period of time in an operating profile (%) PB = diesel engine brake power (kW) Vfuel= available fuel volume (m3) ρfuel = fuel density (kg/m3)
The background is to calculate how long the ship can stay in duty without replenishing or going back to the harbour and with enough fuel left in the storage tanks for reserve.
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6.6.6 Calculating Examples 6.6.6.1 Example Data (Series 2000) Basing on some exemplary data the fuel consumption shall be calculated. The available data are: S t e p
Call for
Exemplary Data
1 Status of the ship
new ship, clean hull, full load
2 Weather condition and sea state
wind Beaufort 2-3, sea state 0-1, no current (trial condition)
3 Ambient condition
Intake air = 45°C, Raw water = 32°C
ship for the chosen displacement, weather condition and sea state as diagram or in tabulated form
1400
Brake Power PB per Ship in (kW)
1200
Annotation: The ship speed (v) – brake power (PB) data can be represented in a lot of different diagrams. The one shown is only one representation of that bunch.
750
Design Point: PB...: 990 (kW) v.....: 27.5 (kn)
⇒ 650
1000
550
⇐ 800
450 Shaft Speed
600
350
400
250
Propeller Shaft Speed in (rpm)
4 Speed (v) – brake power (PB) data of the
⇑ 200
150 Brake Pow er
0
50
6
10
14
18
22
26
30
Ship Speed in (kn)
In tabulated form:
5 Propulsion plant and design condition
TPG-General.doc Rev. 1.0
Ship Speed (v) (kn)
Propeller Speed (nprop) (rpm)
Ship Brake Power (PB) (kW)
10
270
85
24
590
690
>27.5
670
990
Ship design condition: PB = 990 kW per ship, v = 27.5 kn, propeller shaft speed n = 670 rpm The ship is powered by a single diesel engine (design point: PB=1007 kW, n=2300 rpm, 1.5% power reduction due to ambient condition).
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S t e p
Propulsion, Interaction Engine with Application
Call for
Exemplary Data
6 Performance diagram of the diesel engine including the lines of specific fuel consumption
kW 1100 218 1000
900
800
Annotation: The diagram must be referenced to the chosen design conditions. Application group: e.g. 1DS Reference condition: ambient condition and typical intake/exhaust losses. Specific fuel consumption: Lower heating value Hu = 42800 kJ/kg
206
700
202 210
600
500
206 400
210 220
198
300
240 200
202 206 210
100
220
280 240 280 II
I
0 500
800
1000
1200
1400
1600
1800
2000
2200
2400
Power reduction: subtract 1.5% for ambient condition Specific fuel consumption: add 1.5% for ambient condition and 5% for tolerance
7 Lower heating value of fuel
Hu = 42800 kJ/kg
8 Fuel density
ρfuel= 830 kg/m3
9 Gearbox ratio
i = 3.473 = ndiesel / npropeller (e.g. ZF 1960)
10 Fuel consumption of the diesel generator
2 gensets (diesel engine e.g. 6R183T52), generated electric power P = 245kW, n = 1800rpm, be = 0.225 kg/kWh at 50% power, ηGen= 0.942 (includes 2% increased fuel consumption due to ambient condition and 5% tolerance)
11 Usable volume of the fuel storage tank
95%
12 Operating profile
Fuel Tank capacity: 5 m3 No user defined service time. =>Estimated annual usage: 500h =>MTU load profile (1DS) will be used.
sets (one genset running at 50% power)
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Ship Speed (v) (kn)
Time Period (t) (%)
10
20
24
70
27.5
10
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The following examples show some applications on fuel consumption calculation: 6.6.6.2 6.6.6.3 6.6.6.4 6.6.6.5 6.6.6.6
Fuel consumption at design condition Fuel tank volume for a range of 500sm at 18kn Theoretical cruising range at 12kn and a fuel tank volume of 5m3 Annual fuel consumption for an operating profile Correcting the lower heating value
6.6.6.2 Fuel consumption at design condition Main diesel engine: Use equation (E- 6.6.1) PB = 990 kW
(table row step 5)
be = 0.218 kg/kWh
(table row step 6)
add 1.5% for ambient condition and 5% for tolerance be = 0.218 kg/kWh + 1.5% + 5% = 0.232 kg/kWh ρfuel = 830 kg/m3
Bpropulsion =
990 ⋅ 0.224 = 0.277 830
(table row step 8)
(m3/h) per main diesel engine
Genset diesel engine: Use equation (E- 6.6.1) Pmechnical = Pelectrical /ηGen = 125 kW/0.942 Pmechnical = 133kW
(table row step 10)
be = 0.225 kg/kWh
(table row step 10)
(value includes tolerance and ambient condition) ρfuel = 830 kg/m3
B genset =
133 ⋅ 0.225 = 0.0361 830
(table row step 8)
(m3/h) per genset diesel engine
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.277 + 1 ⋅ 0.0361 = 0.313
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6.6.6.3 Fuel tank volume for a range of 500sm at 18kn scr = 500 sm vcr = 18 kn PB = 390 kW per ship and diesel engine
(table row step 4)
npropeller = 470 rpm (propeller shaft speed)
(table row step 4)
ndiesel = 1632 rpm (main diesel engine speed)
(table row step 9)
be = 0.202 kg/kWh + 1.5% + 5% = 0.215 kg/kWh
(table row step 6)
The fuel consumption can be calculated as in example (1). Bpropulsion =
390 ⋅ 0.215 = 0.101 830
B genset = 0.0361
(m3/h) per main diesel engine
(m3/h) per genset diesel engine
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.101 + 1 ⋅ 0.0361 = 0.137
(m3/h)
Theoretical cruising time: Use equation (E- 6.6.5)
t cr =
500 = 27 .8 18
(h)
Fuel volume for the cruising range: Use equation (E- 6.6.7) Vfuel = 0.137 ⋅ 27.8 = 3.8
(m3)
Required fuel tank volume:
Vtan k =
TPG-General.doc Rev. 1.0
3 .8 = 4 .0 0.95
(m3)
(table row step 11)
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6.6.6.4 Theoretical cruising range at 12kn and fuel tank volume of 5m3 Vtank = 5 m3 Vfuel = Vtank ⋅ 0.95 = 4.75 m3
(table row step11)
vcr = 12 kn PB = 145 kW per ship and diesel engine
(table row step 4)
npropeller = 330 rpm (propeller shaft speed)
(table row step 4)
ndiesel = 1146 rpm (main diesel engine speed)
(table row step 9)
be = 0.208 kg/kWh + 1.5% + 5% = 0.222 kg/kWh
(table row step 6)
The fuel consumption can be calculated as in example (1). Bpropulsion =
145 ⋅ 0.222 = 0.039 830
B genset = 0.0361
(m3/h) per main diesel engine
(m3/h) per genset diesel engine
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.039 + 1 ⋅ 0.0361 = 0.075
(m3/h)
Theoretical cruising range: Use equation (E- 6.6.4)
scr =
TPG-General.doc Rev. 1.0
4.75 ⋅ 12 = 760 0.075
(sm)
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6.6.6.5 Annual fuel consumption for an operating profile Operating profile: (table row step 12) Ship Speed (v) (kn)
Time Period (t) (%)
10
20
24
70
27.5
10
Data per ship: (table row step 4 and 9) Ship Speed (v) Propeller Speed (kn) (rpm)
Ship Brake Power (kW)
Diesel Speed (rpm)
10
270
85
938
24
590
690
2049
27.5
670
990
2300
Data per diesel engine: (table row step 4) Ship Speed (v) (kn)
Diesel Speed (n) (rpm)
Diesel Power (PB) (kW)
be (raw) (kg/kWh)
be (corrected) (kg/kWh)
10
938
85
220
0.234
24
2049
690
203
