JP2006131180A - Vehicular air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular air-conditioner using carbon dioxide as a refrigerant capable of easily performing right and left independent temperature adjustment by reducing the dispersion of the inlet-outlet temperature difference of a heater core to improve the air mix property. <P>SOLUTION: A heater core 7 to heat supplied air by heated water is installed in a ventilation passage 17 with supplied air introduced therein, and heated water is supplied to the heater core 7 from a water-refrigerant heat exchanger 8 to perform the heat exchange between the refrigerant in a high-pressure and high-temperature state by a compressor 1 and water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle air conditioner using a refrigerant such as carbon dioxide, and more specifically, a vehicle mounted on an electric vehicle, a fuel cell vehicle, a hybrid vehicle (hereinafter referred to as an electric vehicle) having no heat source such as an engine. The present invention relates to an air conditioner for automobiles.

  Some vehicle air conditioners have a left and right independent temperature control function that allows a passenger to individually control the temperature. For example, two right and left ventilation paths are formed in the heater unit, a heater core using engine cooling water as a heating medium and a partition plate that divides the cooler into two parts are provided, and two air mix doors connected to each ventilation path are opened. It is known that the temperature is adjusted separately for the left and right by adjusting the ratio of the air flowing through the heater core and the ratio of the air flowing through the bypass passage (passage that does not pass through the heater core). (See Patent Document 1).

  In the heater core using engine cooling water as a refrigerant, the temperature difference between the inlet and outlet of the engine cooling water is about 10 ° C. Therefore, in the heater unit with the left and right independent temperature control as described above, the two air mix doors have the same opening, When air of the same air volume is passed to the left and right of the heater core divided by the partition plate (same temperature control on the left and right), there is almost no air outlet temperature difference between the left and right of the heater core. Moreover, when the opening degree of one air mix door is fixed and the opening degree of the other air mix door is adjusted (left and right independent temperature control), the temperature on the fixed side hardly changes. That is, since the temperature of one air outlet can be kept constant, only the temperature of the other air outlet whose temperature is desired to be adjusted can be adjusted.

In addition, when the same left and right temperature control is set, the air mix door opening on each side of the driver seat and the passenger seat is controlled to be the same (the blowing temperature is constant on the driver seat side and the passenger seat side) When left and right independent temperature control is set, it is known to control the air mix door opening on the driver's side and passenger's side based on the set temperature, room temperature, outside temperature, and solar radiation (See Patent Document 2).
Japanese Patent Laid-Open No. 9-328011 Japanese Patent Laid-Open No. 9-323529

  Conventionally, chlorofluorocarbon refrigerants have mainly been used in refrigeration cycles for vehicle air conditioners. However, if these are released into the atmosphere, environmental problems such as global warming due to destruction of the ozone layer are a concern. As a countermeasure, a refrigeration cycle using carbon dioxide, ethylene, ethane nitric oxide or the like (hereinafter, carbon dioxide is a representative example) has been proposed (for example, Japanese Patent Laid-Open No. 2002-130849).

  Such a refrigeration cycle using carbon dioxide as a refrigerant is in principle the same as a conventional refrigeration cycle using CFCs. However, since the critical temperature of carbon dioxide is about 31 ° C., which is significantly lower than the critical temperature of conventional chlorofluorocarbon (for example, R-12 is 112 ° C.), the carbon dioxide temperature on the radiator side is higher than the critical temperature of carbon dioxide. However, the difference is that the temperature of carbon dioxide, which is a refrigerant, decreases from the inlet to the outlet in a gas state.

  On the other hand, the refrigeration cycle of a vehicle air conditioner uses engine cooling water as a heating medium in engine vehicles, but there is no engine cooling water in electric vehicles and the like. Instead, the radiator of the refrigeration cycle is replaced with a sub-gas cooler (engine vehicle). Is considered to be used as a heater core) for heating. Even when a radiator of such a refrigeration cycle using carbon dioxide as a refrigerant is incorporated as a sub gas cooler in a left and right independent temperature control heater unit for heating, there is almost no air outlet temperature difference between the left and right of the sub gas cooler. Not required.

  However, since the temperature change in the sub-gas cooler using carbon dioxide as a refrigerant is a sensible heat change, there is a very large variation in the refrigerant inlet / outlet temperature difference, which makes it difficult to mix air downstream of the sub-gas cooler.

