Two-Stroke Engine Working Principle

The two-stroke engine works in two strokes which are as follows:

Upstroke: During the upstroke, the piston compresses the air-fuel mixture into the upper part of the piston chamber where the spark plug ignites the fuel-air mixture. The ignition of the intake gasses causes the piston to move down to the centre of the piston chamber which opens the inlet port and fresh air comes into the piston chamber forcing the exhaust gasses out through the exhaust port.

Downstroke: During the downstroke, the piston is in the centre of the chamber and due to the momentum gained during the upstroke, it again moves to the upper part of the chamber while compressing the fuel-air mixture and the whole cycle is repeated.

These two strokes combine to move the crankshaft through one full rotation.