Petrol Engine PPT

1. ENGINEERING
THERMODYNAMICS
PRESENTATION
BY
PHALAKSH MANGAL (PB 04)
PRATYANCHA JOSHI (PB 12)
DIVISION 2 BATCH S5

2. What is an Engine?
An ENGINE is a
machine used to convert
HEAT ENERGY into
MECHANICAL
ENERGY.

3. Petrol engine
A petrol engine (known as a gasoline engine) is an
INTERNAL COMBUSTION engine with the spark ignition.
So it is also known as spark ignition engine(S.I. Engine).
Fuel used In a petrol engine is a gasoline ( Petrol ) and
similar volatile fuel.
The petrol engine works on principle of theoretically OTTO
CYCLE.

4. There are TWO types of Petrol Engines
- 4 STROKE PETROL ENGINE.
- 2 STROKE PETROL ENGINE.

5. 4 STROKE
PETROL ENGINE

6. A FOUR STROKE PETROL ENGINE shown in figure.
The valve operating the inlet is called inlet valve and the valve operating the
exhaust is called exhaust valve. The spark plug fitted at the top of cylinder
head initiates the ignition of the air fuel mixture.
The piston performs four stroke to complete one
working cycle. The four different strokes are;
Suction stroke
Compression stroke
Power stroke
Exhaust stroke

7. INTAKE STROKE
INTAKE VALVE OPEN
EXHAUST VALVE CLOSED
PISTON GO TO TDC TO BDC
AIR-FUEL MIXTURE ENTER IN TO THE
CYLINDER

8. COMPRESSION STROKE
INTAKE VALVE CLOSED
EXHAUST VALVE CLOSED
PISTON GO TO BDC TO TDC
AIR-FUEL MIXTURE COMPRESSED IN TO THE
CYLINDER

9. POWER STROKE
INTAKE VALVE CLOSED
EXHAUST VALVE CLOSED
AIR-FUEL MIXTURE BURN INTO THE COMBUSTION
CHAMBER
PISTON GO TO TDC TO BDC

10. EXHAUST STROKE
INTAKE VALVE CLOSED
EXHAUST VALVE OPEN
PISTON GO TO BDC TO TDC
EXHAUST GAS OUT THROUGH THE EXHAUST VALVE

11. THE WORKING OF 4 - STROKE PETROL ENGINE.
Exhaust valve Inlet valve
Petrol and air mixture
Exhaust
gases
TDC
BDC
Spark plug

12. TWO STROKE
PETROL ENGINE

13. As the name itself implies, all the processes in
two stroke cycle engine are completed in two
strokes.
In two stroke engine cycle operations suction , compression ,
expansion and exhaust are completed in one complete
revolution.
These engines have one power stroke per revolution of the
crank shaft.
Two-stroke engines do not have valves, which simplifies their
construction and lowers their weight.

15. Major parts
•CYLINDER
•PISTON
•CRANK SHAFT
•ENGINE VALVE
•CONNECTING ROD
•CAM SHAFT
•SPARK PLUG

16. Advantages of Petrol engine
High engine speeds of about 3000 rpm.
Lighter in a weight because maximum pressure and temperature is less.
Less initial cost.
Less maintenance cost.
Disadvantages of Petrol engine
low compression ratio ranging from 6 to 10.
The thermal efficiency is lower due to lower compression ratio.
Running cost higher because petrol is costly.

17. THANK YOU