Air conditioner for vehicle

Abstract

Provided is an air conditioner for a vehicle which can prevent the controls over cooling cycle and heating cycle from interfering with each other and thereby prevent hunting between the cooling and heating cycles even when a compressor is operated to perform the heating cycle in an overlapping temperature range where air cooling and air heating are both required. An air conditioner ( 4 ) for a vehicle includes a refrigerant circulation circuit ( 9 b ) for air heating to circulate a refrigerant, and a control unit ( 29 ) to selectively perform a normal air conditioning mode in which a normal cooling operation is feasible by circulating the refrigerant through a refrigerant circulation circuit ( 9 a) for air cooling and an auxiliary heating mode in which an auxiliary heating operation is performed by circulating the refrigerant through the refrigerant circulating circuit ( 9 b ) for air heating.

1 . An air conditioner for a vehicle, comprising:
 a refrigerant circulation circuit for air cooling to circulate a refrigerant through a compressor, a refrigerant condenser provided outside a vehicle interior, a first inflator means, an evaporator for air cooling provided in the vehicle interior, and an accumulator for vapor-liquid separation in this order;   a cooling water circulation circuit for air heating to circulate a cooling water between a cooling water passage in a heat generator of a vehicle drive unit and a heater core in the vehicle interior;   a three-way solenoid valve provided between the compressor and the condenser; and   a refrigerant circulation circuit for air heating to circulate a refrigerant through the compressor, the three-way solenoid valve, a heat exchanger means for heating a cooling water, an outside heat exchanger unit including a second inflator means and the accumulator in this order,   the heat exchanger means for heating a cooling water comprising   a heat exchanger for a cooling water provided in a middle of the cooling water circulation circuit for air heating, and   an outside heat exchanger provided in a middle of the refrigerant circulation circuit for air heating to transfer heat with the heat exchanger for a cooling water, and   a control means to selectively execute a normal airconditioning mode and an auxiliary air heating mode by a switching control of the three-way solenoid valve to switch to either of the refrigerant circulation circuits for air cooling and for air heating, the normal air conditioning mode in which the refrigerant is circulated for normal cooling operation in the refrigerant circulation circuit for air cooling, the auxiliary air heating mode in which the refrigerant is circulated for auxiliary air heating operation in the refrigerant circulation circuit for air heating.   
     
     
         2 . The air conditioner according to  claim 1 , further comprising:
 a water temperature sensor for detecting a temperature of the cooling water;   an outside air temperature sensor for detecting an outside temperature of the vehicle interior; and   an inside air temperature sensor for detecting an inside temperature of the vehicle interior, wherein   the control means is configured to selectively execute the normal airconditioning mode and the auxiliary air heating mode on the basis of a condition of the cooling water temperature, outside air temperature, and inside air temperature.   
     
     
         3 . The air conditioner according to  claim 1 , further comprising:
 an air conditioner switch to start the normal airconditioning mode; and   an auxiliary air heating switch to start the auxiliary air heating mode, wherein   the control means is configured to switch the normal airconditioning mode to the auxiliary air heating mode when the auxiliary air heating switch is turned on in non-air cooling operation.   
     
     
         4 . The airconditioner according to  claim 2 , further comprising:
 an air conditioner switch to start the normal airconditioning mode; and   an auxiliary air heating switch to start the auxiliary air heating mode, wherein the control means is configured to   control operation of the compressor to perform a normal air cooling operation when the outside air temperature becomes equal to or over a predetermined air cooling start temperature in a cooling operation of the normal airconditioning mode, and   switch the normal airconditioning mode to the auxiliary air heating mode when the auxiliary air heating switch is turned on in non-air cooling operation and when the outside air temperature is equal to or below a predetermined air heating start temperature and the cooling water temperature becomes equal to or below a predetermined heating start temperature.   
     
     
         5 . The air conditioner according to  claim 1 , wherein
 the air conditioner can operate in a refrigerant recovery mode in which a remnant refrigerant in the condenser and the evaporator is recovered in the accumulator, in switching to the auxiliary air heating mode after the cooling operation.   
     
     
         6 . The air conditioner according to  claim 5 , further comprising
 a memory in which an airconditioning control state of the vehicle air conditioner is stored at a stop of the vehicle drive unit.