JP6047387B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a heat pump type air conditioner that air-conditions a vehicle interior of a vehicle, and more particularly to an air conditioner that can be applied to a hybrid vehicle and an electric vehicle.

  Hybrid vehicles and electric vehicles have come into widespread use due to the emergence of environmental problems in recent years. As an air conditioner that can be applied to such a vehicle, a compressor that compresses and discharges the refrigerant, a radiator (condenser) that is provided on the vehicle interior side to dissipate the refrigerant, and the vehicle interior side A heat absorber (evaporator) that absorbs the refrigerant, and an outdoor heat exchanger that is provided outside the passenger compartment to dissipate or absorb the refrigerant, and dissipates the refrigerant discharged from the compressor in the radiator, A heating mode in which the heat dissipated in the radiator is absorbed in the outdoor heat exchanger, a dehumidification mode in which the refrigerant discharged from the compressor is dissipated in the radiator, and the refrigerant dissipated in the radiator is absorbed in the heat absorber, and compression A refrigerant that has been radiated in an outdoor heat exchanger and is switched and executed in each cooling mode in which heat is absorbed in the heat absorber has been developed. References 1).

  Further, in Patent Document 1, an injection circuit is provided that diverts the refrigerant that has flowed out of the radiator, decompresses the diverted refrigerant, exchanges heat with the refrigerant that has left the radiator, and returns the refrigerant to the middle of compression. As a result, the refrigerant discharged from the compressor is increased, and the heating capacity of the radiator is improved.

Japanese Patent No. 3985384

  However, since the temperature of the refrigerant exiting the radiator is low, the amount of heat exchange with the refrigerant that has been diverted and decompressed is also reduced. Therefore, in order to inject gas during the compression of the compressor, there is a limit to increasing the amount of refrigerant flowing through the injection circuit, and it becomes impossible to sufficiently increase the refrigerant discharged from the compressor. There was a problem that the ability could not be obtained.

  The present invention has been made to solve the conventional technical problems, and an object of the present invention is to provide a vehicle air conditioner capable of obtaining a sufficient heating capacity by gas injection.

An air conditioner for a vehicle according to a first aspect of the present invention includes a compressor that compresses a refrigerant, an air flow passage through which air supplied to the passenger compartment flows, and a radiator that is provided in the air flow passage and radiates heat from the refrigerant. A heat absorber provided in the air flow path for absorbing the refrigerant, an outdoor heat exchanger provided outside the vehicle room for radiating or absorbing the refrigerant, and a control means. At least by this control means, the refrigerant is discharged from the compressor. The refrigerant is radiated by a radiator, and after the decompressed refrigerant is decompressed, a heating mode is performed in which heat is absorbed by an outdoor heat exchanger, and a part of the refrigerant exiting the radiator is divided. And an injection circuit for returning the compressor in the middle of compression. The injection circuit discharges the heat of the decompression unit and the refrigerant decompressed by the decompression unit with the refrigerant before being discharged from the compressor and flowing into the radiator. A heat exchanger, a radiator outlet-side heat exchanger to the refrigerant leaving the radiator and decompressed refrigerant is heat-exchanged by vacuum means or another pressure reducing means provided separately, the heat in the injection circuit It has a flow path control means for controlling the flow of the refrigerant to the exchanger, and the control means evaporates the refrigerant, which is always decompressed by the pressure reduction means by the flow path control means, in the heat exchanger outlet side heat exchanger, and dissipates heat. When the heat radiation of the condenser is insufficient, it is evaporated by the discharge side heat exchanger, and the refrigerant flow rate in the injection circuit is increased by the decompression means .

An air conditioner for a vehicle according to a second aspect of the present invention includes a compressor that compresses the refrigerant, an air flow passage through which air supplied to the passenger compartment flows, and a radiator that is provided in the air flow passage and radiates the refrigerant. A heat absorber provided in the air flow path for absorbing the refrigerant, an outdoor heat exchanger provided outside the vehicle room for radiating or absorbing the refrigerant, and a control means. At least by this control means, the refrigerant is discharged from the compressor. The refrigerant is radiated by a radiator, and after the decompressed refrigerant is decompressed, a heating mode is performed in which heat is absorbed by an outdoor heat exchanger, and a part of the refrigerant exiting the radiator is divided. And a water circulation circuit for circulating the water heated by the heating means through the circulation means. The injection circuit includes the decompression means and the refrigerant decompressed by the decompression means. Water is water and heat exchange flowing in the water circulation circuit - and the refrigerant heat exchanger, a radiator outlet-side heat exchanger to the refrigerant leaving the radiator and decompressed refrigerant is heat-exchanged by the pressure reducing means, in the injection circuit Having a flow path control means for controlling the flow of the refrigerant to each of the heat exchangers, and the control means evaporates the refrigerant, which is always decompressed by the pressure reducing means by the flow path control means, with the heat exchanger outlet side heat exchanger. At the same time, when the heat dissipation of the radiator is insufficient, it is evaporated by a water-refrigerant heat exchanger, and the refrigerant flow rate in the injection circuit is increased by the decompression means .

  A vehicle air conditioner according to a third aspect of the present invention is characterized in that, in the above invention, the water circulation circuit has a water-air heat exchanger provided in the air inflow side of the outdoor heat exchanger or in the air flow passage. To do.

In the vehicle air conditioner according to the invention of claim 4 , in each of the above inventions, the control means compares the required heating capacity Qtgt which is the required heating capacity of the radiator with the heating capacity Qhp generated by the radiator, When the heating capacity Qhp is less than the required heating capacity Qtgt, the refrigerant is caused to flow through the injection circuit by the decompression means.

According to a fifth aspect of the present invention, there is provided an air conditioning apparatus for a vehicle according to the present invention, wherein the control means includes a temperature of air flowing into the radiator, a temperature of air flowing out of the radiator, and an amount of air passing through the radiator. The required heating capacity Qtgt is calculated on the basis of any one of these indicators or a combination thereof, the specific heat of the air flowing into the radiator, and the indicator showing the density of the air, the outside air temperature, the refrigerant Flow rate, air volume in the air flow path, vehicle speed, heat absorber temperature, compressor speed, radiator outlet refrigerant pressure, radiator outlet refrigerant temperature, radiator inlet refrigerant pressure, and radiator inlet refrigerant The heating capacity Qhp is calculated based on any one of the indexes indicating the temperatures or a combination thereof.

