Patent ID: 10611213

Abstract:
There is disclosed a vehicular air-conditioning device of a so-called heat pump system which eliminates or decreases noise generated when an opening/closing valve opens at a changing time of an operation mode. The vehicular air-conditioning device executes a heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, decompress the refrigerant by which heat has been radiated, and then let the refrigerant absorb heat in an outdoor heat exchanger 7, and a dehumidifying and heating mode to open a solenoid valve 22 in a state of the heating mode, decompress at least a part of the refrigerant flowing out from the radiator and then let the refrigerant absorb heat in a heat absorber 9. When the heating mode changes to the dehumidifying and heating mode, the controller decreases a radiator pressure or a pressure difference before and after the solenoid valve to a predetermined value or less, and then opens the solenoid valve 22.