GF83.40-P-0004TX Convenience Automatic Air Conditioning (C-AAC), Function

GF83.40-P-0004TX Convenience Automatic Air Conditioning (C-AAC), Function
- with CODE (581) Comfort automatic air conditioning


Function
The comfort automatic air conditioning (C-AAC) [K-KLA] serves to control the interior temperature desired by the driver and passengers. The C-AAC is operational immediately after the engine is started and re-establishes the last stored temperature- controlled condition before the vehicle was locked. System operation is sensitive to moisture and temperature; even at low outside temperatures the ambient air is first cooled down by way of the evaporator's supply of cold air, and then routed through the heat exchanger and set to the desired passenger compartment temperature.

The C-AAC regulates the interior temperature separately for all 4 seat areas; the air distribution duct separately for driver and passenger side.

The C-AAC can be summarized with the subfunctions listed below.

^ Heater circuit
The coolant is heated up by the engine. When heat is requested, heated coolant passes through the heat exchanger shutoff motor (M16/32) to the heater heat exchange, where heat is dissipated to the interior air. The coolant returns back to the coolant pump via the heater return.

^ Refrigerant circuit
The refrigerant compressor (A9) driven by the engine compresses the refrigerant vapor which is cooled down in the condenser. The refrigerant liquefies during cooling. The liquid refrigerant passes through the expansion valve into the evaporator, where it evaporates, cools down and removes the heat from the air that is flowing past, therefore cooling it down. The refrigerant compressor aspirates the refrigerant which has turned gaseous on account of the heat absorption and then compresses it yet again.

^ Ventilation
The ventilation system ventilates the interior of the vehicle. The air is drawn in by the blower motor (A32m1) and passes through the various air ducts to the air distribution flaps which distribute it in the vehicle interior.

^ Control
The electronic control for the C-AAC is accomplished by various control units and temperature sensors connected with one another by the Controller Area Network bus, class B (interior compartment) (CAN-B), Controller Area Network bus, class C (engine compartment) (CAN-C) and the local interconnect network (LIN). The desired temperature is achieved or maintained at a constant level by cooling or heating the air.

^ Residual engine heat utilization
The residual engine heat utilization feature makes it possible to continue to heat or simply ventilate the vehicle even with the engine shut off. The system makes use of the residual heat of the engine for this purpose.