G47.00-3106-79
1 | Fuel tank | 32 | Fuel feed line from the fuel pumps to the fuel filter module | |
2 | Fuel filter module | 33 | Fuel feed line from fuel filter module to fuel system high pressure pump | |
3 | Fuel pump (FP) | 35 | Fuel return line from 2-stage valve | |
3.1 | Pressure limiting valve | 36 | Fuel return line for pressure transducer | |
3.2 | Wastegate | 37 | Fuel return line for nozzle needle valves | |
5 | Fuel system high pressure pump | 38 | Fuel return line from pressure limiting valve | |
6 | Rail | 39 | Vent line (from water separator) | |
7 | Fuel prefilter | 40 | Vent line (from fuel filter) | |
7.1 | Wastegate | 42 | Fuel return bypass | |
8 | Water separator | B602 | Fuel temperature sensor | |
9 | Fuel filter | B622 | Rail pressure sensor | |
10 | Fuel cooler | B638 | Fuel filter module pressure sensor | |
11 | Restrictor | Y608 | Cylinder 1 fuel injector | |
12 | Check valve | Y609 | Cylinder 2 fuel injector | |
13 | Fuel accumulator | Y610 | Cylinder 3 fuel injector | |
14 | Hand pump | Y611 | Cylinder 4 fuel injector | |
15 | Shutoff valve in the fuel feed (locked in open position) | Y612 | Cylinder 5 fuel injector | |
16 | Shutoff valve in the fuel return (locked in open position) | Y613 | Cylinder 6 fuel injector | |
17 | Shutoff valve (in the form of an elastomer ball, which prevents draining of the suction line during engine off) | Y642 | Quantity control valve | |
19 | 2-stage valve | A | Fuel feed intake side | |
20 | Pressure limiting valve | B | Fuel feed (thrust side) | |
22 | Filling valve | C | Fuel high pressure | |
30 | Fuel return line from fuel cooler to the fuel filter module | D | Fuel return | |
31 | Fuel feed line from fuel filter module to the fuel pump | E | Ventilation |
The fuel pump (3), which is designed as a gear pump, supplies fuel to the low-pressure fuel 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 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 gets into the fuel prefilter (7), in which rough dirt particles (> 100 μm) are filtered out of the fuel 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 being emptied during long vehicle stop times.
If the fuel prefilter (7) is contaminated and the fuel flow rate is blocked as a result, the fuel is then suctioned via the bypass valve (7.1).
The fuel that 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) located inside it.
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 event 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.
The water from the water accumulator can be drained via a mechanical drain valve.
After leaving the water separator (8), the fuel flows through the fuel filter (9).
Extremely fine-grained contamination (> 2 μm) is filtered out in the fuel filter (9) and in the water separator (8).
If air has gathered in the housing of the water separator (8) or fuel filter (9), e.g. due to replacement of a filter element, this air is led into the fuel collection chamber (13) via a ventilation bore in either the water separator housing or fuel filter housing and vent lines (39, 40). The air is then dissipated from there into the fuel tank (1).
The fuel system must occasionally be bled after changing a filter element with the aid of the hand pump (14). In the event of extensive repair work, the filling valve (22) can also be used.
After the contamination has been filtered out by the fuel filter (9), the fuel is delivered out of the fuel filter module (2) to the fuel high-pressure pump (5).
The fuel is compressed in the fuel 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 approx. 2 bar and provides lubrication of the camshaft plain bearings in the fuel high-pressure pump (5).
The second stage opens at approx. 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 via the fuel return line from the 2 stage valve (35) to the fuel collection chamber (13).
If the maximum fuel pressure is exceeded, the pressure limiting valve (20) opens and the excess fuel is led via the fuel return line from the pressure limiting valve (38) to the fuel collection chamber (13).
The required fuel for the hydraulic pressure boosting is collected in a bore in the cylinder head and led via the fuel return line of the pressure converters (36) to the fuel cooler (10) and then led back to the fuel pump (3).
The fuel cooler (10) is used to lower the temperature of the approx. 120 °C fuel.
The excess fuel from the nozzle needle valves is also gathered in a bore in the cylinder head and led into the fuel collection chamber (13) via the fuel return for 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 ensuring the required back pressure of approx. 2 bar with the engine running thus ensuring that the fuel injectors function 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 from escaping when the fuel line between the fuel tank (1) and the fuel filter module (2) is disconnected.
Fuel temperature sensor component description | B602 | ||
Fuel filter module pressure sensor, component description | B638 | ||
Component description for the quantity control valve | Y642 | ||
Pressure limiting valve, component description | |||
Component description for fuel pump | |||
Fuel cooler, component description | |||
Fuel filter module component description |