The components of a petrol and diesel engine are similar. They consist of a sealed cylinder or combustion chamber where the fuel is burned.
They both use a four-stroke cycle to receive the fuel, compress it, use it and finally to expel the gases. The explosion generates a force that moves the piston, which in turn moves the connecting rod and crankshaft. This causes a rotating movement which is used by the vehicle's transmission system to make the wheels turn.