According to a sixth aspect of the present invention, there is provided an air conditioner for a vehicle according to the first to third aspects of the present invention, wherein the control means includes the outside air temperature, the air volume in the air flow passage, the difference between the target radiator temperature and the actual radiator temperature. The environmental condition in the heating mode deteriorated based on the environmental condition determined from any one of the indicators indicating the refrigerant discharge refrigerant temperature and the compressor discharge refrigerant pressure, or a combination thereof. In this case, the refrigerant is caused to flow through the injection circuit by the decompression means.

According to a seventh aspect of the present invention, there is provided a vehicle air conditioner according to any one of the fourth to sixth aspects, wherein the control means includes a required heating capacity Qtgt which is a required heating capacity of the radiator and a heating capacity Qhp generated by the radiator. Based on the difference between the difference between the target radiator temperature and the radiator temperature, the difference between the target radiator pressure and the radiator pressure, the target outlet temperature into the passenger compartment, or a combination thereof. The amount of refrigerant returning from the injection circuit to the compressor is controlled by the means.

An air conditioner for a vehicle according to an eighth aspect of the invention includes a water circulation circuit for circulating the water heated by the heating means according to the fourth to seventh aspects of the invention through the circulation means, and the water circulation circuit is provided in the air flow passage. When the control means has a water-air heat exchanger provided and the heating capacity of the radiator is insufficient even when the refrigerant flows through the injection circuit, the water heated by the heating means is supplied to the water-air heat exchanger. It is characterized by circulating it.

  According to the present invention, the compressor that compresses the refrigerant, the air flow passage through which the air supplied to the passenger compartment flows, the radiator that is provided in the air flow passage to dissipate the refrigerant, and the air flow passage are provided. A heat absorber that absorbs the refrigerant, an outdoor heat exchanger that is provided outside the passenger compartment to dissipate or absorb the refrigerant, and a control means, and at least the control means allows the refrigerant discharged from the compressor to be used as the radiator. In a vehicle air conditioner that executes a heating mode in which heat is radiated and the radiated refrigerant is decompressed and then absorbed by an outdoor heat exchanger, a part of the refrigerant exiting the radiator is shunted and compressed by the compressor An injection circuit for returning to the middle is provided, and in this injection circuit, discharge side heat exchange is performed to exchange heat with the refrigerant before the refrigerant decompressed by the decompression unit is discharged from the compressor and flows into the radiator. Or, since the water-refrigerant heat exchanger that exchanges heat between the refrigerant depressurized by the depressurization means and the heated water flowing in the water circulation circuit is provided, the refrigerant returned to the middle of compression of the compressor by the injection circuit, Heat can be exchanged with the refrigerant discharged from the compressor that has a higher temperature than the refrigerant that has exited the radiator, or with water in the water circulation circuit, and can be evaporated.

  As a result, a sufficient amount of gas injection into the compressor can be ensured, and the amount of refrigerant discharged from the compressor can be increased to improve the heating capacity.

In addition, since the injection circuit further includes a radiator outlet side heat exchanger for exchanging heat between the refrigerant decompressed by the decompression means or another decompression means provided separately and the refrigerant exiting the radiator. It is possible to evaporate the refrigerant returned in the middle of the compression of the compressor also by heat exchange with the refrigerant exiting the radiator.

Further, the injection circuit is further provided with a flow path control means for controlling the flow of the refrigerant to each heat exchanger in the injection circuit, and the control means radiates the refrigerant that is always decompressed by the pressure reduction means by the flow path control means. Evaporate in the outlet heat exchanger, evaporate in the discharge side heat exchanger or water-refrigerant heat exchanger if the heat dissipation of the radiator is insufficient, and increase the refrigerant flow rate in the injection circuit by the decompression means Thus, only when the heating capacity is insufficient, the refrigerant discharged from the compressor or the heated water in the water circulation circuit can be used.

This eliminates the inconvenience of unnecessarily lowering the enthalpy of the refrigerant flowing into the radiator due to gas injection, and improves the operating efficiency while improving the heating capacity.

  In this case, if the water circulation circuit is provided with a water-air heat exchanger provided in the air inflow side of the outdoor heat exchanger or in the air flow passage in the water circulation circuit as in the invention of claim 3, the water flowing in the water circulation circuit is heated. It is possible to suppress frost formation on the outdoor heat exchanger and supplement heating in the passenger compartment with the water.

Further, as in the invention of claim 4 , the control means compares the required heating capacity Qtgt which is the required heating capacity of the radiator and the heating capacity Qhp generated by the radiator, and this heating capacity Qhp is the required heating capacity Qtgt. If there is a shortage, if the refrigerant is caused to flow through the injection circuit by the decompression means, the gas injection to the compressor is appropriately controlled, and the efficiency when the refrigerant flowing through the injection circuit is evaporated by the refrigerant discharged from the compressor It is possible to suppress heating and improve the heating capacity by gas injection with high efficiency.

In this case, as in the fifth aspect of the invention, the control means includes the temperature indicating the temperature of the air flowing into the radiator, the temperature of the air flowing out of the radiator, and the index indicating the amount of air passing through the radiator. The required heating capacity Qtgt is calculated based on any one or a combination thereof, the specific heat of the air flowing into the radiator, and an index indicating the density of the air, and the outside air temperature, the refrigerant flow rate, the air flow passage Of air volume, vehicle speed, heat absorber temperature, compressor rotation speed, refrigerant pressure at the radiator outlet, refrigerant temperature at the radiator outlet, refrigerant pressure at the radiator inlet, and refrigerant temperature at the radiator inlet By calculating the heating capacity Qhp based on any one of the above or a combination thereof, it becomes possible to control the gas injection to the compressor more accurately.

Further, as in the sixth aspect of the invention, the control means includes the outside air temperature, the air volume in the air flow passage, the difference between the target radiator temperature and the actual radiator temperature, the refrigerant discharge refrigerant temperature, and the compressor discharge. If the environmental condition in the heating mode deteriorates based on the environmental condition determined from any one of the indices indicating the refrigerant pressure or a combination thereof, the refrigerant may be caused to flow through the injection circuit by the decompression unit. The gas injection to the compressor can be accurately controlled.

Further, as in the seventh aspect of the present invention, the control means is configured such that the difference between the required heating capacity Qtgt which is the required heating capacity of the radiator and the heating capacity Qhp generated by the radiator, the target radiator temperature and the radiator temperature. Based on one of the difference, the difference between the target radiator pressure and the radiator pressure, the target outlet temperature into the passenger compartment, or a combination thereof, the amount of refrigerant returning from the injection circuit to the compressor is controlled by the decompression means. Thus, the amount of refrigerant returned to the compressor by gas injection can also be adjusted accurately.