0.216
27.5
2300
990
218
0.232
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Fuel consumption: Use equation (E- 6.6.3) B=
(P
B1
⋅ b e 1 ⋅ t 1 + ....... + PB n ⋅ b e n ⋅ t n 100 ⋅ ρ fuel
)
in (m3/h)
Ship Speed (v) (kn)
Ship Brake Power PB (kW)
be (kg/kWh)
Time Period (t) (%)
B (m3/h)
10
85
0.234
20
0.0048
24
690
0.216
70
0.1257
27.5
990
0.232
10
0.0277
Sum
0.1582
The overall fuel consumption (main diesel engine and 1 genset): Use equation (E- 6.6.2) B = 1 ⋅ 0.1582 + 1 ⋅ 0.0361 = 0.1943
(m3/h)
The annual fuel consumption based on an estimated usage of 500 h: Use equation (E- 6.6.7) Vfuel = 0.1943 ⋅ 500 = 97.2
(table row step 12)
(m3)
6.6.6.6 Correcting the lower heating value If the lower heating value of the given specific fuel does not match the required value the data have to be corrected. Use the following procedure:
be, required = be, given
TPG-General.doc Rev. 1.0
Hu, required Hu, given
in (kg/kWh)
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6.7
Propulsion, Interaction Engine with Application
Generator Drive Electrical power supplies on ships is a question of three-phase mains. Following rules are to be considered at the design/dimensioning of the diesel engines for the generator drive: Diesel Engine Speed (n):
n=
f ⋅ 60 p
in (rpm)
(E- 6.7.1) f = shipboard power supply frequency in Hz n = diesel engine speed in rpm p = number of pole pair
Example: Shipboard power supply frequency
f = 60 Hz
Generator
p = 4 pole = 2 pole pair
n=
60 ⋅ 60 = 1800 4
(rpm)
Diesel Engine Brake Power (PB): P = B
Pp ⋅ cos ϕ η Gen
in (kW)
(E- 6.7.2) PB = engine brake power in kW PS = generator apparent power in kVA cos ϕ = generator power factor (e.g. 0.8) ηGen = generator efficiency (0.94; above 1800 kW 0.95)
Pp = Ps ⋅ cos ϕ
in (kW)
(E- 6.7.3) Pp = generator active power in kW PS = generator apparent power in kVA cos ϕ = generator power factor (e.g. 0.8)
Pp P = B η Gen
in (kW)
(E- 6.7.4) Pp = generator active power in kW PB = engine brake power in kW ηGen = generator efficiency (0.94; above 1800 kW 0.95)
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Figure 6.7.1:
Propulsion, Interaction Engine with Application
Power definition
Example: Necessary electrical shipboard power is PSBP = 1600 kW For instance: Power partition onto two genset
: z=2
Load of the genset each 85%
: x = 0.85
Max. electrical power per genset: Pp =
PSBP 1600 = = 941 z ⋅ x 2 ⋅ 0.85
(kW)
Necessary diesel engine power per genset: Use Equation (E- 6.7.4)
η= 0,94 PB =
Pp η
=
941 = 1001 0.94
(kW)
Generator apparent power: Use Equation (E- 6.7.2) PS =
PB ⋅ η 1001 ⋅ 0.94 = = 1176 cos ϕ 0 .8
(kVA)
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Application and Installation Guidelines
APPLICATION AND INSTALLATION GUIDELINES During the arrangement of the engines in the engine room specific distance between the engines or to the bulkhead/shell must be kept for the service of the engines and for maintenance operations.
Figure 6.7.1:
7.1
Engine room arrangement, minimum distance
Foundation ( under preparation )
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7.2
Application and Installation Guidelines
Engine/Gearbox Arrangements A general distinction is made between certain basic drive arrangements, i.e. the way in which engine and drive line disposed in the vessel.
7.2.1 Engine with Flange-Mounted Gearbox (F-Drive) This arrangement is shown in Figure 7.2.1. Engine with torsionally resilient coupling and gearbox form a single unit. The gearbox is connected to the engine by means of a bell housing, which also accommodates the coupling.
Figure 7.2.1:
Engine with flange-mounted gearbox
1 Engine 2 Torsionally resilient coupling 3 Gearbox This drive arrangement with flange-mounted gearbox is possible only with some specific engines. The advantages inherent to this arrangement are as follows:
• The flange-mounted configuration is the most compact of all drive arrangements. Another advantage in addition to compactness is the comparatively low overall weight of the propulsion plant.
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Application and Installation Guidelines
• Time-saving alignment of the propulsion unit in the vessel, because only one operation is necessary, namely aligning the propulsion plant with the propeller shaft. The engine and gearbox are already aligned and do not have to be realigned unless they have been separated for repair or servicing and the gearbox has to be re-mated to the engine. As a rule, a foundation with a total of only four supports suffices for this plant. Of these supports two are required for the engine mounts and two for the gearbox mounts.
7.2.2 Engine with Free-Standing Gearbox, V Drive Inclusive Engine with free-standing gearbox (D-Drive): For this arrangement, shown in Figure 7.2.2 , with free-standing gearbox, the engine combined with torsionally resilient coupling forms one unit, the free-standing gearbox being another.
Figure 7.2.2: 1 2 3 4
Engine Torsionally resilient coupling Coupling to compensate relative displacement (offset compensating coupling) Gearbox
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Engine with free-standing gearbox
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Application and Installation Guidelines
The points of relevance as regards this arrangement are as follows:
• An arrangement with engine and free-standing gearbox is preferable when a flangemounted gearbox is either not desirable or, due to the engine size, is not possible for technical reasons. • One advantage of the arrangement with separate engine and gearbox is the leeway it affords for enhanced requirements regarding structure-borne noise and/or resistance to shock loading. • Given the dimensions and weights of the subassemblies - engine and gearbox being subassemblies in this case - installation and removal can be less complex than in the case of the engine with flange-mounted gearbox, because the subassemblies are handled separately. • If the specification calls for a controllable-pitch propeller (CPP), the O.D. box for pitch control can be mounted on the gearbox output shaft in immediate proximity to the gearbox. • An engine with free-standing gearbox is heavier and requires slightly more space than the configuration with flange-mounted gearbox.
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Engine with free-standing gearbox and universal shaft, V drive arrangement: This arrangement is shown in Figure 7.2.3. The ,,V drive“, as it is sometimes named, consists of the engine and engine-mounted bearing housing and a separate gearbox. The bearing housing accommodates the torsionally resilient coupling. Engine power is transmitted from the coupling to the gearbox by a universal shaft.
