Component description for pump module

W14.40-1562-76

Location

Shown on model 963 with code (M5Z) Engine version Euro VI

1 Pump module

2 EATU

16 AdBlue® tank

The pump module (1) which contains the SCR control unit (A58) and SCR delivery pump (M25) is fastened to a bracket on the inside of the right longitudinal frame member behind the EATU (2).

Task

The pump module (1) sucks in AdBlue® from the AdBlue® container (16), filters it and pumps it to the AdBlue® metering device (A67). The SCR control unit (A58) calculates the injection period and the injection quantity.

W14.40-1570-76

Design

3 Electronics housing

4 Connecting body

5 Filter housing

6 Electrical connection
(communication to AdBlue® metering device)

7 Electrical connection
(communication to exhaust aftertreatment (ACM) control unit)

8 AdBlue® inlet

9 Intake filter
(mesh size 190 μm)

10 AdBlue outlet

11 Vent valves

12 Coolant inlet

13 Coolant outlet

14 Pressure limiting valve

15 Main filter
(mesh size 20 to 30 μm)

A58 SCR control unit

M25 SCR delivery pump

Function

8 AdBlue® inlet

9 Intake filter

10 AdBlue® outlet

12 Coolant inlet

13 Coolant outlet

14 Pressure limiting valve

15 Main filter

M25 SCR delivery pump

W14.40-1560-03

After the engine starts, the exhaust aftertreatment (ACM) control unit (A60) actuates the pump module (1) or more accurately, the SCR control unit (A58) integrated into it. This switches the SCR delivery pump (M25), so that AdBlue® is sucked in from the AdBlue® container and pumped at an operating pressure of approx. 10 bar towards the AdBlue® metering device (A67).

Because the AdBlue® metering device (A67) is cooled be circulation through circulating AdBlue®, AdBlue® is pumped continuously, irrespective of whether injection is necessary or not. The AdBlue® that is not required or not injected flows back through the return line to the AdBlue® container.

Heating

A duct inside the connecting body (4) enables the pump module (1) to have engine coolant flow through it for heating or defrosting. The coolant inflow is regulated by an engine mounted solenoid valve as a function of the temperature by the engine management (MCM) control unit (A60).

Delayed-off running

To avoid any damage through overheating on the AdBlue® metering device (A67), the pump module (1) continues to pump AdBlue® for some time after the engine stops so that the cooling can be maintained for a longer period.