Furthermore, as in the invention of claim 8 , a water circulation circuit for circulating the water heated by the heating means by the circulation means is provided, and a water-air heat exchanger provided in the air flow passage is provided in the water circulation circuit, and In the case where the heating capacity of the radiator is insufficient even when the control means causes the refrigerant to flow through the injection circuit, if the water heated by the heating means is circulated to the water-air heat exchanger, the gas injection by the injection circuit Therefore, when the heating capacity is insufficient, this can be supplemented by the water circulation circuit, and it is possible to realize comfortable vehicle interior heating.

It is a block diagram of the air conditioning apparatus for vehicles of one Embodiment to which this invention is applied. It is a block diagram of the electric circuit of the controller of the vehicle air conditioner of FIG. FIG. 2 is a ph diagram of the vehicle air conditioner of FIG. 1. FIG. 3 is a control block diagram of the controller of FIG. 2. It is a figure explaining determination of the target blowing temperature by the controller of FIG. It is a figure explaining determination of the target injection refrigerant | coolant superheat degree using the target blowing temperature by the controller of FIG. It is a figure explaining the determination of the target injection refrigerant | coolant superheat degree using the difference of the request | requirement heating capability and heating capability (generated heating capability) by the controller of FIG. It is a figure explaining determination of the target injection refrigerant | coolant superheat degree using the difference of the target radiator temperature and radiator temperature by the controller of FIG. It is a figure explaining determination of the target injection refrigerant | coolant superheat degree using the difference of the target radiator pressure and radiator pressure by the controller of FIG. It is a flowchart which shows an example of the injection execution availability judgment by the controller of FIG. It is a figure which shows the example of the injection execution availability judgment of FIG. It is a timing chart which shows the state of each part after starting of the vehicle air conditioner of FIG. It is a figure which shows the other example of the injection execution availability judgment by the controller of FIG. It is a block diagram of the air conditioning apparatus for vehicles of the other Example of this invention. It is a block diagram of the air conditioning apparatus for vehicles of another other Example of this invention. It is a block diagram of the air conditioning apparatus for vehicles of another another Example of this invention. FIG. 17 is a ph diagram of the vehicle air conditioner of FIG. 16. FIG. 17 is another ph diagram of the vehicle air conditioner of FIG. 16. It is a block diagram of the air conditioning apparatus for vehicles of another another Example of this invention. It is a block diagram of the air conditioning apparatus for vehicles of another another Example of this invention. It is a block diagram of the air conditioning apparatus for vehicles of another another Example of this invention. It is a figure explaining the gas injection control of the air conditioning apparatus for vehicles of FIG. 20 and FIG. 21 by the controller of FIG. It is a timing chart explaining the frost formation state estimation operation | movement of the outdoor heat exchanger by the controller of FIG. It is a timing chart explaining the operation | movement from the estimation of the frost formation state of the outdoor heat exchanger by the controller of FIG.

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

  FIG. 1 shows a configuration diagram of a vehicle air conditioner 1 according to an embodiment of the present invention. In this case, the vehicle of the embodiment to which the present invention is applied is an electric vehicle (EV) that does not have an engine (internal combustion engine), and travels by driving an electric motor for traveling with electric power charged in a battery. The vehicle air conditioner 1 of the present invention is also driven by battery power. That is, the vehicle air conditioner 1 of the embodiment performs heating by a heat pump operation using a refrigerant circuit in an electric vehicle that cannot be heated by engine waste heat, and further operates in each operation mode such as dehumidifying heating, cooling dehumidification, and cooling. Is selectively executed.

  The present invention is effective not only for electric vehicles but also for so-called hybrid vehicles that use an engine and an electric motor for traveling, and is also applicable to ordinary vehicles that run on an engine. Needless to say.

  The vehicle air conditioner 1 according to the embodiment performs air conditioning (heating, cooling, dehumidification, and ventilation) in a vehicle interior of an electric vehicle, and includes an electric compressor 2 that compresses refrigerant and vehicle interior air. Are provided in the air flow passage 3 of the HVAC unit 10 through which air is circulated, and a radiator 4 that radiates the high-temperature and high-pressure refrigerant discharged from the compressor 2 into the passenger compartment, and an electric valve that decompresses and expands the refrigerant during heating. An outdoor expansion valve 6 that functions as a radiator during cooling, an outdoor heat exchanger 7 that performs heat exchange between the refrigerant and the outside air so as to function as an evaporator during heating, and an electric valve that expands the refrigerant under reduced pressure. An indoor expansion valve 8, a heat absorber 9 provided in the air flow passage 3 to absorb heat from the outside of the vehicle interior during cooling and dehumidification, and an evaporation capacity control valve 11 for adjusting the evaporation capacity in the heat absorber 9; Accumulator 12 etc. Are sequentially connected by medium pipe 13, the refrigerant circuit R is formed. The outdoor heat exchanger 7 is provided with an outdoor fan 15 for exchanging heat between the outside air and the refrigerant.

  The outdoor heat exchanger 7 has a receiver dryer section 14 and a supercooling section 16 in order on the downstream side of the refrigerant, and the refrigerant pipe 13A exiting from the outdoor heat exchanger 7 is an electromagnetic valve (open / close valve) 17 that is opened during cooling. The outlet of the supercooling unit 16 is connected to the indoor expansion valve 8 via a check valve 18. The receiver dryer section 14 and the supercooling section 16 structurally constitute a part of the outdoor heat exchanger 7, and the check valve 18 has a forward direction on the indoor expansion valve 8 side.

  Further, the refrigerant pipe 13B between the check valve 18 and the indoor expansion valve 8 is provided in a heat exchange relationship with the refrigerant pipe 13C exiting the evaporation capacity control valve 11 located on the outlet side of the heat absorber 9, and internal heat is generated by both. The exchanger 19 is configured. Thus, the refrigerant flowing into the indoor expansion valve 8 through the refrigerant pipe 13B is cooled (supercooled) by the low-temperature refrigerant that has exited the heat absorber 9 and passed through the evaporation capacity control valve 11.

  Further, the refrigerant pipe 13A exiting from the outdoor heat exchanger 7 is branched, and this branched refrigerant pipe 13D is downstream of the internal heat exchanger 19 via an electromagnetic valve (open / close valve) 21 that is opened during heating. The refrigerant pipe 13C is connected in communication. Further, the refrigerant pipe 13E on the outlet side of the radiator 4 is branched in front of the outdoor expansion valve 6, and this branched refrigerant pipe 13F is a check valve via an electromagnetic valve (open / close valve) 22 that is opened during dehumidification. 18 is connected to the refrigerant pipe 13B on the downstream side.

