1. WHEELSPIN 2k17
Bapurao Deshmukh College Of Engineering Sevagrma (Wardha)
Title – WORKING OF FOUR STROKE PETROL ENGINE
Author – Abhijit kumar
Date 28TH February 2017

2. CONTENTS HEAT ENGINE. MAIN PARTS PETROL ENGINE
CLASSIFICATION OF ENGINE
WORKING OF A PETROL ENGINE
SUCTION STROKE
COMPRESSION STROKE
POWER STROKE
EXHAUST STROKE
CONSTANT VOLUME OR OTTO CYCLE

3. 1. HEAT ENGINE
HEAT ENGINE :- An heat engine is a power generating machine, which converts potential energy of the fuel into heat energy and then into motion. It is a combination of various mechanism which avails to do various work according to its purpose.
FIG-1.1 HEAT ENGINE

4. 2. MAIN PARTS PETROL ENGINE
Cylinder Head
Camshaft
Cam
Push Rod
Valves
Spark Plug
Injector
Gaskets
Cylinder block
Piston
Piston Rings
Gudgeon Pin (Piston Pin)
Connecting Rod
Crank Shaft
Engine Bearing
Manifold
Oil Sump
Flywheel
FIG NO-2.1 MAIN PARTS OF ENGINE

5. Rotary type e.g.-gas turbines3.
Heat engine
Internal combustion
External combustion
Steam engine
Reciprocating type
Rotary type e.g.-gas turbines
Spark ignition
Compression ignition
Oil engine/diesel engine
Petrol engine
Gas engine/CNG/LPG
2 stroke
4 stroke
2 stroke
4 stroke

6. 4. WORKING OF A PETROL ENGINE
A Four Stroke Internal Combustion Engine is an engine whose working cycle consists of an intake stroke, a compression stroke, a power stroke and an exhaust stroke.
FIG NO-4.1 FOUR STROKE ENGINE

7. 5. Suction Stroke – with pistons moving downwards and opening of the inlet valve creates suction of the air-fuel mixture.
Fig-5.1 Petrol Suction Stroke

8. 6. Compression Stroke – With closing of Inlet valve, the area above the piston gets closed. The piston moves up resulting in compression of the air-fuel mixture in a confined space.
Fig-6.1 Petrol Compression Stroke

9. 6.1 Combustion Process – At this stage a spark is fired by the spark-plug resulting in instantaneous burning of petrol resulting in an explosion. This causes heat to release resulting in generation of expanding forces known as power.
Fig-6.2 Petrol Combustion process diagram

10. 7. Power Stroke – These forces again push the pistons downwards resulting in their reciprocating motion.
Fig-7.1 Petrol Power Stroke

11. 8. Exhaust Stroke – On their way up, the pistons push the exhaust gases above them thru’ the exhaust valve which opens during the exhaust stroke.
Fig-8.1 Petrol Power Stroke

12. 9. CONSTANT VOLUME OR OTTO CYCLE
Otto Cycle is also known as Four-Stroke Spark-Ignition Cycle. It was named after German engineer Nikolaus Otto, who invented, developed and patented first Four-Stroke petrol engine. The Four-Stroke petrol engine works on the following cycle.
The cycle is so called constant volume because heat is supplied constant volume petrol gas and light oil work on this cycle. In this case petrol engine the proper mixing of petrol and air take place in the carburetor which is situated outside the engine cylinder.
Piston Displacement
Fig-9.1 Ideal Otto Cycle