käyntimoottori

Käyntimoottori, often translated as "idle engine" or "idle control system," refers to a component or system in internal combustion engines responsible for maintaining a stable engine speed when the vehicle is stationary and the accelerator pedal is not pressed. This is crucial for preventing the engine from stalling, providing power for essential accessories like the alternator, power steering pump, and air conditioning compressor, and ensuring smooth operation during low-speed maneuvers.

Early systems often utilized a mechanical throttle bypass or a simple solenoid valve controlled by engine vacuum. As engine control technology advanced, more sophisticated electronic käyntimoottori systems became prevalent. These modern systems typically employ an electric motor, often a stepper motor or a DC motor with a gearbox, to precisely control a small amount of air that bypasses the main throttle plate. An Engine Control Unit (ECU) monitors various sensor inputs, such as engine speed, coolant temperature, and load from accessories, to adjust the air flow and maintain the desired idle speed.

The function of the käyntimoottori is vital for fuel efficiency, emissions control, and overall drivability. By precisely regulating idle speed, it prevents unnecessary fuel consumption and ensures that the engine operates within its optimal parameters even when not under acceleration. Malfunctions in the käyntimoottori system can lead to symptoms like rough idling, stalling, or fluctuating engine speeds.