Figure 7.2.3: 1 2 3 4
Engine with free-standing gearbox and universal shaft, V drive arrangement
Engine Torsionally resilient coupling with engine-mounted bearing housing Universal shaft Gearbox
This engine and gearbox configuration permits the propulsion plant to be installed either at the stern or near the stern of the vessel, if this arrangement is preferable with respect to hull design.
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7.3 Generator Set Arrangement 7.3.1 Engine with Free-Standing Generator
Figure 7.3.1: 1 2 3 4
Engine Generator Base frame Resilient elements
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7.3.2 Engine with Flange-Mounted Generator
Figure 7.3.2: 1 2 3 4 5
Engine Generator Intermediate mass Resilient elements, upper Resilient elements
TPG-General.doc Rev. 1.0
Engine with flange-mounted generator
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Application and Installation Guidelines
7.4 System Interfaces and System Integration 7.4.1 Flexible Connections All pipes from and to the propulsion unit must be fitted with flexible connecting elements. These flexible connecting elements are usually included in the MTU scope of supply and their purpose is to compensate for relative motions between the propulsion plant and the on-board piping systems. If the hoses, bellows or rubber sleeves are not supplied by MTU, they must satisfy the minimum requirements for plant operation. If doubt arises, customers should consult MTU to ascertain the displacements occurring at the interfaces due to movements of the resilient mounts and thermally induced expansion. The invariable rule is that all flexible connecting elements must be connected directly with the on-engine or on-gearbox interfaces. Notes on installation The installation characteristics such as
• • • •
dimensions, permissible operating-pressure range, minimum bending radius and resistance to medium
for the hoses, bellows and rubber sleeves are stated in the corresponding installation drawing. The part numbers are stated in the system schematics, for example for the fuel and coolant systems. If welding is performed on the on-board piping system, it is important to ensure that no hoses, rubber bellows or rubber sleeves are installed in the line, as they could be damaged by the welding operations. If already installed, these elements must be removed for the duration of the welding operations and stored where they are safe from damage such as could be caused by weld spatter, e.g. General notes on system routing
• Hoses must be installed such that they are not subjected to tensile or compressive loads in operation. • Hoses should follow the contour of the foundation as closely as allowed by the specified minimum bending radii. • Multiple hoses should always be routed together and kept parallel. • Suitable fittings (e.g. pipe elbows) can be used to avoid additional stresses and strains on the hoses.
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Application and Installation Guidelines
• When installing hoses, care must be taken to ensure that the hoses are not twisted. • For a curved run, the length of the hose must be such that the curve does not commence less than approx. 1.5*d from the fitting. • Flexible connecting elements should be arranged and/or secured in such a way as to prevent exposure to external mechanical influences, for example rubbing. • The attachments use to secure hoses must be of correct size for the hose diameters. • Hose attachments should not be used at points where they would impede the natural freedom of motion of the hose. • High ambient temperatures significantly reduce the durability of flexible connecting elements and may even lead to the failure of the component. Always ensure adequate clearance from components that radiate heat, or provide suitable heat shielding. These notes on routing hoses, of course, apply by analogy to all other flexible connecting elements. MTU propulsion plants are designed normally such that all small-diameter interfaces (< DN 50) connect by means of hoses, while rubber bellows are used for all large-diameter interfaces (DN 50 or larger). This of course does not apply to the exhaust system, for which steel bellows are required, and for the air intake system, which employs hose connectors (sleeve-type connection). Rubber sleeves are used for connections < DN 50 only in exceptional circumstances and at locations where displacement is slight, e.g. at the gearbox with rigid mount. Hose connections The hoses are fitted with sealing cones (60°) and union nuts and can therefore be secured directly to the corresponding interfaces on the engine, gearbox or accessory. The requisite dimensions are stated in the applicable installation drawing. Bellows connections Both rubber (e.g. raw water) and steel bellows (e.g. exhaust) are used for the plant interfaces, but only the rubber bellows are discussed here. The use of rubber bellows on engines is usually restricted to the lines of diameter in excess of DN 40 of the raw water system, so only this application is discussed here. The interface on the engine, gearbox or accessory is of a design such that the rubber bellows can be secured directly by means of screw fasteners. Connection to the on-board piping system is performed by means of a welding neck to DIN 86037 and the corresponding securing flange to DIN 2642, both of which are included in the standard scope of supply. To avoid excessive strain on the rubber bellows, care must be taken to ensure that the installation length is as specified in the installation drawing. The rubber bellows are usually installed without axial preload. Note, however, that preload may be specified for a rubber bellows for a special application in which non-standard displacements are anticipated. TPG-General.doc Rev. 1.0
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The binding connection and installation dimensions for the rubber bellows are stated in the project- or contract-specific installation drawings. Figure 7.4.1 shows the connection in diagram form. Note that the pipe material used as standard is copper-nickel alloy.
Figure 7.4.1: 1 2 3 A D L
Rubber bellows Welding neck Pipe (not MTU scope of supply) Interface to engine, gearbox or accessory Pipe outside diameter Installation dimension
TPG-General.doc Rev. 1.0
Connection of rubber bellows
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Application and Installation Guidelines
7.4.2 Combustion Air and Cooling/Ventilation Air Supply 7.4.2.1 Combustion-air intake from engine room 7.4.2.2 Combustion-air intake directly from outside 7.4.2.3 Cooling/ventilation air system
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Application and Installation Guidelines
7.4.3 Exhaust System 7.4.3.1 Arrangements, support and connection for pipe and silencer
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7.4.3.2 Underwater discharge (with exhaust flap)
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Application and Installation Guidelines
7.4.3.3 Water-cooled exhaust system
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Application and Installation Guidelines
7.4.4 Cooling Water System 7.4.4.1 Cooling water system with engine-mounted heat exchanger
Figure 7.4.2:
Cooling water system with engine-mounted heat exchanger (Split-circuit cooling system)
1 Engine coolant pump 2 Lube oil heat exchanger 3 Intercooler 4 Coolant heat exchanger 5 Preheating unit, complete, not standard scope of supply 6 Expansion tank, engine coolant, shipyard supply 7 Gearbox 8 Gearbox oil heat exchanger 9 Ship heating, shipyard supply 10 Connecting point, flexible connecting element 11 Flow restrictor 12 Sea water pump 13 Sea water filter, shipyard supply 14 Fuel oil heat exchanger Split-circuit cooling system using heat exchanger with titanium plates. Benefits: • Keeps engine coolant, oil and intake air at optimum temperature under all operating conditions. • Higher temperature during idle or low-load operation. • No seawater in the engine. TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
7.4.4.2 Cooling water system with separately-mounted heat exchanger (including keel cooling)
Figure 7.4.3:
Cooling water system with separately-mounted heat exchanger (e.g. keel cooling)
1 Engine coolant pump 2 Lube oil heat exchanger 3 Intercooler 4 Coolant heat exchanger (Shell cooler/Case cooler), shipyard supply 5 Preheating unit, complete, not standard scope of supply 6 Expansion tank, engine coolant, shipyard supply 7 Gearbox 8 Gearbox oil heat exchanger 9 Ship heating, shipyard supply 10 Connecting point, flexible connecting element 11 Flow restrictor Cooling system for low power and ships operating in the flat water. Advantages: No sea water in pipelines, valves, pumps and heat exchanger in the ship. Low-cost materials for above-mentioned components. Less prone to interference through corrosion.
