Engine | 900.91/92 in model 000.001 |
with BlueTec | |
Engine | 902.91/93 in model 000.001 |
with BlueTec | |
Engine | 904.94/95/96/97 in model 000.001 |
with BlueTec | |
Engine | 906.93/94/95/96/98/99 in model 000.001 |
with BlueTec | |
Engine | 924.91/93/94 in model 000.001 |
with BlueTec | |
Engine | 925.9 in model 000.001 |
with BlueTec | |
Engine | 926.91/92/93/95/97/98 in model 000.001 |
with BlueTec |
18 | AdBlue® pump module |
G49.20-A053-02
Task
The AdBlue® pump module (18) suctions AdBlue® out of the AdBlue® tank via the SCR AdBlue® pump (M25), filters it, and pumps it to the AdBlue® metering device.
Structure
1 | Pressure filter |
2 | Line fitting for AdBlue® (feed line) |
3 | Line fitting for AdBlue® (return line) |
4 | Pneumatic switchover valve |
5 | Connection (compressed air) |
6 | Pressure reservoir |
7 | Pressure filter and pressure reservoir housing |
8 | Line fitting for coolant (outlet) |
9 | Pressure reservoir filling valve |
10 | Pressure reservoir filler connection |
11 | Line fitting for coolant (inlet) |
12 | Pump housing |
13 | Housing cover |
14 | Electrical connector |
15 | Cover vent membrane |
16 | Line fitting for AdBlue® (suction) |
17 | Suction filter (in intake connection) |
M25 | SCR AdBlue® pump |
W14.40-1032-76
The AdBlue® pump module (18) consists of a splash-protected plastic housing, the pump housing (12), and the pressure filter and pressure reservoir housing (7). The pump housing (12) contains the SCR AdBlue® pump, an electric 3-chamber diaphragm pump.
The pressure filter and pressure reservoir housing (7) contains not only the pressure filter (1) and the pressure reservoir (6) but also a pneumatic switchover valve (4) and a duct for coolant flow.
In principle, the pressure reservoir (6) is a rubber reservoir bladder filled with gas, which compensates for pressure fluctuations and reduces the cut-in frequency of the SCR AdBlue® pump. It has a volume of approx. 0.13 l. Ex works it is filled with nitrogen (N2). It can be refilled with oil and grease free air.
Functional diagram |
1 | Pressure filter |
2 | Line fitting for AdBlue® (feed line) |
3 | Line fitting for AdBlue® (return line) |
4 | Pneumatic switchover valve |
5 | Connection (compressed air) |
6 | Pressure reservoir |
8 | Line fitting for coolant (outlet) |
9 | Pressure reservoir filling valve |
10 | Pressure reservoir filler connection |
11 | Line fitting for coolant (inlet) |
16 | Line fitting for AdBlue® (suction) |
17 | Suction filter (in intake connection) |
M25 | SCR AdBlue® pump |
W14.40-1031-12
Function
After the engine start, the exhaust gas aftertreatment control unit (ACM) (A60) actuates the SCR AdBlue® pump so that AdBlue® is intaken from the AdBlue® tank and pumped at an operating pressure of approx. 6 bar in the direction of the AdBlue® metering device.
The AdBlue® is prefiltered via the intake filter (17), which has a mesh width of 100 μm, integrated in the AdBlue® line fitting (16).
The remaining finer dirt particles are then filtered out by the pressure filter (1), which has a mesh width of 30 μm, integrated in the pressure filter and pressure reservoir housing (7).
Ventilation
The automatic venting of the AdBlue® pump module (18) during operation or commissioning takes place via the pneumatic switchover valve (4) and the AdBlue® line fitting (3).
If the SCR AdBlue® pump intakes just air without AdBlue® for more than 10 s, this is detected by the exhaust gas aftertreatment control unit (ACM) and automatic venting is initiated.
The pneumatic switchover valve (4) is closed when it is filled with compressed air.
AdBlue® pressure release
To prevent freezing AdBlue® from damaging the pump module, after the ignition is switched off, the AdBlue® pressure inside the AdBlue® pump module (18) and in the line section between the AdBlue® pump module (18) and the AdBlue® metering device is reduced. The pressure is reduced simultaneously by ventilating the compressed air diverted unit. As a consequence, the pneumatic switchover valve (4) opens and thus enables the return of the AdBlue® to the AdBlue® container.
Heating
Via a duct in the pressure filter and pressure reservoir housing (7), engine coolant flows through the AdBlue® pump module (18) for heating, i.e. defrosting, purposes. The coolant inflow is regulated by the AdBlue® heater coolant solenoid valve (Y107) attached to the engine as a function of the temperature by the engine management control unit (MR) (A6).