WO2021044873A1

WO2021044873A1 - Vehicle air conditioner

Info

Publication number: WO2021044873A1
Application number: PCT/JP2020/031569
Authority: WO
Inventors: 雄満山崎
Original assignee: サンデン・オートモーティブクライメイトシステム株式会社
Priority date: 2019-09-04
Filing date: 2020-08-21
Publication date: 2021-03-11
Also published as: JP2021037876A

Abstract

The purpose of the present invention is to provide a vehicle air conditioner that improves air conditioning performance while in a dehumidifying/cooling mode and that can contribute to saving energy. An air conditioning controller (32) causes a refrigerant discharged from a compressor (2) to dissipate heat in a radiator (4) and an outdoor heat exchanger (7) and, after the refrigerant from which heat has been dissipated is depressurized by an indoor expansion valve (8), executes a dehumidifying/cooling mode in which said refrigerant is made to absorb heat in a heat absorber (9). The air conditioning controller (32) controls the opening degree of an outdoor expansion valve (6) in the dehumidifying/cooling mode on the basis of the supercooling degree SC of the refrigerant in a discharge port of the radiator (4) and a target supercooling degree TGSC that is a target value for the supercooling degree SC.

Description

Vehicle air conditioner

The present invention relates to a heat pump type air conditioner for air-conditioning the interior of a vehicle.

Due to the emergence of environmental problems in recent years, hybrid vehicles and electric vehicles have become widespread. As an air conditioner that can be applied to such a vehicle, a compressor that compresses and discharges the refrigerant, a radiator that is provided on the vehicle interior side to dissipate the refrigerant, and a radiator that is provided on the vehicle interior side are provided. Equipped with a heat absorber that absorbs the refrigerant and an outdoor heat exchanger that is installed outside the vehicle interior to dissipate the refrigerant, or an outdoor heat exchanger that absorbs the refrigerant and dissipates the heat, and dissipates the refrigerant discharged from the compressor. In the heating mode, the refrigerant radiated in the radiator is decompressed by the outdoor expansion valve and then absorbed in the outdoor heat exchanger, and the refrigerant discharged from the compressor is radiated in the radiator and radiated in the radiator. A dehumidifying heating mode in which the refrigerant is decompressed by the outdoor expansion valve and the indoor expansion valve and then absorbed by the heat absorber and the outdoor heat exchanger, and the refrigerant discharged from the compressor is dissipated by the radiator and the outdoor heat exchanger to expand the room. Switching between the dehumidifying and cooling mode in which the heat is absorbed by the heat absorber after decompressing with the valve and the cooling mode in which the refrigerant discharged from the compressor is dissipated by the outdoor heat exchanger and decompressed by the indoor expansion valve and then absorbed by the heat exchanger. Is being developed to run.

Then, in the dehumidifying / cooling mode, the cooling (dehumidifying) capacity of the heat absorber is controlled by controlling the rotation speed of the compressor based on the temperature of the heat absorber. Further, the heating capacity of the radiator is controlled by controlling the valve opening degree of the outdoor expansion valve that reduces the pressure of the refrigerant flowing into the outdoor heat exchanger based on the temperature or pressure of the radiator (for example, patent). Reference 1).

That is, in the dehumidifying / cooling mode, the temperature of the radiator can be raised by reducing the valve opening of the outdoor expansion valve, but when the valve opening of the outdoor expansion valve is reduced, the amount of refrigerant circulating in the heat absorber decreases. Therefore, the temperature distribution of the endothermic device (the temperature varies depending on the part of the endothermic device) becomes large, the dehumidifying performance deteriorates, and it becomes difficult to establish the target blowing temperature. Therefore, in Patent Document 1, the temperature distribution of the heat absorber is prevented from occurring by changing the minimum valve opening degree in the control of the outdoor expansion valve in the dehumidifying / cooling mode based on the amount of ventilation to the heat absorber. It was.

JP-A-2018-95098

Here, if the valve opening of the outdoor expansion valve is reduced (throttled), the degree of supercooling of the refrigerant at the outlet of the radiator increases, and the heating capacity of the radiator also increases. However, if the valve opening of the outdoor expansion valve is reduced too much (if it is throttled too much), the refrigerant will condense too much in the radiator, and the outdoor heat exchanger will exhibit the endothermic function instead of the heat dissipation function. The endothermic capacity of the heat absorber is reduced, and the dehumidifying capacity of the dehumidifying / cooling mode is reduced.

On the other hand, since the outdoor expansion valve has individual variations, the minimum control valve opening degree to be changed as described above also tends to increase in consideration of the individual variation of the outdoor expansion valve. The setting with a predetermined margin will be made. Therefore, the heating capacity of the radiator (heat dissipation of the refrigerant) in the dehumidifying / cooling mode cannot be fully exerted, and an auxiliary heating device such as an electric heater must be heated to establish the target blowing temperature. It was.

Further, if the outdoor heat exchanger exerts a heat dissipation function, the dehumidifying / cooling mode will be established even if the valve opening of the outdoor expansion valve is reduced. Since the valve opening was set, there was a problem that the heating capacity of the radiator could not be fully exerted.

The present invention has been made to solve the conventional technical problems, and to provide an air conditioner for a vehicle that can improve the air conditioning performance in the dehumidifying / cooling mode and contribute to energy saving. The purpose.

The vehicle air conditioner according to claim 1 is provided from a compressor that compresses the refrigerant, a radiator for radiating the refrigerant and heating the air supplied to the vehicle interior, and a radiator provided outside the vehicle interior. An outdoor heat exchanger into which the discharged refrigerant flows, an outdoor expansion valve for controlling the inflow of the refrigerant into the outdoor heat exchanger, and a heat absorber for absorbing the refrigerant and cooling the air supplied to the vehicle interior. An indoor expansion valve for controlling the inflow of the refrigerant into the heat absorber and a control device are provided, and at least the refrigerant discharged from the compressor is dissipated by the radiator and the outdoor heat exchanger by this control device. The dehumidifying / cooling mode in which the radiated refrigerant is decompressed by the indoor expansion valve and then absorbed by the heat absorber is executed. In the dehumidifying / cooling mode, the control device determines the degree of overcooling of the refrigerant at the outlet of the radiator. It is characterized in that the valve opening degree of the outdoor expansion valve is controlled based on the SC and a predetermined target supercooling degree TGSC which is the target value thereof.

In the vehicle air conditioner according to the second aspect of the present invention, in the above invention, when the supercooling degree SC is lower than the target supercooling degree TGSC, the valve opening degree of the outdoor expansion valve is reduced and the supercooling degree SC is increased. When the target supercooling degree TGSC is reached, the reduction of the valve opening degree of the outdoor expansion valve is stopped.

In the vehicle air conditioner according to the third aspect of the present invention, in the above invention, the control device sets predetermined upper limit values TGSCHiLim and lower limit value TGSCLoLim above and below the target supercooling degree TGSC, and the supercooling degree SC sets the target supercooling degree SC. When the temperature rises to the upper limit TGSCHiLim after reaching the degree TGSC, the valve opening of the outdoor expansion valve is expanded, and when the supercooling degree SC decreases to the lower limit TGSCLoLim, the expansion of the valve opening of the outdoor expansion valve is stopped. It is characterized by doing.

The vehicle air conditioner according to the fourth aspect is provided from a compressor for compressing the refrigerant, a radiator for radiating the refrigerant and heating the air supplied to the vehicle interior, and a radiator provided outside the vehicle interior. An outdoor heat exchanger into which the discharged refrigerant flows, an outdoor expansion valve for controlling the inflow of the refrigerant into the outdoor heat exchanger, and a heat absorber for absorbing the refrigerant and cooling the air supplied to the vehicle interior. An indoor expansion valve for controlling the inflow of the refrigerant into the heat absorber and a control device are provided, and at least the refrigerant discharged from the compressor is dissipated by the radiator and the outdoor heat exchanger by this control device. The dehumidifying / cooling mode in which the radiated refrigerant is decompressed by the indoor expansion valve and then absorbed by the heat absorber is executed. In the dehumidifying / cooling mode, the control device uses the temperature TXO of the outdoor heat exchanger and the outside air. It is characterized in that the valve opening degree of the outdoor expansion valve is controlled based on the temperature Tam.

In the vehicle air conditioner according to claim 5, in the above invention, the control device opens the outdoor expansion valve when the temperature TXO of the outdoor heat exchanger is higher than the outside air temperature Tam or the outside air temperature Tam + a predetermined value α. When the temperature of the outdoor heat exchanger is reduced to the outside air temperature Tam or the outside air temperature Tam + a predetermined value α, the reduction of the valve opening degree of the outdoor expansion valve is stopped.

In the vehicle air conditioner according to claim 6, in the above invention, the control device sets a predetermined upper limit value TamHiLim and a lower limit value TamMoLim above and below the outside air temperature Tam or the outside air temperature Tam + the predetermined value α, and outdoors. When the temperature TXO of the heat exchanger reaches the outside air temperature Tam or the outside air temperature Tam + the predetermined value α and then drops to the lower limit value TamMoLim, the valve opening of the outdoor expansion valve is expanded and the temperature TXO of the outdoor heat exchanger is increased. When the temperature rises to the upper limit value TamHiLim, the expansion of the valve opening degree of the outdoor expansion valve is stopped.

