4.3.4.3 Pre-feed module (PFM)
1 Supply to SCR system
(pressure line)
2 Return from SCR system
(suction line)
3 Pressure sensor
4 Heating element
5 Supply from RA tank
6 Plunger solenoids
7 Filters
8 Return to RA tank
9 RA concentration and tem-
perature sensor
The PFM comprises two reciprocating plungers (6) which are activated with a phase displacement of 180° by
a DCM serving as an extension to the ECU of the engine. A filter (7) is installed on the pressurized side.
The PFM is supplied together with the DCM and wiring harness on a common mounting plate.
Sensors (3, 9) monitor pressure, temperature and the concentration of the reducing agent.
A pressure-maintaining valve is installed in the PFM to hold the system pressure at a steady 2.5 bar.
Design criteria
Design criteria
Value
Material
Aluminum (pump block and filter housing)
Technical data
Operating pressure: max. 2.5 bar abs.
RA mass flow rate: Max. 130 kg/h
Suction head: Max. 0.3 bar / 3 m
Rated supply voltage
24 VDC
Protection class
IP69 K
Ambient temperature
-40 °C to 60 °C (with electrical heating)
The PFM must be mounted horizontally ±10° because of the filter.
82 | RA Dosing System | MS15065/01E 2019-01
TIM-ID: 0000072391 - 001
