What are the 4 diferent strokes in a 4 stroke petrol engine?

the four strokes are1. Suction: half rotation of the crank where air fuel mixture is drawn into the piston

2. Compression: other half of the crank is rotated to push the piston inward to compress AF mixture

3.expansion/working: at the end of compression the compressed AF mixture is ignited by spark plugs inside the cyllider and due to detonation the mixture expands pushing the piston and hence work is obtained.

4.Exhaust: after the working stroke the flue gases are pushed out of the cyllinder by the piston

there are intake and outtake valves in the piston which are controlled by cams to facilitate the suction and exhaust