The throttle valve actuators regulate the supply of air or mixture to the combustion engine. Depending on the concept of the engine, this serves different purposes. In the case of gasoline engines, speed and power are regulated by fresh air or metering of mixtures. Diesel engines generally do not need a butterfly valve. However, in modern diesel cars, accelerating the amount of intake air facilitates precision control for exhaust gas recirculation and prevents the engine from shaking when the ignition is turned off.