Position arrangement
The pump module (20) is at the right of the chassis chart at the height of the AdBlue reservoir.
Function
The pump module (20) draws AdBlue from the AdBlue reservoir, filters it and pumps it to the dispensing unit.
Represented on vehicle 382.177 |
20 | Pump module |
B14.40-0064-11
Represented on vehicle 384.223 |
20 | Pump module |
B14.40-0142-10
B14.40-0195-09
Composition |
1 | Pressure filter | 7 | Filter bowl and the pressure accumulator | 13 | housing cover | ||
2 | AdBlue piping - supply | 8 | Coolant piping - outlet | 14 | Electric connection | ||
3 | AdBlue piping - return | 9 | Accumulator blowing valve | 15 | Venting rib cover | ||
4 | Pneumatic control valve | 10 | Accumulator blowing connection | 16 | AdBlue piping - suction | ||
5 | Compressed air connection | 11 | Engine coolant piping - intake | 17 | Drawing filter | ||
6 | Pressure accumulator | 12 | Pump case | 18 | AdBlue pump (17M01) |
The pump module comprises a housing that is synthetic material spill proof - the pump housing (12) and an aluminum block fixed in the filter housing and the pressure accumulator (7). The AdBlue pump (18) is located In the pump housing (12) - a diaphragm electric pump with 3 chambers.
In the filter and the pressure accumulator (7) housing, a pneumatic control valve (4) is located, next to the pressure filter (1) and the pressure accumulator (6). Apart from that there are pipings for the engine coolant flow and a duct to allow its flow.
Function
When the AdBlue pump (18) receives an actuation signal, it draws AdBlue from the AdBlue reservoir. AdBlue is per-filtered by the 100µm-screen suction filter (7) built in the AdBlue suction pipe.
The pump takes the AdBlue to an operating pressure of approx. 6 bar, and routes it to the filter and pressure accumulator housing (7). In order to eliminate smaller impurities particulates, AdBlue goes through the pressure filter (1), with a 30 µm mash, before being pumped towards the dispensing unit.
The pressure accumulator (6) is basically a storage rubber bubble, whose function is to compensate pressure oscillations and reduce the AdBlue pump (18) actuation frequency. It is comprised of a volume of approx. 0,13L. It is stored with factory nitrogen (N2) . When refilling it, it should be blown with air, free from oil and grease.
Vent
The pneumatic control valve (4) and the AdBlue piping - return (3) work for automatic ventilation of pump module during the initial operation. The pneumatic control valve (4) is closed when compressed air is drawn.
The AdBlue pump (18) is not actuated when it is "empty", because it turns off when the AdBlue reservoir level sensor is below a certain threshold. However, when the pump is empty, it may work for a short period if AdBlue moves inside the reservoir. However, when the pump is empty, if it works for 10 seconds more, it will be recognized by the engine control module (MR) and the ventilation will be automatically started.
AdBlue pressure reduction
To prevent the freezing of the AdBlue from damaging the pump module, after the ignition is turned off, the AdBlue pressure is reduced within the pump module and in the route through the pump module. Pressure reduction takes place through the compressed air control module ventilation. Consequently, the pneumatic control valve (4) opens and this way allows AdBlue return to the reservoir.
Heating
The engine coolant flows through the filter bowl and the pressure accumulator (7) to AdBlue heating and defrosting . The coolant supply is commanded by a valve located in the engine controlled by the engine control module (MR).