MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
386
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 6-1-4
Vane type fuel delivery pump
Fig. 6-1-5
Low-pressure actuator (IMV)
Fig. 6-1-6
Gear type fuel delivery pump
2. Components of High Pressure Common
Rail System
2.1 Fuel Delivery Pump
The fuel delivery pump functions to provide enough fuel
for the high-pressure fuel pump.This requirement
should be satisfiled during the whole service life of fuel
delivery pump despite various working conditions and
different necessary pressures of engine.
(1)
Vane Type Fuel Delivery Pump
The GW4D20/GW4D20B turbocharged diesel engine
equipped with a DELPHI common rail system employs
the vane type fuel delivery pump, which has a shifty
volume. The high-pressure fuel pump is integrated with
the fuel delivery pump.The GW4D20B turbocharged
diesel engine equipped with a XINFENG common rail
system also employs the vane type fuel delivery pump.
The vane type fuel delivery pump is used to provide fuel
for the high-pressure fuel pump.
The main parts are a rotor, a stator, 4 vanes equally
divided by 90°(each vane is tightly pressed on the stator
by the helical spring) and 2 sealing discs, as is shown in
Fig. 6-1-4.
The vane type fuel delivery pump delivers fuel to the
high-pressure fuel pump through the low-pressure
actuator (MV).The fuel delivery volume is in direct
proportion to diesel engine speed.
The low-pressure actuator (i.e. IMV, see Fig. 6-1-5)
sends a certain volume of fuel into the high-pressure
fuel pump so as to make the common-rail pressure
meet the ECU requirements.
The low pressure actuator (IMV) is installed on the
pump head.The fuel delivery pump offers fuel to the
low-pressure actuator (IMV) through two semicircular
holes.
A cylindrical filter is attached at the fuel inlet of the
low-pressure actuator (IMV) to protect the actuator
(IMV) and also all the parts behind it (IMV).
(2)
Gear Type Fuel Delivery Pump
The GW4D20B turbocharged diesel engine equipped
with a BOSCH common-rail system employs a gear fuel
delivery pump (see Fig. 6-1-6).The fuel delivery pump
and high-pressure fuel pump are integrated.
The gear type fuel delivery pump is used to provide fuel
for the high-pressure fuel pump as shown in Fig. 6-1-6.
Fuel is sucked into the cavity between the fuel delivery
pump and the gear, and delivered to the fuel outlet on
pressure side. Turning the contacting line between the
gears can ensure a good sealing effect and avoid the
fuel backflow.
The fuel supply volume of gear fuel delivery pump is in
Fuel delivery
pressure
control valve
Transported to high-pressure fuel
pump via IMV
Fuel inlet
Rotor
Vane
Fuel inlet
pressure
Stator
Fuel delivery pressure
Fuel
suction
end
Driving
gear
Pressure
end
