The Best Tutorial on All About Marine Diesel Engines Theory

All About Marine Diesel Engines Theory

Diesel Engines & Systems

DIESEL ENGINE BASICS is a necessary read for anyone who wants to gain an understanding of diesel engines. This post will explore the basics of diesel engines and help you to understand what is going on inside them. We will also cover the different parts of a diesel engine and give you some tips on how to keep them running smoothly.

In this post on DIESEL ENGINE BASICS, i will discuss about the basics of Marine Diesel Engines. . This post will be useful for the engineering students.

Combustion process takes place inside the cylinder of an Internal combustion Engine. A Diesel engine reforms the heat power in to mechanical power.  
Following are the example of these types of engines.

  • Diesel Engines
  • Gas Turbines.

Advantages of ICE over ECE

  1. Simple in mechanical design
  2. Enhanced Power weight ration
  3. Lower initial cost
  4. Less requirement of cooling water
  5. Occupies less space
  6. Higher economy
  7. Low maintenance


In ICE (Internal Combustion Engine, transformation of motions takes place.. This process is achieved through connecting rod.

The piston fits closely n the cylinder liner. The leakage of gases is prevented by installing piston rings into circumferential grooves of the piston. Usually, the cylinder is bored into the cylinder liners, and in large Diesel Engines, a separately manufactured cylinder liner is inserted in the cylinder block.

Combustion takes place in the space in the upper part of cylinder liner above the piston.

The Crankshaft and pistons are connected through the connecting rod.

The reciprocating of the piston is conveyed through connecting rod, makes the crankshaft to rotate around its axis.

The Crankshaft is supported by main bearings fitted in a cylinder block. The uneven torques produced by the engine is smoothened by a flywheel fitted at the drive end of the Crankshaft.

Engine is provided with a pan at the bottom end, known as the sump of engine. In wet sump type of the engines, oil gets collected in to this pan/sump.

  1. Spark Ignition Engines.
  2. Compression-Ignition Engines

Spark Ignition Engines:-In, this type of Internal Combustion Engine combustion process, takes place by the spark plug igniting the air-fuel mixture, and generally, petrol engines are the typical examples.
Compression-Ignition Engines:- An Engine in which injected fuel in to the cylinders is ignited by the high temperature of the compressed air and the combustion takes place. The expansion of combustion gases acts on the top of the piston and causes the vertical or horizontal movement through the connecting rod transmitting the movement to rotate Crankshaft.  Production of mechanical energy is by the conversion of fuel chemical energy. Because of the process of ignition, these type of internal combustion engines are also known as Diesel Engines.

In a Diesel Engine production of mechanical energy is by the conversion of fuel chemical energy.
Due to this process, Compression ignition engines are also known as Diesel Engines..
Classification of the Diesel engines is as per the listed below categories.

  1. Diesel Engine By use.
  2. Diesel Engine By Speed
  3. Diesel Engine By Design
  4. Diesel Engine By Size

By use: – By application, DIESEL ENGINE BASICS are categorized.

  1. Marine: – In marine, Diesel Engines are used for propulsion and power generation purpose.
  2. Industrial: – In Industries, Diesel Engines are used for Power generation as DG sets, For driving the compressors and Pumps.
  3. Automotive: – Diesel Engines For land transport.
  4. Traction: – For locomotives and trains.

By Speed:- Weight and capacity of Diesel Engine are determined by the speed of Engine. There are the following three types of speed classes for Diesel Engines.

  • High-Speed Diesel Engines– Engines above 1000 RPM
  • Medium Speed Diesel Engines– Engines from  400 to 1000 RPM
  • Slow Speed Diesel Engines– Below 400 RPM

Design:– DIESEL ENGINE BASICS are again sub-classified as per the following designs.

  • For Stroke/Two Strokes.
  • Piston action- Single acting, Double acting and opposed piston arrangements.
  • Cylinder arrangements.
  • Kind of fuel (Heavy fuel, Low Sulfur, High-speed Diesel, Gaseous, and Dual fuel.
  • Natural aspirated and turbocharged.

