HEAT PUMP SYSTEM FOR VEHICLE

摘要

PURPOSE: A heat pump system for vehicles is provided to perform the defrosting control by controlling an upper limit of the rotation number of a compressor below the predetermined rotation number preventing the frosting of an evaporator while the defrosting mode is maintained when the frosting of the evaporator is recognized for operating a defrosting mode of a heat pump mode. CONSTITUTION: A heat pump system for vehicles comprises a first bypass line (R1), a second bypass line (R2), a branch line (R4), and a control unit. The first bypass line allows the refrigerant circulating in a refrigerant circulating line (R) to selectively bypass a first expansion unit (140) and an evaporator (160). The second bypass line is installed to connect a refrigerant circulating line of an entrance and an exit of an outdoor heat exchanger (130) and allows the refrigerant circulating in the refrigerant circulating line to bypass the outdoor heat exchanger. The branch line connects the first bypass line and the refrigerant circulating line of the entrance of the evaporator. The control unit performs the defrosting control by controlling an upper limit of the rotation number of a compressor (100) below the predetermined rotation number while a defrosting mode is maintained when the frosting of the evaporator is recognized from a frosting recognizing member for operating the defrosting mode of a heat pump mode. In the defrosting mode of the heat pump mode, a part of the refrigerant circulating in the refrigerant circulating line bypasses the evaporator through the first bypass line and the other part defrosts the indoor vehicle by passing the evaporator through the branch line. [Reference numerals] (AA) Regulate the maximum rotating number of a compressor