  If air mixing becomes difficult in this way, the difference in heat exchange between the left and right of the sub-gas cooler will increase even if the same amount of air is passed to the left and right of the sub-gas cooler divided by the partition plate. The air outlet temperature difference at each outlet of the passenger seat becomes large.

  Also, when it is desired to use the left and right independent temperature control type heater units to make the left and right the same temperature, the two air mix doors have the same opening, and the air of the same air volume is passed to the left and right of the sub gas cooler divided by the partition plate. Even so, there is a difference in temperature between the left and right air outlets at each outlet of the sub-gas cooler.

  Furthermore, in the heater unit of the left and right independent temperature control system, for example, when adjusting the temperature only on the passenger seat side, the opening of the air mix door on the driver seat side is fixed, and the opening of the air mix door on the passenger seat side is adjusted. The sub-gas cooler that uses carbon dioxide as the refrigerant has a large temperature difference between the refrigerant inlet and outlet, so there is a difference in the amount of heat exchange between the left and right sides. The air outlet temperature cannot be kept constant.

  Further, in order to improve the variation in the inlet / outlet temperature difference, it is necessary to provide a large chamber space, a mix rib or the like on the downstream side of the sub-gas cooler, and it becomes difficult to make the unit compact because the unit size increases.

  As described above, in a vehicle air conditioner using carbon dioxide as a refrigerant, the temperature difference between the entrance and exit of the sub-gas cooler is large, resulting in poor air mixing and unevenness in the temperature of the conditioned air. Independent temperature control was difficult. Therefore, in an electric vehicle or the like that does not have a heat source such as an engine, it has been a technical problem to improve the air mixing property downstream of the sub gas cooler and facilitate left and right independent temperature control.

  An object of the present invention is to provide a vehicle air conditioner that can easily achieve right and left independent temperature control in a refrigeration cycle using carbon dioxide as a refrigerant by reducing variations in the temperature difference between the inlet and outlet of the sub-gas cooler and improving air mixing. To provide an apparatus.

  In order to achieve the above-mentioned object, the invention of claim 1 includes at least a compressor that compresses and raises the temperature of a refrigerant, a radiator that exchanges heat between the refrigerant and outside air, and heat between the supply air and the refrigerant. An evaporator to be exchanged, an internal heat exchanger that exchanges heat between the refrigerant compressed and heated by the compressor or the refrigerant cooled by the radiator and the low-pressure refrigerant returning to the compressor, and the evaporation A first depressurizing means for depressurizing the refrigerant sent to the heat exchanger and a second depressurizing means for depressurizing the refrigerant sent to the radiator, and circulates the refrigerant that has passed through the internal heat exchanger back to the compressor An air conditioner for a vehicle that executes a refrigeration cycle, which is installed on the downstream side of the evaporator in a ventilation path into which supply air is introduced, and includes supply air that has passed through the evaporator and water that has been heated A heater core that exchanges heat between the compressor and the compressor, And the refrigerant was allowed, characterized in that it comprises a water-refrigerant heat exchanger for heat exchange with the water supplied to the heater core.

  According to a second aspect of the present invention, in the first mode, in the heating mode, the refrigerant compressed and heated by the compressor is introduced into the water-refrigerant heat exchanger, and heat is supplied to water supplied to the heater core. The supply air that passes through the heater core is heated by exchanging, and the medium that has exchanged heat with the water-refrigerant heat exchanger is heat-exchanged with the low-pressure side refrigerant in the internal heat exchanger, and this refrigerant is expanded in the second expansion. By reducing the pressure with a valve and introducing it into the radiator, heat is exchanged with the outside air to absorb heat.

  According to a third aspect of the present invention, in any one of the first and second aspects, in the dehumidifying heating mode, the refrigerant compressed and heated by the compressor is introduced into the water refrigerant heat exchanger and supplied to the heater core. Heat supply air that passes through the heater core by exchanging heat with water, and the refrigerant that has exchanged heat with the water refrigerant heat exchanger is decompressed by the first decompression means and introduced into the evaporator, The supply air passing through the evaporator is dehumidified by exchanging heat with the supply air introduced into the ventilation path.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, in the cooling mode, the refrigerant compressed and heated by the compressor is cooled by exchanging heat with the outside air by the radiator, and the refrigerant is The supply air passing through the evaporator is cooled by reducing the pressure by the first pressure reducing means and introducing it into the evaporator and exchanging heat with the supply air introduced into the ventilation path. .

