4 stroke Petrol Engine working explained in Malayalam by queen on wheels.
A 4-stroke engine is an IC engine that uses four strokes of the piston to complete a working cycle. It converts the thermal energy of the fuel into useful mechanical work due to the upward and downward movement of the piston. Therefore, it belongs to the category of the reciprocating engine.The main difference between the 2-stroke and 4-stroke engines is that a 2-stroke engine completes a working cycle in just two strokes while a four-stroke engine completes a working cycle in four strokes of the piston.The movement of piston from top to bottom or vice-versa is referred as a stroke.Lets look at the cycle of a four stroke petrol engine.The four strokes are called Suction/intake stroke, compression stroke, power stroke and finally exhaust stroke.As the piston reciprocates toward BCD from TDC (downward), a vacuum starts producing inside the cylinder.When the inlet valve opens, the air-fuel mixture starts entering to the cylinder.This stroke is called Suction stroke.As the piston moves upward (from BCD to TDC), it compresses the air-fuel mixture inside the compression chamber and increases the temperature and pressure of the air-fuel mixture.This is called compression stroke.
When the compression stroke is nearly to be complete, a spark plug burns the compressed air-fuel mixture.
As the fuel gets ignited, the power is generated so that the piston moves from TDC to BDC by expanding the chemical reaction. This is called power stroke.After the completion of the power stroke, the exhaust stroke starts.
In the exhaust stroke, the piston again moves upward (from BDC to TDC).
During this stroke,the exhaust valve opens. The piston pushes the exhaust gases out of the cylinder.And this stroke is called exhaust stroke.This process continues and the engine works.
This is the basic working of a four stroke petrol engine.
In this video we also discuss about the major engine parts and how they works like how the intake and exhaust valve open ,the working of camshaft, timing chain, connecting rod,crank case etc.
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To know more watch the video till the end.