DAF CF65 Series Service Manual page 67

4
CE ENGINE FUEL SYSTEM
series General
2.2 SYSTEM DESCRIPTION, ECS-DC3 FUEL SYSTEM
4
d
6
a
3 2
b
a
U
P
b
c
b
7 7 7 7 7 7
5
a
8
2
1
I400867
The fuel lift pump (4a) draws the fuel from the fuel
tank (1) through the cooling plate of the electronic
unit (3).
The purpose of the cooling plate (3) is to ensure
that the electronic unit does not become too hot.
The fuel lift pump (4a) is fitted against the high-
pressure pump (4c) and is driven by the camshaft
gear.
From the fuel lift pump, fuel is forced towards the
fuel fine filter (5).
After the filter, the fuel enters the high-pressure
pump (4c) via the fuel pump control solenoid
valve (4b), which controls the amount of fuel
going to the high-pressure pump. Fuel not taken
in by the high-pressure pump returns via the by-
pass valve (4d) to the fuel lift pump supply pipe
and part of it is used for lubricating the high-
pressure pump.
The high-pressure pump forces the fuel under
high pressure to the fuel rail (6). The fuel rail
distributes the fuel among the injectors (7). The
fuel rail (6) also functions as an accumulator to
ensure that large fluctuations in pressure,
resulting from injector openings and pump
pressure pulses, are prevented as much as
possible.
The pressure in the fuel rail is registered by the
rail pressure sensor (6a). The electronic unit uses
this data to control the high-pressure pump (via
the fuel pump control solenoid valve), so that the
rail pressure can be kept at the desired level. The
desired pressure is not constant, but depends on
the operating conditions.
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200416 2-7
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