  According to the first aspect of the present invention, since water having a high specific heat is used as the refrigerant that exchanges heat with the supply air in the heater core, there is less variation in the inlet / outlet temperature difference in the heater core 7 than in the case where carbon dioxide gas is used. The air mix property in the downstream of the can be improved. Further, since the temperature unevenness of the supply air is almost eliminated, the left and right independent temperature control can be facilitated. Furthermore, since it is not necessary to provide a large chamber space, a mix rib or the like on the downstream side of the heater core in order to improve the variation in the inlet / outlet temperature difference, the unit can be made compact.

  According to the second aspect of the present invention, the refrigerant that has exchanged heat with the supply air in the heater core exchanges heat with the refrigerant on the low-pressure side in the internal heat exchanger, further absorbs heat from the outside air in the radiator, and heats again in the internal heat exchanger. By circulating the exchange cycle, heating as a heat pump can be performed by pumping heat from the outside air with a low-temperature refrigerant.

  According to the third aspect of the present invention, the supply air is heated by the heater core by exchanging heat between the refrigerant and water that have become high pressure and high temperature by the compressor, and the refrigerant is heated by the heater core by introducing the refrigerant into the evaporator. The previous supply air can be cooled and dehumidified.

  According to the invention of claim 4, since the refrigerant whose temperature has been lowered by the radiator is further heat-exchanged with the refrigerant on the low-pressure side by the internal heat exchanger, it is possible to improve performance efficiency. Further, when the radiator is frozen by frost or icing, it is possible to release the freezing of the radiator by introducing the refrigerant having high pressure and high temperature by the compressor into the radiator.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments as the best mode for carrying out a vehicle air conditioner according to the present invention will be described below.

  FIG. 1 is a system diagram showing a configuration of a vehicle air conditioner according to the present embodiment. The vehicle air conditioner of the present embodiment uses carbon dioxide as a refrigerant. And the vehicle air conditioner of a present Example makes it heat-exchange between the compressor 1 which compresses and heats a refrigerant | coolant, the heat radiator 2 which heat-exchanges between a refrigerant | coolant and external air, and supply air and a refrigerant | coolant. An evaporator 3, an internal heat exchanger 4 for exchanging heat between the refrigerant compressed and heated by the compressor 1 or the heat absorbed by the radiator 2 and the low-pressure refrigerant returning to the compressor, and the evaporator 3 Between the first expansion valve 5 for depressurizing the refrigerant sent to the second expansion valve 6, the second expansion valve 6 for depressurizing the refrigerant sent to the radiator 2, and the supply air that has passed through the evaporator 3 and the heated water. A heater core 7 to be exchanged, a water refrigerant heat exchanger 8 for exchanging heat between the refrigerant compressed and heated by the compressor 1 and the water supplied to the heater core 7, and the heater core 7 and the water refrigerant heat exchanger 8 A water pump 9 that circulates water between them, an accumulator 10 that gas-liquid separates the refrigerant, and heat dissipation Check valves 11, 12 that prevent the refrigerant from flowing back to 2, check valves 13 that prevent the refrigerant from flowing back to the evaporator 3, refrigerant discharged from the radiator 2, and refrigerant flowing into the radiator 2 A three-way valve 14 for switching the flow direction of the refrigerant, an electromagnetic valve 15 for switching the flow of the refrigerant from the water refrigerant heat exchanger 8, an air mix door 16 for adjusting the amount of supply air sent from a blower fan (not shown), An air conditioning duct (ventilation path) 17 in which the evaporator 3, the heater core 7 and the air mix door 16 are installed, and a control unit 18 that controls switching of operation modes in the vehicle air conditioner are configured.

  The compressor 1 obtains a driving force from a motor (not shown) or a vehicle drive device, compresses and raises the temperature of gas phase carbon dioxide, and discharges it as a high-pressure and high-temperature refrigerant.

  In the heating mode, the radiator 2 exchanges heat between the low-pressure refrigerant output from the second expansion valve 6 and the outside air, and causes the low-pressure refrigerant to absorb the heat of the outside air. In the cooling mode, heat is exchanged between the high-pressure and high-temperature refrigerant output from the water-refrigerant heat exchanger 8 and the outside air, and the high-pressure and high-temperature refrigerant is radiated to the outside air.