Working cycles:

  • Two-Stroke Diesel Engines
  • Four Stroke Diesel Engines

Two-Stroke Diesel Engine (DIESEL ENGINE BASICS): – This type of engine completes a power cycle in two strokes of Piston Movement and one revolution of Crankshaft. In a two-stroke engine end of combustion and starting of compression stroke take place simultaneously;

All About Marine Diesel Engines Theory
2 Stroke Diesel cycle

Four Stroke DIESEL ENGINE BASICS :- In this type of Engine, the Piston completes the following four strokes in two revolutions of the Crankshaft.

4 stroke working cycle
4 stroke working cycle
  • Intake Stroke: – This stroke is also known as suction or induction stroke. This stokes starts at the top dead center and finishes at the bottom dead center. During the Piston, Air’s downward movement is sucked, and in the turbocharged engines,, the air is forced with positive pressure inside the cylinders.
  • Compression: – Compression stroke begins at BDC (Bottom dead centre) and ends just at the end of suction stroke. In this stroke, the piston compresses the air to a pressure between 32 to 50 bar and the temperature in the range of 6000
  • Ignition Stroke:- his stroke is also known as Power/Combustion stroke. This stroke starts in the 2nd revolution of the crankshaft. During this stroke, the Chemical Energy of fuel’s mechanical energy pushes the piston downward, transmitting the power to the crankshaft.
  • Exhaust:– This stroke is also known as exhaust expulsion stroke.  Exhaust stroke begins at BDC (Bottom dead centre) and finishes at

Notations used by MAN B&W engines

MAN – Germany – Maschinenfabrik Augsburg Nurnberg,
B&W – Denmark – Burmeister & Wain Motorfabrik A/S

The merger of above two Giants is now known as Man B&W.

MAN B&W ENGINE Specifications:


7 – Number of cylinders
74 – Cylinder diameter in cm
V – Single acting 2-stroke
T – Cross Head
2B – Degree of Turbocharging
F – Marine applicationS – Stationary Application


7 – Number of cylinders
K – Two stroke cross head
74 – Cylinder diameter in cm
E/G – Engine model/Hydraulically Operated Exhaust Valve
F – Marine application


7 – Number of cylinders
L – Long stroke
80 – Cylinder diameter in cm
G – Engine model/Hydraulically Operated Exhaust Valve
F – Marine Application
C – Constant pressure turbocharging
A – Engine rating


7 – Number of cylinders
L – Long stroke
80 – Cylinder diameter in cm
G – Engine Model/Hydraulically Operated Exhaust Valve
B – Engine rating
E – Economy layout


7 – Number of cylinders
S – Super long stroke
80 – Cylinder Diameter in cm
MC – Engine model/Programme


6 – Number of cylinders
K – Two stroke cross head
90 – Cylinder diameter in cm
MC – Engine model/Programme-
C – Short stroke container ship application-
S – Stationary Application

5L60MC MK-5

5- Number of cylinders
L – Long stroke
60 – Diameter of cylinder in cm
MC – Engine Programme
MK 5 – Engine version/Mark Number


6 – Number of cylinders
S – Stroke/bore ratio – (G – ‘Green’ Ultra long stroke, S – Super long stroke,
L – Long stroke, K – short stroke)
90 – Diameter of the Cylinder in mm
M – Engine programme series
E – Concept – (E – Electronically controlled, C – Camshaft controlled)
C – Design – (E – Exhaust valve controlled by camshaft, C – Compact engine)
9 – Mark NumberGI – Fuel injection concept – (“blank” – Fuel oil only, GI – Gas injection)TII – Emission regulation – (TII – IMO Tier level)
Stroke/ Bore ratio:
K – Short stroke (approximately ratio = 2.8)
L – Long stroke (approximately ratio = 3.2)
S – Super long stroke (approximately ratio = 3.8)
G – Ultra long stroke (approximately ratio=4.7)


