Leerlaufregelungsvorichtung

Leerlaufregelung is a German term that translates to idle speed control in English. It refers to the system in an internal combustion engine that maintains a stable engine speed when the vehicle is stationary and the engine is running, but the transmission is in neutral or park. This stable idle speed is crucial for several reasons. It ensures the engine doesn't stall, provides sufficient power for accessories like the air conditioning and power steering to operate, and helps to minimize fuel consumption and emissions at idle.

The leerlaufregelung system typically consists of an electronic control unit (ECU), sensors, and an actuator. The ECU monitors various engine parameters such as engine speed, coolant temperature, and manifold absolute pressure. Based on this information, it commands the actuator to adjust the amount of air entering the engine. This adjustment fine-tunes the air-fuel mixture to achieve the target idle speed under different operating conditions. Early systems often used mechanical methods, but modern vehicles employ sophisticated electronic control for greater precision and efficiency. A malfunctioning leerlaufregelung can lead to symptoms like rough idling, stalling, or an engine speed that is too high or too low.