  The evaporator 3 is installed in the air conditioning duct 17 and heat-exchanges the low-pressure and low-temperature refrigerant decompressed by the first expansion valve 5 with the supply air from the blower fan, thereby cooling and dehumidifying the supply air. .

  The internal heat exchanger 4 exchanges heat between the gas-phase refrigerant output from the accumulator 10 and the high-pressure refrigerant that has passed through the water-refrigerant heat exchanger 8 or the radiator 2 and sends the refrigerant to the compressor 1.

  The first expansion valve (first decompression means) 5 decompresses (expands) the high-pressure refrigerant sent from the internal heat exchanger 4 and outputs the decompressed refrigerant to the evaporator 3.

  The second expansion valve (second decompression means) 6 decompresses the high-pressure refrigerant sent from the internal heat exchanger 4 and outputs it to the radiator 2.

  The heater core 7 is installed in the air-conditioning duct 17 and heats the supply air that has passed through the evaporator 3 with the heated water sent from the water-refrigerant heat exchanger 8. The heater core 7 is configured such that heat exchange is performed in a core portion in which, for example, flat tubes and fins are stacked, and water introduced from the inlet side is guided to the outlet side while turning inside the core portion a plurality of times.

  The water refrigerant heat exchanger 8 raises the temperature of the water supplied to the heater core 7 by the refrigerant compressed and heated by the compressor 1.

  The water pump 9 circulates water between the heater core 7 and the water-refrigerant heat exchanger 8 by obtaining driving force from a motor (not shown) or the like and sucking and discharging water.

  The accumulator 10 gas-liquid separates the refrigerant discharged from the radiator 2 or the evaporator 3, sends only the gas-phase refrigerant to the internal heat exchanger 4, and temporarily stores the liquid-phase refrigerant. Yes.

  The switching of the three-way valve 14 is controlled by the control unit 18, and the valve is switched so that the refrigerant flows from the radiator 2 to the accumulator 10 in the heating mode and the refrigerant flows from the internal heat exchanger 4 to the radiator 2 in the cooling mode. Yes.

  The solenoid valve 15 is controlled to be opened and closed by the control unit 18, and is opened in the heating mode and the dehumidifying heating mode to flow the refrigerant from the water / refrigerant heat exchanger 8 to the internal heat exchanger 4, and is closed in the cooling mode to be water refrigerant. The valve is switched so that the refrigerant flows from the heat exchanger 8 to the radiator 2.

  The air mix door 16 is installed in front of the heater core 7, and the opening degree (mixing ratio) of the door is controlled by the control unit 18. When the supply air sent from the blower fan is heated by the heater core 7, the door is rotated downward according to the heating degree (mixing ratio to 100%), and when the supply air is not heated, the door is moved upward. (Mixing ratio 0%). FIG. 1 shows a state where the door is rotated downward to obtain a mixing ratio of 100%.

  The control unit 18 is composed of a microcomputer including a CPU, a ROM, a RAM, and the like, and fetches various signals and data sent from various sensors and timers (not shown) periodically or as needed and stored in the ROM. Calculation processing is executed based on various control programs and data, and valve switching control in the three-way valve 14 and electromagnetic valve 15, blower fan air volume, air mix door 16 opening degree, and the like are controlled. These controls are mainly executed according to switching of the operation mode.

  Next, the operation | movement in each operation mode in the vehicle air conditioner of a present Example is demonstrated.

[1] Dehumidifying Heating Mode FIG. 2 is a system diagram showing the flow of refrigerant and water in the dehumidifying heating mode. In the figure, a solid line indicates a portion where the refrigerant or water flows, and a broken line indicates a portion where the refrigerant does not flow.

  In this embodiment, the three-way valve 14 is closed and the electromagnetic valve 15 is opened, and the refrigerant flows to the internal heat exchanger 4 side, so that the compressor 1-water refrigerant heat exchanger 8-electromagnetic valve 15-inside A first circulation path L1 through which the refrigerant circulates is set in the order of heat exchanger 4 -first expansion valve 5 -evaporator 3 -accumulator 10 -internal heat exchanger 4. Moreover, the water circulation flow path W1 through which water circulates in the order of the heater core 7 -water refrigerant heat exchanger 8 -water pump 9 is set.

