Knock Sensors, Function

Knock Sensors, Function




A16 Knock sensor
a Signal pattern in the case of controlled combustion
b Signal pattern in the case of uncontrolled combustion (knocking)
c Oscilloscope
t Time
U Electrical voltage

Any vibrations which occur are converted with the aid of the piezo ceramic into electrical signals.
Piezo-electric effect: If a mechanical force acts on a crystal, electrical voltages are produced.

Note: Knock sensor signals may also indicate engine damage, e.g. increased engine noise resulting from a widened piston groove.