In the vehicle air conditioner according to the invention of claim 7, in the invention of claim 5 or 6, the temperature TXO of the outdoor heat exchanger is lowered to the outside air temperature Tam or the outside air temperature Tam + a predetermined value α. Previously, when the degree of supercooling SC of the refrigerant at the outlet of the radiator rises to the predetermined target degree of overcooling TGSC, which is the target value, the reduction of the valve opening degree of the outdoor expansion valve is stopped. ..

In the vehicle air conditioner according to the eighth aspect of the present invention, in the above invention, the control device sets predetermined upper limit values TGSCHiLim and lower limit value TGSCLoLim above and below the target supercooling degree TGSC, and the supercooling degree SC sets the target supercooling degree SC. When the temperature rises to the upper limit TGSCHiLim after reaching the degree TGSC, the valve opening of the outdoor expansion valve is expanded, and when the supercooling degree SC decreases to the lower limit TGSCLoLim, the expansion of the valve opening of the outdoor expansion valve is stopped. It is characterized by doing.

The vehicle air conditioner according to claim 9 is characterized in that, in each of the above inventions, the control device controls the valve opening degree of the indoor expansion valve in a direction in which the refrigerant discharged from the heat absorber is not superheated SH. To do.

In the vehicle air conditioner according to the tenth aspect of the present invention, in the above invention, the control device changes the valve opening degree of the indoor expansion valve in the opening direction when the refrigerant discharged from the heat absorber has a superheat degree SH. It is characterized by.

In the vehicle air conditioner according to the eleventh aspect of the present invention, in the above invention, the control device adjusts the valve opening degree of the indoor expansion valve when the degree of superheat SH of the refrigerant discharged from the heat absorber becomes larger than the predetermined threshold value SH1. , The feature is to change in the opening direction.

The vehicle air conditioner according to the twelfth aspect of the present invention is characterized in that, in the ninth to eleventh aspects of the invention, the accumulator provided in the refrigerant circuit from the refrigerant outlet of the heat absorber to the refrigerant suction side of the compressor is provided. And.

According to the invention of claim 1, a compressor for compressing the refrigerant, a radiator for radiating the refrigerant and heating the air supplied to the vehicle interior, and a refrigerant provided outside the vehicle interior and emitted from the radiator are used. The inflowing outdoor heat exchanger, the outdoor expansion valve for controlling the inflow of the refrigerant into the outdoor heat exchanger, the heat absorber for absorbing the refrigerant and cooling the air supplied to the vehicle interior, and the heat absorber. An indoor expansion valve for controlling the inflow of the refrigerant into the vessel and a control device are provided, and at least the refrigerant discharged from the compressor is radiated by the radiator and the outdoor heat exchanger to dissipate the heat. In the vehicle air conditioner that executes the dehumidifying / cooling mode in which the refrigerant is decompressed by the indoor expansion valve and then absorbed by the heat absorber, the control device determines the degree of supercooling SC of the refrigerant at the outlet of the radiator in the dehumidifying / cooling mode. Since the valve opening of the outdoor expansion valve is controlled based on the predetermined target supercooling degree TGSC, which is the target value, the target supercooling degree TGSC is set to an appropriate value so that the refrigerant does not condense too much in the radiator. By setting it, the valve opening of the outdoor expansion valve can be reduced and the heating capacity of the radiator can be maximized without considering the individual variation of the outdoor expansion valve while establishing the dehumidifying / cooling mode. It will be possible.

As a result, the need to generate heat in the auxiliary heating device is eliminated or suppressed, so that it is possible to contribute to energy saving while improving the air conditioning performance in the dehumidifying / cooling mode.

In this case, for example, when the supercooling degree SC is lower than the target supercooling degree TGSC as in the invention of claim 2, the valve opening degree of the outdoor expansion valve is reduced, and the supercooling degree SC is the target supercooling degree TGSC. When it rises to, the reduction of the valve opening of the outdoor expansion valve is stopped. Further, as in the invention of claim 3, a predetermined upper limit value TGSCHiLim and a lower limit value TGSCLoLim are set above and below the target supercooling degree TGSC, and after the supercooling degree SC becomes the target supercooling degree TGSC, the upper limit value TGSCHiLim When the valve opening of the outdoor expansion valve is increased to, the valve opening of the outdoor expansion valve is expanded, and when the supercooling degree SC is lowered to the lower limit value TGSCLoLim, the expansion of the valve opening of the outdoor expansion valve is stopped. Based on the supercooling degree SC of the refrigerant at the outlet and the target supercooling degree TGSC, it is possible to smoothly and accurately control the outdoor expansion valve that maximizes the heating capacity of the radiator in the dehumidifying and cooling mode. Become.

According to the invention of the fourth aspect, a compressor for compressing the refrigerant, a radiator for radiating the refrigerant and heating the air supplied to the vehicle interior, and a radiator provided outside the vehicle interior and exiting the radiator. An outdoor heat exchanger into which the refrigerant flows, an outdoor expansion valve for controlling the inflow of the refrigerant into the outdoor heat exchanger, and a heat absorber for absorbing the refrigerant and cooling the air supplied to the vehicle interior. An indoor expansion valve for controlling the inflow of the refrigerant into the heat absorber and a control device are provided, and at least the refrigerant discharged from the compressor is dissipated by the radiator and the outdoor heat exchanger to dissipate heat. In the vehicle air conditioner that executes the dehumidifying / cooling mode in which the refrigerant is decompressed by the indoor expansion valve and then absorbed by the heat absorber, the control device controls the temperature TXO of the outdoor heat exchanger and the outside air in the dehumidifying / cooling mode. Since the valve opening degree of the outdoor expansion valve is controlled based on the temperature Tam, for example, as in the invention of claim 5, the temperature TXO of the outdoor heat exchanger is the outside air temperature Tam or the outside air temperature Tam +. If it is higher than the predetermined value α, the valve opening of the outdoor expansion valve is reduced, and if the temperature TXO of the outdoor heat exchanger drops to the outside air temperature Tam or the outside air temperature Tam + the predetermined value α, the valve opening of the outdoor expansion valve. By stopping the reduction of the air, the heat dissipation function of the outdoor heat exchanger in the dehumidifying and cooling mode is secured, and while the dehumidifying and cooling mode is established, the heating capacity of the radiator can be increased without considering the individual variation of the outdoor expansion valve. It will be possible to maximize it.

As a result, the need to generate heat in the auxiliary heating device is also eliminated or suppressed, so that it is possible to contribute to energy saving while improving the air conditioning performance in the dehumidifying / cooling mode.

In this case, for example, as in the invention of claim 6, the control device sets a predetermined upper limit value TamHiLim and a lower limit value TamMoLim above and below the outside air temperature Tam or the outside air temperature Tam + the predetermined value α, and the temperature of the outdoor heat exchanger. When the TXO reaches the outside air temperature Tam or the outside air temperature Tam + the predetermined value α and then drops to the lower limit value TamMoLim, the valve opening of the outdoor expansion valve is expanded and the temperature TXO of the outdoor heat exchanger reaches the upper limit value TamHiLim. When the temperature rises, the expansion of the valve opening of the outdoor expansion valve is stopped, so that the heating capacity of the radiator is maximized in the dehumidifying / cooling mode based on the temperature TXO of the outdoor heat exchanger and the outside air temperature Tam. It is possible to smoothly and accurately control the outdoor expansion valve.

Further, also in this case, as in the invention of claim 7, the control device supercools the refrigerant at the outlet of the radiator before the temperature TXO of the outdoor heat exchanger drops to the outside air temperature Tam or the outside air temperature Tam + a predetermined value α. When the cooling degree SC rises to a predetermined target supercooling degree TGSC, which is the target value, the reduction of the valve opening degree of the outdoor expansion valve is stopped. Further, as in the invention of claim 8, a predetermined upper limit value TGSCHiLim and a lower limit value TGSCLoLim are set above and below the target supercooling degree TGSC, and after the supercooling degree SC becomes the target supercooling degree TGSC, the upper limit value TGSCHiLim If it rises to, the valve opening of the outdoor expansion valve is expanded, and if the supercooling degree SC drops to the lower limit value TGSCLoLim, the expansion of the valve opening of the outdoor expansion valve is stopped. By setting the supercooling degree TGSC to an appropriate value so that the refrigerant does not condense too much in the radiator, before the temperature TXO of the outdoor heat exchanger drops to the outside air temperature Tam or the outside air temperature Tam + the predetermined value α. , Stops the reduction of the valve opening of the outdoor expansion valve based on the refrigerant supercooling degree SC and the target supercooling degree TGSC at the outlet of the radiator, and then dehumidifies based on the supercooling degree SC and the target supercooling degree TGSC. It is possible to smoothly and accurately control the outdoor expansion valve that maximizes the heating capacity of the radiator in the cooling mode.