  In FIG. 2, the refrigerant is compressed and heated by the compressor 1 to become high pressure and high temperature, and is heat-exchanged with water in the water circulation passage W <b> 1 in the water refrigerant heat exchanger 8. The water heated by the water-refrigerant heat exchanger 8 is guided to the heater core 7 where heat is exchanged with the supply air sent from the blower fan to heat the supply air, and the increased supply air is heated. It is blown into the passenger compartment as wind. At this time, the rotation amount of the air mix door 16 is controlled according to the set temperature. Then, the water whose heat has been exchanged with the heater core 7 returns to the water pump 9 and is discharged from here again to the water refrigerant heat exchanger 8 at a predetermined water pressure.

  The refrigerant that has exchanged heat with water in the water refrigerant heat exchanger 8 passes through the electromagnetic valve 15 and is sent to the internal heat exchanger 4, where it exchanges heat with the low-pressure side refrigerant, and further the first expansion valve. The pressure is reduced at 5 to a low pressure and low temperature, and is sent to the evaporator 3. The low-pressure and low-temperature refrigerant exchanges heat with the supply air sent from the blower fan to cool and dehumidify the supply air. The dehumidified supply air is heated by the heater core 7 and blown into the vehicle interior.

  Further, the refrigerant having exchanged heat with the evaporator 3 is sent to the accumulator 10. Here, the refrigerant is gas-liquid separated, the gas phase refrigerant is output to the low pressure side of the internal heat exchanger 4, and the liquid phase refrigerant is temporarily stored in the accumulator 10.

  Then, the refrigerant heat-exchanged by the internal heat exchanger 4 is compressed and heated again by the compressor 1 to become high pressure and high temperature, and is sent to the water refrigerant heat exchanger 8.

  According to the present embodiment, the refrigerant and water that have become high pressure and high temperature in the compressor 1 are heat-exchanged between the water refrigerant heat exchanger 8 and are sent from the water and the blower fan that are heated here. The supplied air is heat-exchanged by the heater core 7 to heat the supplied air and blow it into the passenger compartment. As described above, since water having high specific heat is used as the refrigerant for exchanging heat with the supply air in the heater core 7, there is less variation in the inlet / outlet temperature difference in the heater core 7 than in the case of using carbon dioxide gas, and downstream of the heater core 7. The air mix property of can be improved. Further, since the temperature unevenness of the supply air is almost eliminated, the left and right independent temperature control can be facilitated. Furthermore, since it is not necessary to provide a large chamber space, a mix rib or the like on the downstream side of the heater core in order to improve the variation in the inlet / outlet temperature difference, the unit can be made compact (the effect of claim 1).

  In the dehumidifying and heating mode shown in FIG. 2, the supply air is heated by the heater core 7 by exchanging heat between the refrigerant and the water that have become high pressure and high temperature in the compressor 1, and the refrigerant is introduced into the evaporator 3. Thus, the supply air before heating can be cooled and dehumidified by the heater core 7 (effect of claim 3).

  Here, the difference between the vehicle air conditioner of the present embodiment provided with the water refrigerant heat exchanger 8 and the vehicle air conditioner of the conventional example provided with the brine circuit will be described. Japanese Patent Application Laid-Open No. 9-169207 proposes a vehicle air conditioner that improves heat exchange efficiency by exchanging heat between a secondary refrigerant such as HFC134a or combustible HC and water in a brine circuit.

  The vehicle air conditioner proposed here is premised on the use of engine coolant of the engine vehicle, so that even if this is applied to an electric vehicle or the like that does not have a heat source, the operation is not established. It was impossible to perform dehumidification simultaneously in the mode. However, in the vehicle air conditioner of the present embodiment, dehumidification can be performed simultaneously with heating, and further cooling can be performed.

[2] Heating Mode FIG. 3 is a system diagram showing refrigerant and water flows in the heating mode.

  In this embodiment, the three-way valve 14 is switched to connect the flow path from the radiator 2 to the accumulator 10, and the electromagnetic valve 15 is opened to allow the refrigerant to flow to the internal heat exchanger 4 side. 1-water refrigerant heat exchanger 8-electromagnetic valve 15-internal heat exchanger 4-second expansion valve 6-check valve 13-radiator 2-three-way valve 14-check valve 12-accumulator 10-internal heat exchanger A second circulation path L2 in which the refrigerant circulates in the order of 4 is set. Moreover, the water circulation flow path W1 through which water circulates in the order of the heater core 7 -water refrigerant heat exchanger 8 -water pump 9 is set.

