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Contents

1. Purpose of Training and about Diesel Engine…………………. 1

2. Working Principle………………………………………………. 4

3. Classification of Diesel Engine…………………………………. 6

4. Terminology in Diesel Engine………………………………….. 7

5. Engine Components……………………………………………. 9

6. Identification of some more parts……………………………... 17

7. Tools……………………………………………………………. 19

8. Piping System of Ship…………………………………………. 21

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Chapter – 1

Purpose of training and about Diesel Engine

The Purpose:

Diesel Engine

Working Principle of Diesel Engine.

Diesel Engine Process.

Classification of Diesel Engine.

Terminology used in Diesel Engine.

Components of Diesel Engine.

Operation of Maintenance.

Piping System of Ship

Diesel Engine:

The diesel engine (also known as a compression-ignition engine) is an internal

combustion engine that uses the heat of compression to initiate Ignition and burn the fuel

that has been injected into the combustion chamber.

The diesel engine has the highest thermal efficiency of any standard internal or

external combustion engine due to its very high compression ratio and inherent

lean burn which enables heat dissipation by the excess air.

Diesel engines are manufactured in two-stroke and four-stroke versions. They

were originally used as a more efficient replacement for stationary steam engines.

The world's largest diesel engine is currently a Wärtsilä-Sulzer RTA96-C

Common Rail marine diesel of about 84.42 MW (113,210 hp) at 102 rpm[4] output.

Fig: 1(a & b) Diesel Engine

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History of Diesel Engine:

In 1885, the English inventor Herbert Akroyd Stuart began investigating the

possibility of using paraffin oil (very similar to modern-day diesel) for an engine,

which unlike petrol would be difficult to vaporize in a carburetor as its volatility is

not sufficient to allow this.

His engines, built from 1891 by Richard Hornsby and Sons, were the first internal

combustion engine to use a pressurized fuel injection system. The Hornsby-

Akroyd engine used a comparatively low compression ratio, so that the

temperature of the air compressed in the combustion chamber at the end of the

compression stroke was not high enough to initiate combustion. Combustion

instead took place in a separated combustion chamber; the "vaporizer" (also called

the "hot bulb") mounted on the cylinder head, into which fuel was sprayed. Self-

ignition occurred from contact between the fuel-air mixture and the hot walls of

the vaporizer. As the engine's load increased, so did the temperature of the bulb,

causing the ignition period to advance; to counteract pre-ignition, water was

dripped into the air intake.

Fig: 2(a & b) Old Diesel Engines

In 1991Herbert Akroyd Stuart invents the first internal combustion engine to use a

pressurized fuel injection system. But now these days Piaggio launches a twin-

cinder turbo diesel engine, with common rail injection, on its new range of micro

vans.

Fig – 3 Diesel Engines

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Chapter – 2

Working Principle

Working Principle:

A reciprocating engine, in the cylinders of which an introduced

charge of air is compressed sufficiently to ensure spontaneous ignition

and combustion of an atomized stream of fuel injected into the said

charge of compressed air.

Engine which works on the Diesel principle or Diesel cycle.

The diesel internal combustion engine differs from the gasoline powered Otto

cycle by using highly compressed hot air to ignite the fuel rather than using a spark

plug (compression ignition rather than spark ignition).

In the true diesel engine, only air is initially introduced into the combustion

chamber. The air is then compressed with a compression ratio. This high

compression heats the air to 550 °C (1,022 °F). At about the top of the

compression stroke, fuel is injected directly into the compressed air in the

combustion chamber. This may be into a (typically toroidal) void in the top of the

piston or a pre-chamber depending upon the design of the engine. The fuel injector

ensures that the fuel is broken down into small droplets, and that the fuel is

distributed evenly. The heat of the compressed air vaporizes fuel from the surface

of the droplets. The vapour is then ignited by the heat from the compressed air in

the combustion chamber, the droplets continue to vaporise from their surfaces and

burn, getting smaller, until all the fuel in the droplets has been burnt.

Diesel Cycle:

1-2 ISENTROPIC COMPRESSION

2-3 HEAT ADDITION AT CONST. PR

3-4 ISENTROPIC EXPANSION

4-1 HEAT REJECTION AT CONST. V

P-V Diagram for the Ideal Diesel cycle. The

cycle follows the numbers 1-4 in clockwise

direction. In the diesel cycle the combustion

occurs at almost constant pressure and the

exhaust occurs at constant volume. On this

diagram the work that is generated for each cycle

corresponds to the area within the loop.

