LR3/Disco 3
When there is no power supplied, the piston (2) closes the opening between the two connections (1) and (3) through the
force of the compression spring. The fuel supply to the HPP is interrupted.
VCV Actuated (B)
The ECM energizes the coil (4) of the valve, according to the engines requirements. The armature force is proportional to
the control current and counteracts the compression spring through the moving piston (2).
As a result, the opening between the two connections (1) and (3) and hence the quantity of fuel (5) supplied through the
connector (3) to the HPP is also proportional to the control current (6). This means that the greater the opening cross-
section, the greater the quantity of fuel supplied.
Pressure Control Valve (PCV)
The PCV is located on the HPP. It governs the fuel pressure at the HP outlet of the HPP and thus, the fuel pressure within
the rail. In addition, the PCV dampens the fluctuations in the pressure, which occur during the delivery of fuel through the
HPP and through the injection process.
The PCV ensures that optimum pressure exists in the rail for every operating condition of the engine.
The PCV is an electro-magnetically operated valve with spring support.
The electrical current supplied by the ECM through the solenoid pulls back the control pin. This allows the diesel fuel to
pass the ball valve and thus the fuel flow into the common rails.
The entire armature is coated with fuel for lubrication and cooling.
NOTE :
The PCV cannot be replaced as a separate component in service.
