Question

Explain briefly the stages of a petrol engine.

Answer 1

When the piston reaches the top of the cylinder, the sparking plug (yellow) fires. Power: The spark ignites the fuel-air mixture causing a mini explosion. The fuel burns immediately, giving off hot gas that pushes the piston back down. The energy released by the fuel is now powering the crankshaft.

These processes include:

The suction of air (also known as breathing or aspiration).

Mixing of the fuel with air after breaking the liquid fuel into highly atomised / mist form.

Igniting the air-fuel mixture either with a spark (petrol engine) or by self-ignition after raising the temperature of the air by compressing it (dieselengine).

Burning of highly atomized fuel particles which results in releasing / ejection of heat energy.

How does an Engine work?

The engine converts Heat Energy into Kinetic Energy in the form of ‘Reciprocating Motion’. The expansion of heated gases and their forces act on the engine pistons. The gases push the pistons downwards which results in reciprocating motion of pistons.

This motion of the piston enables the crank-shaft to rotate. Thus, it finally converts the reciprocating motion into the 'Rotary motion' and passes on to wheels.