Control Concept - Volkswagen Golf Diesel 2009 Mode D'emploi

Fuel System

Control Concept

The diagram shows the high-pressure regulation
function of the high-pressure pump. The complete
delivery cycle for a cam is shown here.
Fig. 1
– Pump piston intake stroke, fuel fl ows into pump
chamber
– N276 de-energizes
– Intake Valve (IV) opens because spring force is less than
fl ow force of transfer fuel pump — vacuum is present
inside pump
– Exhaust Valve (EV) closes
40
FRV De-Energized
IV
Delivery Chamber
Intake Stroke
I FRV
This cycle takes place four times during a single
revolution of the camshaft. The bottom diagram
shows the movement of the pump piston and the
activation of Fuel Pressure Regulator N276.
FRV De-Energized
EV
Fig. 2
– Pump piston feed stroke, fuel fl ows back to inlet
– N276 de-energizes
– IV opens due to upward motion of pump piston, fuel
moves from pump chamber into inlet
– EV closes
Delivery Chamber