MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
394
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 6-1-27 Working principles of crankshaft
position sensor
cylinder head cover, and use the specified torque to
tighten 2 hexagon flange bolts (M6×12). See Fig.
6-1-26.
Attention:
A close fit between sensor plane and
cylinder head cover installation plane shall be
maintained after the installation.
Tightening torque for the fastening bolts of
camshaft position sensor:
9 N•m±3 N•m
2.7.3 Crankshaft Position Sensor
The installed crankshaft position sensor is opposite to
the ferromagnetic trigger wheel, and they are separated
by a small air gap.There is a soft iron core in the
sensor. This core is surrounded by the coils and
connected with a permanent magnet.
Fig. 6-1-28 Working principle of Hall-Effect phase sensor (camshaft position sensor)
Sensor coil
Sensor coil
Alternating current sine wave
Positive
voltage
Negative
voltage
Controlled voltage
Constant current
Magnetic field
Direction of
turning
Permanent
magnet
Impeller
Vane
Window
Ignition switch
Gallium arsenide crystal
Weak
analog
signal
Amplifier
Amplified
phase
inversion
signal
Schmidt
trigger
Transistor
switch
Turned off
Digital
signal
Turned on
Switch
transistor
Collector
Emitter
Two circuit
designs are
optional
Computer
Voltage
sensing circuit
Computer
Voltage
sensing circuit
When the transistor comes
into the ―On‖ status from the
―Off‖ status, the voltage of
collector circuit will increase
to approximately 12V.