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Four stroke cycle

• Intake stroke:

Intake valve opens while the piston moves down from its highest position in the cylinder

to its lowest position, drawing air into the cylinder in the process.

• Compression stroke:

Intake valve closes and the piston moves back up the cylinder. This compresses the air &

therefore heats it to a high temperature, typically in excess of 1000°F (540°C). Near the

end of the compression stroke, fuel is injected into the cylinder. After a short delay, the

fuel ignites spontaneously, a process called auto ignition.

• Combustion stroke:

The hot gases produced by the combustion of the fuel further increase the pressure in the

cylinder, forcing the piston down

• Exhaust stroke:

Exhaust valve opens when the piston is again near its lowest position, so that as the piston

once more moves to its highest position, most of the burned gases are forced out of the

cylinder.

Fig – 3 Strokes

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Chapter – 3

Classification of Diesel Engine

Classification:

Diesel Engine is classified in five types:

Number of strokes: Two strokes and four strokes.

Ignition: Compression and Spark.

Cylinder Arrangement: Inline and ‘V’.

Speed:

1. Low:

Commonly used on ships and for generation of electricity.

2. Medium:

Used for wide range of purposes including ship propulsion, electricity

generation, traction, gas compression & propulsion and pumping of

liquids.

3. High.

Used for automobiles and small gen-sets.

Size:

1. Small - Under 188 kW (252 hp) output,

2. Medium and

3. Large.

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Chapter – 4

Terminology of Diesel Engine

Terminology:

Looking the Engine from Flywheel End

Operating side – left hand or in V-engine A-side.

Back side – opposite of operating side or in V-engine B-side.

Flywheel end – end where flywheel is

Free end – opposite of flywheel end

Bottom – underside

Top – opposite of the bottom

Fig – 4 Terminological figure of Engine

o TDC & BDC

Top Dead Center: Top maximum position of piston in side liner.

Bottom Dead Center: Bottom maximum position of piston inside liner.

o Piston Stroke / Swept Volume

Distance between TDC & BDC is piston stroke.

Volume between these points is swept volume.

o Compression Ratio

Ratio of volumes before and after compression.

Volume between these points is swept volume.

o Combustion Chamber

Space between piston top and flame plate (underside) of cylinder head.

B1

A2

A3A4

A5A6

A7A8

B3B2

B4B5

B6B7

B8

A1

REAR SIDE

FREE END

MANOUVERING SIDE

FLYWHEEL END

B1

A2

A3A4

A5A6

A7A8

B3B2

B4B5

B6B7

B8

A1

REAR SIDE

FREE END

MANOUVERING SIDE

FLYWHEEL END

REAR SIDE

FREE END

MANOUVERING SIDE

FLYWHEEL END

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o Peak Pressure / Combustion Pressure

Maximum pressure developed during combustion.

o Mean Effective Pressure

Theoretical mean pressure acting on piston during power stroke.

o Indicated Power

Power calculated on the with MIP within cylinder.

Calculated from indicator diagram.

= PLANn Here

P – MIP (Nm)

L – Stroke length (m)

A –Area of cylinder (m2)

N – Number of power stroke(4 stroke – RPM/2)

n – Number of cylinders

o Break Power

Actual power available at crankshaft

o Thermal Efficiency

Ratio of energy received by piston during power stroke to the energy

supplied, in terms of fuel.

In other words, it is a ratio of break power to indicated power.

o Mechanical Efficiency

Part of power developed in engine is used to overcome friction of engine

parts. This power is not available as power output.i.e. I.P. = B.P. + F.P.

(friction power)

Ratio.

o Limitations

Friction losses in piston & liner

Acceleration stresses in components

Service life of components

Mechanical load & Thermal load on components

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Chapter – 5

Engine Components

Engine Block:

Cast in one piece. The material is special quality of grey iron or nodular cast iron. Frame

(skeleton) of engine onto/into which all other parts are fixed .Material is special quality

gray iron or nodular cast iron. Charge air receiver and camshaft bearing housing

integrated in the block. Crankshaft is under slung, i.e. supported by main bearing caps

from underneath. Camshaft bearing housings are directly machined in the engine block

Jacket water distribution pipes, lubrication oil pipes and charge air receiver can be

incorporated in the engine block. Main bearing caps are usually bolted to the block also

with a pair of side bolts, for increased engine block stiffness. The bolts are hydraulically

tightened.

