MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
398
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 6-1-32 Air flow sensor
Fig. 6-1-33 Installing the air flow sensor
Fig.
6-1-34
Installing
the
turbocharger
pressure sensor
2.7.6 Air flow sensor
The hot-film air flow sensor is an air flow sensor with
logic output. In order to obtain air flow, the sensor film
on the sensor element is heated by the heating
resistance mounted in the center, then the temperature
distribution is measured by the temperature resistance
mounted parallel to the heating resistance. The
temperature distribution is changed by the air flow
through the sensor, so the values of the two
temperature resistances are different. The difference of
the resistance values depends on the direction and flow
of air; therefore, the air flow sensor has high
requirements for the air flow and direction. If necessary,
an air intake temperature sensor can be mounted
inside the sensor to measure the air intake
temperature. See Fig. 6-1-32.
Installation of the air flow sensor: Mount the air flow
sensor between the air intake guide pipe and the
exhaust pipe of air flow meter, and then tighten the clip.
See Fig. 6-1-33.
Attention:
The arrow on the air flow sensor
should be in the direction of air intake.
2.7.7 Turbocharger pressure sensor
The function of the turbocharger pressure sensor is to
detect the pressure and temperature of the air intake
compressed by the turbocharger.
Installation of the turbocharger pressure sensor: Check
whether the O-ring on the turbocharger pressure
sensor is properly installed, then mount the sensor in
the sensor hole of air intake manifold pipe
’s pressure
maintaining chamber; screw up the 2 hexagon flange
face bolts (M6×10) to the specified torque. Air leakage
is not allowed. See Fig. 6-1-34.
Tightening torque for the fastening bolts of the
turbocharger pressure sensor
9 N•m±3 N•m
2.8 Diesel engine harshness
See Fig. 6-1-35 for the schematic diagram of the
GW4D20 turbocharged diesel engine harshness.
Attention:
The harshness connector is equipped
with a self-lock device; when remove or mount the
harshness, hold the harshness connector tightly. It is
strictly prohibited to violently remove or mount the
harness by directly holding the harshness.
Sensor casing
Wire
connecting
terminal for the
measuring
component
Integrated
circuit
Integrated
circuit
O-ring
Temperature sensor
Mounting
plate
Sensor
Casing
Sensor seat
Air flow sensor
Turbocharger
pressure
sensor
Intake manifold