Basic components of an ICE engine
Basic components of an ICE engine
  • Cylinder Block
  • Base Frame
  • Crankshaft
  • Connecting Rod
  • Piston
  • Cylinder Liner
  • Cylinder Head
  • Flywheel
  • Camshaft
  • Valve Train
  • Fuel Injection Pump
  • Fuel Injector
  • Vibration Damper
Cylinder Block
The Best Tutorial on All About Marine Diesel Engines Theory 34

Cylinder Block

Cylinder Block

A Cylinder Block is made of Cast Iron as a single unit in the liquid-cooled type engines. Block is designed to provide the following.

  • Rigid frame with string structure to house the Cylinder Liners.
  • Water passage.
  • Lube oil Passages.
  • Cylinder block supports the crankshaft and camshaft bearings..


The Best Tutorial on All About Marine Diesel Engines Theory 35
  • Solid forged: – One to four throw crankshafts are made from a single ingot.
  • Semi built:- In Semi-built Each pair of webs and crank-pin joining them are on one piece, and the separate journals are shrunk in.
  • Built:-Built-up crankshaft comprises separate webs, crank-pins, and journals.

 Functions of Crankshaft

  • Crankshaft transforms the motion of the piston to flywheel. From flywheel the power is transferred to the Alternator or propeller.
  • The throw of the Crankshaft controls the piston stroke.
  • Transmits drive to Camshaft for operating the valves, Fuel Pumps as per the timing of Engine.
  • Transmits the drive to all the lube oil, fuel oil, and water pumps.

Crankshaft components

  • Crank-throw:-
  • Crank-webs
  • Main-bearing Journal
  • Connecting-rod Big-end (Crank-pin) Journals

Connecting Rod

Con Rod
  • Big End
  • Small End

Big End: – Big end of the connecting rod is attached to crankshaft through crank pin.

Small End:-   Small end of the connecting rod and piston are attached to each other through gudgeon pin ( Piston Pin).


  • Connecting rod attaches the piston with crankshaft.
  • Expanding gases on completion of Power stroke transmit the force to Piston downward and the movement is transmitted to Crankshaft.

The piston has two parts.

  • Piston Crown
  • Piston Skirt

   Characteristics of a Piston

  •  Piston should be capable of rapid movement without any friction. With a running clearance in hot position should form a sealing surface?
  • Should have less weight to work with minimum inertia forces.
  • Should have enough strength to transmit the firing loads without getting distorted.
Piston Rings
  • Ring should form a seal between working surface of cylinder liner and piston.
  • Amount of oil and scrape of the excess oil is performed by piston design.
  • The piston rings should be able to transfer the combustion heat to the cooling water through cylinder liners.

Piston Rings

  • Top ring ( Fire ring)
  • 2nd Ring ( Compression and oil control)
  • 3rd Ring ( Compression)
  • 4th Ring ( Oil scrapper ring)
Cylinder Liner


Cylinder Liner

Engine cylinders

Engine Cylinders are popularly known as the liners. There are two type of liners based on their cooling design and fitment in cylinder blocks.

  1. Dry liners
  2. Wet liners

Dry Liners;- This type of design of liners is not cooled directly by the cooling water as is not exposed to the water circulation. Water circulates through the cavities. These type of cylinders are with thin wall design and are shrunk fit in the cylinder blocks. Tight fit of cylinders is beneficial since there are no chances of the cylinders suffering the corrosive effect.

Wet Liners.;- These type of cylinders are directly cooled by the cooling water circulating  around  the external surface of the cylinders. The water leakage sealing is affected by the Orings fitted in the grooves. There is also one metallic sealing rings provided between the cylinder block and cylinder liners.

These liners have the better cooling effect due to the direct conduction of heat. These liners have one serious drawback of getting affected by the corrosion and erosion due to the cooling water. In such type of cylinders, special attention need to taken to maintain the cooling water standards as per the manufacturers recommendations.


