ENGINES
471.9 in MODEL 963 with CODE (M5R) Engine version EEV
ENGINES
471.9 in MODEL 963 with CODE (M5Y) Engine version Euro V
W47.00>1043>79
1 Fuel tank 2 Fuel filter module 3 Fuel pump
3.1 Pressure limiting valve 3.2 Bypass valve
5 Fuel system high pressure pump 6 Rail 7 Fuel prefilter 7.1 Wastegate 8 Water separator 9 Fuel filter 10 Fuel cooler 11 Throttle 12 Check valve 13 Fuel accumulator
14 Hand>operated delivery pump 15 Shutoff valve in the fuel feed (locked
in open position)
16 Shutoff valve in the fuel return (locked in open position) 17 Shutoff valve (in the form of an
elastomer ball, which prevents draining of the intake duct for standstill of the engine)
18 Evaporation volume of the diesel fuel metering device (for regeneration of the diesel particulate filter (DPF) > for engine version Euro VI)
B602 Fuel temperature sensor B622 Rail pressure sensor
B638 Fuel filter module pressure sensor Y608 Cylinder 1 fuel injector
Y609 Cylinder 2 fuel injector Y610 Cylinder 3 fuel injector Y611 Cylinder 4 fuel injector Y612 Cylinder 5 fuel injector Y613 Cylinder 6 fuel injector Y642 Quantity control valve
A Fuel feed/suction side B Fuel feed (thrust side) C Fuel high pressure D Fuel return
E Bleeding
19 2>stage valve
20 Pressure limiting valve 22 Filling valve
23 Pressure preparation flange for the fuel supply of the diesel fuel metering device
(for engine version Euro VI) 30 Fuel return line from fuel cooler to
fuel filter module
31 Fuel feed line from fuel filter module to fuel pump
32 Fuel feed line from fuel pump to fuel filter module
33 Fuel feed line from fuel filter module to fuel system high pressure pump 35 Fuel return line from 2>stage valve 36 Fuel return line of pressure booster 37 Fuel return line of nozzle needle
valves
38 Fuel return line from pressure limiting valve
39 Vent line (from water separator) 40 Vent line (from fuel filter) 41 Fuel return line from pressure
preparation flange for fuel supply of diesel fuel metering device
(with engine version Euro VI) 42 Fuel return bypass
The fuel pump (3), which has been designed as a gear pump, supplies fuel to the fuel low pressure circuit.
When the engine is started, the fuel pump (3) draws in the fuel in the fuel tank (1) and delivers it into the fuel filter module (2) via the shutoff valve in the fuel feed (15).
The shutoff valve in the fuel feed (15) prevents fuel from escaping when the fuel line between the fuel tank (1) and the fuel filter module (2) is disconnected.
The fuel in the fuel filter module (2) first passes into the fuel prefilter (7), in which large dirt particles (> 100 om) are filtered out of the fuel that is flowing through it.
A shutoff valve (17) which is located at the fuel inlet of the fuel prefilter (7) prevents the suction line in the fuel tank (1) from emptying during long vehicle stop times.
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i If the fuel prefilter (7) is contaminated and the flow of fuel is therefore inhibited, the fuel is drawn in via the bypass valve (7.1). The fuel which has been cleaned by the fuel prefilter (7) is led out of the fuel filter module (2) and enters the fuel pump (3) which delivers it back into the fuel filter module (2) and into the water separator (8) that it contains.
i The system pressure in the fuel feed thrust side (B) which can already be achieved at idle speed is determined by the opening pressure of the pressure limiting valve (3.1).
The bypass valve (3.2) is installed for the case of external filling of the fuel system.
The water inside the fuel is separated out in the water separator (8) and led to the water accumulator. Small dirt particles are also filtered out due to the construction.
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The water from the water collector can be drained by means of a mechanical drain valve.
After leaving the water separator (8), the fuel flows through the fuel filter (9).
Extremely small contamination (> 2 om) is filtered out in the fuel filter (9), similarly to the water separator (8).
If air has gathered in the water separator (8) housing or the fuel filter (9) due to replacement of a filter insert, for example, this is led into the fuel collection chamber (13) via one ventilation bore each with vent lines (39, 40). The air is then dissipated from there into the fuel tank (1).
The fuel system must be bled occasionally after changing an air filter element with the aid of the hand>operated delivery pump (14). In the case of extensive repair work one can also use the filling valve (22).
Once the contamination has been filtered out by the fuel filter (9), the fuel is pumped out of the fuel filter module (2) to the fuel system high pressure pump (5).
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The fuel is compressed in the fuel system high pressure pump (5) and then led to the rail (6).
When this occurs, the quantity control valve (Y642) restricts the amount of fuel to be delivered by the fuel system high pressure pump (5) to exactly the right quantity.
The remaining fuel is led away via the 2>stage valve (19). The first stage of the 2>stage valve (19) opens at around 2 bar and provides the lubrication of the camshaft plain bearings in the fuel system high pressure pump (5).
The second stage opens at around 4.5 bar and regulates the system pressure in the thrust side fuel feed (B) to a range between 4.5 and 6.5 bar by leading excess fuel from the 2>stage valve (35) to the fuel collection chamber (13) via the fuel return line. If the maximum rail pressure is exceeded, the pressure limiting valve (20) opens and the excess fuel is led from the pressure limiting valve (38) to the fuel collection chamber (13) via the fuel return line.
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.
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.
Component description for fuel temperature sensor
B602
Page 147
Fuel filter module pressure sensor, component description
B638
Page 159
Component description for quantity control valve
Y642
Page 182
Pressure limiting valve, component description
Page 185
Component description for fuel pump
Page 203
Component description for fuel cooler
Page 204
Component description for fuel filter module