Vehicle view from the rear |
N118/5 | AdBlue® control unit |
P07.16-4067-76
Location
The AdBlue® control unit is located in the trunk at the lower right.
Task
The AdBlue® control unit controls the following tasks based on a characteristics map:
AdBlue® delivery
Fuel injection
Antifreeze protection and recirculation
Input and output signals
The following input signals are evaluated by the AdBlue® control unit and the respective output signal is issued:
Direct input signals
Direct output signals
CAN input signals
CAN output signals
Direct input signals
Circuit 31
Signal of AdBlue® fill level sensor (A103/1b5)
Signal of AdBlue® tank temperature sensor (A103/1b1)
Recording of the power consumption for diagnosis of the AdBlue® delivery pump (A103/2m1)
Direct output signals
Supply and actuation of the AdBlue® supply relay (K27/7)
Supply of AdBlue® delivery pump
Supply and actuation of the AdBlue® extraction pump (A103/2m2)
Pulse width modulated signal for actuation of the AdBlue® delivery pump
Pulse width modulated signal for actuation of the AdBlue® metering valve (Y129)
Power supply for the AdBlue® container heating element (A103/1r1)
Power supply for AdBlue® pressure line heating element (R7/1)
CAN input signals
from CDI control unit (N3/9)
Request for reduction agent injection
Specification of the reduction agent quantity to be injected
Specification for the run-on time of the AdBlue® control unit
Diagnosis request
CAN output signals
To the CDI control unit
Reduction agent quantity to be injected for NOx reduction
Reduction agent quantity to be injected for cooling the AdBlue® metering valve
Fill level status in the AdBlue® container
Requested diagnostic data
AdBlue® delivery
Feed to AdBlue® delivery pump to obtain the operating current consumption as a basis for the diagnosis of the AdBlue® delivery pump
Actuation of AdBlue® delivery pump to generate a pressure of 5 bar before and during the injection of reduction agent for nitrogen oxide (NOx) reduction. The delivery pressure is adjustable by the control unit software and can be different according to the variant.
Actuation of the AdBlue® metering valve for ventilation of the AdBlue® pressure line when filling the AdBlue® pressure line
Fuel injection
Actuation of the AdBlue® metering valve during the reduction agent injection for NOx reduction
Antifreeze protection and recirculation
After "circuit 15 ON", the pump is given an initial run (warm-up) if the weather is cold. The pump flow serves to remove the friction in the case of cold, so that the desired pressure can be made available as soon as possible after the pressure request.
Actuation of the AdBlue® tank heating element to liquefy the AdBlue® reduction agent in the AdBlue® tank, which freezes at about –10 °C
Actuation of the AdBlue® pressure line heating element to guarantee flowability of the AdBlue® reduction agent, which freezes at about –10 °C, in the AdBlue® pressure line to the AdBlue® metering valve
Actuation of the AdBlue® extraction pump for return delivery of the AdBlue® reduction agent in the pressure line in the AdBlue® container during power-down of the AdBlue® control unit after "terminal 15 OFF"
The AdBlue® metering valve can be actuated without the float needle being opened. This serves to heating of the valve.
The duration of the return flow of the AdBlue® reduction agent and the duration of the pressure line filling dependent on the length of the pressure line.
The quantity of reduction agent injected by AdBlue® the metering valve is sent by the AdBlue® control unit via the drive train sensor CAN (CAN I) to the CDI control unit. This is taken into account in the subsequent computation of the necessary quantity of reduction agent by the CDI control unit.