  A bypass pipe 13J is connected to the outdoor expansion valve 6 in parallel. The bypass pipe 13J is opened in a cooling mode, and is an electromagnetic valve (open / close valve) for bypassing the outdoor expansion valve 6 and flowing refrigerant. ) 20 is interposed. Further, the refrigerant pipe 13G on the discharge side of the compressor 2 is branched, and the branched refrigerant pipe 13H is opened in a defrosting mode in which the outdoor heat exchanger 7 is defrosted, and the high-temperature refrigerant discharged from the compressor 2 ( The refrigerant between the parallel circuit of the outdoor expansion valve 6 and the bypass pipe 13J and the outdoor heat exchanger 7 through the solenoid valve (open / close valve) 23 and the check valve 24 for allowing the hot gas) to flow directly into the outdoor heat exchanger 7 The pipe 13I is connected in communication. This electromagnetic valve 23 constitutes a defrosting means. The check valve 24 has a forward direction in the direction of the refrigerant pipe 13I.

  Further, the refrigerant pipe 13E immediately after exiting the radiator 4 (before branching to the refrigerant pipes 13F and 13I) is branched, and the branched refrigerant pipe 13K is provided with an injection expansion valve 30 comprising an electric valve for injection control. The compressor 2 is in communication with the compressor 2 during compression. The refrigerant pipe 13K between the outlet side of the injection expansion valve 30 and the compressor 2 is in a heat exchange relationship with the refrigerant pipe 13G located on the discharge side of the compressor 2 (downstream from the branch point with the refrigerant pipe 13H). The discharge side heat exchanger 35 is configured by both of them.

  The refrigerant pipe 13K, the injection expansion valve 30, and the discharge side heat exchanger 35 constitute an injection circuit 40 in the present invention. The injection circuit 40 is a circuit for diverting a part of the refrigerant from the radiator 4 and returning it to the middle of compression of the compressor 2 (gas injection). The injection expansion valve 30 is a refrigerant that has flowed into the refrigerant pipe 13K. After the pressure is reduced, it is caused to flow into the discharge side heat exchanger 35. The refrigerant flowing into the discharge side heat exchanger 35 is discharged from the compressor 2 to the refrigerant pipe 13G, exchanges heat with the refrigerant before flowing into the radiator 4, and absorbs heat from the refrigerant flowing through the refrigerant pipe 13G to evaporate. It is said that. Gas refrigerant to the compressor 2 is performed by evaporating the refrigerant diverted to the refrigerant pipe 13K in the discharge side heat exchanger 35.

  The air flow passage 3 on the air upstream side of the heat absorber 9 is formed with each of an outside air inlet and an inside air inlet (represented by the inlet 25 in FIG. 1). 25 is provided with a suction switching damper 26 for switching the air introduced into the air flow passage 3 between the inside air (inside air circulation mode) which is air inside the passenger compartment and the outside air (outside air introduction mode) which is outside the passenger compartment. Yes. Furthermore, an indoor blower (blower fan) 27 for supplying the introduced inside air or outside air to the air flow passage 3 is provided on the air downstream side of the suction switching damper 26.

  An air mix damper 28 is provided in the air flow passage 3 on the air upstream side of the radiator 4 to adjust the degree of flow of inside air and outside air to the radiator 4. Further, in the air flow passage 3 on the downstream side of the radiator 4, foot, vent, and differential air outlets (represented by the air outlet 29 in FIG. 1) are formed. Is provided with a blower outlet switching damper 31 for switching and controlling the blowing of air from each of the blowout ports.

Next, reference numeral 32 in FIG. 2 denotes a controller (ECU) as a control means constituted by a microcomputer, and an input to the controller 32 is an outside air temperature sensor 33 for detecting the outside air temperature of the vehicle, and an outside air humidity is detected. An outside air humidity sensor 34, an HVAC suction temperature sensor 36 that detects the temperature of air sucked into the air flow passage 3 from the suction port 25, an inside air temperature sensor 37 that detects the temperature of the air (inside air) in the vehicle interior, and the vehicle interior The inside air humidity sensor 38 that detects the humidity of the air in the vehicle, the indoor CO ₂ concentration sensor 39 that detects the carbon dioxide concentration in the vehicle interior, and the blowout temperature sensor 41 that detects the temperature of the air blown from the blowout port 29 into the vehicle interior. A discharge pressure sensor 42 for detecting the discharge refrigerant pressure of the compressor 2, a discharge temperature sensor 43 for detecting the discharge refrigerant temperature of the compressor 2, and a compression The suction pressure sensor 44 for detecting the suction refrigerant pressure 2 and the temperature of the radiator 4 (the temperature immediately after coming out of the radiator 4, the temperature of the radiator 4 itself, or immediately after being heated by the radiator 4) A radiator temperature sensor 46 for detecting the air temperature), and a radiator pressure sensor 47 for detecting the refrigerant pressure of the radiator 4 (in the radiator 4 or immediately after leaving the radiator 4). An endothermic temperature sensor 48 for detecting the temperature of the endothermic device 9 (the temperature immediately after exiting the endothermic device 9, or the endothermic device 9 itself, or the temperature of air immediately after being cooled by the endothermic device 9); A heat absorber pressure sensor 49 for detecting the refrigerant pressure of the heat absorber 9 (the pressure of the refrigerant in the heat absorber 9 or immediately after leaving the heat absorber 9) and, for example, a photosensor for detecting the amount of solar radiation into the vehicle interior Type solar radiation sensor 51 and a vehicle speed sensor for detecting the moving speed (vehicle speed) of the vehicle Sensor 52, air-conditioning (air conditioner) operation unit 53 for setting the set temperature and operation mode, and the temperature of the outdoor heat exchanger 7 (the temperature of the refrigerant immediately after coming out of the outdoor heat exchanger 7, or the outdoor The outdoor heat exchanger temperature sensor 54 for detecting the temperature of the heat exchanger 7 itself, and the refrigerant pressure of the outdoor heat exchanger 7 (in the outdoor heat exchanger 7 or immediately after the refrigerant is discharged from the outdoor heat exchanger 7). Each output of the outdoor heat exchanger pressure sensor 56 for detecting (pressure) is connected.

  Further, the input of the controller 32 further includes an injection pressure sensor 50 that detects the pressure of the injection refrigerant that flows into the refrigerant pipe 13K of the injection circuit 40 and returns to the middle of the compression of the compressor 2 via the discharge side heat exchanger 35; Each output of an injection temperature sensor 55 that detects the temperature of the injection refrigerant is also connected.