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7.4.4.3 Central cooling water system
Figure 7.4.4:
1 Engine coolant pump 2 Lube oil heat exchanger
9 Ship heating, shipyard supply 10 Flexible connecting element
3 Intercooler 4 Coolant heat exchanger 5 Preheating unit, complete, not standard scope of supply 6 Expansion tank, engine coolant, shipyard supply 7 Gearbox 8 Gearbox oil heat exchanger
11 Flow restrictor ② 12 Sea water pump, shipyard supply 13 Sea water filter, shipyard supply
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Central cooling water system
15 Sea water stand-by pump, shipyard supply 16 Harbour sea water pump, shipyard supply
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Application and Installation Guidelines
7.4.5 Fuel System The standard scope of supply requires the shipyard to connect the fuel feed and return lines for the engine. The standard scope of supply includes flexible connectors and a fuel prefilter for connecting the fuel supply line to the engine.
Figure 7.4.5: 1 2 3 4 5 6
Fuel System
Fuel prefilter with water separator Service tank, shipyard supply Fuel transfer pump, shipyard supply Fuel coarse filter or (water) separator, shipyard supply Flexible connecting element Fuel heat exchanger, not standard scope of supply
An engine with a safety-enhanced fuel system (comprising jacketed high-pressure fuel lines and an on-engine tank for leak-off fuel) requires an additional line to carry off an overflow. When routing this overflow, bear in mind that the leak-off fuel is not under pressure, i.e. it must return to the on-board collecting tank or the fuel tank via a line routed on a declining plane and venting to atmosphere. Only fuels listed in the Fluids and Lubricants Specification are approved for use in MTU diesel engines. TPG-General.doc Rev. 1.0
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7.4.5.1 General notes
• The supply pipe must be connected to the on-engine interface by means of a flexible connector. See Chapter 8.4.1, Flexible connections. • If, as maybe the case in exceptional circumstances, the flexible connector (hose) is not supplied by MTU, it must satisfy the requirements laid down in Chapter 8.4.1. • We recommend the use of steel piping (e.g. St 35). The engineering guidelines apply with regard to wall thickness of piping. • Pipe runs should be kept as short as possible and a measuring connection must be provided immediately in front of the on-engine interface to permit system checking, e.g. for commencement. • If an auxiliary diesel engine receives its fuel supply via a bypass incorporated in the fuel supply system of the main diesel engine, this design feature must be taken into account when calculating the cross-section of the lines. Failure to take this factor into account may result in the auxiliary diesel receiving insufficient fuel when the main diesel engine is in operation, with the danger of engine malfunction as a result.
7.4.5.2 Design data Compliance with the limits defined for the system interface is essential in order to ensure compliance with the limits for engine operation. Data such as required for design/dimensioning of the fuel system
• Fuel volume flows, feed an return • Pressure limitations at on-engine interface, min./max. • Temperature limitations for supply, min./max. • Fuel temperature increase before/after engine • Heat to be removed from return fuel is specified in the data sheet for the project or contract. The needs of the engine must be taken into account with regard to the arrangement of the fuel tanks in the vessel and the dimensioning of the tanks. As general rule, the fuel supply system should incorporate at least one supply tank, plus a service tank for the engine or the engines. The location of the service tank has an effect on the efficiency of heat exchange and the routing of the fuel lines from and to the engine. In order to avoid malfunctions, it is important to observe the following points:
• The service tank must be of a size such that the temperature in the tank caused by return fuel mixing with residual fuel in the tank always remains below a permissible maximum.
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Application and Installation Guidelines
The equations below can be used to calculate the requisite volume of the service tank (size of service tank).
Vtank = Vtank = t = = be PB = Vreturn = W =
t ⋅ (0.04 ⋅ be ⋅ PB + Vreturn ⋅ 2 .1) w
m3
Total volume of service tank in m3 Time to replenish of the service tank in h Specific fuel consumption at fuel stop power in kg/kWh Fuel stop power in kW Fuel return flow from engine at fuel stop power in litre/min Evaluation value for max. fuel inlet temperature (Figure 7.4.6)
70
Evaluation value W.
60 50 40 30 20 10 0 25
30
35
40
45
50
55
60
65
70
Max. fuel inlet temperature T in °C
Figure 7.4.6:
Evaluation value for max. fuel inlet temperature
The calculation of the total volume of the service tank is taken with regard to a maximal permissible level of 85 % and of a remaining level of 10 %.
• If the available service tank volume is less than the calculated volume and the engine has return fuel, the temperature of the fuel in the service tank exceeds the permissible limit for the fuel supply to the engine and a fuel heat exchanger must be installed in the return fuel line from the engine. • The fuel supply from the service tank to the engine must be • such that no sludge seasoned on the bottom of the service tank or water precipitated from the fuel is drawn into the supply line to the engine. This is achieved by locating the supply pipe at an adequate height above the bottom of the service tank (at least 100 mm clearance from the bottom of the tank). TPG-General.doc Rev. 1.0
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• If the service tank is on a level higher than that of the fuel delivery pump (overhead tank, header tank) the return line carrying excess fuel from the engine must be routed above the maximum level of fuel in the service tank. This precaution is adopted in order to prevent fuel flooding the engine while it is at a standstill, because it is not possible to guarantee that the non-return valves in the delivery line always remain absolutely leak tight. • If the service tank is on a level lower than that of the fuel delivery pump (low level tank, bottom tank), the return line carrying excess fuel from the engine must be routed below the minimum level of the fuel in the service tank. This precaution is adopted in order to prevent air entering the fuel system and the fuel delivery pump when the engine is at a standstill. • The min./max. pressures at the on-engine interfaces must be as specified in the data sheet. If the plant incorporates a bottom tank and/or a relatively long fuel supply line, a booster pump must be installed in order to prevent an impermissibly high intake depression before the engine. • A water drain valve and sludge drain valve must be provided at the lowest point of the service tank. The tank must be provided with adequate breather facilities, which in turn must afford adequate protection against the ingress of water.
( under preparation )
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Application and Installation Guidelines
7.4.6 Lube Oil System
Figure 7.4.7:
Lube oil system
1 2 3 4 5 6 7 8
Lube oil pump Lube oil heat exchanger Drain plug on oil pan Oil dipstick Lube oil hand pump 3-way cock, lube oil, shipyard supply Gearbox Automatic lube oil level monitoring and replenishment system, not standard scope of supply (according to classification societies for watch-free operation) 9 Lube oil tank, shipyard supply 10 Flexible connecting element
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Application and Installation Guidelines
7.4.7 Starting System The engines may employ one of three different methods of starting. There are principally two types of starting systems which differ by the way in which the energy, required to start the engine is stored: -
Electric starting with battery-powered starter motor
-
Compressed air starting, by means of
• pneumatic starter motor, operating pressure range from 1 x 106 to 3 x 106 Pa (10 to 30 bar) • air-in-cylinder, operating pressure range from 2 x 106 to 4 x 106 Pa (20 to 40 bar) The regulations to which the plant is subject govern the choice of the starting system, i.e. electric or pneumatic. Unless otherwise specified by the customer, the engines are supplied with electric starting Systems by default (series 2000 and 4000), because the electric system is more straightforward and involves fewer system components. In terms of reliability, there is a difference between the systems - all three are thoroughly satisfactory. Compressed air starting is preferable on vessels with a central compressed air supply system, because under these circumstances there is no need to provide an additional supply system and so there is a weight advantage when compared with the electric starter. The starting procedure is controlled and monitored by a control system included in the standard scope of supply. The control unit incorporates both the controller logic circuits and all requisite control elements. 7.4.7.1 Electric starter motor The starter motor (some engine models have two starter) mounted on the engine requires a 24 VDC supply. Starter motors with other voltage ratings are available on request for special applications. Design data such as
• nominal power • current consumption and • requisite storage-battery capacity required for the design of the starting system are part of the data sheet of the project or contract. The starter batteries are usually recharged by means of an alternator which is usually included in the engine scope of supply.
