The combustion process of automobile gasoline engine is divided into several stages.

The combustion process of gasoline engine is called power stroke. In this process, normal combustion is divided into two stages. The first stage is the ignition period, that is, the spark is generated from the spark plug, which promotes the rapid oxidation of the mixed gas near the spark and the temperature rises to the first flame; The second stage is the flame propulsion period. At this time, the piston is near the top dead center, and the flame front gradually pushes around at a speed of 30-70m/s. At the farthest point, the pressure and temperature in the cylinder rise rapidly until the combustible mixture is burned out.