As a result, the dehumidifying and cooling mode is surely established based on the temperature TXO of the outdoor heat exchanger and the outside air temperature Tam, and the heating capacity of the radiator is maximized based on the supercooling degree SC and the target supercooling degree TGSC. By controlling the outdoor expansion valve, it becomes possible to realize comfortable vehicle interior air conditioning.

Further, if the control device controls the valve opening degree of the indoor expansion valve in a direction in which the superheat degree SH is not attached to the refrigerant discharged from the heat absorber as in the invention of claim 9, the refrigerant discharged from the heat absorber can be used. Does not have the degree of superheat SH, or even if it does, it is extremely small. As a result, the refrigerant evaporates in the entire or substantially the entire heat absorber, and heat can be absorbed from the air supplied to the passenger compartment. Therefore, the inconvenience of temperature distribution in the heat absorber can be eliminated or suppressed. , It will be possible to effectively cool the passenger compartment. In addition, since the oil return is improved, the seizure of the compressor can be avoided in advance.

In particular, when the control device has a degree of superheat SH attached to the refrigerant discharged from the heat absorber as in the invention of claim 2, the temperature distribution of the heat absorber is obtained by changing the valve opening degree of the indoor expansion valve in the opening direction. It becomes possible to effectively eliminate or suppress the occurrence of the occurrence of oil and the deterioration of oil return.

In this case, specifically, as in the invention of claim 11, when the superheat degree SH of the refrigerant discharged from the endothermic absorber becomes larger than the predetermined threshold value SH1, the valve opening degree of the indoor expansion valve is opened. By changing the direction, by setting the threshold value SH1 to an extremely small value, it becomes possible to appropriately eliminate or suppress the occurrence of the temperature distribution of the heat absorber and the deterioration of the oil return. ..

Further, by providing an accumulator in the refrigerant circuit from the refrigerant outlet of the heat absorber to the refrigerant suction side of the compressor as in the invention of claim 12, it becomes possible to effectively eliminate the liquid back to the compressor. ..

It is a block diagram of one Example of the air conditioner for a vehicle to which this invention is applied (heating mode). It is a block diagram of the air-conditioning controller as a control device of the air conditioner for a vehicle of FIG. It is a figure explaining the dehumidifying heating mode by the air-conditioning controller of FIG. It is a figure explaining the dehumidifying cooling mode and the cooling mode by the air-conditioning controller of FIG. It is a figure explaining the vehicle cooling system cooling mode by the air-conditioning controller of FIG. It is a figure explaining the relationship between the valve opening degree of the outdoor expansion valve in a dehumidifying cooling mode, the heat dissipation amount of an outdoor heat exchanger, and the temperature distribution of a heat absorber. It is a figure explaining an example of valve opening degree control of the outdoor expansion valve in the dehumidifying cooling mode executed by the air conditioning controller of FIG. 2 (Example 1). It is a figure explaining another example of valve opening degree control of the outdoor expansion valve in the dehumidifying cooling mode executed by the air conditioning controller of FIG. 2 (Example 2).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration diagram of an air conditioner 1 for a vehicle according to an embodiment to which the present invention is applied. The vehicle of the embodiment to which the present invention is applied is an electric vehicle (EV) without an engine (internal combustion engine), and the vehicle is equipped with a battery (for example, a lithium ion battery) to charge the battery from an external power source. It is driven and traveled by supplying the generated electric power to a traveling motor (electric motor). The vehicle air conditioner 1 is also driven by being supplied with power from a battery.

That is, the vehicle air conditioner 1 of the embodiment performs the heating mode by the heat pump device HP having the refrigerant circuit R in the electric vehicle that cannot be heated by the waste heat of the engine, and further, the dehumidifying heating mode, the dehumidifying cooling mode, and the cooling mode. By selectively executing each of the above operation modes, the interior of the vehicle is air-conditioned. Furthermore, a vehicle cooling system cooling mode for cooling the vehicle cooling system 61 including the battery using a refrigerant is also executed as described later. Needless to say, the present invention is effective not only for the electric vehicle as a vehicle but also for a so-called hybrid vehicle that uses an engine and an electric motor for traveling.

The vehicle air conditioner 1 of the embodiment air-conditions (heats, cools, dehumidifies, and ventilates) the interior of the electric vehicle, and is an electric compressor (powered from a battery to compress the refrigerant). The electric compressor) 2 and the high-temperature and high-pressure refrigerant discharged from the compressor 2 are provided in the air flow passage 3 of the HVAC unit 10 through which the air inside the vehicle is ventilated and circulated, and flow in through the refrigerant pipe 13G and the strainer 55. It functions as a radiator 4 for radiating the refrigerant and heating the air supplied to the vehicle interior, an outdoor expansion valve 6 composed of an electric expansion valve, and a radiator (radiation function) for radiating the refrigerant during cooling. Indoor expansion consisting of an outdoor heat exchanger 7 for exchanging heat between the refrigerant and the outside air so as to function as a heat absorber (heat absorption function) for absorbing the refrigerant during heating, and an electric expansion valve for decompressing and expanding the refrigerant. The valve 8, the heat exchanger 9 provided in the air flow passage 3 for cooling the air supplied to the vehicle interior by absorbing heat from the outside of the vehicle interior to the refrigerant during cooling (during dehumidification), the accumulator 12 and the like are the refrigerants. The refrigerant circuit R of the heat pump device HP is sequentially connected by the pipe 13. The outdoor expansion valve 6 controls the inflow of the refrigerant into the outdoor heat exchanger 7, and the indoor expansion valve 8 controls the inflow of the refrigerant into the heat absorber 9. The refrigerant is decompressed and expanded, and can be fully opened or fully closed. It is possible.

The outdoor heat exchanger 7 is provided with an outdoor blower 15. The outdoor blower 15 forcibly ventilates the outdoor air to the outdoor heat exchanger 7 to exchange heat between the outside air and the refrigerant, whereby the outdoor air is outdoors even when the vehicle is stopped (that is, the vehicle speed is 0 km / h). The heat exchanger 7 is configured to ventilate outside air.

Further, the refrigerant pipe 13A connected to the refrigerant outlet side of the outdoor heat exchanger 7 is connected to the refrigerant pipe 13B via the check valve 18. The check valve 18 has a forward direction on the refrigerant pipe 13B side, and the refrigerant pipe 13B is connected to the indoor expansion valve 8.

Further, the refrigerant pipe 13A coming out of the outdoor heat exchanger 7 is branched, and the branched refrigerant pipe 13D is located on the outlet side of the heat absorber 9 via a heating valve 21 composed of a solenoid valve opened at the time of heating. It is connected to the refrigerant pipe 13C to be connected. Then, the check valve 20 is connected to the refrigerant pipe 13C downstream from the connection point of the refrigerant pipe 13D, the refrigerant pipe 13C downstream from the check valve 20 is connected to the accumulator 12, and the accumulator 12 is the compressor 2. It is connected to the refrigerant suction side of. The check valve 20 has the accumulator 12 side in the forward direction.

Further, the refrigerant pipe 13E on the refrigerant outlet side of the radiator 4 is branched into the refrigerant pipe 13J and the refrigerant pipe 13F in front of the outdoor expansion valve 6 (on the refrigerant outlet side of the radiator 4 on the upstream side of the refrigerant), and one of the branches. The refrigerant pipe 13J of the above is connected to the refrigerant inlet side of the outdoor heat exchanger 7 via the outdoor expansion valve 6. Further, the other branched refrigerant pipe 13F is a refrigerant pipe located on the downstream side of the refrigerant of the check valve 18 via a dehumidifying valve 22 composed of a solenoid valve opened at the time of dehumidification, and on the upstream side of the refrigerant of the indoor expansion valve 8. It is connected to 13B in communication.

As a result, the refrigerant pipe 13F is connected in parallel to the series circuit of the outdoor expansion valve 6, the outdoor heat exchanger 7, and the check valve 18, and the outdoor expansion valve 6, the outdoor heat exchanger 7, and the check valve are connected in parallel. It is a bypass circuit that bypasses 18.

Further, in the air flow passage 3 on the air upstream side of the heat absorber 9, each suction port of the outside air suction port and the inside air suction port is formed (represented by the suction port 25 in FIG. 1), and this suction port is formed. The suction switching damper 26 for switching the air introduced into the air flow passage 3 into the inside air (inside air circulation), which is the air inside the vehicle interior, and the outside air (outside air introduction), which is the air outside the vehicle interior, is provided. Further, an indoor blower fan 27 for supplying the introduced inside air and outside air to the air flow passage 3 is provided on the air downstream side of the suction switching damper 26.

Further, in FIG. 1, 23 is an auxiliary heater as an auxiliary heating device. The auxiliary heater 23 is composed of an electric heater such as a PTC heater, and is provided in the air flow passage 3 on the leeward side of the radiator 4 with respect to the air flow in the air flow passage 3 in the embodiment. .. Then, by energizing the auxiliary heater 23, the heating of the vehicle interior can be assisted.

Further, in the air flow passage 3 on the air upstream side of the radiator 4, the air (inside air or outside air) in the air flow passage 3 after flowing into the air flow passage 3 and passing through the heat absorber 9 is radiated. An air mix damper 28 for adjusting the ratio of ventilation to the vessel 4 and the auxiliary heater 23 is provided. Further, FOOT (foot), VENT (vent), and DEF (diff) outlets (represented by outlet 29 in FIG. 1) are formed in the air flow passage 3 on the air downstream side of the radiator 4. The outlet 29 is provided with an outlet switching damper 31 that switches and controls the blowing of air from each of the outlets.

