Vehicle air conditioner

1. A vehicle air conditioner comprising:

a compressor which compresses a refrigerant;

an air flow passage through which air to be supplied into a vehicle interior flows;

a radiator disposed in the air flow passage to let the refrigerant radiate heat;

a heat absorber disposed in the air flow passage to let the refrigerant absorb heat;

an outdoor heat exchanger disposed outside the vehicle interior to let the refrigerant radiate or absorb heat;

an expansion valve which decompresses the refrigerant flowing into the outdoor heat exchanger;

and control means,

wherein the vehicle air conditioner includes an internal cycle mode in which inflow of the refrigerant into the outdoor heat exchanger and outflow of the refrigerant from the outdoor heat exchanger are inhibited, the refrigerant discharged from the compressor radiates heat in the radiator, and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the heat absorber;

wherein, in the internal cycle mode, the control means is configured to judge when an amount of the refrigerant to be circulated is excessively large and in response execute a refrigerant sealing mode to seal the refrigerant in the outdoor heat exchanger in a case where a refrigerant subcool degree of the radiator enlarges to be a predetermined threshold or more, and the control means is configured to judge when the amount of the refrigerant to be circulated is insufficient and in response execute a refrigerant discharge mode to discharge the refrigerant from the outdoor heat exchanger in a case where an operating status of the compressor is stable and a discharged refrigerant superheat degree of the compressor enlarges to become another threshold or more;

the control means being configured to allow for selective execution among the internal cycle mode and one of:

a heating mode in which the refrigerant discharged from the compressor radiates heat in the radiator, and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the outdoor heat exchanger;

a dehumidifying and heating mode in which the refrigerant discharged from the compressor radiates heat in the radiator, and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the heat absorber and the outdoor heat exchanger;

a dehumidifying and cooling mode in which the refrigerant discharged from the compressor radiates heat in the radiator and the outdoor heat exchanger, and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the heat absorber; and

a cooling mode in which the refrigerant discharged from the compressor radiates heat in the outdoor heat exchanger, and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the heat absorber.

2. The vehicle air conditioner according to claim 1 , wherein the vehicle air condition includes at least one additional mode of operation selected among the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode and the cooling mode.

3. The vehicle air conditioner according to claim 2 ,

wherein the control means judges whether or not the amount of the refrigerant to be circulated is excessively large on the basis of the refrigerant subcool degree of the radiator, and judges whether or not the amount of the refrigerant to be circulated is insufficient on the basis of the discharged refrigerant superheat degree of the compressor.

4. The vehicle air conditioner according to claim 1 ,

wherein the vehicle air condition includes a plurality of additional modes of operation selected among the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode and the cooling mode; and

wherein the control means is configured to allow for the selection and execution among the internal cycle mode and the plurality of additional modes of operation.

5. The vehicle air conditioner according to claim 4 ,

wherein the control means judges whether or not the amount of the refrigerant to be circulated is excessively large on the basis of the refrigerant subcool degree of the radiator, and judges whether or not the amount of the refrigerant to be circulated is insufficient on the basis of the discharged refrigerant superheat degree of the compressor.

6. The vehicle air conditioner according to claim 1 ,

wherein the vehicle air condition includes a plurality of additional modes of operation including each of the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode and the cooling mode; and

wherein the control means is configured to allow for the selection and execution among the internal cycle mode and the plurality of additional modes of operation.

7. The vehicle air conditioner according to claim 6 ,

wherein the control means judges whether or not the amount of the refrigerant to be circulated is excessively large on the basis of the refrigerant subcool degree of the radiator, and judges whether or not the amount of the refrigerant to be circulated is insufficient on the basis of the discharged refrigerant superheat degree of the compressor.

8. The vehicle air conditioner according to claim 1 , wherein the vehicle air conditioner includes the dehumidifying and heating mode.

9. The vehicle air conditioner according to claim 1 , wherein the vehicle air conditioner includes the dehumidifying and cooling mode.

10. The vehicle air conditioner according to claim 1 , wherein the control means allows for selective execution among each of the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode and the cooling mode.