The task of the knock sensor is the recognition of knocking combustion.
Knock sensors are used for the detection of knocking combustion. Using the knock sensors, an especially effective combustion of the fuel-air mixture can be achieved through the retraction of the angular ignition spacing and a renewed approach of the knocking limit.

In doing so, the engine output is optimized while fuel consumption and exhaust emissions are reduced. In addition, the knock sensors provide protection of the engine components involved in the combustion process.

The knock sensor is based on a Piezo element which is compressed by an installed weight depending on the structure-borne sound of the fastening point on the engine. In the process, the Piezo element generates a charge depending on this compression and/or acceleration, which is Converted to an output voltage.