Knock Sensor

The knock sensor prevents damaging spontaneous ignition in your engine. The knocking effect is created by uncontrolled combustion at the wrong phase of the engine cycle, causing extreme temperatures in the cylinder. This places a severe strain on engine components such as the pistons, valves and cylinder head, and can lead to damage. The knock sensor registers the sound of the engine and converts it into electrical pulses. The engine control unit cross-checks the measured pulses against the stored specification values and intervenes to control the engine, fuel injection and ignition as necessary, before the combustion reaches the knock limit. The sensor also detects the fuel quality. The higher the octane number, the more knock-proof the fuel, as it ignites at a higher temperature than normal petrol. If only a lower quality of fuel is available, the engine control unit automatically corrects the ignition timing, based on the information from the sensor. This prevents damage to the engine.