Diesel Emissions Fluid Coolant Control Valve: Description and Operation
GF14.40-D-3035HU Component Description For AdBlue Delivery Module
- with CODE (MG5) Engine OM 642 DE 30 LA, 140 kW (190 hp) 3800 rpm
- with CODE (MH1) Low-emission engine EPA 10/CARB
- with CODE (ZU7) National version for Canada
- with CODE (MG5) Engine OM 642 DE 30 LA, 140 kW (190 hp) 3800 rpm
- with CODE (MH1) Low-emission engine EPA 10/CARB
- with CODE (ZU8) National version for USA
30 AdBlue(R) tank
31 AdBlue(R) delivery module
Location
The AdBlue(R) delivery module is located on the AdBlue(R) tank.
Task
The function of the AdBlue(R) delivery module is divided into the following subfunctions:
^ Pressure generation
^ Pressure measurement
^ Flow reversal
^ Antifreeze protection
Pressure generation
The AdBlue control unit (N141) actuates the AdBlue delivery pump (M89) with a pulse width modulation (PWM) signal according to a performance map. Part of the suctioned in AdBlue(R) reducing agent is passed back via a bypass in the AdBlue(R) delivery module into the 2-tank system (AdBlue(R) tank with AdBlue(R) removal tank). This ensures that the AdBlue(R) removal tank is always filled and no air is suctioned in otherwise the required system pressure of 5 bar cannot be generated.
Pressure measurement
Through the AdBlue(R) pressure sensor (B151), the AdBlue(R) control unit detects the system pressure generated by the AdBlue(R) delivery pump.
If the system pressure of 5 bar is not reached, the AdBlue(R) system is shut down, an entry is made in the fault memory of the CDI control unit (N3/30) and a message is shown in the display (A1p1) of the IC (A1).
Flow reversal
Power-down of the AdBlue(R) control unit is started for "circuit 15 OFF".
During power-down of the control unit, residual AdBlue(R) reducing agent is pumped out of the injection line by the AdBlue(R) delivery pump through the AdBlue(R) switchover valve (Y129) which is actuated by the AdBlue(R) control unit. The AdBlue(R) injection valve (Y130) is opened at the same time so that no vacuum occurs.
The duration of power-down and the timing of the reducing agent return flow depend on the exhaust temperature, since the injection line and other system components can be damaged if the exhaust gas is too hot.
Antifreeze protection
The AdBlue(R) tank heating element (R51) ensures that the AdBlue(R) reducing agent pumped out of the 2-tank system remains fluid even in cold temperatures.
In cold temperatures, the AdBlue(R) delivery module and the AdBlue(R) reducing agent are also warmed up by the AdBlue(R) delivery pump heating element (M89r1) according to a performance map. Furthermore the AdBlue(R) injection line is also heated dependent on a performance map by the AdBlue(R) injection line heating element (R52).
Pumping back the residual AdBlue(R) reducing agent prevents the AdBlue(R) injection line and AdBlue(R) delivery module from freezing up and being damaged at about -10°C.
Design
B151 AdBlue(R) pressure sensor
M89 AdBlue(R) delivery pump
M89r1 AdBlue(R) delivery pump heating element
Y129 AdBlue(R) switchover valve
The AdBlue(R) switchover valve is a 4-2 directional control valve