The 2-stroke petrol engine is different from the 4-stroke petrol engine. In a 2-stroke engine the inlet and exhaust ports are open and closed by the movement of the piston. But it is still an internal combustion engine and has the 5 events common to all such engines.
Intake occurs when the air-fuel mixture enters the crankcase. It is then transferred from the crankcase to above the piston.
Compression, forcing the mixture into a small volume.
Ignition when the spark from the spark plug ignites the mixture, and it burns.
Power, where energy released by combustion generates the force that turns the crankshaft.
And Exhaust, removing leftover gases.
As in all internal combustion engines, these 5 events must occur, but not always in the same way.
The whole process is a cycle. A new mixture enters and is ignited. Combustion occurs. Expanding gases drive the piston down and turn the crankshaft which pushes the piston back up the cylinder.
