Component Description For Fuel Pump - Mercedes-Benz OM 471 Introduction Into Service Manual

GF47.20>W>2000H
ENGINES 471.9 in MODEL 963
Location
1 Fuel pump
A Fuel feed/suction side
B Fuel feed (thrust side)
The fuel pump (1) is located at the fuel high
pressure pump.
Task
The fuel pump (1) draws the fuel out of the
fuel tank via the fuel filter module, and
supplies the fuel system high pressure pump
with the required quantity in all engine
operating conditions.
Design
2 Fuel inlet
3 Bypass valve
4 Fuel outlet
5 Pressure limiting valve
A Fuel feed/suction side
B Fuel feed (thrust side)
Function
The fuel pump (1) is designed as a gear pump and is driven via the
fuel high pressure pump. As soon as the engine starts and runs,
the right gearwheel in the fuel pump (1) is driven via a drive plate
on the camshaft of the fuel high pressure pump. Since the teeth
on the right gearwheel engages in the teeth on the left
gearwheel, it turns simultaneously in the opposite direction. The
rotating movement of both gearwheels and the design of the
pump chamber cause the fuel to be drawn in via the fuel inlet (2)
and delivered to the fuel outlet (4) along the inner wall of the
pump. During this operation fuel is compressed until the fuel
pressure or system pressure required is reached.
i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >

Component description for fuel pump

– This printout will not be recorded by the update service. Status: 09 / 2011 –
System components
The max. permissible system pressure that can already be reached
at idle speed is determined by the opening pressure of the
pressure limiting valve (5).
If the system and/or the opening pressure is reached and
therefore the pressure limiting valve (5), that is designed as an
overflow valve, is opened, thrust side fuel feed (B) is connected to
the suction side fuel feed (A) via a duct to prevent a further build>
up of pressure.
If the fuel system is being filled externally, the bypass valve (3) is
installed through which fuel can flow past the stationary
gearwheels to the thrust side fuel feed (B).
20.7.11
W47.20>1083>76
W47.20>1061>81
203