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Application and Installation Guidelines
The battery does not usually form part of the MTU scope of supply. The following points require consideration:
• The position of the battery in the engine room must be such as to permit easy access for maintenance. • The battery must be protected against moisture, mechanical damage and extreme temperature. • The battery must be as close as possible to the engine or, more precisely, to the starter motor, so that the electric cables are as short as possible. • In order to avoid corrosion in the vicinity of the battery, it must be well, ventilated because it is not always possible to prevent acid vapor escaping from the battery cells. There are no design-related restrictions on the choice of battery type, e.g. lead-acid or nickel-cadmium battery. Note, however, that the ambient conditions must be taken into account in this respect. The engine documentation and the special documentation for the electronic accessories contain information that must be taken into account with regard to the electric wiring of the starting system and the calculation of the cross-section of the conductors to suit the cable lengths and currents carried.
7.4.7.2 Compressed-air starting, compressed-air starter motor If the engine is equipped with a pneumatic starter motor, the compressed air supply connects to the starter motor mounted on the diesel engine. The starting air supply valve mounted on the starter motor is electrically actuated with provision for emergency manual actuation. The system components required for the starting system (flexible connecting element, air filter and pressure reducing valve from 4 x 106 to 1 x 106 Pa) are usually part of the MTU scope of supply. Figure 7.4.8 is a schematic view of the compressed air starting system with pneumatic starter motor as of the on-engine interface. The incorporation of a pressure reducing valve makes it feasible to dimension the compressed air storage tanks for a pressure considerably higher than the operating pressure of the starter motor, with the result that the size of the tanks can be minimized (by a factor of between 6 and 8).
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Figure 7.4.8:
Application and Installation Guidelines
Starting system with pneumatic starter motor
1 Compressed air starter
6 Safety valve ②
2 Lubricator (optional) ②
7 Pressure gauge ②
3 Air filter ②
8 Flexible connecting element
4 Pressure reducing globe valve ②
9 Pneumatic starter motor
5 Starting air receiver ②
② Shipyard
7.4.7.3 Compressed-air starting, air-in-cylinder If the engine is equipped for air-in-cylinder starting, it features an interface at which compressed air from the starting valve must be made available. The starting valve is electrically actuated but is also designed for emergency manual operation. It usually forms part of the MTU scope of supply and is supplied with, but not mounted on, the engine. Figure 7.4.9 is a schematic view of the air-in-cylinder starting system as of the on-engine interface. The compressed air tanks used to store the starting air can be supplied by MTU or by the shipyard. If they are not supplied by MTU, the tanks must be dimensioned by the shipyard as to contain an air supply adequate for the number of engine starts specified by the applicable regulations. TPG-General.doc Rev. 1.0
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Figure 7.4.9:
Application and Installation Guidelines
Starting system with air-in-cylinder starting
1 Starting air distributor 2 Starting valve 3 Starting air receiver ② 4 Flexible connecting element 5 Safety valve ② 6 Pressure gauge ② ② Shipyard
Design data Data such as
• min./max. starting air pressures for engine • average air consumption per start • regulation number of engine starts are specified in the data sheet for the project or contract. Unless the number of engine starts is specified elsewhere, we recommend dimensioning the compressed air tanks such that at least six starts are possible without recharging the tanks. In twin-engine or multiple-engine configurations, the engines housed in a single engine room can be supplied from a common compressed air storage system. TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
The equations below can be used to calculate the requisite volume of the compressed air storage system (size of compressed air tank or tanks).
V =
V s Vn1 ∆p p1 p2 pmax pmin pn
= = = = = = = = = =
s × Vn1 × p n ∆ p
m3
Volume of compressed air tank in m3 Number of engine starts Air consumption per start (at normal pressure pn) in m3 Pressure differential in compressed air tank in Pa p1 - p2 or pmax - pmin Pressure in air tank before engine start in Pa Pressure in air tank after engine start in Pa Max. permissible starting air pressure in Pa Min. permissible starting air pressure in Pa Normal pressure = 1,013 x 105 Pa
The starting air supply valve should be located in the engine room and as close as possible to the engine, and in such a way that it is protected against damage and moisture. The supply pipe must be connected to the on-engine interface by means of a flexible connector. We recommend the use of steel piping (e.g. St 35 according to DIN 2391). Pipe runs should be kept as short as possible and a measuring adapter (Ml8xl,5) must be provided immediately in front of the on-engine interface to permit system checking, e.g. for commencement.
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Application and Installation Guidelines
7.4.8 Electric Power Supply
Figure 7.4.10: Electric power supply
( under preparation )
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7.5
Application and Installation Guidelines
Safety System ( under preparation )
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Application and Installation Guidelines
7.6 Emission 7.6.1 Exhaust Gas Emission, General Information The MTU standard reduction of exhaust gas emissions for navy applications are in accordance with International Maritime Organization (IMO)
Limitation of NOx-Emission 18
NOx in g/kWh
16 14 12 10 8 6 4 2 0 0
200
400
600
800
1000 1200 1400 1600 1800 2000 2200 -1
Engine rates speed in min
Figure 7.6.1:
Limitation of NOx-emission (IMO)
The IMO NOx emission limit depends on the rated engine speed: n < 130 min-1
NOx = 17 g/kWh
n = 130 to < 2000 min-1
NOx = 45 x n-0,2 g/kWh
n ≥ 2000 min-1
NOx = 9,8 g/kWh
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Application and Installation Guidelines
The test procedure and measurement methods shall be in accordance with the NOx Technical Code, taking into consideration the Test Cycles and Weighting Factors: Speed (%)
100
100
100
100
Test cycle type E2 Power (%)
100
75
50
25
0.2
0.5
0.15
0.15
Weighting Factor Figure 7.6.2:
Test cycle for “Constant Speed Main Propulsion” application (including diesel electric drive and variable pitch propeller installation)
Speed (%)
100
91
80
63
Test cycle type E3 Power (%)
100
75
50
25
0.2
0.5
0.15
0.15
Weighting Factor Figure 7.6.3:
Test cycle for “Propeller Law operated Main and Propeller Law operated Auxiliary Engines” application
Speed (%)
100
100
100
100
100
Test cycle type D2 Power (%)
100
75
50
25
10
0.05
0.25
0.3
0.3
0.1
Weighting Factor Figure 7.6.4:
Test cycle for “Constant Speed Auxiliary Engine” application
Speed Test cycle type C1 Torque (%) Figure 7.6.5:
Rated 100
75
50
Intermediate
Idle
10
100
75
50
0
Weighting Factor 0.15 0.15 0.15 0.1
0.1
0.1
0.1 0.15
Test cycle for “Variable Speed, Variable Load Auxiliary Engine” application
( under preparation )
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Application and Installation Guidelines
7.6.2 Acoustical Emission, General Information Low noise on board of yachts, passenger vessels and on naval ships is an important demand. Noise spectra, i.e. frequency analyses for operating noises distinguishing between
• air-borne noise as - engine free-field noise - undamped exhaust noise - undamped air intake noise • structure-borne noise have been performed for all engines listed in the current Sales Program. The results of these analyses are available on request for projects and contracts. Note that these analyses do not take into account the air intake noise. In the noise spectra the information relating to noise pressure level and level of oscillation velocity is valid only for to the rated engine power and engine speed as stated, and thus merely informative for other power/speed combinations. 7.6.2.1 Airborne noise level A noise spectrum of the engine operating noise emitted to the environment (free-field) is available for each engine in the Sales Program. These spectra are available on request for projector contract-specific purposes. The figures in the noise spectrum are in dB(A) and comply with ISO standards. The datum level is 2*10-5 Pa and the noise pressures are measured at a distance of 1 m, unless otherwise stated in the diagram.