On the other hand, the output of the 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 outlet switching damper 31, and the outdoor expansion. The valve 6, the indoor expansion valve 8, the electromagnetic valves 23, 22, 17, 21, 20, the injection expansion valve 30, and the evaporation capacity control valve 11 are connected. And the controller 32 controls these based on the output of each sensor, and the setting input in the air-conditioning operation part 53. FIG.

  Next, the operation of the vehicle air conditioner 1 having the above-described configuration will be described. In the embodiment, the controller 32 is roughly divided into a heating mode, a dehumidifying heating mode, an internal cycle mode, a dehumidifying cooling mode, and a cooling mode, and executes them. First, the refrigerant flow in each operation mode will be described.

(1) Flow of refrigerant in heating mode When the heating mode is selected by the controller 32 or by manual operation to the air conditioning operation unit 53, the controller 32 opens the solenoid valve 21, and the solenoid valve 17, the solenoid valve 22, and the solenoid valve. 20 and the solenoid valve 23 are closed. Then, the compressor 2 and the blowers 15 and 27 are operated, and the air mix damper 28 sets the air blown out from the indoor blower 27 to the heat radiator 4. Thereby, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 after passing through the discharge-side heat exchanger 35. Since the air in the air flow passage 3 is passed 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. Deprived, cooled, and condensed into liquid.

  After the refrigerant liquefied in the radiator 4 exits the radiator 4, a part thereof is diverted to the refrigerant pipe 13K of the injection circuit 40, and mainly reaches the outdoor expansion valve 6 via the refrigerant pipe 13E. The functional operation of the injection circuit 40 will be described later. The refrigerant flowing 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 pumps heat from the outside air that is ventilated by traveling or by the outdoor blower 15 (heat pump). Then, the low-temperature refrigerant exiting the outdoor heat exchanger 7 enters the accumulator 12 from the refrigerant pipe 13C through the refrigerant pipe 13D and the electromagnetic valve 21, and after being gas-liquid separated there, the gas refrigerant is sucked into the compressor 2. repeat. Since the air heated by the radiator 4 is blown out from the air outlet 29, the vehicle interior is thereby heated.

  The controller 32 controls the number of revolutions of the compressor 2 based on the high pressure of the refrigerant circuit R detected by the discharge pressure sensor 42 or the radiator pressure sensor 47, and the temperature of the radiator 4 detected by the radiator temperature sensor 46. The valve opening degree of the outdoor expansion valve 6 is controlled based on the refrigerant pressure of the radiator 4 detected by the radiator pressure sensor 47, and the degree of supercooling of the refrigerant at the outlet of the radiator 4 is controlled.

(2) Flow of refrigerant in dehumidifying and heating mode Next, in the dehumidifying and heating mode, the controller 32 opens the electromagnetic valve 22 in the heating mode. As a result, a part of the condensed refrigerant flowing through the refrigerant pipe 13E via the radiator 4 is diverted to reach the indoor expansion valve 8 via the electromagnetic valve 22 and the refrigerant pipes 13F and 13B via the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Since the moisture in the air blown out from the indoor blower 27 by the heat absorption action at this time condenses and adheres to the heat absorber 9, the air is cooled and dehumidified.

  The refrigerant evaporated in the heat absorber 9 merges with the refrigerant from the refrigerant pipe 13D in the refrigerant pipe 13C through the evaporation capacity control valve 11 and the internal heat exchanger 19, and then repeats circulation sucked into the compressor 2 through the accumulator 12. . Since the air dehumidified by the heat absorber 9 is reheated in the process of passing through the radiator 4, dehumidifying heating in the passenger compartment is thereby performed.

  The controller 32 controls the number of revolutions of the compressor 2 based on the high pressure of the refrigerant circuit R detected by the discharge pressure sensor 42 or the radiator pressure sensor 47 and adjusts the temperature of the heat absorber 9 detected by the heat absorber temperature sensor 48. Based on this, the valve opening degree of the outdoor expansion valve 6 is controlled. In this dehumidifying and heating mode, gas injection by the injection circuit 40 is not performed, so the injection expansion valve 30 is fully closed (fully closed position).

(3) Flow of Refrigerant in Internal Cycle Mode Next, in the internal cycle mode, the controller 32 fully closes the outdoor expansion valve 6 (fully closed position) and closes the electromagnetic valve 21 in the dehumidifying and heating mode. Since the outdoor expansion valve 6 and the electromagnetic valve 21 are closed, the inflow of refrigerant to the outdoor heat exchanger 7 and the outflow of refrigerant from the outdoor heat exchanger 7 are blocked. All the condensed refrigerant flowing through the refrigerant pipe 13E through the refrigerant flows through the electromagnetic valve 22 to the refrigerant pipe 13F. And the refrigerant | coolant which flows through the refrigerant | coolant piping 13F reaches the indoor expansion valve 8 through the internal heat exchanger 19 from the refrigerant | coolant piping 13B. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Since the moisture in the air blown out from the indoor blower 27 by the heat absorption action at this time condenses and adheres to the heat absorber 9, the air is cooled and dehumidified.

  The refrigerant evaporated in the heat absorber 9 flows through the refrigerant pipe 13C through the evaporation capacity control valve 11 and the internal heat exchanger 19, and repeats circulation that is sucked into the compressor 2 through the accumulator 12. Since the air dehumidified by the heat absorber 9 is reheated in the process of passing through the radiator 4, dehumidification heating is performed in the vehicle interior, but in this internal cycle mode, the air flow path on the indoor side 3, the refrigerant is circulated between the radiator 4 (heat radiation) and the heat absorber 9 (heat absorption), so that heat from the outside air is not pumped up, and the heating capacity for the power consumption of the compressor 2 Is demonstrated. Since the entire amount of the refrigerant flows through the heat absorber 9 that exhibits the dehumidifying action, the dehumidifying capacity is higher than that in the dehumidifying and heating mode, but the heating capacity is lowered.

  The controller 32 controls the rotation speed of the compressor 2 based on the temperature of the heat absorber 9 or the high pressure of the refrigerant circuit R described above. At this time, the controller 32 controls the compressor 2 by selecting the lower one of the compressor target rotational speeds obtained from either calculation, depending on the temperature of the heat absorber 9 or the high pressure. Even in this internal cycle mode, gas injection by the injection circuit 40 is not performed, so the injection expansion valve 30 is fully closed (fully closed position).

