Automatic Air Conditioning Refrigerant Circuit, Function

GF83.40-P-2005RI Automatic Air Conditioning Refrigerant Circuit, Function

Component Identification:

Function requirements, general
^ Circuit 61
^ Air conditioning switched on

Automatic air conditioning refrigerant circuit, general
Cooling is performed via the automatic air conditioning refrigerant circuit depending on the AAC [KLA] control and operating unit (N22) setting. The individual components are interconnected through lines and form a closed system.

The automatic air conditioning refrigerant circuit comprises the following subfunctions:
^ Function sequence, high-pressure side
^ Function sequence, low-pressure side

Function sequence, high-pressure side
The refrigerant compressor driven by the engine draws in and compresses the gaseous refrigerant. The refrigerant is heated up intensely in the process. The refrigerant is pressed through the condenser under high pressure via a line. During this process, compression heat is absorbed from the intensely heated refrigerant. The refrigerant condenses and changes state from gaseous to liquid.
The compression heat is dissipated via the condenser surface (cooling fins).
The refrigerant flows from the condenser to the fluid reservoir (drier) via a line. While it flows through the fluid reservoir, the refrigerant is cleansed of any chemical and mechanical impurities in order to protect the subsequent components. The cleaned refrigerant reaches the expansion valve via a feed line. This ensures that the pressure at the high-pressure side is maintained.

Function sequence, low-pressure side
The expansion valve injects the refrigerant into the evaporator, where it then evaporates because of its low pressure. During this process, the physical state of the refrigerant changes from liquid to gas.
The heat required for evaporation is taken from the ambient air. The cooled air is led to the vehicle interior via the blower motor (A32m1).

To prevent the evaporator from icing up, the refrigerant compressor is switched off by the control and operating unit if the evaporator temperature drops below a certain level.The evaporator temperature is registered by the evaporator temperature sensor.