Knock Sensor: Description and Operation

Knock Sensor:

PURPOSE
To help prevent engine damage due to pre-ignition or pinging.

OPERATION
A knocking vibration from the cylinder block is applied as pressure to the piezoelectric element. This vibrational pressure is then converted into a voltage signal which is delivered as output to the Engine Control Module (ECM).


CONSTRUCTION
(C) The knock sensor, consists of a (3) housing a (4) piezoelectric crystal mounted on a (5) threaded sleeve between (6) two connector strips. One side of the assembly is fitted with a (7) damping weight and (8) spring washer secured by a (9) nut.