(4) Flow of refrigerant in dehumidifying and cooling mode Next, in the dehumidifying and cooling mode, the controller 32 opens the electromagnetic valve 17 and closes the electromagnetic valve 21, the electromagnetic valve 22, the electromagnetic valve 20, and the electromagnetic valve 23. Then, the compressor 2 and the blowers 15 and 27 are operated, and the air mix damper 28 sets the air blown out from the indoor blower 27 to the heat radiator 4. Thereby, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 through the discharge-side heat exchanger 35. Since the air in the air flow passage 3 is passed 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 and cooled, and condensates.

  The refrigerant that has exited the radiator 4 reaches the outdoor expansion valve 6 through the refrigerant pipe 13E, and flows into the outdoor heat exchanger 7 through the outdoor expansion valve 6 that is controlled to open. The refrigerant flowing into the outdoor heat exchanger 7 is cooled and condensed by running there or by the outside air ventilated by the outdoor blower 15. The refrigerant that has exited the outdoor heat exchanger 7 sequentially flows from the refrigerant pipe 13 </ b> A through the electromagnetic valve 17 into the receiver dryer unit 14 and the supercooling unit 16. Here, the refrigerant is supercooled.

  The refrigerant that has exited the supercooling section 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13 </ b> B through the check valve 18, and reaches the indoor expansion valve 8 through the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Since the moisture in the air blown out from the indoor blower 27 by the heat absorption action at this time condenses and adheres to the heat absorber 9, the air is cooled and dehumidified.

  The refrigerant evaporated in the heat absorber 9 passes through the evaporation capacity control valve 11 and the internal heat exchanger 19, reaches the accumulator 12 through the refrigerant pipe 13 </ b> C, and repeats circulation sucked into the compressor 2 through the refrigerant pipe 13 </ b> C. The air cooled and dehumidified by the heat absorber 9 is reheated (having a lower heat dissipation capacity than that during heating) in the process of passing through the radiator 4, thereby dehumidifying and cooling the vehicle interior. .

The controller 32 controls the number of revolutions of the compressor 2 based on the temperature of the heat absorber 9 detected by the heat absorber temperature sensor 48 and controls the valve opening degree of the outdoor expansion valve 6 based on the high pressure of the refrigerant circuit R described above. To control the refrigerant pressure of the radiator 4 (radiator pressure Pci ). In addition, since the gas injection by the injection circuit 40 is not performed even in this dehumidifying and cooling mode, the injection expansion valve 30 is fully closed (fully closed position).

(5) Refrigerant Flow in Cooling Mode Next, in the cooling mode, the controller 32 opens the electromagnetic valve 20 in the dehumidifying and cooling mode state (in this case, the outdoor expansion valve 6 is fully opened (the valve opening is controlled to an upper limit)). The air mix damper 28 is in a state in which no air is passed through the radiator 4. Thereby, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 through the discharge-side heat exchanger 35. Since the air in the air flow passage 3 is not ventilated to the radiator 4, the air only passes therethrough, and the refrigerant exiting the radiator 4 reaches the electromagnetic valve 20 and the outdoor expansion valve 6 through the refrigerant pipe 13 </ b> E.

  At this time, since the solenoid valve 20 is opened, the refrigerant bypasses the outdoor expansion valve 6 and passes through the bypass pipe 13J, and flows into the outdoor heat exchanger 7 as it is, where it travels or is ventilated by the outdoor fan 15. It is air-cooled by the outside air and becomes condensed liquid. The refrigerant that has exited the outdoor heat exchanger 7 sequentially flows from the refrigerant pipe 13 </ b> A through the electromagnetic valve 17 into the receiver dryer unit 14 and the supercooling unit 16. Here, the refrigerant is supercooled.

  The refrigerant that has exited the supercooling section 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13 </ b> B through the check valve 18, and reaches the indoor expansion valve 8 through the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Since the moisture in the air blown out from the indoor blower 27 by the heat absorption action at this time condenses and adheres to the heat absorber 9, the air is cooled.

  The refrigerant evaporated in the heat absorber 9 passes through the evaporation capacity control valve 11 and the internal heat exchanger 19, reaches the accumulator 12 through the refrigerant pipe 13 </ b> C, and repeats circulation sucked into the compressor 2 through the refrigerant pipe 13 </ b> C. The air that has been cooled and dehumidified by the heat absorber 9 is blown into the vehicle interior from the outlet 29 without passing through the radiator 4, thereby cooling the vehicle interior. In this cooling mode, the controller 32 controls the rotation speed of the compressor 2 based on the temperature of the heat absorber 9 detected by the heat absorber temperature sensor 48. In this cooling mode, since the gas injection by the injection circuit 40 is not performed, the injection expansion valve 30 is fully closed (fully closed position).

(6) Gas Injection in Heating Mode Next, gas injection in the heating mode will be described. FIG. 3 shows a ph diagram of the vehicle air conditioner 1 of the present invention in the heating mode. The refrigerant exiting the radiator 4 and entering the refrigerant pipe 13E, and then being diverted and flowing into the refrigerant pipe 13K of the injection circuit 40 is decompressed by the injection expansion valve 30, and then enters the discharge side heat exchanger 35 where it is compressed. It exchanges heat with the refrigerant discharged from the machine 2 (the refrigerant discharged from the compressor 2 and before flowing into the radiator 4), absorbs heat and evaporates. The evaporated gas refrigerant then returns to the middle of compression of the compressor 2 and is further compressed together with the refrigerant sucked and compressed from the accumulator 12, and then discharged from the compressor 2 to the refrigerant pipe 13G again.

  In FIG. 3, two places indicated by 35 and arrows between them indicate heat exchange in the discharge side heat exchanger 35. By returning the refrigerant from the injection circuit 40 during the compression of the compressor 2, the amount of refrigerant discharged from the compressor 2 increases, so that the heating capacity in the radiator 4 is improved. When the refrigerant returns, liquid compression is caused. Therefore, the refrigerant returned from the injection circuit 40 to the compressor 2 must be a gas.

  For this purpose, the controller 32 monitors the degree of superheat of the refrigerant toward the middle of compression of the compressor 2 from the pressure and temperature of the refrigerant after the discharge side heat exchanger 35 detected by the injection pressure sensor 50 and the injection temperature sensor 55, as will be described later. In this embodiment, the opening degree of the injection expansion valve 30 is controlled so that a predetermined degree of superheat is obtained by heat exchange with the discharged refrigerant. Since a very high-temperature refrigerant before being discharged and flowing into the radiator 4 is heat-exchanged with the refrigerant flowing through the injection circuit 40, a large amount of heat exchange can be obtained. Therefore, even if the valve opening degree of the injection expansion valve 30 is increased to increase the injection amount, the refrigerant can be sufficiently evaporated in the discharge side heat exchanger 35, and a necessary degree of superheat can be obtained.

