What are the different phases of combustion in a petrol engine?

1) Inlet, 2) Compression, 3) Ignition, 4) Exhaust. Otherwise known as; Suck, squeeze, bang, blow. 1) Fuel / air mixture is injected/drawn into chamber. 2) Mixture is compressed by piston. 3) Spark, and mixture burns, pushing piston down 4) Piston returning to top of cycle pushes out burnt exhaust gases.