Chapter VI Fuel System
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
387
Fig. 6-1-7
Structure of fuel filter
Fig. 6-1-8 DELPHI DFP3.4 high-pressure fuel
pump assembly
Fig. 6-1-9 BOSCH CP1H high-pressure fuel
pump assembly
direct proportion to the speed of diesel engine.The fuel
supply volume is limited by the throttle valve on fuel inlet
end or the overflow valve on fuel outlet end.
2.2 Fuel Filter
The fuel containing impurities will cause damage to the
high-pressure fuel pump parts, fuel outlet valve and fuel
injector.Therefore the diesel engine must be installed
with a fuel filter to filter the fuel.
The fuel filter must meet the specific requirements for
the injection system, or else a normal working of the fuel
supply system and the designed service lives of
relevant elements will not be obtained.
Diesel oil contains soluble emulsion or free water (such
as the cooling water used for shifting the temperature).
If such water enters the injection system, it will cause
cavitations to the fuel system elements.
The GW4D20/GW4D20B turbocharged diesel engine is
equipped with a fuel filter, which has an oil-water
separator used for draining (see Fig. 6-1-7).With the
engine application time increasing and the water level in
the fuel filter reaching a certain height, the water level
alarm lamp of automatic alarm device will light and
remind the driver of draining.
2.3 High-pressure Fuel Pump
The high-pressure fuel pump functions to provide the
sufficient high-pressure fuel for the diesel engine and
meanwhile ensure the extra fuel supply volume and
required pressure for the quick start of diesel engine.
2.3.1 DELPHI DFP3.4 High-pressure Fuel Pump
The GW4D20/GW4D20B turbocharged diesel engine
having a DELPHI common-rail system is equipped with
a DELPHI DFP3.4 high-pressure fuel pump as shown in
Fig. 6-1-8.
The DELPHI DFP3.4 high-pressure fuel pump produces
high pressure through two stages:
①
sucking the fuel
from the fuel tank through the filter;
②
enhancing the
pressure.
Technical parameters of DELPHI DFP3.4 high-pressure
fuel pump:
Plunger: two, with a diameter of 6.5mm.
Capacity: 0. 5cc/rev~0. 7cc/rev.
Pressure: 1600-1800 bar.
The low pressure actuator is used to control the fuel
volume.
Drive method: by belt.
Maximum speed: 4000 r/min.
2.3.2 BOSCH CP1H High-pressure Fuel Pump
Filter cover
Filter cover
Paper filter
core
Housing
Moisture
collector
Drain plug
Fuel outlet
