Kia Niro: Engine Control System / Knock Sensor (KS) Description and operation

Knocking is a phenomenon characterized by undesirable vibration and noise that can cause engine damage. Knock Sensor (KS) is installed on the cylinder block and senses engine knocking.

When knocking occurs, the vibration from the cylinder block is applied as pressure to the piezoelectric element, and the sensor produces voltage signal to ECM. On receipt of this signal, ECM will control the ignition timing by retarding the ignition timing and then advancing the ignition timing when the knocking disappears. This sequential control can improve engine power, torque and fuel economy.