  Thereby, according to this invention, compared with the case where the refrigerant | coolant after a heat radiator and the injection refrigerant | coolant are heat-exchanged conventionally, the gas injection amount to the compressor 2 is ensured enough, and discharge of the compressor 2 is carried out. Heating capacity can be improved by increasing the amount of refrigerant.

  Next, control of the injection circuit 40 in the heating mode will be described with reference to FIGS.

(6-1) Control Block of Compressor, Outdoor Expansion Valve and Injection Expansion Valve FIG. 4 is a control block diagram of the compressor 2, the outdoor expansion valve 6 and the injection expansion valve 30 by the controller 32 in the heating mode. The controller 32 inputs the target blowing temperature TAO to the target radiator temperature calculation unit 57, the target radiator subcooling degree calculation unit 58, and the target injection refrigerant superheat degree calculation unit 59. This target blowing temperature TAO is a target value of the air temperature blown into the vehicle compartment from the blowout port 29, and is calculated by the controller 32 from the following formula (I).

TAO = (Tset−Tin) × K + Tbal (f (Tset, SUN, Tam))
.. (I)
Here, Tset is the set temperature in the passenger compartment set by the air conditioning operation unit 53, Tin is the temperature of the passenger compartment 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 This is a balance value calculated from the amount of solar radiation SUN to be performed and the outside air temperature Tam detected by the outside air temperature sensor 33. And generally this target blowing temperature TAO is so high that the outside temperature Tam is low, as shown in FIG. 5, and it falls as the outside temperature Tam rises.

  The target radiator temperature calculating unit 57 of the controller 32 calculates the target radiator temperature TCO from the target blowing temperature TAO. Next, based on the target radiator temperature TCO, the controller 32 uses the target radiator temperature calculating unit 61. Calculate the target radiator pressure PCO. Then, based on the target radiator pressure PCO and the pressure (radiator pressure) Pci of the radiator 4 detected by the radiator pressure sensor 47, the controller 32 rotates the compressor 2 at the compressor rotational speed calculation unit 62. The number Nc is calculated, and the compressor 2 is operated at this rotational speed Nc. That is, the controller 32 controls the pressure Pci of the radiator 4 by the rotation speed Nc of the compressor 2.

  Further, the controller 32 calculates a target radiator subcooling degree TGSC of the radiator 4 based on the target blowout temperature TAO in the target radiator subcooling degree calculation unit 58. On the other hand, the controller 32 uses the radiator supercooling degree calculation unit 63 based on the radiator pressure Pci and the temperature of the radiator 4 (the radiator temperature Tci) detected by the radiator temperature sensor 46 to exceed the amount of refrigerant in the radiator 4. The cooling degree (radiator supercooling degree SC) is calculated. Based on the radiator subcool degree SC and the target radiator subcool degree TGSC, the target outdoor expansion valve opening calculator 64 calculates the target valve opening degree of the outdoor expansion valve 6 (target outdoor expansion valve opening degree TGECCV). calculate. And the controller 32 controls the valve opening degree of the outdoor expansion valve 6 to this target outdoor expansion valve opening degree TGECVV.

  The radiator subcooling degree calculation unit 63 of the controller 32 calculates the target radiator subcooling degree TGSC so as to increase as the target blowout temperature TAO increases. However, the present invention is not limited to this, and the required heating capacity Qtgt and heating capacity Qhp described later are not limited thereto. May be calculated based on the difference (capacity difference), the radiator pressure Pci, and the difference (pressure difference) between the target radiator pressure PCO and the radiator pressure Pci. In this case, the controller 32 decreases the target radiator subcooling degree TGSC as the capacity difference is smaller, the pressure difference is smaller, the air volume of the indoor blower 27 is smaller, or the radiator pressure Pci is smaller.

  Further, the controller 32 uses the target injection refrigerant superheat degree calculation unit 59 based on the target blowing temperature TAO to set the target value of the superheat degree of the injection refrigerant returned from the injection circuit 40 during the compression of the compressor 2 (target injection refrigerant superheat degree TGSH). ) Is calculated. On the other hand, the controller 32 is based on the pressure of the injection refrigerant detected by the injection pressure sensor 50 (injection refrigerant pressure Pinj) and the temperature of the injection refrigerant detected by the injection temperature sensor 55 (injection refrigerant temperature Tinj). At 66, the superheat degree INJSH of the injection refrigerant is calculated.

  Based on the injection refrigerant superheat degree INJSH and the target injection refrigerant superheat degree TGSH, the target injection expansion valve opening degree calculation unit 67 calculates the target valve opening degree of the injection expansion valve 30 (target injection expansion valve opening degree TGINJCV). . And the controller 32 controls the valve opening degree of the injection expansion valve 30 to this target injection expansion valve opening degree TGINJCV.

  FIG. 6 shows the calculation of the target injection refrigerant superheat degree TGSH using the target blowing temperature TAO executed by the target injection refrigerant superheat degree calculation unit 59 of the controller 32. As is apparent from this figure, the target injection refrigerant superheat degree calculation unit 59 lowers the target injection refrigerant superheat degree TGSH (with hysteresis) as the target blowing temperature TAO increases. Reducing the target injection refrigerant superheat degree TGSH means increasing the valve opening of the injection expansion valve 30 to increase the injection amount. That is, the controller 32 increases the amount of injection returned to the compressor 2 by the injection expansion valve 30 and increases the amount of refrigerant discharged from the compressor 2 to increase the heating capacity as the target blowing temperature TAO increases.

  The target injection refrigerant superheat degree TGSH is not limited to this, or in addition to this, the difference between the required heating capacity Qtgt and the heating capacity Qhp (capacity difference, FIG. 7) described later, the target radiator temperature TCO and the radiator temperature. Difference (temperature difference, FIG. 8) between Tci (detected value of air temperature immediately after radiator 4 or estimated value of air temperature immediately after radiator 4), difference between target radiator pressure PCO and radiator pressure Pci ( Pressure difference, based on FIG. 9) or a combination thereof. In this case, the controller 32 decreases the target injection refrigerant superheat degree TGSH from γ (for example, 50) to α (for example, 5) between the predetermined value 1 and the predetermined value 2, as shown in FIG. As the temperature difference is larger, the target injection refrigerant superheat degree TGSH is reduced from OFF to 10 (eg, with hysteresis) between the predetermined value 1 and the predetermined value 2 as shown in FIG. 8 (with hysteresis). As shown in FIG. 9, the target injection refrigerant superheat degree TGSH is reduced between OFF and, for example, 10 between the predetermined value 1 and the predetermined value 2 (with hysteresis).

