Marine Low Speed Diesel Engines

This publication considers the general principles of marine low speed diesel engines and provides examples of engine parts from the three different engine designs. There is a chapter on engine construction which describes the design and purpose of key engine components, together with their maintenance requirements and common malfunctions. General guidance is provided on engine selection, installation, operation, maintenance and emission control.

The term ‘low speed’ is not exact but in marine terms it is generally accepted as an engine operating at a speed below approximately 200 revolutions per minute. In addition, low speed engines are invariably of the crosshead type and operate on the two-stroke cycle. There are various designs of low speed crosshead engines powering merchant ships but many of these designs have not been built for almost twenty years and can now be considered obsolete. Only designs in production during the last 20 years have been considered in detail within this MEP.

1 The Low Speed Diesel Engine

1.1 Definition of a low speed diesel engine

1.2 The crosshead engine

1.3 The crosshead

1.4 Two-stroke operating cycle

1.5 Turbocharging and supercharging

1.6 Engine parameters

2 Engine Construction

2.1 Engine structure

2.2 Bedplate

2.3 Frames

2.4 Cylinder block

2.5 Tie rods

2.6 Cylinder liner

2.7 Cylinder cover

2.8 Piston

2.9 Piston rod gland

2.10 Crosshead

2.11 Connecting rod

2.12 Bearings

2.13 Crankshaft

2.14 Camshaft

2.15 Fuel injection system

2.16 Reversing systems

2.17 High pressure (HP) fuel oil pipes

2.18 Fuel leakage alarm

2.19 Fuel injectors

2.20 Governors

2.21 Lubrication systems

2.22 Engine cooling systems

2.23 Combustion air supply

2.24 Engine chocking

2.25 Vibration

3 Safety, Additional Engine Systems, Monitoring and Control

3.1 Crankcase explosion

3.2 Scavenge fire

3.3 Two stage turbochargers

3.4 Power take in (PTI) systems

3.5 Electrical generation

3.6 Engine monitoring systems

3.7 Unmanned machinery space (UMS)

3.8 Engine management systems

3.9 Noise

4 Engine Selection and Installation

4.1 Engine selection

4.2 Engine air supply

4.3 Exhaust gas system

4.4 Turbocharger choice

4.5 Engine services

4.6 Engine space requirement

4.7 Holding down system

4.8 Shaft earthing device

5 Engine Operation

5.1 Engine starting

5.2 Running procedure

5.3 Speed adjustment

5.4 Stopping

5.5 Emergency stopping

5.6 Continuous slow running

5.7 Cylinder cut-out system

5.8 Emergency running

5.9 Turbocharger failure

5.10 Record keeping

5.11 Exhaust emissions

6 Engine Maintenance

6.1 Maintenance

6.2 Maintenance records

6.3 Crankshaft and main bearings

6.4 Connecting rod bearings

6.5 Cylinder inspection

6.6 Cylinder cover and valves

6.7 Chain drive and camshaft

6.8 Turbocharger cleaning

6.9 Jacket cooling water

6.10 System oil testing

Appendix A The Electronically Controlled Engine

A1 Introduction

A2 Wärtsilä RT-flex engine

A3 MAN B&W electronic engines

Appendix B

B1 Engine emissions and emission control

B2 CO2 (carbon dioxide)

B3 NOx (oxides of nitrogen)

IMarEST

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Here you will find all the information you need about who we are, what we do and why we do it.

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https://www.imarest.org/about-imarest

Dr Denis Griffiths

Dr Denis Griffiths, BEng (Hons), MSc, PhD, CEng, FIMarEST, was a seagoing engineering officer before turning to teaching. As a Senior Lecturer at Liverpool John Moores University, he taught and developed many marine engineering courses, all involving marine propulsion. Having served on the IMarEST Council, Dr Griffiths then became a member of the Institute’s Technical Committee.