  In FIG. 3, the refrigerant is compressed and heated by the compressor 1 to become a high pressure and high temperature, and heat is exchanged with water in the water refrigerant heat exchanger 8. The water heated by the water-refrigerant heat exchanger 8 is guided to the heater core 7 where heat is exchanged with the supply air sent from the blower fan to heat the supply air, and the increased supply air is heated. It is blown into the passenger compartment as wind. At this time, the rotation amount of the air mix door 16 is controlled according to the set temperature. And the water which heat-exchanged supply air with the heater core 7 is again sent to the water refrigerant | coolant heat exchanger 8 from the water pump 9 with a predetermined water pressure.

  The refrigerant that has exchanged heat with water in the water refrigerant heat exchanger 8 passes through the electromagnetic valve 15 and is sent to the internal heat exchanger 4, where it exchanges heat with the low-pressure side refrigerant, and the second expansion valve 6. The pressure is then reduced, and further passes through the check valve 13 and sent to the radiator 2. Then, it exchanges heat with the outside air to absorb heat, and then passes through the three-way valve 14 and the check valve 12 and is guided to the accumulator 10. In the accumulator 10, gas-liquid separation is performed and the gas-phase refrigerant is output to the low pressure side of the internal heat exchanger 4, and the liquid-phase refrigerant is temporarily stored in the accumulator 10.

  Then, the refrigerant heat-exchanged by the internal heat exchanger 4 is compressed and heated again by the compressor 1 to become high pressure and high temperature, and is sent to the water refrigerant heat exchanger 8.

  In the heating mode shown in FIG. 3, the refrigerant that has become high pressure and high temperature in the compressor 1 exchanges heat with water and heats the supply air with the heater core 7. Thereafter, the internal heat exchanger 4 exchanges heat with the low-pressure side refrigerant, the pressure is reduced by the second expansion valve 6, the heat is absorbed from the outside air by the radiator 2, and the heat is again exchanged by the internal heat exchanger 4 to the compressor 1. Return. According to this cycle, heating as a heat pump can be performed by pumping heat from the outside air with a low-temperature refrigerant (effect of claim 2).

[3] Cooling Mode FIG. 4 is a system diagram showing the flow of refrigerant and water in the cooling mode.

  In this embodiment, the three-way valve 14 is switched to connect the flow path from the water / refrigerant heat exchanger 8 to the radiator 2, and the electromagnetic valve 15 is closed so that the refrigerant flows to the radiator 2 side to compress the refrigerant. Machine 1-water refrigerant heat exchanger 8-three-way valve 14-radiator 2-check valve 11-internal heat exchanger 4-first expansion valve 5-evaporator 3-accumulator 10-internal heat exchanger 4 Is set to circulate in the third circulation path L3.

  In FIG. 4, the refrigerant is compressed and heated by the compressor 1 to become high pressure and high temperature, and is heat-exchanged with water in the water circulation passage W <b> 1 in the water refrigerant heat exchanger 8. The water heated by the water / refrigerant heat exchanger 8 is guided to the heater core 7. At this time, since the air mix door 16 is rotated upward, heat exchange is not performed with the supply air.

  Moreover, the refrigerant | coolant which heat-exchanged with water with the water refrigerant | coolant heat exchanger 8 passes the three-way valve 14, and is sent to the heat radiator 2, and heat-exchanges with external air here, radiates heat, and falls temperature. Then, the cooled refrigerant passes through the check valve 11 and is sent to the internal heat exchanger 4 where heat is also exchanged to lower the temperature, and the pressure is further reduced by the first expansion valve 5 to become a low pressure and a low temperature. Sent to vessel 3. The low-pressure, low-temperature refrigerant exchanges heat with the supply air sent from the blower fan to cool the supply air, and the supply air whose temperature has dropped is blown into the vehicle interior as a cooling air.

  Further, the refrigerant having exchanged heat with the evaporator 3 is sent to the accumulator 10. Here, the refrigerant is gas-liquid separated, the gas phase refrigerant is output to the low pressure side of the internal heat exchanger 4, and the liquid phase refrigerant is temporarily stored in the accumulator 10.

  Then, the refrigerant heat-exchanged by the internal heat exchanger 4 is compressed and heated again by the compressor 1 to become high pressure and high temperature, and is sent to the water refrigerant heat exchanger 8.

