Knock Sensor (KS) Description and Operation

Description

Knock is a phenomenon characterized by undesirable vibration and noise, which can lead to engine damage. Two knock sensors (KS) are installed inside the V-bank of the cylinder block and detect engine knock. When knocking occurs, the vibration of the cylinder block is transmitted to the piezoelectric element as pressure. When knock is detected, the sensor outputs a voltage signal. The ECM retards the ignition timing when knock occurs. If the knock disappears after ignition timing retard, the ECM advances the ignition timing. This sequential control can improve engine output, torque and fuel economy.