Vehicular air-conditioning unit

Patent metadata

Field	Value
Publication number	US-9562712-B2
Application number	US-201314406113-A
Country	US
Kind code	B2
Filing date	Jun 12, 2013
Priority date	Jun 29, 2012
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The heating capacity particularly at low outside air temperatures in a vehicular air-conditioning unit that heats the vehicle interior by heat pump operation of a refrigerant circuit using a compressor is improved. During heating, a refrigerant discharged from a compressor 2 releases heat in a radiator 4 into the vehicle interior, and the refrigerant decompressed after the heat release in the radiator evaporates in at least one of an external heat exchanger 7 and a ventilation heat exchanger 24 . During cooling, the refrigerant discharged from the compressor releases heat in the external heat exchanger, and the refrigerant decompressed after the heat release in the external heat exchanger evaporates in an internal heat exchanger 9 to absorb heat from the vehicle interior. The vehicular air-conditioning unit includes a hot gas cycle circuit 31 for decompressing a part of the refrigerant discharged from the compressor, and causing the decompressed part of the refrigerant to flow through the internal heat exchanger to release heat into the vehicle interior.

First claim

The invention claimed is:

1. A vehicular air-conditioning unit in which: a refrigerant circuit includes a compressor, a radiator, an external heat exchanger, an internal heat exchanger, and a ventilation heat exchanger for absorbing heat from air discharged from a vehicle interior to outside; during heating, a refrigerant discharged from the compressor releases heat in the radiator into the vehicle interior, and the refrigerant decompressed after the heat release in the radiator evaporates in at least one of the external heat exchanger and the ventilation heat exchanger; and during cooling, the refrigerant discharged from the compressor releases heat in the external heat exchanger, and the refrigerant decompressed after the heat release in the external heat exchanger evaporates in the internal heat exchanger to absorb heat from the vehicle interior, the vehicular air-conditioning unit comprising
a hot gas cycle circuit for decompressing a part of the refrigerant discharged from the compressor, and causing the decompressed part of the refrigerant to flow through the internal heat exchanger to release heat into the vehicle interior.

2. The vehicular air-conditioning unit according to claim 1 , wherein in at least one of the case where the external heat exchanger is to be defrosted and the case where an outside air temperature is a predetermined low value during heating, the refrigerant having released heat in the radiator is decompressed and caused to flow through the ventilation heat exchanger while the refrigerant is kept from flowing through the external heat exchanger, and the part of the refrigerant discharged from the compressor is caused to flow through the hot gas cycle circuit.

3. The vehicular air-conditioning unit according to claim 2 , wherein the refrigerant having evaporated in the external heat exchanger or the refrigerant having passed through the hot gas cycle circuit and released heat in the internal heat exchanger is sucked into a low pressure part of the compressor, and the refrigerant having evaporated in the ventilation heat exchanger is returned to an intermediate pressure part of the compressor.

4. The vehicular air-conditioning unit according to claim 3 , wherein in the case where the refrigerant is kept from flowing through the external heat exchanger and the hot gas cycle circuit or in the case where a temperature of the vehicle interior is a predetermined low value, the refrigerant having evaporated in the ventilation heat exchanger is returned to the low pressure part of the compressor.

5. The vehicular air-conditioning unit according to claim 2 , wherein in a state where flow of the refrigerant into the external heat exchanger and flow of the refrigerant into the ventilation heat exchanger are stopped alternately during heating, whether or not the heat exchanger needs to be defrosted is determined, and the refrigerant is kept from flowing through the ventilation heat exchanger in the case of defrosting the ventilation heat exchanger.

6. The vehicular air-conditioning unit according to claim 2 , wherein during heating, a state in which the refrigerant is caused to flow through the external heat exchanger while the refrigerant is kept from flowing through the hot gas cycle circuit is resumed in the case where defrosting of the external heat exchanger is completed, and whether or not the defrosting of the external heat exchanger is completed is not determined in the case where a temperature of the outside is below freezing.

7. The vehicular air-conditioning unit according to claim 1 , comprising
an evaporation pressure regulation valve for preventing an evaporation temperature of the refrigerant in the ventilation heat exchanger from dropping below freezing.

8. The vehicular air-conditioning unit according to claim 1 , wherein air of the vehicle interior having passed through the ventilation heat exchanger is circulated through the external heat exchanger.

9. The vehicular air-conditioning unit according to claim 8 , comprising
a duct for circulating outside air through the external heat exchanger,
wherein the air of the vehicle interior having passed through the ventilation heat exchanger is caused to flow into the duct on an upstream side of the external heat exchanger, and an opening of an inflow part for the air of the vehicle interior is narrowed.

10. The vehicular air-conditioning unit according to claim 9 , comprising
a damper for regulating the opening of the inflow part for the air of the vehicle interior in the duct.

11. The vehicular air-conditioning unit according to claim 1 , comprising
an electric heater for heating the vehicle interior during heating.

12. A vehicular air-conditioning unit in which: a refrigerant circuit includes a compressor, a radiator, an external heat exchanger, an internal heat exchanger, and a ventilation heat exchanger for absorbing heat from air discharged from a vehicle interior to outside; during heating, a refrigerant discharged from the compressor releases heat in the radiator into the vehicle interior, and the refrigerant decompressed after the heat release in the radiator evaporates in at least one of the external heat exchanger and the ventilation heat exchanger; and during cooling, the refrigerant discharged from the compressor releases heat in the external heat exchanger, and the refrigerant decompressed after the heat release in the external heat exchanger evaporates in the internal heat exchanger to absorb heat from the vehicle interior, the vehicular air-conditioning unit comprising
an electric heater,
wherein in the case of defrosting the external heat exchanger during heating, the refrigerant having released heat in the radiator is decompressed and caused to flow through the ventilation heat exchanger while the refrigerant is kept from flowing through the external heat exchanger, and the vehicle interior is heated by the electric heater.

Assignees

• Sanden Corp
• Sanden Holdings Corp

Inventors

• Kasuya Junichiro

Classifications

• F25B5/00

  Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity (with cascade operation F25B7/00) · CPC title

• F25B47/022

  hot gas defrosting · CPC title

• F25B49/02

  for compression type machines, plants or systems · CPC title

• F25B2700/21175

  of the refrigerant at the outlet of the evaporator · CPC title

• B60H2001/00949

  comprising additional heating/cooling sources, e.g. second evaporator · CPC title