Vehicle air conditioner with hot-gas heater cycle

• US 20030089493A1
• Filed: 11/05/2002
• Published: 05/15/2003
• Est. Priority Date: 11/12/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shimizu, Toshitaka, Takano, Yoshiaki
• Granted Patent: US 7,028,767 B2
• Time in Patent Office: Days
• US Class Current: 165/202
• CPC Class Codes: B60H 1/00914 where the flow direction of the refrigerant does not change and there is a bypass of the condenser
• CPC Class Codes: B60H 1/034 from the cooling liquid of the propulsion plant and from an electric heating device
• CPC Class Codes: B60H 1/3213 for increasing the efficiency in a vehicle heat pump
• CPC Class Codes: B60H 2001/00949 comprising additional heating/cooling sources, e.g. second evaporator
• CPC Class Codes: B60H 2001/325 of the refrigerant at a compressing unit
• CPC Class Codes: B60H 2001/3255 related to temperature
• CPC Class Codes: B60H 2001/3261 of the air at an evaporating unit
• CPC Class Codes: B60H 2001/327 related to a compressing unit
• CPC Class Codes: B60H 2001/3288 Additional heat source
• CPC Class Codes: F25B 2400/0403 for the condenser
• CPC Class Codes: F25B 2400/0411 for the expansion valve or capillary tube
• CPC Class Codes: F25B 2500/28 Means for preventing liquid refrigerant entering into the compressor
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/2104 of an indoor room or compartment
• CPC Class Codes: F25B 2700/2106 of fresh outdoor air
• CPC Class Codes: F25B 2700/2113 of a suction accumulator
• CPC Class Codes: F25B 2700/21173 at the outlet
• CPC Class Codes: F25B 41/20 Disposition of valves, e.g. of on-off valves or flow control valves expansion valves F25B41/31
• CPC Class Codes: F25B 41/24 Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
• CPC Class Codes: F25B 43/006 Accumulators

Abstract

A vehicle air conditioner selectively switches one of a cooling mode in which an interior heat exchanger of a refrigerant cycle is operated as an evaporator for cooling air, and a heating mode in which the interior heat exchanger is operated as a radiator for heating air. In the vehicle air conditioner, an accumulator, for separating gas refrigerant and liquid refrigerant from each other and for storing the separated liquid refrigerant therein, is disposed between an outlet of the interior heat exchanger and a suction port of a compressor. Further, the accumulator includes a heating device for heating the liquid refrigerant stored in the accumulator in the heating mode. Therefore, heating performance for heating air in heating mode can be efficiently improved.

Claims

1. An air conditioner for a vehicle, comprising:

a compressor for compressing and discharging refrigerant;

an exterior heat exchanger for cooling refrigerant discharged from the compressor in a cooling mode;

an air conditioning case in which air flows toward a passenger compartment;

an interior heat exchanger for cooling air by absorbing heat from air in the cooling mode, the interior heat exchanger being disposed in the air conditioning case to heat air in a heating mode where the refrigerant discharged from the compressor is introduced into the interior heat exchanger through a hot-gas heater cycle while bypassing the exterior heat exchanger;

a switching member disposed to selectively switch one of the cooling mode and the heating mode;

an accumulator for separating refrigerant into gas refrigerant and liquid refrigerant and for storing the separated liquid refrigerant therein, the accumulator being disposed between an outlet of the interior heat exchanger and a suction port of the compressor, wherein;

the accumulator includes a heating device for heating the liquid refrigerant stored in the accumulator.

2. The air conditioner according to claim 1, further comprising

a heating heat exchanger for heating air using hot water from an engine of the vehicle as a heating source, the heating heat exchanger being disposed in the air conditioning case at a downstream air side of the interior heat exchanger,

wherein the compressor is driven by the engine.

3. The air conditioner according to claim 2, wherein the heating device is a hot water pipe into which hot water from the engine is circulated.

4. The air conditioner according to claim 3, wherein the hot water pipe is disposed to heat an outer peripheral surface of the accumulator at a position where the liquid refrigerant is stored.

5. The air conditioner according to claim 1, wherein:

the accumulator includes a tank body in which the liquid refrigerant is stored; and

the heating device is provided to heat an outer peripheral surface of the tank body at a position where the separated liquid refrigerant is stored.

6. The air conditioner according to claim 5, wherein:

the heating device is provided to heat the outer peripheral surface of the tank body and a bottom outer surface of the tank body.

7. The air conditioner according to claim 5, wherein:

the tank body has a cylindrical outer shape.

8. The air conditioner according to claim 1, wherein the heating device is an electric heater.

9. The air conditioner according to claim 8, wherein:

the electric heater includes a heater body having a thin plate shape, and a film member covering the heater body; and

the heater body has an electrical resistance material.

10. The air conditioner according to claim 9, wherein:

the accumulator includes a tank body in which the separated liquid refrigerant is stored;

the tank body has a cylindrical outer peripheral surface; and

the electric heater is cylindrically bent to be attached to the outer peripheral surface of the tank body at a lower side position.

11. The air conditioner according to claim 8, further comprising:

a pressure detection device for detecting pressure of refrigerant at a high-pressure side of the hot-gas heater cycle in the heating mode; and

a heater control unit for controlling an operation state of the electric heater based on the pressure detected by the pressure detection device so that the pressure of refrigerant at the high-pressure side becomes higher than a predetermined pressure.

12. The air conditioner according to claim 1, wherein the accumulator has a tank body in which the separated liquid refrigerant is stored, the air conditioner further comprising:

a surface temperature detection device for detecting an outer surface temperature of the tank body, wherein;

when the temperature detected by the surface temperature detecting device is lower than a predetermined temperature, the heating device heats the liquid refrigerant in the tank body of the accumulator.

13. The air conditioner according to claim 2, further comprising

a water temperature detecting device for detecting temperature of water flowing from the engine to the heating heat exchanger, wherein:

when the temperature detected by the water temperature sensor is lower than a predetermined temperature, the heating device heats the liquid refrigerant in the accumulator.

14. The air conditioner according to claim 1, further comprising

an air temperature detecting device for detecting at least one of an air temperature immediately blown from the interior heat exchanger and an air temperature in the passenger compartment, in the heating mode,

when the air temperature detected by the air temperature detecting device is lower than a predetermined temperature, the heating device heats the liquid refrigerant in the accumulator.