Knock Sensor: Description and Operation

Knock Sensor:

The knock sensor, Fig. 11, is a piezo-electric accelerator accelerometer with the sensor designed to resonate at approximately the same frequency as the engine knock frequency.. The sensor uses the resonant frequency to mechanically amplify the engine knock frequency (5-6 KHz).

This method allows relatively large signals to be achieved without electrical amplification. The sensor has a thin circular piezoelectric ceramic disk which is bonded to a metal diaphragm. Electrical connections are made through a two-pin integral connector.