1. Intake stroke: The piston moves down the cylinder, drawing in air and fuel.
2. Compression stroke: The piston moves up the cylinder, compressing the air and fuel.
3. Power stroke: The spark plug ignites the air and fuel mixture, causing it to burn and expand, driving the piston down the cylinder.
4. Exhaust stroke: The piston moves up the cylinder, expelling the burnt gases from the cylinder.
Thus, the engine produces one power stroke for every two complete revolutions of the crankshaft.