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Figure 7.6.6:
TPG-General.doc Rev. 1.0
Application and Installation Guidelines
Engine surface noise analysis (example)
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Application and Installation Guidelines
7.6.2.2 Exhaust gas noise level
Figure 7.6.7:
TPG-General.doc Rev. 1.0
Undamped exhaust gas noise analysis (example)
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Application and Installation Guidelines
7.6.2.3 Structure-borne noise level (e.g.: single-(standard), single-(shock resistance), double-resilient mounting) Depending on different requirements, we offer additionally to our standard design four different “Quiet Systems”. All options are based on proven design. Standard single resilient mounting system: (Standard) Standard single resilient mounting system for ships without any special shock or acoustic requirements, e.g. working ships and fast ferries. Technical Features: -
Standard acoustic, no shock requirements
-
Single resilient mounting system
-
Standard coupling system for torsional vibration and misalignment
Single resilient mounting system with shock: (Option 1) Single resilient mounting system for applications with shock requirements for ships, such as OPV´s and Corvettes. Technical Features:
TPG-General.doc Rev. 1.0
-
Shock requirements according to BV 043/85; STANAG 4142 combined with moderate acoustic requirements
-
Special single resilient mounting system
-
Resilient coupling system for increased shock and structure-borne noise attenuation
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Application and Installation Guidelines
Typical Arrangement 1
2
1 Engine 2 Gearbox 3 Ship foundation 4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements 4
3
Engine with flange-mounted gearbox 1 Engine 2
1
5
6
2 Gearbox 3 Ship foundation
3
4
Engine with free-standing gearbox
4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements 5 Standard coupling system for torsional vibration and misalignment, optional with resilient coupling system for increased shock and structure-borne noise attenuation 6 Noise case (optional)
1
2
1 Engine 2 Generator 3 Ship foundation 4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements
3
4
Engine with flange-mounted generator
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Application and Installation Guidelines
Typical Arrangement 1 Engine 2
1
5
6
2 Generator 3 Ship foundation
3
4
Engine with free-standing generator
Figure 7.6.8:
4 Resilient elements, standard or special single resilient mounting system, with or without shock requirements 5 Standard coupling system for torsional vibration and misalignment, optional with resilient coupling system for increased shock and structure-borne noise attenuation 6 Noise case (optional)
Single resilient mounting system with shock
Standard double resilient mounting system: (Option 2) Double resilient mounting system improves the acoustic behaviour for ASW ships, comfortable pleasure crafts and casino ships. Technical Features: -
Higher acoustic demands, shock requirements according to BV 043/85; STANAG 4142, weight critical application
-
Double resilient mounting system consist of: Rubber elements shock proved, with shock buffers Light/stiff base frame with 30% of engine weight as intermediate mass
-
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Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
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Application and Installation Guidelines
Double resilient mounting system for low noise: (Option 3) Double resilient mounting system to achieve low noise levels onboard of yachts, passenger vessels and most naval applications. Technical Features: -
High acoustic demands, shock requirements according to BV 043/85; STANAG 4142
-
Double resilient mounting system consist of: Rubber elements shock proved, with shock buffers Polymeric concrete/steel base frame with 50% of engine weight as intermediate mass
-
Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
-
Noise enclosure
Double resilient mounting system for extreme acoustic requirements: (Option 4) Double resilient mounting system for extreme acoustic requirements for ASW ships and research vessels. Technical Features: -
Extreme acoustic demands, shock requirements according to BV 043/85; STANAG 4142
-
Double resilient mounting system consisting of: Rubber elements shock proved, with shock buffers Polymeric concrete/steel combination base frame with 70% of engine weight as intermediate mass Double stage steel springs with silicon damping filling
TPG-General.doc Rev. 1.0
-
Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
-
Noise enclosure
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Application and Installation Guidelines
Typical Arrangement 2
5
1 Engine
6
1
2 Gearbox 3 Ship foundation 4 Resilient elements, double resilient mounting system, with shock requirements
3
7
5 Resilient coupling system for torsional vibration and increased shock and structure-borne noise attenuation
4
Engine with free-standing gearbox
6 Noise enclosure 7 Intermediate mass
2
1
5
1 Engine
6
2 Generator 3 Ship foundation 4 Resilient elements, double resilient mounting system, with shock requirements
3
4
5 Coupling system for torsional vibration, misalignment and increased shock attenuation
7
Engine with free-standing generator
6 Noise enclosure 7 Intermediate mass
Figure 7.6.9:
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Double resilient mounting system for extreme acoustic requirements
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Application and Installation Guidelines
90
Lv in dB re 5x10
-8
m/s
80 70 Standard Option 1 Option 2 Option 3 Option 4
60 50 40 30 20 10 0 31,5
63
125
250
500 1000 2000 4000 8000
Frequency in Hz
Figure 7.6.10: Examples for different “Quiet Systems”, structure-borne noise levels below the resilient mountings (e.g. diesel engine 20V 1163)
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Application and Installation Guidelines
Figure 7.6.11: Structure borne noise analysis at engine feet, above rubber mounts (example)
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7.7
Mounting and Foundation
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7.8
Acoustic Enclosure/Acoustic Case
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7.9
Application and Installation Guidelines
Mechanical Power Transmission There are different possibilities and combinations for the mechanical power transmission with internationally system-specific terms established. In the following one the most customary denotation is used: CODAD = COMBINED DIESEL ENGINE AND DIESEL ENGINE This kind of power plants offers e.g. the possibilities to transmit the power to on one shaft optionally from one or several diesel engines.