Cylinder Head

  • It reduces the vibration through inertia by normalising it in each firing stroke.
  • To control the unbalance forces on the crankshaft and maintain the regular speed, Fly wheel is mounted on the crankshaft –end.
  • The gears on the flywheel facilitate the engagement of starting motor and crankshaft.

Flywheel weight is concentrated towards the outer circumference. It stores the energy due to the angular momentum while in rotation. Rotational speed changes are resisted by Flywheel. Flywheel gains momentum in the power stroke of the engine and maintains the even speed in the other three strokes of the engine. Flywheel also dampens the process of torsional vibration.
By choosing the suitable weight of Flywheel engine can work smoothly at various workloads.




I hope the post on DIESEL ENGINE BASICS has been useful to students.

The Best Book On Diesel Egines

Fundamentals of Medium/Heavy Duty Diesel Engines

Based on the 2014 National Automotive Technicians Education Foundation (NATEF) Medium/Heavy Truck Tasks Lists and ASE Certification Test Series for truck and bus specialists, Fundamentals of Medium/Heavy Duty Diesel Engines is designed to address these and other international training standards. The text offers comprehensive coverage of every NATEF task with clarity and precision in a concise format that ensures student comprehension and encourages critical thinking. Fundamentals of Medium/Heavy Duty Diesel Engines describes safe and effective diagnostic, repair, and maintenance procedures for today’s medium and heavy vehicle diesel engines, including the most current, relevant, and practical coverage of: • HD-OBD emission diagnostics • Common rail injection systems

Pounder’s Marine Diesel Engines and Gas Turbines

Ponders 3

 Pounder’s Marine Diesel Engines has served seagoing engineers, students of the Certificates of Competency examinations and the marine engineering industry throughout the world.

Now in its ninth edition, Pounder’s retains the directness of approach and attention to essential detail that characterized its predecessors. There are new chapters on monitoring control and HiMSEN engines as well as information on developments in electronic-controlled fuel injection. It is fully updated to cover new legislation including that on emissions and provides details on enhancing overall efficiency and cutting CO2 emissions.
After experience as a seagoing engineer with the British India Steam Navigation Company, Doug Woodyard held editorial positions with the Institution of Mechanical Engineers and the Institute of Marine Engineer

* Helps engineers to understand the latest changes to marine diesel engineers
* Careful organisation of the new edition enables readers to access the information they require
* Brand new chapters focus on monitoring control systems and HiMSEN engines.
* Over 270 high quality, clearly labelled illustrations and figures to aid understanding and help engineers quickly identify what they need to know.

Lamb’s Questions and Answers on the Marine Diesel Engine

Lambs Questions and Answers

The book is comprehensive and includes almost all topics needed to understand marine diesel engines. The book explains the role of heat in engineering science, the principles behind internal combustion engines, the role of fuels and lubricants, the cooling systems, the lubricating systems and the heat exchangers.

The book also explains the various parts of the marine engines and their functions. Air-storage tanks and air compressors are also dealt with in the book. Information on balancing and vibration, various instrumentation and control methods, along with the safety measures are covered in the book.

Lamb’s Questions and Answers on the Marine Diesel Engine was published by Butterworth-Heinemann in 1990. The eighth revised edition is available in hardcover.

A Pocket Book of Marine Engineering: Questions and Answers

A Pocket Book webp

A Pocket Book of Marine Engineering: Questions and Answers is a book that covers the topic of air filter for engine in great detail. This book is a great resource for anyone who wants to learn more about this topic. The author, John Myatt, is a world-renowned expert on marine engineering. In this book, he covers everything from the basics of how these engines work to more advanced topics like choosing the right air filter for your engine. If you’re looking for a comprehensive guide to air filter for engine, this is the book for you.

This handy pocket-sized guide is filled with hundreds of questions and answers on marine engineering, covering all the basics from engines and propulsion to steering and safety. It’s perfect for anyone who wants to learn more about this fascinating subject, whether they’re studying for a qualification or just interested in how boats work. With clear explanations and plenty of diagrams, this book is an essential reference for anyone with an interest in maritime engineering.

