8-VALVE 1.4
ENGINE
FIAT PUNTO TRAINING OUTLINE
Fiat Auto S.p.A.
After Sales Training
4.4 Sensors
4.4.1 Knock sensor
Description
The piezoelectric knock sensor is fitted to the engine base and measures the intensity of the
vibrations caused by the knock in the combustion chamber.
The knocks generate a mechanic rebound on a piezoelectric crystal that sends a signal to the
control unit: the engine control unit will, based on this signal, reduce the ignition advance until
the phenomenon disappears. Next, the advance is gradually restored to the base values.
Position on the vehicle
1
1: phase sensor
gb Fiat Grande Punto OK
241 / 532
© 2004 Fiat Auto S.p.A. – All rights reserved