Air is suctioned into a cylinder in the petrol engine. Fuel is also supplied through the fuel injection. A combustible mixture arises and is then ignited by the ignition sparks.
1. Suction: The piston moves downwards. Environmental air and fuel are suctioned in through the intake valves.
2. Compression: The piston moves upwards again. The mixture in the cylinder is compressed heavily. The ignition takes place in the upper "dead point" area.
3. Operating: The combustion temperature in the combustion chamber increases to up to 2600 °C and the pressure increases to up to 120 bar. The piston is pushed towards the crankshaft at a speed of up to 20 metres per second.
4. Emission: The exhaust leaves through the exhaust valve on the next upward movement of the piston in the cylinder.