Introduction to Marine Engineering

Introduction to Marine Engineering webp

This second edition deals comprehensively with all aspects of a ship’s machinery from propulsion and steering to deck machinery and electrical equipment with a strong emphasis upon correct and safe procedures.

Material has been added and revised to reflect the greater weight now being placed upon the cost-effective operation of ships; in terms of greater equipment reliability, more fuel-efficient engines, the ever-increasing shift towards automatically operated machinery, and the need for fewer engineering crew. This is an invaluable guide for professionals but equally covers the requirements for Class 4 and Class 3 Engineer’s Certificates of Competency, the first two years of the Engineer Cadet Training Scheme, and the Engineering Knowledge syllabus for the Master’s Certificate.

Diesel Generator Handbook

Diesel Generator Handbook 1

Diesel Generator Handbook meets the need for an authoritative reference work covering the range of mechanical and electrical topics embodied in the practical design and application of diesel generating plant. It will be particularly welcomed in many parts of the developing world where the diesel generator is basic to the electricity supply system.

The discussion covers, in fifteen chapters, the prime mover, power ratings, synchronous generators, load assessment, control principles and systems, switchgear and controlgear, standby power, fuels and lubricating oilss, installation and commissioning, noise reduction, and plant operation and maintenance.

The book thus caters for all who are concerned with the selection, specification, testing, commissioning, operation and maintenance of diesel-based generator systems: not only the practising plant or services engineers, but also non-specialist engineers and users. The young technician or trainee engineer who is embarking on a career in the supply industry will find this handbook an invaluable investment.

L L J Mahon, FIEE, FBIM, after an engineering apprenticeship with BTH in Rugby, gained over 30 years’ experience in the design, development, manufacture, installation and commissioning of both stationary and highly specialised mobile diesel generator plant for a range of applications.

Marine Engineers Tools and working gears

Rechargeable LED Flashlight

Rechargeable LED Flashlight

The Rechargeable LED Flashlight is the perfect gift for anyone. With its color A LED light, it is perfect for illuminating the darkest places. The powerful beam can easily illuminate the surroundings and can provide you with a farther and clearer vision. The included bulb can provide you with a max of 10,000 lumens, making it the perfect choice for an emergency lighting needs.

Vibration Meter

Viberation Meter

The Vibration Meter, High Accuracy Split Type Digital Vibration Meter is the perfect tool for measuring vibration levels in the environment. With a wide measurement range of acceleration: 0.1~199.9m/s2 peak, it can measure the environment temperature with 2 temperature units (℃ and ℉). The vibrometer gauge adopts piezoelectric acceleration transducer transfer the vibration signal in to electrical signal, analyze the input signals, and show the vibration level.

Men’s Long Sleeve Zip-Front Coverall

Mens Long Sleeve Zip Front Coverall

The CQR Men’s Long Sleeve Zip-Front Coverall is perfect for a work environment. The mix of polyester and cotton fabric is breathable, wrinkle-free, and comfortable. The fabric is opaque and hidden stains. TheCQR Twill Coveralls Series is designed for work and utility essentials for hands-on professionals.

Timberland Men’s Pit Boss 6 Inch Steel Safety Shoes

Steel Safety Toe Industrial Work Boot

The Timberland Men’s Pit Boss 6 Inch Steel Safety Shoes are a must-have for any safety-conscious man. Made with 100% leather and imported from the USA, these shoes are perfect for Work, Play, or any other activity where you need a pair of shoes that will keep you on your feet all day long. The heeled design provides a secure grip on your foot while the padded collar and ankle collar keep you comfortable all day long. Plus, the rugged nubuck leather will keep you looking sharp while you work or play.

Blog Conclusion

We hope you enjoyed our blog post on DIESEL ENGINE BASICS! We hope that you found it helpful in your research and that you found it informative. If you have any questions, please don’t hesitate to reach out to us at Thank you for reading, we would love to hear from you!

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