Further, in FIG. 1, 61 is the vehicle cooling system described above. The vehicle cooling system 61 includes vehicle-mounted equipment that requires cooling, such as a battery and a traveling motor, and is a system for cooling these vehicle-mounted equipment using a refrigerant. In the case of the embodiment, the refrigerant pipe 13B located at the outlet of the refrigerant pipe 13F of the refrigerant circuit R, that is, the refrigerant downstream side of the connection portion between the refrigerant pipe 13F and the refrigerant pipe 13B and on the refrigerant upstream side of the indoor expansion valve 8. One end of the branch pipe 72 is connected to. The branch pipe 72 is provided with an auxiliary expansion valve 73 composed of an electric expansion valve. The auxiliary expansion valve 73 decompresses and expands the refrigerant flowing from the branch pipe 72 into the vehicle cooling system 61, and can be fully closed.

Then, one end of the refrigerant pipe 74 is connected to the vehicle cooling system 61, and the other end of the refrigerant pipe 74 is on the downstream side of the refrigerant of the check valve 20 and is connected to the refrigerant pipe 13C in front of the accumulator 12 (upstream side of the refrigerant). It is connected. When the auxiliary expansion valve 73 is open, the refrigerant (part or all of the refrigerant) flowing through the refrigerant pipe 13B flows into the branch pipe 72, is depressurized by the auxiliary expansion valve 73, and then flows into the vehicle cooling system 61. , Evaporates there. The refrigerant absorbs heat from the battery and the traveling motor in the process of flowing through the vehicle cooling system 61, cools them, and then is sucked into the compressor 2 through the refrigerant pipe 74 and the accumulator 12.

Next, in FIG. 2, reference numeral 32 denotes an air conditioning controller 32 as a control device that controls the vehicle air conditioner 1. The air conditioning controller 32 is composed of a microcomputer as an example of a computer including a processor.

The input of the air conditioning controller 32 (control device) is sucked into the air flow passage 3 from the outside air temperature sensor 33 that detects the outside air temperature (Tam) of the vehicle, the outside air humidity sensor 34 that detects the outside air humidity, and the suction port 25. The HVAC suction temperature sensor 36 that detects the temperature of the air, the inside air temperature sensor 37 that detects the temperature of the air (inside air) in the vehicle interior, the inside air humidity sensor 38 that detects the humidity of the air inside the vehicle interior, and the dioxide in the vehicle interior. _{The indoor CO 2} concentration sensor 39 that detects the carbon concentration, the blowout temperature sensor 41 that detects the temperature of the air blown into the vehicle interior from the blowout port 29, and the discharge refrigerant pressure (discharge pressure Pd) of the compressor 2 are detected. The discharge pressure sensor 42, the discharge temperature sensor 43 that detects the discharge refrigerant temperature of the compressor 2, the suction sensor 44 that detects the temperature and pressure of the refrigerant sucked into the compressor 2, and the temperature of the refrigerant that flows into the radiator 4. A radiator inlet temperature sensor 46 that detects (radiator inlet temperature TCIin), and a radiator outlet sensor 47 that detects the temperature (radiator outlet temperature TCIout) and pressure (radiator pressure PCI) of the refrigerant emitted from the radiator 4. The heat absorber temperature sensor 48 that detects the temperature of the heat absorber 9 (heat absorber temperature Te), and the temperature (heat absorber outlet temperature Teout) and pressure (heat absorber pressure Pe) of the refrigerant emitted from the heat absorber 9 are detected. A heat absorber outlet sensor 49, for example, a photosensor type solar radiation sensor 51 for detecting the amount of solar radiation into the vehicle interior, a vehicle speed sensor 52 for detecting the moving speed (vehicle speed) of the vehicle, a set temperature and air conditioning operation. The air conditioning operation unit 53 for setting the switching, the outdoor heat exchanger outlet sensor 54 for detecting the temperature (outdoor heat exchanger temperature TXO) and pressure of the refrigerant emitted from the outdoor heat exchanger 7, and the auxiliary heater 23. Each output of the auxiliary heater temperature sensor 76 that detects the temperature is connected.

On the other hand, the output of the air conditioning controller 32 includes the compressor 2, the outdoor blower 15, the indoor blower (blower fan) 27, the suction switching damper 26, the air mix damper 28, the air outlet switching damper 31, and the outdoor. The expansion valve 6, the indoor expansion valve 8, the dehumidifying valve 22, the heating valve 21, each solenoid valve, the auxiliary expansion valve 73, and the auxiliary heater 23 are connected. The air conditioning controller 32 controls these based on the output of each sensor and the settings input by the air conditioning operation unit 53.

With the above configuration, the operation of the vehicle air conditioner 1 of the embodiment will be described next. In this embodiment, the air conditioning controller 32 (control device) switches and executes each operation mode of the heating mode, the dehumidifying heating mode, the dehumidifying cooling mode, and the cooling mode, and cools the vehicle cooling system 61. Execute the cooling mode (operation mode). First, an operation mode for air-conditioning the interior of the vehicle will be described.

(1) Heating mode First, the heating mode will be described with reference to FIG. FIG. 1 shows the flow of the refrigerant (solid arrow) in the refrigerant circuit R in the heating mode. When the heating mode is selected by the air conditioning controller 32 (auto mode) or by manual operation to the air conditioning operation unit 53 (manual mode) at low outside temperature such as in winter, the air conditioning controller 32 has the heating valve 21 and the dehumidifying valve 22. Is opened, and the indoor expansion valve 8 is fully closed. The outdoor expansion valve 6 and the auxiliary expansion valve 73 are opened to reduce the pressure and expand the refrigerant.

Then, the compressor 2 and the

blowers

15 and 27 are operated, and the air mix damper 28 is in a state of adjusting the ratio of the air blown from the indoor blower 27 to the radiator 4 and the auxiliary heater 23. As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4. Since the air in the air flow passage 3 is ventilated through the radiator 4, the air in the air flow passage 3 is heated by the high temperature refrigerant in the radiator 4, while the refrigerant in the radiator 4 heats the air. It is deprived, cooled, and condensed.

After leaving the radiator 4, the refrigerant liquefied in the radiator 4 is divided into the outdoor expansion valve 6 and the dehumidifying valve 22 via the refrigerant pipe 13E, and one of the refrigerants passes through the refrigerant pipe 13J to the outdoor expansion valve 6. To reach. The refrigerant that has flowed into the outdoor expansion valve 6 is decompressed there, and then flows into the outdoor heat exchanger 7. The refrigerant that has flowed into the outdoor heat exchanger 7 evaporates and draws heat from the outside air that is ventilated by the outdoor blower 15 (heat absorption function). Then, the low-temperature refrigerant leaving the outdoor heat exchanger 7 reaches the refrigerant pipe 13C via the refrigerant pipe 13A, the refrigerant pipe 13D, and the heating valve 21, and enters the accumulator 12 via the check valve 20 of the refrigerant pipe 13C. After the gas-liquid separation, the circulation in which the gas refrigerant is sucked into the compressor 2 is repeated. The other refrigerant that has been split reaches the auxiliary expansion valve 73 via the dehumidifying valve 22, the refrigerant pipe 13F, and the refrigerant pipe 13B. Here, after the refrigerant is depressurized, it flows into the vehicle cooling system 61 and evaporates there. At this time, it exerts an endothermic action to cool the battery and the traveling motor, and recovers waste heat from them. The refrigerant evaporated in the vehicle cooling system 61 repeats circulation that is sucked into the compressor 2 in sequence through the

refrigerant pipes

74 and 13C and the accumulator 12. Since the air heated by the radiator 4 is blown out from the air outlet 29, the interior of the vehicle is heated by the heat pumped from the outside air and the waste heat of the battery and the traveling motor.

The air conditioning controller 32 calculates the target radiator pressure PCO (target value of the radiator pressure PCI) from the target heater temperature TCO (target value of the air temperature on the leeward side of the radiator 4) calculated from the target blowout temperature TAO described later. Then, the rotation speed of the compressor 2 is controlled based on the target radiator pressure PCO and the refrigerant pressure of the radiator 4 (radiator pressure PCI; high pressure side pressure of the refrigerant circuit R) detected by the radiator outlet sensor 47. ..

Further, the supercooling degree SC of the refrigerant emitted from the radiator 4 obtained from the temperature of the radiator 4 (radiator outlet temperature TCIout) detected by the radiator outlet sensor 47 and the radiator pressure PCI, and a predetermined target excess during heating. The valve opening degree of the outdoor expansion valve 6 is controlled based on the cooling degree TGSC, and the supercooling degree SC of the refrigerant at the outlet of the radiator 4 is controlled to the target supercooling degree TGSC. The target heater temperature TCO is basically TCO = TAO, but a predetermined control limit is provided. When the heating capacity (heating capacity) of the radiator 4 is insufficient, the auxiliary heater 23 is energized to generate heat to supplement the heating capacity.