Fig – 5 Engine Block

Fig - 6 Engine Block Cross-section

Crankshaft:

The crankshaft converts the up and down movements of the pistons (via the connecting

rods) to a rotary motion. Made of forged alloy steel in one piece and heat treated to obtain

optimum strength. The heat treatment is tempered, quenched and tempered which gives a

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uniform hardness through the entire shaft, or the bearing journals have also been surface

hardened for maximum wear resistance. Drilled oil passages.Fully balanced by

counterweights.In the non-driving end of the crankshaft there is usually a damper to

control the torsional vibrations originating from the combustion pulses. There are

basically two different types of dampers. The most common is the oil filled damper with a

square section ring inside, which rotates driven by the friction of the very thick oil inside

the damper. The other type is built up of many leaf springs. The torsional vibration

damper prevents a premature fatigue of the crankshaft.

Converts up and down motion of piston (via connecting rod) to rotary

motion.

Made of Forged alloy steel in one piece.

Heat treated to obtain optimum strength.

Drilled oil passages.

Oil supplied through main bearing caps.

Fully balanced by counterweights.

Under slung to engine block.

Fig - 7 Crankshaft

Fig – 8 Crankshaft Diagram

Flywheel:

Bolted to flywheel end of crankshaft by flange connection

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Specific number of bolts are reamed

Thin and large diameter disk with high inertia

Smoothens out the speed fluctuations caused by non uniform flow of

power to and from the piston during each stroke

Fig – 9 Flywheel

Piston:

The piston fits snugly in the cylinder liner, to form a tight “plug” that moves up and down

in the cylinder. The tightness is further improved with the piston rings that with their

inherent spring force are pressed towards the cylinder wall. The engine oil strongly

contributes to secure the tightness. The connecting rod’s upper end is fixed to the piston

with the gudgeon pin.

Fig – 10 Pistons

Piston Rings:

Made of high quality cast iron

Cylinder tightness is further improved by inherent spring force

Piston Ring set consist:

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3+1 combination i.e. 3 compression rings plus one oil scrapper ring or

2+2 combination or

Two comp. + one oil scrapper ring in 32LN

Fig - 11 Piston Rings

Connecting Rod:

The connecting rods connect the pistons to the crankshaft, enabling the conversion of an

up and down movement of the pistons to a rotary motion. The force exerted on the piston

top is transferred via the connecting rod to the crankshaft. The connecting rod upper end,

usually called small end, is equipped with a bearing bush, while the lower end, called the

big end, is split into two pieces, with replaceable half moon bearing shells. There are

channels in the connecting rod for transport of lubrication oil from the big end into the

gudgeon pin and piston.

Fig – 12 Connecting Rod

Connects piston to crankshaft

Forces acting on the piston top are transferred to crankshaft through

connecting rod

Connecting rod upper end, called small end, is equipped with bearing bush

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Connecting rod lower end, called big end, is split into two pieces. This is

equipped with replaceable two piece bearing shell.

There are channels to transfer the lube oil from big end to gudgeon pin and

piston.

Types of connecting rod

Fig – 13 types of Connecting rod

Cylinder Head:

The cylinder head forms the cover on top of the cylinder, making the cylinder

hermetically tight. In the cylinder head there are inlet and exhaust valves, controlled by

the camshaft. These valves make the gas exchange in the cylinder possible. The flame

plate is relatively thin and is cooled efficiently with cooling water. Cooling water is

forced from periphery to center. Multi deck design. The box section makes it very strong.

The mech. load is absorbed by a strong intermediate deck.

Fig – 14 Engine Head

Camshaft:

The camshaft is a shaft with an eccentric portion, a cam, which during its rotation pushes

a tappet and pushrod, which in turn pushes on a lever, the rocker arm, pivoted in its mid-

section and located in the cylinder head, pushing to open the valves. The valves are thus

opened and closed in a certain order, making the four stroke process possible. The closing

force for the valves is arranged with springs. The camshaft gets its rotation via gear

wheels connected to the crankshaft. Two revolutions of the crankshaft correspond to one

revolution of the camshaft.