2 3 1
2
2 3 2
1
Figure 7.9.1:
Combined diesel engine and diesel engine 2 3
1
2
2 3 2
1
Figure 7.9.2:
Combined diesel engine and diesel engine with separate gear compartment
1 Controllable pitch propeller (CPP) 2 Diesel engine 3 Gearbox TPG-General.doc Rev. 1.0
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Application and Installation Guidelines
CODOG = COMBINED DIESEL ENGINE OR GAS TURBINE This kind of power plant offers the possibilities to transmit the power to a shaft optionally only with a diesel engine or only from a gas turbine. 3
4 1
2
2
3
4
1
Figure 7.9.3:
Combined diesel engine or gas turbine
CODAG = COMBINED DIESEL ENGINE AND GAS TURBINE This kind of power plants offers the possibilities to transmit the power to both shafts optionally only from one diesel engine, or to transmit the power to one shaft separately from one diesel engine, or to transmit the power to one or two shafts only from the gas turbine, or to transmit the power onto both shafts together from all driving engines .
3 1
2
3
2
4
3
1
Figure 7.9.4: 1 2 3 4
Controllable pitch propeller (CPP) Diesel engine Gearbox (distribution gear/multi-staged gear) Gas turbine
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Combined diesel engine and gas turbine
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Application and Installation Guidelines
Further denotation for combinations of mechanical power transmission is used as follows: COGAG
= COMBINED GAS TURBINE AND GAS TURBINE
COGOG
= COMBINED GAS TURBINE OR GAS TURBINE
CODLAG
= COMBINED DIESEL-ELECTRIC AND GAS TURBINE
CODLAGL = COMBINED DIESEL-ELECTRIC AND GAS TURBINE-ELECTRIC
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7.10
Application and Installation Guidelines
Auxiliary Power Take-Off
Figure 7.10.1: Power take-off (PTO), gear driven
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7.11
Example Documents
Back to Start of Chapter
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Application and Installation Guidelines
Back to Contents
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8 8.1
Standard Acceptance Test
STANDARD ACCEPTANCE TEST Factory Acceptance Test In general, engines are to be subject to a test bed trial under the supervision of the scope stated below.
8.2
Acceptance Test According to a Classification Society (e.g. Germanischer Lloyd).
8.2.1 Main Engines for Direct Propeller Drive: • 100 % power (rated power) at rated speed n0: 60 minutes • 100 % power at n = 1,032 · n0: 45 minutes • 90 %, 75 %, 50 % and 25 % power in accordance with the nominal propeller curve. In each case the measurements shall not be carried out until the steady operating condition has been achieved. • Starting and reversing manoeuvres • Test of governor and independent overspeed protection device • Test of engine shutdown devices
8.2.2 Main Engines for Indirect Propeller Drive The test is to be performed at rated speed with a constant governor setting under conditions of:
• 100 % power (rated power): 60 minutes • 110 % power: 45 minutes • 75 %, 50 % and 25 % power and idle run. In each case the measurements shall not be carried out until the steady operating condition has been achieved. • Start-up tests
8.2.3 Auxiliary Driving Engines and Engines Driving Electric Generators Tests to be performed in accordance with 9.2.2. The manufacturer's test bed reports are acceptable for auxiliary driving engines rated at ≤ 100 kW.
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8.3
Example Documents
Back to Start of Chapter
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9
Control, Monitoring and Data Acquisition (LOP)
CONTROL, MONITORING AND DATA ACQUISITION (LOP) MTU engines for marine applications are provided with an Electronic Control System matched to special marine requirements. The high functional efficiency and simple system design with plug connectors and pre-fabricated system cables for engine installation make incorporation into ships an easy operation. This system ensures optimised engine functioning under all operating conditions. Economical engine operation with low fuel consumption and minimum exhaust emission over the complete load range is guaranteed by the MDEC system. Important Information ! All descriptions herein have reference to the following Standard Diesel Engine Series:
• 2000 M60 / M70 / M80 / M90 / M91 • 4000 M60 / M70 / M80 / M90 The project guide describes the Propulsion Remote Control System RCS-5 for Fixed Pitch Propeller FPP. For applications with Controllable Pitch Propeller CPP, Waterjet WJ or Voith Schneider VS please ask TZPV for assistance. This systems are also available as standard applications. Furthermore MTU Electronic offers on request, after technical clarification, RCS-5 versions for combined propulsion plants e.g. CODAD, CODAG, CODOG etc., in combination with current propeller systems.
9.1
Standard Monitoring and Control Engine Series 2000/4000 Complete monitoring and control, ready for installation and operation, for Non-Classified and Classified automation and single- to four-engine plant with or without gearbox consisting of:
• Monitoring and Control System for the propulsion plant within the Engine Room (FPP, WJ or CPP). • Monitoring and Control System MCS-5 Type 1 for the propulsion plant within the Control Stands. • Monitoring and Control System MCS-5 Type 1 for the shipboard equipment (auxiliary systems in engine room and general ship area). • Remote Control System RCS-5 for the propulsion plant (FPP) within the Control Stands. The meaning of MDEC: MTU Diesel Engine Control. The MDEC System satisfies the following units: • ECU = Engine Control Unit Mounted on engine • EMU = Engine Monitoring Unit Mounted on engine if classification is required • LOP = Local Operating Panel Loose supplied for Engine Room installation
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9.2
Control, Monitoring and Data Acquisition (LOP)
Engine Governing and Control Unit ECU-MDEC Engine governing and control unit ECU-MDEC with integrated safety system, load profile recorder and data modules (for engine and plant specific parameter), for engine speed control in response to rated value setting with fuel injection and speed limitation as a function of engine status and operating conditions as well as MTU sequential turbo charging. Set of sensors including on-engine cabling.
9.3
Engine Monitoring Unit EMU-MDEC Separate Safety System Engine Monitoring Unit EMU-MDEC is used to cover the additional requirements and scope of redundant measuring points specified for classified marine plants. In such cases, EMUMDEC also represents the second, independent safety system, which protects the engine from states assumed to be a risk to continued operation.
9.4
Local Operating Panel LOP-MDEC Local operating panel LOP-MDEC in sheet-metal housing, for ship-side installation in the engine room, comprising the following components and functions: -
-
Interface for ECU-MDEC, gearbox GCU, Shipside Monitoring System and Remote Control. Automatic start/stop and emergency stop sequencing control.
-
LCD display (standard language English, switch-over to other language on request) with selector keyboard for monitoring data of engine and gearbox sensors and status display of turbochargers. System-integrated alarm unit with visual individual alarm and output for visual and audio alarm.
-
Combined control and display elements for engine and gearbox: Ready for operation, Local control, Engine Start/Stop/Emergency Stop, Gearbox clutch control, Engine speed increase/decrease, Lamp test, Alarm acknowledgement and illumination dim control.
Set of connecting cables (10 m each with plug connectors at both ends) for connecting the individual electronic components. Flashing light and horn for alarm in engine room.
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Control, Monitoring and Data Acquisition (LOP)
9.5 Propulsion Plant Management System Version 9.5.1 Manufacturer Specification In accordance with manufacturer specification. (Not classifiable)
Figure 9.5.1:
TPG-General.doc Rev. 1.0
Propulsion Plant Management System version in accordance with manufacturer specification
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Control, Monitoring and Data Acquisition (LOP)
9.5.2 Classification Society Regulation Version in compliance with Classification society regulations (GL, ABS, BV, CCS, DNV, KR, LRS, NK, RINA type test approval).
