VEHICLE HEAT PUMP SYSTEM SUITABLE FOR PERFORMING A DEFROST CONTROL WHEN THE FROST ON AN EVAPORATOR IS RECOGNIZED IN THE OPERATION OF A HEAT PUMP MODE

摘要

PURPOSE: A vehicle heat pump system is provided to perform a defrost control in which a refrigerant supply to an evaporator is cut off by closing a branch line with an opening/closing valve when the frost on the evaporator is recognized, thereby dehumidifying a vehicle indoor space even in the operation of a heat pump mode.;CONSTITUTION: A vehicle heat pump system includes a first bypass line (R1), a second bypass line (R2), a branch line (R4), and a control unit. The first bypass line makes refrigerant circulating in a refrigerant circulation line (R) selectively bypass a first expansion unit (140) and an evaporator (160). The second bypass line makes the refrigerant circulating in the refrigerant circulation line bypass an indoor-outdoor heat exchanger (130). The branch line connects the first bypass line and the refrigerant circulation line on an inlet of the evaporator. When the frost of the evaporator is recognized by frost recognition member, the control unit closes the branch line with an opening/closing valve and cuts off a refrigerant supply to the evaporator.;COPYRIGHT KIPO 2013;[Reference numerals] (AA) Inflow of indoor air