The fuel supply function is described by way of example on engine 926.9 (6 cylinder).
2.1 | Fuel prefilter |
3.1 | Plug-on valve in fuel feed flow (opened by pressure) |
3.2 | Plug-on valve in fuel return (locked in open position) |
5 | Fuel pump (FP) |
6 | Fuel filter |
7 | Fuel injector with nozzle holder assembly |
8 | Overflow valve (4.5 bar) |
Y600 | Cylinder 1 single injection pump |
Y601 | Cylinder 2 single injection pump |
Y602 | Cylinder 3 single injection pump |
Y603 | Cylinder 4 single injection pump |
Y604 | Cylinder 5 single injection pump |
Y605 | Cylinder 6 single injection pump |
A | Fuel feed line, suction side and / or vacuum side |
B | Fuel feed line, pressure side |
C | Fuel high pressure line |
D | Fuel return line |
G47.00-A000-76
Function
The fuel supply ensures that the fuel required for combustion is available under all operating conditions in the sufficient quantity, at the correct time and with the required pressure.
The fuel supply to the individual cylinders is realized by the pump-line-nozzle system (PLN system) that is supplied with fuel from the low-pressure fuel circuit.
Low-pressure fuel circuit
The low-pressure fuel circuit ensures that the fuel is cleaned and available to the unit pumps of the PLN system in sufficient quantity and at the required pressure.
It basically consists of the following components:
Fuel tank
Fuel prefilter (2.1)
Fuel pump (5)
Fuel filter (6)
Overflow valve (8)
Suction or vacuum side fuel feed line (A)
Pressure side fuel feed line (B)
Fuel return lines (D)
High-pressure fuel delivery (pump-line-nozzle system (PLN system))
Via the PLN system, the fuel provided by the low-pressure fuel circuit is injected into the cylinders at the right point in time, with the required pressure and in sufficient quantity.
The PLN system consists of the single injection pumps for cylinders 1 to 6, the fuel injectors with nozzle holder assembly (7), the connection fitting and the fuel high pressure lines (C) via which the individual single injection pumps for cylinders 1 to 6 are connected with the respective fuel injectors with nozzle holder assembly (7).
The excess fuel delivered during a high-pressure fuel delivery is returned to the low-pressure fuel circuit via the fuel return lines (D).