Patent ID: 7739881

Claim:
A refrigeration cycle for a vehicle, the refrigerant cycle comprising a compressor compressing a refrigerant, a radiator cooling the refrigerant discharged from said compressor, first and second pressure reducers reducing the pressure of said refrigerant flowing out from said radiator, a first evaporator cooling a front seat region of a vehicle cabin and evaporating said refrigerant flowing out from said first pressure reducer, a second evaporator cooling a rear seat region of the vehicle cabin and evaporating said refrigerant flowing out from said second pressure reducer, one of a second evaporator solenoid valve for opening and cutting off the inflow of said refrigerant to said second evaporator, and a second evaporator downstream solenoid valve for opening and cutting off the outflow of said refrigerant from said second evaporator, a switch for generating a command signal to select an operating state of said second evaporator, a control unit, detecting a differential pressure between an inlet refrigerant pressure and an outlet refrigerant pressure of said one of said second evaporator solenoid valve and said second evaporator downstream solenoid valve and controlling a compression amount of said compressor and said one of said second evaporator solenoid valve and said second evaporator downstream solenoid valve based on said command signal and said differential pressure, wherein when said control unit controls said one of said second evaporator solenoid valve and said second evaporator downstream solenoid valve for starting or stopping operation of said second evaporator, said control unit includes means for changing said differential pressure to a predetermined value by reducing the compression amount of said compressor, then opening or closing the one of said second evaporator solenoid valve and said second evaporator downstream solenoid valve; after opening or closing the one of the second evaporator solenoid valve and said second evaporator downstream solenoid valve, the control unit increases the compression amount of said compressor in accordance with the cooling load, and wherein when starting or stopping the operation of said second evaporator, said control unit includes means for changing said compression amount slower when decreasing the compression amount of said compressor compared to when increasing the compression amount of said compressor.