(2) Dehumidifying / heating mode Next, the dehumidifying / heating mode will be described with reference to FIG. FIG. 3 shows the flow of the refrigerant (solid arrow) in the refrigerant circuit R in the dehumidifying / heating mode. In the dehumidifying and heating mode, the air conditioning controller 32 fully closes the auxiliary expansion valve 73 and opens the indoor expansion valve 8 to decompress and expand the refrigerant in the heating mode. As a result, the refrigerant flows into the refrigerant pipe 13F via the dehumidifying valve 22, and the refrigerant flowing into the refrigerant pipe 13B flows into the indoor expansion valve 8, is decompressed by the indoor expansion valve 8, and then flows into the heat absorber 9 and evaporates. Will come to do.

The air conditioning controller 32 controls the valve opening degree of the indoor expansion valve 8 so as to maintain the superheat degree SH of the refrigerant at the outlet of the heat absorber 9 at a predetermined value at the time of dehumidification and heating. Moisture in the air blown out from the indoor blower 27 by the endothermic action condenses and adheres to the heat absorber 9, so that the air is cooled and dehumidified. The remaining refrigerant that has been split and flows into the refrigerant pipe 13J is decompressed by the outdoor expansion valve 6 and then evaporated by the outdoor heat exchanger 7 to absorb heat from the outside air.

The refrigerant evaporated in the heat absorber 9 goes out to the refrigerant pipe 13C, merges with the refrigerant from the refrigerant pipe 13D (refrigerant from the outdoor heat exchanger 7), and then is sucked into the compressor 2 via the check valve 20 and the accumulator 12. Repeat the cycle. The air dehumidified by the heat absorber 9 is reheated in the process of passing through the radiator 4, so that the dehumidifying and heating of the vehicle interior is performed.

The air conditioning controller 32 controls the rotation speed of the compressor 2 based on the target radiator pressure PCO calculated from the target heater temperature TCO and the radiator pressure PCI (high pressure of the refrigerant circuit R) detected by the radiator outlet sensor 47. At the same time, the valve opening degree of the outdoor expansion valve 6 is controlled based on the heat absorber temperature Te detected by the heat absorber temperature sensor 48.

(3) Dehumidifying / cooling mode Next, the dehumidifying / cooling mode will be described with reference to FIG. In this dehumidifying / cooling mode, the air conditioning controller 32 controls the valve opening degree of the outdoor expansion valve 6 as described later, so that the outdoor heat exchanger 7 dissipates heat (condensing function). Further, the indoor expansion valve 8 is opened to reduce the pressure and expand the refrigerant, and the heating valve 21 and the dehumidifying valve 22 are closed. Then, the compressor 2 and the

blowers

15 and 27 are operated, and the air mix damper 28 adjusts the ratio of the air blown from the indoor blower 27 to the radiator 4 and the auxiliary heater 23.

As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 as shown by the solid arrow in FIG. Since the air in the air flow passage 3 is ventilated through the radiator 4, the air in the air flow passage 3 is heated by the high temperature refrigerant in the radiator 4, while the refrigerant in the radiator 4 heats the air. It is deprived, cooled, and condensed.

The refrigerant leaving the radiator 4 reaches the outdoor expansion valve 6 via the refrigerant pipe 13E, and flows into the outdoor heat exchanger 7 via the outdoor expansion valve 6 controlled as described later. The refrigerant flowing into the outdoor heat exchanger 7 is air-cooled by traveling there or by the outside air ventilated by the outdoor blower 15, and the refrigerant dissipates heat and condenses.

The refrigerant leaving the outdoor heat exchanger 7 enters the refrigerant pipe 13B via the refrigerant pipe 13A and the check valve 18, and reaches the indoor expansion valve 8. In the indoor expansion valve 8, the refrigerant is depressurized by controlling the valve opening degree as described later, and then flows into the heat absorber 9 and evaporates. Due to the endothermic action at this time, the moisture in the air blown out from the indoor blower 27 condenses and adheres to the heat absorber 9, and the air is cooled and dehumidified.

The refrigerant evaporated in the heat absorber 9 reaches the accumulator 12 via the refrigerant pipe 13C and the check valve 20, and is repeatedly sucked into the compressor 2 through the accumulator 12. The air cooled by the heat absorber 9 and dehumidified is reheated in the process of passing through the radiator 4. As a result, the interior of the vehicle is dehumidified and cooled.

In this dehumidifying / cooling mode, the air conditioning controller 32 controls the rotation speed of the compressor 2 based on the endothermic temperature Te detected by the endothermic temperature sensor 48, and as described in detail later, the outdoor expansion valve 6 and the indoor expansion valve. The valve opening degree of 8 is controlled.

(4) Cooling mode Next, the cooling mode will be described. In this cooling mode, which is executed at a high outside temperature such as in summer, the air conditioning controller 32 has the same flow of refrigerant as the dehumidifying cooling mode (FIG. 4) described above, while the valve opening degree of the outdoor expansion valve 6 is fully opened. As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4. In the cooling mode, the air in the air flow passage 3 is hardly ventilated to the radiator 4 and the auxiliary heater 23, or even when the air is ventilated, the ratio is small (because of only reheating during cooling). The refrigerant that has dissipated heat for the reheat during cooling by the radiator 4 reaches the outdoor expansion valve 6 via the refrigerant pipe 13E. At this time, since the outdoor expansion valve 6 is fully opened, the refrigerant passes through the outdoor expansion valve 6 as it is, passes through the refrigerant pipe 13J, flows into the outdoor heat exchanger 7, and travels there or by the outdoor blower 15. It is air-cooled by the ventilated outside air, and the refrigerant dissipates heat and becomes a condensed liquid.

The refrigerant leaving the outdoor heat exchanger 7 enters the refrigerant pipe 13B via the refrigerant pipe 13A and the check valve 18, and reaches the indoor expansion valve 8. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Due to the endothermic action at this time, the moisture in the air blown out from the indoor blower 27 condenses and adheres to the endothermic device 9, and the air is cooled.

The refrigerant evaporated in the heat absorber 9 reaches the accumulator 12 via the refrigerant pipe 13C and the check valve 20, and is repeatedly sucked into the compressor 2 through the accumulator 12. The air cooled by the heat absorber 9 and dehumidified is blown out into the vehicle interior from the air outlet 29, so that the vehicle interior is cooled. In this cooling mode, the air conditioning controller 32 controls the rotation speed of the compressor 2 based on the endothermic temperature Te detected by the endothermic temperature sensor 48.

(5) Switching control of air conditioning operation The air conditioning controller 32 calculates the target blowout temperature TAO described above from the following formula (I). This target outlet temperature TAO is a target value of the temperature of the air blown into the vehicle interior from the outlet 29.
TAO = (Tset-Tin) x K + Tbal (f (Tset, SUN, Tam))
・・ (I)
Here, Tset is the set temperature in the vehicle interior set by the air conditioning operation unit 53, Tin is the temperature of the vehicle interior air detected by the inside air temperature sensor 37, K is a coefficient, Tbal is the set temperature Tset, and the solar radiation sensor 51 detects it. It is a balance value calculated from the amount of solar radiation SUN and the outside air temperature Tam detected by the outside air temperature sensor 33. In general, the target blowing temperature TAO increases as the outside air temperature Tam decreases, and decreases as the outside air temperature Tam increases.

Then, the air conditioning controller 32 selects one of the above operation modes based on the outside air temperature Tam detected by the outside air temperature sensor 33 and the target outlet temperature TAO at the time of activation. Further, after the start-up, each of the operation modes is selected and switched according to changes in the environment and setting conditions such as the outside air temperature Tam and the target blowout temperature TAO.

(6) Vehicle Cooling System Cooling Mode The air conditioning controller 32 executes the vehicle cooling system cooling mode when charging the battery with, for example, a quick charger or the like. FIG. 5 shows how the refrigerant flows in the refrigerant circuit R (solid arrow) in this vehicle cooling system cooling mode. In the vehicle cooling system cooling mode, the air conditioning controller 32 opens the auxiliary expansion valve 73 to reduce the pressure and expand the refrigerant, and the outdoor expansion valve 6 is set to all times. Further, the dehumidifying valve 22 and the heating valve 21 are closed, and the indoor expansion valve 8 is fully closed. Then, the compressor 2 is operated.

As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4. The refrigerant radiated by the radiator 4 flows into the refrigerant pipe 13J via the refrigerant pipe 13E, passes through the outdoor expansion valve 6, and then enters the refrigerant pipe 13B via the outdoor heat exchanger 7 and the refrigerant pipe 13A. The refrigerant that has flowed into the refrigerant pipe 13B flows into the branch pipe 72 and reaches the auxiliary expansion valve 73. Here, after the refrigerant is depressurized, it flows into the vehicle cooling system 61 and evaporates there. At this time, it exerts an endothermic action to cool the battery and the traveling motor. The refrigerant evaporated in the vehicle cooling system 61 repeats circulation that is sucked into the compressor 2 in sequence through the

refrigerant pipes

74 and 13C and the accumulator 12.

