Component Description For Quantity Control Valve - Mercedes-Benz OM 471 Introduction Into Service Manual

System components
GF07.05>W>6010H
ENGINES 471.9 in MODEL 963
Location
Y642 Quantity control valve
The quantity control valve (Y642) is located on the fuel high
pressure pump.
Task
The quantity control valve (Y642) has the following tasks to fulfill:
f Regulation of the fuel feed to the pump elements of the
high>pressure pump
f Regulation of the rail pressure
f Discontinuity of fuel supply to pump elements of the fuel
high pressure pump for "Engine stop"
Design
1 Fuel high pressure pump housing
2 Coil
3 Float needle
4 Valve spring
Y642 Quantity control valve
Function
The engine management (MCM) control unit (A4) actuates the
coil (2) of the quantity control valve (Y642) using a pulse width
modulated signal. The magnetic field of the coil (2) produced in
this way influences the position of the float needle (3) and thus
the flow cross>section in the quantity control valve (Y642) and
flow rate of the fuel.
At "Engine stop" the float needle (3) is pushed back by the valve
spring (4) and the fuel flow is interrupted.
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Component description for quantity control valve

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20.7.11
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