3. BRIEF INTRODUCTION
• A diesel engine is an internal combustion
engine.
• It converts gasoline into motion
• It is the most common car engine type
• It is relatively efficient
• It is relatively inexpensive
• The engine works on the
principle of diesel cycle
4. HISTORY
Rudolf Christian Karl Diesel (March 18,
1858 – September 29, 1913) was a
German inventor and mechanical engineer,
famous for the invention of the 4-stroke diesel
engine.
RUDOLPH DIESEL
5. Working of Four Stroke Diesel Engine
Following are the four strokes:-
1 – Intake/Suction stroke
2 – Compression stroke
3 – Expansion stroke
4 – Exhaust stroke
6. 1. Intake Stroke
In suction stroke piston starts at Top
Dead Center (TDC) of the cylinder and
moves to the Bottom Dead Center
(BDC).
Outlet valve will be closed
and inlet valve will be open to allowing
the fresh charge of mixed fuel & air
into the cylinder.
7. 2 . Compression stroke
In compression stroke, Once piston
reaches BDC & moves back TDC, inlet
valve will be closed. As the piston
moves towards TDC. It compress air
inside the cylinder & compression takes
place. Hence it is called compression
stroke.
8. 3. Power Stroke
In expansion stroke, Both the valves
are closed. When piston reaches top
of its stroke. the fuel is sprinkled by
the Fuel Injector and the fuel mixture
is ignited due to high temperature &
pressure generated inside the cylinder
& push down the piston to BDC.
Hence it is known as Power or
expansion stroke. The Power
generated in this stroke is stored in
the flywheel for its furthur utilisation
in the other strokes.
9. 4. Exhaust stroke
In this stroke exhaust valve is opened
when piston reaches to BDC & moves
to upward.
Piston pushes out the burnt gases to the
atmosphere through the exhaust valve.
Hence called exhaust stroke & the
engine is ready to begin the cycle again.
10. P-V AND T-S DIAGRAM FOR DIESEL
CYCLE
P-V GRAPH T-S GRAPH
12. DETAILED VIEW OF THE COMPONENTS
1. ENGINE BLOCK
– Cast in one piece. The basis for most of the parts
of the engine.
– ‘V’ Shape
– 2 Sides
• Generator Side
• Free Side
13. 2. CRANKSHAFT
– Singular costliest item in diesel engine.
– Medium of transforming reciprocating motion to
rotary motion.
– Balance weights can be either bolted up or welded.
14. 3. CAM SHAFT
– Performs the vital role of opening & closing inlet &
exhaust valves.
– Allow timely injection of fuel inside the cylinder.
– Usually 3 cams for each cylinder-
2 outer cams for exhaust & inlet valves
1 central cam for fuel injection.
15. 4. PISTON
–Compresses the air to required pressure &
temperature
–Receives the thrust of expanding gases &
transmits the force through connecting rod.
–With the help of piston rings, prevents
leakage of gas from combustion chamber.
16. 5. SOME OTHER PARTS
– PISTON RINGS
• Seal the combustion chamber
• Prevent blow by of air & high
temperature combustion gases.
– CONNECTING ROD
• Connects piston & crank shaft
• Medium of converting reciprocating
motion to rotary motion.
– LINERS
• Forms the wall of the combustion chamber.
• Guides the movement of piston.
17. ADVANTAGES
• More efficient.
• More reliable.
• More durable.
• Release less amount of harmful fumes.
• Easily turbo-charged.
• Produce minimal carbon monoxide.
• Can easily accept synthetic fuels.
CAN ACCEPT SYNTHETIC
FUELS
NO HARMFUL EMISSIONS
18. DISADVANTAGES
• More expensive.
• Occasionally servicing can be more costly.
• Parts tend to be more expensive.
• The cost of diesel at the pump is higher.
• Contribute to Greenhouse effect.
• Generally more noisy.
EXPENSIVE
A BIT NOISY
19. • Diesel Engine relies upon compression ignition.
• Compression ratio lies b/w 16:1 and 25:1.
• Temp. increases to 700C to 900C.
• Piston approaches TDC, fuel is injected.
• Ignition instantly occurs, causing a rapid increase in
cylinder temperature & pressure.
• Piston is driven downward with great force, pushing
on the connecting rod & turning the crankshaft.
• Exhaust gases are expelled then.