In this vehicle cooling system cooling mode, the air conditioning controller 32 cools the battery and the traveling motor of the vehicle cooling system 61 by controlling the rotation speed of the compressor 2 in response to a cooling request from the vehicle cooling system 61, for example. ..

(7) Control of Indoor Expansion Valve 8 in Dehumidifying and Cooling Mode Next, control of the valve opening degree of the indoor expansion valve 8 executed by the air conditioning controller 32 in the above-mentioned dehumidifying and cooling mode will be described in detail. The air-conditioning controller 32 of the embodiment basically controls the valve opening degree of the indoor expansion valve 8 in a direction in which the refrigerant discharged from the heat absorber 9 is not superheated SH, so that the temperature distribution does not occur in the heat absorber 9. To. In this case, for example, when the refrigerant discharged from the heat absorber 9 has a superheat degree SH, the air conditioning controller 32 changes the valve opening degree of the indoor expansion valve 8 in a predetermined pulse [PLS] in the opening direction.

More specifically, in the air conditioning controller 32, the refrigerant discharged from the heat absorber 9 by the temperature (heat absorber outlet temperature Teout) and pressure (heat absorber pressure Pe) of the refrigerant emitted from the heat absorber 9 detected by the heat absorber outlet sensor 49. The degree of superheat SH is calculated. This method of calculating the degree of superheat SH is a well-known technique and will not be described here. Then, the valve opening degree of the indoor expansion valve 8 is controlled based on the superheat degree SH and the predetermined threshold value SH1.

In the embodiment, the air conditioning controller 32 determines whether or not the superheat degree SH of the refrigerant discharged from the heat absorber 9 is larger than the threshold value SH1. This threshold value SH1 is an extremely small predetermined value, and is determined in advance by an experiment and set in the air conditioning controller 32. When the refrigerant discharged from the heat absorber 9 has a superheat degree SH and the value becomes larger than the threshold value SH1, the air conditioning controller 32 changes the valve opening degree of the indoor expansion valve 8 in a predetermined pulse and opening direction. As a result, the amount of refrigerant flowing into the heat absorber 9 increases, so that the degree of superheat SH changes in the direction of decreasing or disappearing.

The air conditioning controller 32 obtains, for example, information on the degree of superheat of the refrigerant discharged from the compressor 2 (calculated from the above-mentioned sensor information), and when the degree of superheat drops to a predetermined value, the valve of the indoor expansion valve 8 The opening shall be changed in a predetermined pulse and closing direction.

In this way, the air conditioning controller 32 controls the valve opening degree of the indoor expansion valve 8 in a direction in which the refrigerant discharged from the heat absorber 9 is not superheated SH, so that the refrigerant discharged from the heat absorber 9 is superheated SH. Is not attached, or even if it is attached, it will be extremely small. As a result, the refrigerant evaporates in the entire or substantially the entire heat absorber 9, and heat can be absorbed from the air supplied to the vehicle interior. Therefore, the inconvenience that the temperature distribution occurs in the heat absorber 9 is eliminated, or It will be possible to suppress and effectively cool the passenger compartment. Further, since the oil return is improved, the seizure of the compressor 2 can be avoided in advance.

In particular, when the air conditioning controller 32 has a degree of superheat SH attached to the refrigerant discharged from the heat absorber 9 as in the embodiment, the valve opening degree of the indoor expansion valve 8 can be changed in the opening direction. It becomes possible to effectively eliminate or suppress the occurrence of the temperature distribution and the deterioration of the oil return. In this case, specifically, as in the embodiment, the air conditioning controller 32 opens the valve opening degree of the indoor expansion valve 8 when the superheat degree SH of the refrigerant discharged from the endothermic device 9 becomes larger than the predetermined threshold value SH1. Since the direction is changed, by setting this threshold value SH1 to an extremely small value, it is possible to appropriately eliminate or suppress the occurrence of the temperature distribution of the heat absorber 9 and the deterioration of the oil return. Will be.

Further, in the embodiment, since the accumulator 12 is provided in the refrigerant circuit R from the refrigerant outlet of the heat absorber 9 to the refrigerant suction side of the compressor 2, the liquid back to the compressor 2 can be effectively eliminated. become.

(8) Heat Dissipation Amount of Outdoor Heat Exchanger 7 and Temperature Distribution of Heat Absorber 9 Here, FIG. 6 shows the valve opening ECCVohx [PLS] of the outdoor expansion valve 6 in the dehumidifying / cooling mode and the heat dissipation amount of the outdoor heat exchanger 7. And the relationship with the temperature distribution of the heat exchanger 9. In the dehumidifying / cooling mode, when the valve opening ECCVohx of the outdoor expansion valve 6 is large, the outdoor heat exchanger 7 is in the heat dissipation function region where the refrigerant dissipates heat, and the larger the valve opening ECCVohx as shown by L4 in FIG. The amount of heat radiated from the outdoor heat exchanger 7 also increases (on the right side when facing FIG. 6).

In that state, if the valve opening ECCVohx of the outdoor expansion valve 6 is reduced (when the outdoor expansion valve 6 is throttled), the amount of heat radiation of the refrigerant in the outdoor heat exchanger 7 decreases, and conversely, the radiator The heating capacity (heating capacity) of No. 4 increases, and the degree of supercooling SC of the refrigerant emitted from the radiator 4 obtained from the radiator outlet temperature TCIout and the radiator pressure PCI detected by the radiator outlet sensor 47 also increases. .. Then, from a certain small valve opening ECCVohx, the refrigerant absorbs heat in the outdoor heat exchanger 7, and the outdoor heat exchanger 7 enters the endothermic functional region (on the left side when facing FIG. 6). As a result, the temperature of the outdoor heat exchanger 7 (outdoor heat exchanger temperature TXO) also decreases.

On the other hand, when the valve opening ECCVohx of the outdoor expansion valve 6 becomes smaller, the amount of refrigerant circulating in the endothermic device 9 decreases by that amount, so that the refrigerant completely evaporates at an early stage when it flows into the endothermic device 9. Therefore, in the endothermic device 9, the temperature is low and high depending on the part, and the temperature distribution (temperature variation) is generated. As shown by L1 to L3 in FIG. 6, the valve opening ECCVohx of the outdoor expansion valve 6 is increased. The smaller the temperature, the larger the temperature distribution.

When a temperature distribution is generated in the endothermic device 9 and becomes large, the dehumidifying performance deteriorates, and it becomes difficult to cool the ventilated air in some parts, making it difficult to establish the target blowout temperature TAO, and the air conditioning performance in the vehicle interior. Will get worse.

There is a correlation between the amount of ventilation to the heat absorber 9 by the indoor blower 27 and the temperature distribution, and the higher the amount of ventilation (the larger the amount), the more likely the temperature distribution will occur. This is L1 to L3 in FIG. 6, where L1 in FIG. 6 is the temperature distribution of the heat absorber 9 when the ventilation volume is high, L2 is the temperature distribution when the air volume is medium, and L3 is the temperature distribution when the air volume is low. The temperature distribution of each is shown.

Further, the broken lines L1 to L3 show the temperature distribution when the indoor expansion valve is used as a conventional mechanical expansion valve and the refrigerant discharged from the heat absorber 9 is superheated SH, and the solid lines L1 to L3 are the above-mentioned (7). As described above, the temperature distribution when the refrigerant discharged from the endothermic device 9 is controlled without the superheat degree SH depending on the valve opening degree of the indoor expansion valve 8 is shown. As is clear from this figure, when a superheat degree SH is added to the refrigerant discharged from the endothermic device 9 (the superheat degree SH is large), the refrigerant evaporates faster, and therefore, regardless of the amount of ventilation, it is outdoors. From the stage where the valve opening degree ECCVohx of the expansion valve 6 is large, the temperature distribution of the heat absorber 9 becomes larger than the permissible value (permissible value of the heat absorber temperature distribution).

On the other hand, when the valve opening degree of the indoor expansion valve 8 is controlled by the air conditioning controller 32 in a direction in which the superheat degree SH is not attached to the refrigerant discharged from the heat exchanger 9, the valve opening degree ECCVohx of the outdoor expansion valve 6 is set. Even if it is reduced, as long as the outdoor heat exchanger 7 exerts the heat dissipation function (as long as it is in the outdoor heat exchanger heat dissipation function region), the temperature distribution of the heat exchanger 9 is hardly large, and the temperature distribution of the endothermic absorber 9 is not large. It can be seen that the value is smaller than the permissible value (solid lines L1 to L3 in FIG. 6).

(9) Control of the outdoor expansion valve 6 in the dehumidifying / cooling mode (No. 1)
Therefore, in the dehumidifying / cooling mode, the air conditioning controller 32 controls the valve opening degree of the indoor expansion valve 8 in a direction in which the refrigerant discharged from the heat absorber 9 is not superheated SH as described above, and the outdoor heat exchanger 7 moves. While the heat radiating function is exhibited, the valve opening degree of the outdoor expansion valve 6 is reduced (squeezed) as much as possible, and control is performed so as to increase the heating capacity of the heat radiator 4. Next, an example of controlling the valve opening degree of the outdoor expansion valve 6 in the dehumidifying / cooling mode will be described in detail with reference to FIG. 7.