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Fig -15 Camshaft

Fig – 16 Top view of Camshaft

One-cylinder pieces with integrated cams.

Separate bearing journals pieces.

Cam piece mounted and removed sideways.

The bearing housings are integrated in the engine block.

The cams are integrated in the drop forged shaft material.

Rotates half the speed of the crankshaft.

Operate inlet and exhaust valve mechanism, fuel pumps.

Forces Acting -

1. Impact Forces.

2. Torsion.

Oil Sump:

Sump is of welded construction

Bolted to bottom of engine block

Hold the entire lube oil quantity unless it is so called a dry sump

installation

Accommodates oil pipes for engine distribution & lube oil separator

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Oil is led through a hydraulic jack to the main bearing.

Fig – 17 Oil Sump

Cylinder Liner :

Centrifugally casted

Made of Grey cast iron

Externally cooled by water

Upper part is metal to metal sealed with the block

Sealed by two ‘O’ rings against the block to avoid water leakage

Fig – 18 Cylinder Liner

Valve Mechanism:

Spring loaded guide blocks

Barrel shaped rollers

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Yoke - to ensure equal opening of valves

Fig – 19 Valve Mechanisms

Parts of Valve Mechanism:

1. Nut 2. Retainer ring 3. Rocker arm 4. Push rod 5. Protecting sleeve

6. Nut 7. Guide block 8. Cover 10. Guiding pin

11. Valve tappet 12. Bearing journal 13. Bearing bracket 14. Yoke

15. Cylindrical pin 16. Spring

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Chapter - 6

Identification of Some More Parts

Some Parts of Diesel Engine:

The fuel injection pumps are separate for each cylinder, operated by the

camshaft.

The oil sump, bolted to the bottom of the engine block, holds the entire

lubrication oil quantity, unless it is a so called dry sump installation.

The fuel pump, lubrication oil pump and cooling water pumps can be

mounted on the engine and driven from the crankshaft, or can be

electrically driven and located outside the engine.

The turbo charger(s) converts the thermal energy in the exhaust gases to

kinetic energy. It is usually the uppermost part of the engine.

The charge air cooler(s) cools the compressed and hot air after the turbo

charger before the air enters the cylinders. They are located under the

turbo chargers.

The lubrication oil cooler can be fixed to the engine or located outside it.

The cooler is either a plate heat exchanger or a tube type cooler. Both

types are water cooled.

Fig – 20 Fuel Injection Pump

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Fig – 21 Lubrication Oil Pump & Cooling water Pump

Fig - 22 Turbo Chargers

Fig – 23 Air Cooler

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Chapter – 7

Tools

Tools:

Tools are used to make maintenance of machinery possible/easier.

Hand tools are such tools which do not require any other power source than

manpower.

Electrically, hydraulically and pneumatically operated tools are called power

tools.

Standard tools are such tools that can be purchased from shops

Special tools are those which are supplied by the engine manufacturer and are

designed only for specific maintenance and repair work on their engine.

Tool requirements for a particular installation may vary greatly depending on the

use and service area. Standard tool sets are therefore selected to meet basic requirements.

Some Hand tools are

Hand Tools

Fig – 24 combined socket and open end wrench

Fig – 25 Wrench and socket set

Fig – 26 Plaier

Fig -27 Screw Driver

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Fig – 28 Hammer

Power Tools

Fig – 29 Drill and Socket Wrench

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Chapter – 8

Piping System of Ship

Piping System of Ship:

A ship’s piping systems are responsible for providing shipboard drainage, ballast, fire protection, tap water supply, sewage disposal, heat andsteam supply, ventilation and air cond

itioning, refrigeration, and compressed air. A ship contains a total of approximately 80 separate pipingsystems. Pumps, blowers, and other mechanisms in the systems may be powered by the ship’s main or auxiliary power systems or byindividual motors.

Operating pressures in the piping may be as high as 15-20 meganewtons per m2, and pipe diameters range from 3-5 mm to 1 m and more.Some piping systems are tens of kilometers long, and fluids are fo

rced through the pipes by pumps that generate power in excess of 15megawatts. The mandatory complement of systems designed to ensure the safety of a ship and prevent it from

polluting the environment isspecified by classification societies and other organizations, which also perform operational inspections of the piping systems.

Fig – 30 Piping System