Mercedes-Benz OM 471 Introduction Into Service Manual page 98

The fuel that is required for hydraulic pressure boosting is
collected in a bore in the cylinder head and led to the fuel cooler
(10) via the fuel return line of the pressure booster (36), from
where it is led back to the fuel pump (3).
The fuel cooler (10) serves to cool down the fuel, which is at a
temperature of about
120 ∞C.
The excess fuel from the injector needle valves is also collected in a
bore in the cylinder head and led into the fuel collection chamber
(13) via the fuel return of the nozzle needle valves (37) and the
check valve (12).
The check valve (12) in the fuel return of the nozzle needle valves
(37) has the task of achieving the required back pressure of about
2 bar while the engine is running, therefore ensuring that the fuel
injectors work perfectly.
Component description for fuel
temperature sensor
Fuel filter module pressure sensor,
component description
Component description for quantity
control valve
Pressure limiting valve, component
description
Component description for fuel pump
Component description for fuel cooler
Component description for fuel filter
module
i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >
– This printout will not be recorded by the update service. Status: 09 / 2011 –
Part of the returned fuel is taken from the fuel collection chamber
(13) and returned to the fuel low pressure circuit via the fuel
return bypass (42), just upstream of the fuel prefilter (7).
The fuel quantity is determined by the throttle (11) and the check
valve (12) in the fuel return bypass (42), which reduces the fuel
pump (3) suction load.
The remaining fuel from the fuel collection chamber (13) is led
back to the fuel tank (1).
The shutoff valve in the fuel return line (16) prevents fuel leaking
out when the fuel line between the fuel tank (1) and the fuel filter
module (2) is disconnected.
B602
B638
Y642
Functions
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