Knock Sensor: Description and Operation

V6 DFI Engine

Knock Sensors










One knock sensor is bolted to the crankcase on the left -KL- and another on the right -KR-. They detect knocking in individual cylinders. To prevent knocking, the cylinder selective knock control system monitors the electronic ignition timing control system. Based on the signals from the knock sensors, the DME control unit adjusts the ignition timing angle for the knocking cylinder until the knocking stops.

If a knock sensor fails, the ignition timing angles of the affected cylinder group (1-3-5 or 2-4-6) are retarded. This means that a safety ignition timing angle is set to "late". Knock control for the cylinder group of the remaining, intact knock sensors is unaffected. If both knock sensors fail, the DME control unit goes into knock control emergency operation during which the ignition timing angles are generally retarded, thereby reducing engine power considerably and increasing fuel consumption.