MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
396
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 6-1-30 Installing knock sensor
2.7.4 Knock Sensor
A knock sensor is an essential part of the electronic
control system in the diesel engine. It is used to check
the diesel engine for any knock and to send the signal
to ECU.
GW4D20/GW4D20B turbocharged diesel engine adopt
piezoelectric knock sensor. See Fig. 6-1-30.
This kind of sensor takes advantage of piezoelectricity
of crystal or ceramic polycrystalline crystal to work, but
some use the
piezoresistance with silicon
to work. The
sensor is equipped with piezoelectric component,
clump weight and wire, etc. Its working principle is as
follows: when the shock of the cylinder body of the
diesel engine occurs and it is transferred to the sensor
housing, relative movement happens between the
housing and the clump weight. The pressure on the
piezoelectric component between the housing and the
clump weight changes, thus resulting in voltage.
Knock sensor
Cylinder body