In this example, the air conditioning controller 32 has a radiator outlet temperature TCIout detected by the radiator outlet sensor 47, a supercooling degree SC [K] of the refrigerant emitted from the radiator 4 obtained from the radiator pressure PCI, and a dehumidifying / cooling mode. The valve opening degree ECCVohx [PLS] of the outdoor expansion valve 6 is controlled based on the target supercooling degree TGSC, which is the target value of the supercooling degree SC. Specifically, first, the target supercooling degree TGSC is set in the air conditioning controller 32. This target supercooling degree TGSC is, for example, a value of a limit (the limit of the outdoor heat exchanger heat dissipation function region of FIG. 6) in which the refrigerant does not condense too much in the radiator 4 and the outdoor heat exchanger 7 can exert the heat dissipation function. It shall be obtained by experiment in advance.

Further, the air conditioning controller 32 of the embodiment sets a predetermined upper limit value TGSCHiLim and a lower limit value TGSCLoLim above and below the target supercooling degree TGSC. Then, as shown at the left end of FIG. 7, when the supercooling degree SC of the refrigerant at the outlet of the radiator 4 is lower than the target supercooling degree TGSC, the valve opening degree ECCVohx of the outdoor expansion valve 6 is set to a predetermined pulse per predetermined time. Reduce at a rate.

As the valve opening ECCVohx of the outdoor expansion valve 6 is reduced, the refrigerant stops for a longer time in the radiator 4, and as described above, the refrigerant eventually condenses and becomes supercooled in the radiator 4. The degree of supercooling SC of the refrigerant at the outlet of the radiator 4 begins to increase. Then, when the supercooling degree SC rises to the target supercooling degree TGSC at the time t1 in FIG. 7, the air conditioning controller 32 stops the reduction of the valve opening degree ECCVohx of the outdoor expansion valve 6.

After that, when the supercooling degree SC rises and rises to the upper limit value TGSCHiLim at time t2, the air conditioning controller 32 expands the valve opening ECCVohx of the outdoor expansion valve 6 at a predetermined pulse rate per predetermined time. As a result, the refrigerant flows out from the radiator 4 faster, so that the supercooling degree SC starts to decrease. Then, when the supercooling degree SC drops to the lower limit value TGSCLoLim at time t3, the air conditioning controller 32 stops the expansion of the valve opening degree ECCVohx of the outdoor expansion valve 6. The valve opening ECCVohx at this point is the minimum valve opening of the outdoor expansion valve 6.

As described above, in the dehumidifying / cooling mode of the air conditioning controller 32, the valve opening degree of the outdoor expansion valve 6 is based on the supercooling degree SC of the refrigerant at the outlet of the radiator 4 and the predetermined target supercooling degree TGSC which is the target value thereof. Since the ECCVohx is controlled, the target supercooling degree TGSC is set to an appropriate value in the radiator 4 so that the refrigerant does not condense too much as in the embodiment, so that the dehumidifying and cooling mode can be established while outdoors. It is possible to reduce the valve opening degree ECCVohx of the outdoor expansion valve 5 and maximize the heating capacity of the radiator 4 without considering the individual variation of the expansion valve 6.

As a result, the need to generate heat of the auxiliary heater 23 is eliminated or suppressed, so that it is possible to contribute to energy saving while improving the air conditioning performance in the dehumidifying / cooling mode.

In particular, in the embodiment, when the supercooling degree SC is lower than the target supercooling degree TGSC, the valve opening ECCVohx of the outdoor expansion valve 6 is reduced, and the supercooling degree SC rises to the target supercooling degree TGSC. , Stops the reduction of the valve opening ECCVohx of the outdoor expansion valve 6. Then, when the supercooling degree SC reaches the target supercooling degree TGSC and then rises to the upper limit value TGSCHiLim, the valve opening ECCVohx of the outdoor expansion valve 6 is expanded, and the supercooling degree SC decreases to the lower limit value TGSCLoLim. Since the expansion of the valve opening ECCVohx of the outdoor expansion valve 6 is stopped, the radiator 4 is heated in the dehumidifying cooling mode based on the supercooling degree SC of the refrigerant at the outlet of the radiator 4 and the target supercooling degree TGSC. It is possible to smoothly and accurately control the outdoor expansion valve 6 that maximizes the capacity (heating capacity).

(10) Control of the outdoor expansion valve 6 in the dehumidifying / cooling mode (Part 2)
Next, another example of controlling the valve opening degree of the outdoor expansion valve 6 in the dehumidifying / cooling mode will be described with reference to FIG. In this example, the air conditioning controller 32 uses the temperature of the refrigerant emitted from the outdoor heat exchanger 7 detected by the outdoor heat exchanger outlet sensor 54 (outdoor heat exchanger temperature TXO [° C.]) and the outside air detected by the outdoor air temperature sensor 33. The valve opening degree ECCVohx [PLS] of the outdoor expansion valve 6 is controlled based on the temperature Tam [° C.].

Specifically, when the outdoor heat exchanger temperature TXO is higher than the outside air temperature Tam + the predetermined value α as shown at the left end of FIG. 8, the air conditioning controller 32 determines the valve opening ECCVohx of the outdoor expansion valve 6 per predetermined time. It is reduced at the rate of the pulse. Since the predetermined value α is either a positive or negative value including zero, when the predetermined value α is zero, the outside air temperature Tam itself is obtained. That is, it is assumed that the outside air temperature Tam + the predetermined value α is any temperature near the outside air temperature Tam.

As the valve opening ECCVohx of the outdoor expansion valve 6 is reduced, the refrigerant stops for a longer time in the radiator 4, and as described above, the refrigerant eventually condenses and becomes supercooled in the radiator 4. The degree of supercooling SC of the refrigerant at the outlet of the radiator 4 begins to increase. Further, since the amount of the high-temperature refrigerant flowing into the outdoor heat exchanger 7 decreases, the outdoor heat exchanger temperature TXO also decreases.

Then, when the outdoor heat exchanger temperature TXO drops to the outside air temperature Tam + a predetermined value α at the time t4 in FIG. 8, the air conditioning controller 32 stops the reduction of the valve opening ECCVohx of the outdoor expansion valve 6. Further, in the air conditioning controller 32, a predetermined upper limit value TamHiLim and a predetermined lower limit value TamMoLim are set above and below the outside air temperature Tam + predetermined value α, and after the outdoor heat exchanger temperature TXO becomes the outside air temperature Tam + predetermined value α, the figure is shown in FIG. When the temperature drops to the lower limit TamMoLim at time t5 at 8, the air conditioning controller 32 expands the valve opening ECCVohx of the outdoor expansion valve 6 at a predetermined pulse rate per predetermined time.

As a result, a larger amount of high-temperature refrigerant flows into the outdoor heat exchanger 7, so that the outdoor heat exchanger temperature TXO begins to rise. Then, when the outdoor heat exchanger temperature TXO rises to the upper limit value TamHiLim at time t6, the air conditioning controller 32 stops the expansion of the valve opening ECCVohx of the outdoor expansion valve 6. The valve opening ECCVohx at this point is the minimum valve opening of the outdoor expansion valve 6. As a result, the outdoor heat exchanger temperature TXO is maintained within the upper and lower limit values TamHiLim and TamMoLim of the outside air temperature Tam + the predetermined value α, so that the outdoor heat exchanger 7 reliably exhibits the heat dissipation function (FIG. 6). The outdoor heat exchanger heat dissipation function region is maintained), and the valve opening degree ECCVohx of the outdoor expansion valve 6 is reduced as much as possible.

As described above, in this embodiment, the air conditioning controller 32 controls the valve opening ECCVohx of the outdoor expansion valve 6 based on the outdoor heat exchanger temperature TXO and the outside air temperature Tam in the dehumidifying / cooling mode. When the outdoor heat exchanger temperature TXO is higher than the outside air temperature Tam + the predetermined value α (including the outside air temperature Tam; the same applies hereinafter) as in the embodiment, the valve opening ECCVohx of the outdoor expansion valve 6 is reduced to reduce the outdoor heat exchanger temperature. When TXO drops to the outside air temperature Tam + predetermined value α, by stopping the reduction of the valve opening ECCVohx of the outdoor expansion valve 6, the heat dissipation function in the outdoor heat exchanger 7 in the dehumidifying / cooling mode is secured, and the dehumidifying / cooling mode is secured. It is possible to maximize the heating capacity (heating capacity) of the radiator 4 without considering the individual variation of the outdoor expansion valve 6 while establishing the above.

As a result, the need to generate heat of the auxiliary heater 23 is also eliminated or suppressed, so that it is possible to contribute to energy saving while improving the air conditioning performance in the dehumidifying / cooling mode.

Further, in the embodiment, after the air conditioning controller 32 sets the predetermined upper limit value TamHiLim and the lower limit value TamMoLim above and below the outside air temperature Tam + predetermined value α, and after the outdoor heat exchanger temperature TXO becomes the outside air temperature Tam + predetermined value α, When the temperature drops to the lower limit TamLoLim, the valve opening ECCVohx of the outdoor expansion valve 6 is expanded, and when the outdoor heat exchanger temperature TXO rises to the upper limit TamHiLim, the expansion of the valve opening ECCVohx of the outdoor expansion valve 6 is stopped. Therefore, based on the outdoor heat exchanger temperature TXO and the outside air temperature Tam, the control of the outdoor expansion valve 6 that maximizes the heating capacity (heating capacity) of the radiator 4 in the dehumidifying / cooling mode can be smoothly and smoothly performed. It will be possible to realize it accurately.

