Following strokes are performed in four stroke petrol engine
(Based on these strokes, you can draw a Valve Timing Diagram for an Engine)
Piston starts moving from top dead center resulting opening of the inlet valve. The fresh charge of air-fuel mixture enters in a cylinder. The piston moves further to bottom dead center.
Inlet and exhaust valves are in closed position. And the piston starts moving upward from bottom dead center to top dead center. Hence compression of charge took place.
The ignition is started by spark plug just before the end of compression stroke. Both inlet and exhaust valves are still closed.
A rapid explosion takes place which is followed by expansion of hot gases pushing the piston to its bottom dead center.
In this stroke, the useful work is obtained from the engine that is why it is also called as working stroke.
Piston starts moving upward from bottom dead center, resulting the burnt gases are pushed out through the exhaust valve till it reaches to top dead center.
Up to this point, inlet valve remains closed. When the burnt gases totally exhausted to atmosphere, the piston starts moving down. At this time inlet valve opens, fresh charge is sucked and the cycle is again repeated as earlier.
Theoretically above cycle is well perfect but in actual practice, it is slightly modified. It is done by the opening of an inlet valve and delayed the closing of an exhaust valve.
Valve Timing Diagram details
Will I get your opinion on valve timing diagram?
Besides this information, you are suggested to read something more
To get the more details about the topic, I further recommended reading
- Internal Combustion Engines
- Internal Combustion Engine Fundamentals
- Engineering Fundamentals of the Internal
- A Textbook of Internal Combustion Engines
If you like the post, share it with your friends or on social sites