(Component Description For Exhaust Aftertreatment Control Unit - GF14.40-P-3030ORC)

Engine 654.9 in model 213 

Engine 654.9 in model 238 

Courtesy of MERCEDES-BENZ USA

Vehicle view from the front left on model 213.0 

Location 

The AdBlue® control unit is located in the trunk at the lower right.

Tasks 

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
• Circuit 30, over AdBlue® circuit 87 relay (K40/5kV)
• Signal of AdBlue® fill level sensor (A103/1 b5)
• 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® relay
• 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)

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 NO_x reduction
• Reduction agent quantity injected for cooling the AdBlue® metering valve
• Fill level status in the AdBlue® container
• Requested diagnostic data

AdBlue® delivery 

• Feed to the 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 (NO_x ) 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 NO_x 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 (AdBlue® freezes at approx. -10°C)
• Actuation of the AdBlue® pressure line heating element to guarantee the flowability of the AdBlue® reduction agent in the pressure line to the AdBlue® metering valve (AdBlue® freezes at approx. -10°C)
• Actuation of the AdBlue® extraction pump to return the AdBlue® reduction agent in the pressure line to the AdBlue® container during power-down of the AdBlue® control unit after "circuit 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 pressure line filling depend 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.+

Wiring diagram for AdBlue® control unit

PE14.40-P-2101-97DBB