Patent ID: 8418490

Claim:
A controlling method of air conditioning system for vehicles, the air conditioning system having at least one variable displacement swash plate type compressor and at least one evaporator, wherein the controlling method comprises the steps of: (a) setting up a target temperature inside the vehicle determined by a user; (b) detecting and inputting temperatures inside and outside the vehicle and solar radiation from sensors mounted on certain positions of the vehicle; (c) calculating a target discharge temperature (T 1 ) of a vent by using the target temperature inside, the temperatures inside and outside the vehicle and solar radiation; (d) inputting a maximum evaporator temperature (T 2 ), wherein the maximum evaporator temperature (T 2 ) is calculated and inputted depending on the temperature of the air flowed into the evaporator at the minimum operation of the compressor; (e) setting up a target evaporator temperature determined by comparing the T 1 with the T 2 wherein when T 1 <T 2 , T 1 is determined as the target evaporator temperature and when T 1 >T 2 , T 2 is determined as the target evaporator temperature; (f) calculating the opening degree of a temperature control door depending on the target evaporator temperature; (g) measuring the actual evaporator temperature while controlling the discharge capacity of the at least one variable displacement swash plate type compressor according to the target evaporator temperature, and transmitting the actual evaporator temperature to a certain step; (h) calculating the opening degree of the temperature control door by using the actual evaporator temperature and the opening degree of the discharge capacity control valve of the compressor determined by the target evaporator temperature; and (i) outputting the calculated opening degree of the temperature control door.