GF83.40-P-0001MCU Automatic Air Conditioning (AAC), Function

GF83.40-P-0001MCU Automatic Air Conditioning (AAC), Function
- with CODE (I01) Air conditioning Plus


The automatic air conditioning has an electronically controlled cooling and heating system. It controls the temperature of the vehicle interior.
Even at low outside temperatures, the air is first cooled down by the evaporator and dehumidified, it is then routed through the heat exchanger where it is heated up to the desired interior temperature.

The following functions are implemented
^ Ventilation
^ Heating circuit
^ Refrigerant circuit
^ Safety shutoff

Ventilation
The ventilation system ventilates the interior of the vehicle. The air is drawn in by the blower motor (M2) and passes through the various air ducts to the air distribution flaps, which distribute it in the vehicle interior.

Heating circuit
The coolant is heated up by the engine. The heated coolant is subsequently guided through the heat exchanger, where the heat is emitted into the air in the interior. The coolant returns back to the coolant pump via the coolant return line.

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 refrigerant flows into the evaporator via the expansion valve and is heated there indirectly by the warm air blowing by on the outside of the evaporator. The refrigerant compressor aspirates the refrigerant which has turned gaseous on account of the heat absorption and then compresses it yet again.

Safety shutoff
To prevent damages to the refrigerant compressor, the following automatically shutoffs are integrated:
^ Hot gas shutoff (through integrated sensor in refrigerant compressor)
^ High-pressure shutoff in the system (through refrigerant pressure sensor (B12))
^ Low-pressure shutoff in the event of missing refrigerant (through refrigerant pressure sensor)
^ Overtemperature deactivation (coolant temperature above 115 °C)
^ Undertemperature shutoff (if temperature on evaporator is below 3 °C)
At outside temperatures below 3 °C, the refrigerant compressor cannot be activated.