In the case of this embodiment as well, before the outdoor heat exchanger temperature TXO drops to the outside air temperature Tam + predetermined value α, the supercooling degree SC of the refrigerant at the outlet of the radiator 4 is set to the above-mentioned target supercooling degree TGSC ( When the temperature rises to FIG. 7), the air conditioning controller 32 stops the reduction of the valve opening degree ECCVohx of the outdoor expansion valve 6 in the same manner as in the control of (9) described above. Then, when the supercooling degree SC reaches the target supercooling degree TGSC and then rises to the above-mentioned upper limit value TGSCHiLim, the air conditioning controller 32 controls the outdoor expansion valve 6 in the same manner as in the above-mentioned control (9). When the supercooling degree SC drops to the lower limit value TGSCLoLim, the expansion of the valve opening degree ECCVohx of the outdoor expansion valve 6 is stopped.

That is, before the outdoor heat exchanger temperature TXO drops to the outside air temperature Tam + predetermined value α, the valve opening degree of the outdoor expansion valve 6 is based on the supercooling degree SC of the refrigerant at the outlet of the radiator 4 and the target supercooling degree TGSC. After stopping the reduction of ECCVohx, the outdoor expansion valve 6 is controlled to maximize the heating capacity (heating capacity) of the radiator 4 in the dehumidifying / cooling mode based on the supercooling degree SC and the target supercooling degree TGSC. Let's go.

As a result, in the case of this embodiment, the dehumidifying and cooling mode is surely established based on the outdoor heat exchanger temperature TXO and the outside air temperature Tam, and the radiator 4 is based on the supercooling degree SC and the target supercooling degree TGSC. By controlling the outdoor expansion valve 6 that maximizes the heating capacity (heating capacity), it becomes possible to realize comfortable vehicle interior air conditioning.

In the above-described embodiment, the valve opening ECCVohx of the outdoor expansion valve 6 is reduced / expanded by the upper limit value TGSCiLim and the lower limit value TGSCLoLim of the supercooling degree SC and the target supercooling degree TGSC, but the target is not limited to this. The valve opening degree ECCVohx of the outdoor expansion valve 6 may be controlled by so-called PID control based on the deviation e between the supercooling degree TGSC and the supercooling degree SC.

Further, the configuration of the air conditioning controller 32 described in the examples, the configuration of the heat pump device HP of the vehicle air conditioner 1 and the configuration of the heat medium circulation circuit 61 are not limited to this, and are changed within a range that does not deviate from the gist of the present invention. It goes without saying that it is possible.

1 Vehicle air conditioner 2 Compressor 4 Heater 6 Outdoor expansion valve 7 Outdoor heat exchanger 8 Indoor expansion valve 9 Heat absorber 12 Accumulator 32 Air conditioning controller (control device)
47 Heat Dissipator Outlet Sensor 49 Heat Absorber Outlet Sensor 54 Outdoor Heat Exchanger Outlet Sensor R Refrigerant Circuit

Claims

A compressor that compresses the refrigerant and
A radiator for radiating the refrigerant and heating the air supplied to the passenger compartment,
An outdoor heat exchanger that is installed outside the vehicle interior and into which the refrigerant emitted from the radiator flows in,
An outdoor expansion valve for controlling the inflow of refrigerant into the outdoor heat exchanger,
An endothermic absorber for absorbing heat from the refrigerant and cooling the air supplied to the passenger compartment.
An indoor expansion valve for controlling the inflow of refrigerant into the heat absorber,
Equipped with a control device
At least the refrigerant discharged from the compressor is dissipated by the control device by the radiator and the outdoor heat exchanger, the radiated refrigerant is depressurized by the indoor expansion valve, and then heat is absorbed by the heat absorber. In a vehicle air conditioner that executes a dehumidifying / cooling mode
In the dehumidifying / cooling mode, the control device controls the valve opening degree of the outdoor expansion valve based on the supercooling degree SC of the refrigerant at the outlet of the radiator and the predetermined target supercooling degree TGSC which is the target value thereof. An air conditioner for vehicles characterized by
When the supercooling degree SC is lower than the target supercooling degree TGSC, the control device reduces the valve opening degree of the outdoor expansion valve, and when the supercooling degree SC rises to the target supercooling degree TGSC. The vehicle air conditioner according to claim 1, wherein the reduction of the valve opening degree of the outdoor expansion valve is stopped.
The control device sets predetermined upper limit values TGSCHiLim and lower limit value TGSCLoLim above and below the target supercooling degree TGSC, and at the same time,
When the supercooling degree SC reaches the target supercooling degree TGSC and then rises to the upper limit value TGSCHiLim, the valve opening of the outdoor expansion valve is expanded and the supercooling degree SC decreases to the lower limit value TGSCLoLim. The vehicle air conditioner according to claim 2, further comprising stopping the expansion of the valve opening degree of the outdoor expansion valve.
A compressor that compresses the refrigerant and
A radiator for radiating the refrigerant and heating the air supplied to the passenger compartment,
An outdoor heat exchanger that is installed outside the vehicle interior and into which the refrigerant emitted from the radiator flows in,
An outdoor expansion valve for controlling the inflow of refrigerant into the outdoor heat exchanger,
An endothermic absorber for absorbing heat from the refrigerant and cooling the air supplied to the passenger compartment.
An indoor expansion valve for controlling the inflow of refrigerant into the heat absorber,
Equipped with a control device
At least the refrigerant discharged from the compressor is dissipated by the control device by the radiator and the outdoor heat exchanger, the radiated refrigerant is depressurized by the indoor expansion valve, and then heat is absorbed by the heat absorber. In a vehicle air conditioner that executes a dehumidifying / cooling mode
The control device is a vehicle air conditioner that controls the valve opening degree of the outdoor expansion valve based on the temperature TXO of the outdoor heat exchanger and the outside air temperature Tam in the dehumidifying / cooling mode.
When the temperature TXO of the outdoor heat exchanger is higher than the outside air temperature Tam or the outside air temperature Tam + a predetermined value α, the control device reduces the valve opening degree of the outdoor expansion valve and reduces the temperature TXO of the outdoor heat exchanger. The vehicle air conditioner according to claim 4, wherein when the outside air temperature Tam or the outside air temperature Tam + a predetermined value α is lowered, the reduction of the valve opening degree of the outdoor expansion valve is stopped.
The control device sets a predetermined upper limit value TamHiLim and a predetermined lower limit value TamLoLim above and below the outside air temperature Tam or the outside air temperature Tam + the predetermined value α, and at the same time,
When the temperature TXO of the outdoor heat exchanger reaches the outside air temperature Tam or the outside air temperature Tam + a predetermined value α and then drops to the lower limit value TamLoLim, the valve opening of the outdoor expansion valve is expanded and the outdoor The vehicle air conditioner according to claim 5, wherein when the temperature TXO of the heat exchanger rises to the upper limit value TamHiLim, the expansion of the valve opening degree of the outdoor expansion valve is stopped.
In the control device, the degree of supercooling SC of the refrigerant at the outlet of the radiator is set to the target value before the temperature TXO of the outdoor heat exchanger drops to the outside air temperature Tam or the outside air temperature Tam + a predetermined value α. The vehicle air conditioner according to claim 5 or 6, wherein when the temperature rises to a predetermined target supercooling degree TGSC, the reduction of the valve opening degree of the outdoor expansion valve is stopped.
The control device sets predetermined upper limit values TGSCHiLim and lower limit value TGSCLoLim above and below the target supercooling degree TGSC, and at the same time,
When the supercooling degree SC reaches the target supercooling degree TGSC and then rises to the upper limit value TGSCHiLim, the valve opening of the outdoor expansion valve is expanded and the supercooling degree SC decreases to the lower limit value TGSCLoLim. The vehicle air conditioner according to claim 7, further comprising stopping the expansion of the valve opening degree of the outdoor expansion valve.
The control device according to any one of claims 1 to 8, wherein the control device controls the valve opening degree of the indoor expansion valve in a direction in which the refrigerant discharged from the heat absorber is not superheated SH. The vehicle air conditioner described.
The vehicle air according to claim 9, wherein the control device changes the valve opening degree of the indoor expansion valve in the opening direction when the refrigerant discharged from the heat absorber has a superheat degree SH. Harmonizer.
The control device is characterized in that when the superheat degree SH of the refrigerant discharged from the heat absorber becomes larger than a predetermined threshold value SH1, the valve opening degree of the indoor expansion valve is changed in the opening direction. 10. The vehicle air conditioner for a vehicle.
The vehicle air conditioning according to any one of claims 9 to 11, wherein an accumulator provided in a refrigerant circuit extending from the refrigerant outlet of the heat absorber to the refrigerant suction side of the compressor is provided. apparatus.