The document discusses diesel engines and how they work. It explains that diesel engines ignite fuel through heat of compressed air rather than a spark plug. It provides details on the 4-stroke diesel engine cycle including intake, compression, power, and exhaust strokes. It also describes the simpler 2-stroke engine cycle and discusses advantages and disadvantages of each.

1. Diesel Engines
Energy & Environment

2. Uses of Diesel Engines
Cars & Buses & Lorries Motor bikes
Mills
Pump water from wells Agriculture equipment

3. Diesel Engines
Heat Kinetic
Chemical
They are very useful in areas where electricity is not
reliable.

4. Why is a Diesel Engine also
known as Compression-Ignition
Engine?
Uses the heat of compressed air to ignite fuel which is
injected into the combustion chamber.
Compressed
Air heats the
air to 550 °C
Examples of
combustion under
compression
Compression-Ignition Engine does not
require a spark plug like a petrol engine.

5. The Internal Combustion Engine
(IC Engines)
1. Fuel and air is Burns its
mixed in the
combustion chamber
fuel inside
the engine
2. Mixture pressurizes
3. Mixture ignites and
expands
4. Forces the piston
down
5. Turns the crankshaft
that through gears
turns wheels

6. The Internal Combustion Engine
(IC Engines)

7. The External Combustion Engine
(EC Engines)
Fuel is burned in a
boiler and then steam
is carried out to the
engine
Steam used to force
piston down
Fuel is
burnt
outside
the engine

8. Two types of Internal Combustion
engines
Two Stroke Engine
Fuel is
burnt
inside the
Four Stroke Engine
engine

9. Four Stroke Engine
Most commonly used for automotive
and industrial purposes
The piston completes four separate strokes
This makes two separate revolutions of the
engine's crankshaft ( rotating disk). This is
connected to gears that often make wheels
turn.
The four-stroke cycle is more efficient, larger and quieter
than the two-stroke cycle, but requires more moving
parts and manufacturing expertise

10. Essential parts of 4 stroke diesel
engine
Cylinder is hollow &
Combustion Chamber. Stationary
Where the air
combusts due to Piston slides up and
increased pressure down in cylinder
Piston rings provide a
Crankshaft turns the up
tight seal between the
and down motion into a
piston and cylinder
rotating motion
wall. Reduce friction
and control the
lubrication.

11. Four Stroke Engine: Intake
stroke
4. Air & Fuel enters in
2. Inlet
valve open
1. Piston at top
3. Piston moves down
reducing pressure in
cylinder

12. Four Stroke Engine: Compression
Stroke
1. Inlet Valve
3. Air-Fuel mixture
closed
gets compressed.
Heats air to 550°C
2. Piston moves up

13. Four Stroke Engine: Power
Stroke
1. Air-Fuel mixture
2. The burning fuel puts gets so compressed
pressure on piston, that it combusts
pushing it downwards

14. Exhaust Stroke
.
1. Exhaust valve
opens. Exhaust gas
leaves cylinder
2. This releases the
pressure so the piston
goes up

15. Four Stroke Engine
1.Intake Stroke
2. Compression Stroke
3. Power Stroke
4. Exhaust Stroke
4 strokes means 2
revolutions of the crankshaft

16. Operation of a Four Stroke Engine
Strokes Movement Intake Valve Exhaust Action in
of Piston Valve combustion
chamber/
Cylinder
Intake Stroke Open Closed Fuel & air enters
chamber
Compression Closed Closed Fuel & air is
Stroke compressed
Power Stroke Closed Closed Compressed fuel
and air ignites
Exhaust Closed Open Piston pushes
Stroke exhausts out of
cylinder

17. 4 Stroke Diesel Engine
The four strokes complete the engine’s cycle. As soon as one
cycle is complete, the other begins
The pistons move due to momentum
But to get started, they need external
energy
An electric motor or manual rotation
of the crank is needed to start the
engine
4 stroke engines have a dedicated
lubrication system

18. Two Stroke Engine
In a two stroke engine, a cycle is completed in two strokes
of a piston or one complete revolution (360º) of a
crankshaft.
Up Down
This is achieved by
exhausting and
recharging the cylinder
at the same time

19. Two Stroke Engine:
Intake/Exhaust Stroke
No valves for exhaust and air but holes on the side of the
cylinder wall. The piston covers and uncovers these holes.
Exhaust
Intake hole is open
and air and fuel comes
in. This forces
exhausts out

20. Two Stroke Engine:
Compression Stroke
Up
Inlet port gets closed and
Air-fuel mixture in the
Piston moves chamber starts getting
compressed.
upwards

21. Two Stroke Engine: Power
Stroke
Fuel combusts
Down
The engine is lubricated using special oil
mixed with the diesel.
Piston gets
pushed down
by hot gases
This leads to
the intake and
exhaust holes
being open and
so the engine
exhausts &
recharges

22. Two Stroke Engine
Fuel combusts
Air & Fuel in
2 strokes of Exhaust out
piston
1 rotation of
crank shaft

23. Two Stroke Engine
Advantages
Simple Design
Less weight
Easier to manufacture
High power to weight ratio
Disadvantages
Do not consume fuel efficiently.
Produce more pollution.
2-stroke engines should be used for light
vehicles that are used for short periods of
time

24. Vigyan Ashram Diesel Engine

25. Vigyan Ashram Diesel Engine

26. Advantages of Diesel Engines
against Petrol Engines
They burn less fuel than a petrol engine performing the
same work
More efficient than petrol engines
They are more reliable as less electrical parts
Diesel engines last about twice as long as petrol
engines due to the increased strength of parts used

27. Noise & Air Pollution
This can cause
asthma, lung
cancer, and early
death
Diesel produces carbon
dioxide, soot & nitrogen
oxides
Diesel contains impurities
that which makes acid
rain
Diesel Engines can be very noisy
and can disturb people and
animals.

28. Summary Questions
1. Why is an IC engine different from an EC
engine?
2. What is different about petrol and diesel
engines with the way they ignite fuel?
3. Where would you expect to find a 4 stroke
engine?
4. What are some of the advantages of a 2
stroke engine and when should they be
used?
5. What type of pollution do we get from
diesel engines?

29. Trouble Shooting of Diesel Engine.
Cause / Fault Remedy To Remove it.
No fuel in tank Fill tank with fresh fuel.
Water in fuel Drain the tank. Clean carburetor and fuel lines.
Fill tank with fresh and clean fuel.
Carbon in Remove the cylinder.
combustion Clean carbon from head and piston
chamber
Loose flywheel Check fly key
Tighten flywheel
Loose Replace connecting rod.
connecting Rod

30. Trouble Shooting of Diesel Engine.
Engine Overheats
Cause / Fault Remedy / To Remove it.
1 Engine improperly Time the Engine
timed
2 Carburetor Adjust Carburetor
improperly adjusted
3 Excessive load on Check operation of associated
engine equipment
Reduce excessive load.
4 Lack of Lubrication Full crankcase with proper oil.

31. Trouble Shooting of Diesel
Engine
Engine Vibration (heavy)
Cause / Fault Remedy / To Remove it.
1 Engine not securely Tighten the loose mounting
mounted bolts.
2 Bent crankshaft Replace crankshaft
3 Associated equipment out Check associated equipments
of balance