  In the cooling mode shown in FIG. 4, the refrigerant that has become high-pressure and high-temperature in the compressor 1 undergoes heat exchange with the outside air in the radiator 2, and the temperature is lowered. Further, in the internal heat exchanger 4, the refrigerant that is discharged from the evaporator 3 Then, heat is absorbed from the supply air by the evaporator 3, and heat is again exchanged by the internal heat exchanger 4 to be returned to the compressor 1.

  According to this cooling cycle, since the refrigerant whose temperature has been lowered by the radiator 2 is further heat-exchanged with the refrigerant on the low pressure side by the internal heat exchanger 4, it is possible to improve performance efficiency. Moreover, when the heat radiator 2 is frozen by frost or icing, the freezing of the heat radiator 2 can be released by introducing the refrigerant having high pressure and high temperature in the compressor 1 into the heat radiator 2 ( Effect of claim 4).

  In each of the above embodiments, water is shown as an example of the coolant to be circulated through the water circulation channel W1, but other liquids and gases can be used as long as the medium has a high specific heat.

  The present invention relates to a vehicle air conditioner using a refrigerant such as carbon dioxide, and is particularly useful as a vehicle air conditioner mounted on an electric vehicle or the like that does not have a heat source such as an engine.

The system diagram which shows the structure of the vehicle air conditioner concerning an Example. The system diagram which shows the flow of the refrigerant | coolant and water in dehumidification heating mode. The system diagram which shows the flow of the refrigerant | coolant and water in heating mode. The system diagram which shows the flow of the refrigerant | coolant and water in air_conditioning | cooling mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Radiator 3 ... Evaporator 4 ... Internal heat exchanger 5 ... First expansion valve 6 ... Second expansion valve 7 ... Heater core 8 ... Water refrigerant heat exchanger 9 ... Water pump 10 ... Accumulator 11, 12 , 13 ... Check valve 15 ... Solenoid valve 16 ... Air mix door 17 ... Air conditioning duct 18 ... Control unit

Claims (4)

A compressor (1) that compresses and raises the temperature of the refrigerant, a radiator (2) that exchanges heat between the refrigerant and the outside air, and an evaporator (3) that exchanges heat between the supply air and the refrigerant An internal heat exchanger that exchanges heat between the refrigerant compressed and heated by the compressor (1) or the refrigerant cooled by the radiator (2) and the low-pressure refrigerant returning to the compressor (1) (4), first decompression means (5) for decompressing the refrigerant sent to the evaporator (3), and second decompression means (6) for decompressing the refrigerant sent to the radiator (2). The vehicle air conditioner executes a refrigeration cycle for circulating the refrigerant that has passed through the internal heat exchanger (4) back to the compressor (1),
Heat is exchanged between the supply air that has been installed downstream of the evaporator (3) in the ventilation path (17) through which the supply air is introduced and has passed through the evaporator (3), and the water that has been heated. Heater core (7) to be
A water-refrigerant heat exchanger (8) for exchanging heat between the refrigerant compressed and heated by the compressor (1) and water supplied to the heater core (7);
A vehicle air conditioner comprising:   In the heating mode, the refrigerant compressed and heated by the compressor (1) is introduced into the water refrigerant heat exchanger (8) to exchange heat with water supplied to the heater core (7). To heat the supply air passing through the heater core (7), and to exchange heat with the low-pressure side refrigerant in the internal heat exchanger (4). 2. The vehicle air conditioner according to claim 1, wherein the refrigerant is depressurized by the second expansion valve 6 and introduced into the radiator (2) to exchange heat with outside air to absorb heat. 3.   In the dehumidifying heating mode, the refrigerant compressed and heated by the compressor (1) is introduced into the water refrigerant heat exchanger (8) to exchange heat with water supplied to the heater core (7). As a result, the supply air passing through the heater core (7) is heated, and the refrigerant which has been heat-exchanged by the water-refrigerant heat exchanger (8) is depressurized by the first depressurization means (5), and the evaporator (3) The supply air passing through the evaporator (3) is dehumidified by introducing heat into the ventilation passage (17) and exchanging heat with the supply air introduced into the ventilation path (17). The vehicle air conditioner according to any one of the above. In the cooling mode, the refrigerant compressed and heated by the compressor (1) is cooled by exchanging heat with the outside air by the radiator (2), and the refrigerant is depressurized by the first decompression means (5). The supply air that passes through the evaporator (3) is cooled by introducing heat into the evaporator (3) and exchanging heat with the supply air introduced into the ventilation path (17). The vehicle air conditioner according to any one of claims 1 to 3.

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