Vehicular air-conditioning system

Abstract

A vehicular air-conditioning system has a heat pump circulation passage for circulating a coolant with a compressor. To the heat pump circulation passage, there are connected a condenser for performing a heat exchange between a coolant and ambient air, an expansion valve, a first evaporator, a heater, and a second evaporator. The heat pump circulation passage includes a coolant retrieval passage extending from a divider between the condenser and the gas-liquid separator and connected to the compressor. A second backflow check valve for preventing the coolant from flowing from the compressor to the divider and a solenoid-operated valve are connected to the coolant retrieval passage.

1 . An air-conditioning system for use on a vehicle, comprising:
 a heat pump circulation passage for circulating a coolant with a compressor;   a condenser disposed in the heat pump circulation passage, for performing a heat exchange between the coolant and ambient air;   an expansion valve disposed in the heat pump circulation passage, for depressurizing the coolant which is delivered from the condenser;   a first evaporator disposed in the heat pump circulation passage, for performing a heat exchange between the coolant which has passed through the expansion valve and air-conditioning air;   a heater disposed in the heat pump circulation passage, for performing a heat exchange between the coolant which is delivered from the compressor and the air-conditioning air which has passed through the first evaporator;   a second evaporator disposed in a branch passage branched from the heat pump circulation passage, for performing a heat exchange between the coolant and a heating medium obtained from within or outside the vehicle; and   a gas-liquid separator and an auxiliary condenser which are disposed downstream of the condenser and connected between the condenser and the expansion valve;   wherein the heat pump circulation passage includes a coolant retrieval passage extending from a divider between the condenser and the gas-liquid separator and connected to the compressor.   
     
     
         2 . The air-conditioning system according to  claim 1 , further comprising backflow check means connected to the coolant retrieval passage, for preventing the coolant from flowing from the compressor to the divider. 
     
     
         3 . The air-conditioning system according to  claim 1 , further comprising an on-off valve connected to the coolant retrieval passage;
 wherein the on-off valve is opened in a heating mode and closed in a cooling mode.   
     
     
         4 . The air-conditioning system according to  claim 2 , further comprising an on-off valve connected to the coolant retrieval passage;
 wherein the on-off valve is opened in a heating mode and closed in a cooling mode.   
     
     
         5 . The air-conditioning system according to  claim 3 , further comprising a controller for switching between the heating mode and the cooling mode and controlling opening and closing of the on-off valve;
 wherein in the heating mode, the controller opens the on-off valve and thereafter activates the compressor for a prescribed time and then closes the on-off valve.   
     
     
         6 . The air-conditioning system according to  claim 4 , further comprising a controller for switching between the heating mode and the cooling mode and controlling opening and closing of the on-off valve;
 wherein in the heating mode, the controller opens the on-off valve and thereafter activates the compressor for a prescribed time and then closes the on-off valve.   
     
     
         7 . The air-conditioning system according to  claim 1 , wherein the heating medium which is supplied to the second evaporator for a heat exchange with the coolant comprises a medium which is higher in temperature than the coolant.