Component description for exhaust aftertreatment control unit - GF14.40-P-3030G

ENGINE 642.886 in MODEL 463.306/336/346 up to 31.5.12 as of Model Year 2011/YoM 10 

Location 

The AdBlue® control unit is located in the trunk on the left behind the wheel arch.

Task 

The AdBlue® control unit controls the following functions based on a characteristics map:

• AdBlue® delivery
• Fuel injection
• Antifreeze and recycling

The AdBlue® control unit has the following tasks:

• Reading in of sensors, pickups and signals 
• Evaluation of input factors 
• Actuating components 

Reading in of sensors, pickups and signals 

The input factors are read in via the following connections:

• Direct line 
• Drive train sensor CAN (CAN I) 

Direct line 

The AdBlue® control unit reads in the following component signals via a direct line:

• AdBlue® pressure sensor (A103/2b1)
• Fill level sensor Full (A103/1b2)
• "Reserve" fill level sensor (A103/1b3)
• "Empty" fill level sensor (A103/1b4)
• AdBlue® tank temperature sensor (A103/1b1)
• The function of the AdBlue® delivery pump (A103/2m1) is diagnosed by the power consumption

Drive train sensor CAN 

The AdBlue® control unit reads in the following signals from the CDI control unit (N3/9) via drive train sensor CAN:

• Request for reduction agent injection
• Specification of the reduction agent quantity to be injected
• Specification of the run-on period of the control units
• Diagnosis request

Evaluation of input factors 

The input factors are evaluated by the microprocessor and the corresponding components are actuated.

Actuating components 

The actuation of the components takes place via the following connections:

• Direct line 
• Drive train sensor CAN 

Direct line 

The following components are actuated via a direct line:

• AdBlue® delivery pump
• AdBlue® reversing valve (A103/2y1)
• AdBlue® metering valve (Y129)
• AdBlue® tank (A103/1r1) heating element
• AdBlue® pressure line heating element (A103/1r2)
• AdBlue supply module heating element (A103/2r1)

Drive train sensor CAN 

The AdBlue® control unit transmits the following signals to the CDI control unit via drive train sensor CAN:

• Reduction agent quantity to be injected for NO_x reduction
• Reduction agent quantity to be injected for cooling the AdBlue® metering valve
• Fill level status in the AdBlue® tank
• 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 the AdBlue® delivery pump (to generate pressure of P = 5 bar before and during reduction agent injection to nitrogen oxide (NO_x reduction)

  The delivery pressure can be adjusted with the control unit software and can vary depending on the version.

• Actuation of the AdBlue® delivery pump to generate a pressure of (p =5 bar before and during injection of the reducing agent for cooling the AdBlue® metering valve)
• Actuation of the AdBlue® metering valve (for ventilation of the AdBlue® pressure line when filling the AdBlue® pressure line)

Injection:

• Actuation of the AdBlue® metering valve during injection of the reducing agent for (NO_x reduction and for cooling the AdBlue® metering valve)

Antifreeze and recycling:

• After "circuit 15 ON", the pump is given an initial run (warm-up) if the weather is cold. The initial run serves to reduce the friction in cold weather, so that, following a demand for pressure, the required compression can be made available as soon as possible.
• - Actuation of the AdBlue® tank heating element (to liquefy the AdBlue® reducing agent in the AdBlue® tank, which freezes at about) -10 °C
• Actuation of the AdBlue® feed unit heating element and AdBlue® pressure line heating element to ensure flowability of the AdBlue® reducing agent (which freezes at about T = -10°C in the AdBlue® feed module (A103/2) and in the pressure line to the AdBlue® metering valve
• Actuation of the AdBlue® delivery pump, AdBlue® reversing valve and AdBlue® metering valve to return the AdBlue® reducing agent from the pressure line to the AdBlue® tank during power-down of the AdBlue® control unit after "circuit 15 OFF"

  The duration of the return flow of the AdBlue® reducing agent and the duration of the pressure line filling depend on the length of the pressure line.

Information on injected reduction agent quantity is transmitted by the AdBlue® control unit to the CDI control unit via drive train sensor CAN. This quantity is taken into account in the next computation of the quantity of reducing agent by the CDI control unit.