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

System components
GF07.02>W>3012H
ENGINES 471.9 in MODEL 963
Location
1 Fuel system high pressure pump
B Fuel feed (thrust side)
C Fuel high pressure
D Fuel return
The fuel high pressure pump (1) is located at
the rear on the left side of the crankcase
and is driven via the pinion gear drive.
Task
The fuel high>pressure pump (1) supplies
the fuel high>pressure circuit with fuel and
ensures that the fuel required for
combustion is available in sufficient
quantity and at the required pressure at the
fuel injectors, under all operating
conditions.
Design
1 Fuel system high pressure pump
2 Fuel high pressure pump housing
3 Suction valves
4 High pressure piston
5 Compression springs
6 Roller tappet
7 Camshaft
8 High pressure valve
9 High pressure connection
Function
The camshaft (7) for the fuel high pressure pump (1) is driven by
the pinion gear drive.
The fuel is compressed by two high>pressure pistons (4) and led via
the respective high>pressure connection (9) and corresponding
high>pressure lines to the rail.
Both roller tappets (6) on the double cams of the camshaft (7) are
pressed together by the two push springs (5) which are offset by
90∞. Thus two power strokes occur for one camshaft revolution per
high>pressure piston (4).
If the high pressure piston (4) is in a downward movement, the
fuel can flow over the corresponding intake valve (3) into the
clearance volume via the high pressure piston (4).
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Component description for fuel system high pressure pump

– This printout will not be recorded by the update service. Status: 09 / 2011 –
If the high pressure piston (4) now changes to an upward
movement, the corresponding intake valve (3) is closed by the
compression pressure arising and the fuel in compressed until the
high pressure valve (8) opens a transfer duct between the high
pressure compartment and the corresponding high pressure
connection (9). The highly compressed fuel can now flow into the
rail.
If the high pressure piston (4) again changes to a downward
movement, the transfer duct is closed by the spring>loaded high
pressure valve (8) and new fuel can flow through the now opened
intake valve (3) into the clearance volume.
20.7.11
W47.20>1084>76
W07.20>1000>81