kaasuläppäkotelo

A kaasuläppäkotelo, commonly known in English as a throttle body, is a crucial component of an internal combustion engine's air intake system. Its primary function is to regulate the amount of air that enters the engine, thereby controlling engine speed and power output. The name "kaasuläppäkotelo" directly translates to "gas flap housing" in Finnish, referring to the key part within it.

Inside the housing is a throttle plate, also known as a butterfly valve. This plate is a rotating disc that is connected to the accelerator pedal, either mechanically via a cable or electronically through a sensor. When the driver presses the accelerator, the throttle plate opens, allowing more air to flow into the engine. Conversely, when the pedal is released, the plate closes, restricting airflow and reducing engine speed.

The airflow passing through the throttle body is measured by a throttle position sensor (TPS). This sensor sends information to the engine control unit (ECU), which then adjusts the fuel injection and ignition timing to optimize combustion based on the amount of air entering. Modern vehicles often feature electronic throttle control (ETC), also called drive-by-wire, where there is no direct mechanical link between the pedal and the throttle plate. Instead, the pedal's position is read by a sensor, and the ECU commands an electric motor to open or close the throttle plate accordingly. This allows for more precise control and integration with other vehicle systems like cruise control and traction control.