Method for operating a vehicle air conditioning system with a refrigerant circuit and vehicle air conditioning system for carrying out this method

摘要

The invention relates to a method for operating a vehicle air conditioning system (1) having a refrigerant circuit (2) which comprises at least one evaporator (3, 3.1) through which a refrigerant can flow, a controllable refrigerant compressor (4) with a minimum delivery volume, a refrigerant condenser (5) or a gas cooler (5), an expansion element (6, 6.1) associated with the evaporator (3, 3.1) and controllable electrically by means of a control device (7) with an adjustable valve cross-sectional area, the expansion element (6) being arranged on a minimal valve cross-sectional area ( A_EXV_Min) and a sensor unit (Tv, pT3) for direct or indirect determination of an actual value (T_IST) of the evaporator air temperature (T). According to the invention, it is provided that a) a desired value (T_SOLL) for the evaporator air temperature (T) is generated by means of the control unit (7), b) the actual value (T_IST) of the evaporator air temperature (T) is compared with its desired value (T_SOLL), and c ) is increased at a below the setpoint (T_SOLL) of the evaporator air temperature (T) actual value (T_IST), the valve cross-sectional area by a predetermined value when a minimum delivery volume of the refrigerant compressor (4) is detected, and otherwise the delivery volume is reduced, if the detected delivery volume of the refrigerant compressor (4) is greater than the minimum delivery volume.