Figure 9.5.2:
Propulsion Plant Management System version in compliance with classification society regulations
Back to Contents
Back to Start of Chapter
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11 Assembling Instructions (Lifting, Transportation)
10 10.1
MAINTENANCE CONCEPT / MAINTENANCE SCHEDULE Reason for Information MTU has revised the engine maintenance concept. The former combination of several maintenance tasks in maintenance echelons (W1 to W6) is now obsolete. It is replaced by a concept of maximum service time periods for single components (items) until their next scheduled maintenance is due. The preventive maintenance principle remains effective with the new maintenance concept. The Maintenance Schedules for all MTU engine series and applications, with effect from Sales Program 2003, will be converted to the new concept this year. The current maintenance schedules may continue to be used for engines already in service, they will not, however, be subjected to any up-dating or amendment procedures.
10.2
Advantages of the New Maintenance Concept: Technical: -
Individual maintenance tasks per operating period interval resulting in reduced down time per maintenance operation.
-
Utilisation of the maximum service life of the single components.
-
Reduced life cycle costs.
Data Processing:
10.3
-
Central administration of the individual tasks in a data bank.
-
Common designation of identical maintenance tasks irrespective of engine series.
-
Efficient translation and availability in 5 languages.
New Maintenance Schedule: The new maintenance schedule is divided into three sections.
10.3.1 Cover Sheet The cover sheet provides the following information: -
Engine series/production model, application group, load profile.
-
Order No. (only with order-specific maintenance schedules).
-
Maintenance schedule and version numbers.
-
General information with respect to the maintenance concept.
-
Cross-reference to other applicable documentation (Fluids and Lubricants Specification).
-
Maintenance tasks that are not included in the maintenance schedule matrix as their maintenance intervals are strictly related to the individual operating conditions (fuel prefilter, battery).
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10.3.2 Maintenance Schedule Matrix
Engine oil
Engine operation
Engine oil filter
Centrifugal oil filter
Fuel duplex filter
Valve gear
Air filter
Fuel injectors
Fuel injection pumps
Combustion chambers
Belt drive
Component maintenance
Extended component maintenance
The maintenance schedule matrix provides an overview of the minimum scope of maintenance tasks.
Maint. Level
W1
W1
W2
W2
W3
W3
W4
W4
W4
W4
W4
W5
W6
Time limit,
-
-
2
-
2
-
3
-
-
-
2
18
18
Operating ho rs Daily
X
X
500
X
X
X
1000
X
X
X
1500
X
X
X
2000
X
X
X
2500
X
X
X
3000
X
X
X
3500
X
X
X
4000
X
X
X
X
X
X
X
X
X
X
X
X
Figure 10.3.1: Example of a maintenance schedule matrix -
The matrix headings contain the individual maintenance items. The item content is described in the task list (see below).
-
In comparison to the previous maintenance concept, the “Maintenance Levels” listed in the 2nd line have a new meaning. They indicate the qualifications (scope of training) required for the maintenance personnel and the scope of tools required; these are combined in tool kits.
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-
In addition to the operating hours limits, some maintenance tasks are subject to a time restriction, “Time limit in years”. This is indicated in the 3rd line. As a matter of principle the limit value (operating hours or years) that first becomes effective is to be used.
-
The 1st column of the matrix indicates the “Operating hours” at which a maintenance operation is to be executed. The associated tasks are indicated by an “x” in the appropriate line. The maintenance schedule matrix normally ends with the “Extended component maintenance”. Thereafter, the maintenance tasks are to continue in accordance with the related intervals (see task list), i.e. as a matter of principle, maintenance is to be carried out at the intervals indicated and not recommenced at the beginning of the matrix. If required (on request) a maintenance schedule with an extended matrix can be provided.
10.3.3 Task List The task list describes the maintenance tasks listed as positions in the matrix. Maint. Interval Item Level (hours/years)
W1
-/-
W1 W2
-/-/2
W2
500/-
W3 W3 W4
500/500/2 2000/3
W4
2000/2
W4 W4 W4
3000/3000/4000/-
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Maintenance tasks
Check general conditions of engine and verify that there are no leaks. Check drain lines of intercooler. Check service indicator of air filter. Check relief bores of water pump(s). Engine operation Check for abnormal running noises, exhaust gas colour, vibration. Drain off water and contamination at drain cock of fuel prefilter (if fitted). Check service indicator of fuel prefilter (if fitted). Engine oil Check level. Engine oil filter Replace. Or replace when changing engine oil. Check thickness of oil residue layer, clean and Centrifugal oil filter change sleeve. Valve gear Check valve clearance. Fuel duplex filter Replace filters. Air filter Fit new air filter(s). Check belt condition and tension, replace if Belt drive necessary. Combustion chambers Inspect cylinder chambers using endoscope. Fuel injectors Fit new fuel injectors. Fuel injection pumps Fit new fuel injector pumps.
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11 Assembling Instructions (Lifting, Transportation) Maint. Interval Item Level (hours/years)
W5
4000/18
Maintenance tasks
Component maintenance
Before starting maintenance work, drain coolant and flush cooling systems. Check rocker arms, valve bridges, pushrods and ball joints for wear. Check wear pattern of cylinder-liner running surfaces. Replace turbocharger. Check vibration damper. Clean air ducting. Clean intercooler and check it for leaks.
Figure 10.3.2: Example task list
-
The “Maintenance level” serves only as an orientation for the qualifications required for the maintenance personnel and the tool kits required.
-
The “Interval” defines the maximum permissible operational period between the individual maintenance tasks for each component/item in operating hours/years referenced to the specified load profile (see cover sheet). The time intervals are based on the average results of operational experience and, therefore, are guideline values only. In the case of arduous operating conditions, modifications may be necessary.
-
The “Item” matches the data given in the headings of the maintenance schedule matrix.
-
The “Maintenance tasks” column lists the individual maintenance tasks per item. Detailed task descriptions are contained in the engine-related Operation Manual.
Note: Change intervals for fluids and lubricants are no longer included in the maintenance schedule. These are defined in the MTU Fluids and Lubricants Specification A001061. Reason: -
The oil service life is influenced by the quality of the oil, oil filtration, operational conditions and the fuel used. In individual applications, oil service life may be optimized by regular laboratory analyses.
-
The coolant service life depends on the type of coolant additive(s) used.
With the new maintenance schedule concept it is still possible for tasks to be combined in individual blocks in accordance with the customer's wishes. It is, however, mandatory to ensure that the maximum permissible maintenance intervals for each position are not exceeded. Reduction of the intervals is, as a matter of principle, possible. However, this can have a negative effect on overall maintenance costs. Back to Start of Chapter TPG-General.doc Rev. 1.0
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11 Assembling Instructions (Lifting, Transportation)
11
ASSEMBLING INSTRUCTIONS (LIFTING, TRANSPORTATION)
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12 Transportation, Storage, Starting
12
TRANSPORTATION, STORAGE, STARTING
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13 Pilot Installation Description (PID)
13
PILOT INSTALLATION DESCRIPTION (PID)
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