  Alternatively, when the limit line of the heating capacity Qhp by the radiator 4 when previously controlled by each target injection refrigerant superheat degree TGSH is measured or estimated according to the outside air temperature Tam, and the required heating capacity Qtgt described later, The target injection refrigerant superheat degree TGSH may be determined by determining whether or not the heating capacity Qhp at any target injection refrigerant superheat degree TGSH is satisfied.

(6-2) Injection execution possibility determination 1
Next, an embodiment of determining whether or not to perform gas injection using the injection circuit 40 will be described with reference to FIGS. 10 and 11. First, the controller 32 performs the required heating capacity Qtgt, which is the heating capacity of the radiator 4 required using the formulas (II) and (III), and when the refrigerant is not flowing through the injection circuit 40, that is, the gas injection. The heating capacity Qhp (that is, the limit value of the heating capacity) that can be generated by the radiator 4 when not performed is calculated.

Qtgt = (TCO−Te) × Cpa × ρ × Qair (II)
Qhp = f (Tam, Nc, BLV, VSP, Te) (III)
Here, Te is the temperature of the heat absorber 9 detected by the heat absorber temperature sensor 48, Cpa is the specific heat [kj / kg · K] of the air flowing into the radiator 4, and ρ is the density of the air flowing into the radiator 4 ( Specific volume) [kg / m ³ ], Qair is the air flow [m ³ / h] passing through the radiator 4 (estimated from the blower voltage BLV of the indoor blower 27, etc.), and VSP is the vehicle speed obtained from the vehicle speed sensor 52.

  In the formula (II), instead of or in addition to Qair, the temperature of air flowing into the radiator 4 or the temperature of air flowing out of the radiator 4 may be adopted. Further, the rotational speed Nc of the compressor 2 in the formula (III) is an example of an index indicating the refrigerant flow rate, the blower voltage BLV is an example of an index indicating the air volume in the air flow passage 3, and the heating capacity Qhp is expressed by these Calculated from the function. Further, Qhp is calculated from any one or a combination of them, the outlet refrigerant pressure of the radiator 4, the outlet refrigerant temperature of the radiator 4, the inlet refrigerant pressure of the radiator 4, and the inlet refrigerant temperature of the radiator 4. May be.

  The controller 32 reads data from each sensor in step S1 of the flowchart of FIG. 10, and calculates the required heating capacity Qtgt using the above equation (II) in step S2. Next, in step S3, the above formula (III) is used to calculate the heating capacity Qhp when gas injection is not performed, and in step S4, it is determined whether the required heating capacity Qtgt is greater than the heating capacity Qhp.

  The diagonal lines in FIG. 11 indicate the limit line of the heating capacity Qhp by the radiator 4 when gas injection is not performed by the injection circuit 40, the horizontal axis indicates the outside air temperature Tam, and the vertical axis indicates the heating capacity. When the required heating capacity Qtgt is equal to or less than the heating capacity Qhp (limit line thereof) in FIG. 11, that is, when the heating capacity Qhp of the radiator 4 satisfies the required heating capacity Qtgt, the process proceeds to step S6 and control without injection (no gas injection) 11), when the required heating capacity Qtgt is larger than the limit line (diagonal line) of the heating capacity Qhp, that is, the heating capacity Qhp of the radiator 4 is insufficient with respect to the required heating capacity Qtgt. In this case, the process proceeds to step S5, and injection control (gas injection is possible) is set. When it is determined in step S6 that no injection control is performed, the controller 32 fully closes the injection expansion valve 30 (fully closed position) and does not cause the refrigerant to flow through the injection circuit 40. On the other hand, when the injection control is performed in step S5, the valve opening degree of the injection expansion valve 30 is opened as a predetermined value, and gas injection is performed on the compressor 2.

  FIG. 12 shows a timing chart after activation of the vehicle air conditioner 1 of the embodiment. When the required heating capacity Qtgt is higher than the heating capacity Qhp, the injection control is performed, and the target injection superheat degree TGSH is lowered by the control of the injection expansion valve 30 to increase the amount of injection to be returned to the compression state of the compressor 2 (small INJSH). In the embodiment, gas injection is prohibited while the discharge pressure Pd of the compressor 2 is low immediately after startup. Then, as time elapses from the start and the operation state becomes stable, the injection amount is decreased (INJSH is increased), and if the heating capacity Qhp finally satisfies the required heating capacity Qtgt, there is no injection. Control.

  Thus, the controller 32 compares the required heating capacity Qtgt, which is the required heating capacity of the radiator 4, with the heating capacity Qhp generated by the radiator 4, and this heating capacity Qhp is less than the required heating capacity Qtgt. In this case, if the refrigerant is caused to flow through the injection circuit 40 by the injection expansion valve 30, the gas injection to the compressor 2 is appropriately controlled, and the refrigerant flowing through the injection circuit 40 is evaporated by the refrigerant discharged from the compressor 2. The reduction in efficiency can be suppressed, and the heating capacity can be improved with high efficiency by gas injection.

  Note that the present invention is not limited to the above. Among the indexes indicating the temperature of the air that the controller 32 flows into the radiator 4, the temperature of the air that flows out of the radiator 4, and the amount of air that passes through the radiator 4, Either or a combination thereof, the specific heat Cpa of the air flowing into the radiator 4 and an index indicating the density ρ of the air, the required heating capacity Qtgt is calculated, the outside air temperature Tam, the refrigerant flow rate, By calculating the heating capacity Qhp based on any one of the indexes indicating the air volume in the air flow passage 3, the vehicle speed, and the temperature Te of the heat absorber 9, or a combination thereof, to the compressor 2. This makes it possible to control the gas injection more accurately.

  Further, as described above, the difference between the required heating capacity Qtgt of the radiator 4 required by the controller 32 and the heating capacity Qhp of the radiator, the target radiator temperature TCO and the radiator temperature Tci (the air temperature immediately after the radiator 4) Or the estimated value of the air temperature immediately after the radiator 4), the difference between the target radiator pressure PCO and the radiator pressure Pci, the target outlet temperature into the passenger compartment, or these By controlling the amount of refrigerant returned from the injection circuit 40 to the compressor 2 by the injection expansion valve 30 based on this combination, the amount of refrigerant returned to the compressor 2 by gas injection can be adjusted accurately.

(6-3) Injection execution possibility determination 2
Next, another embodiment of determining whether or not to perform gas injection using the injection circuit 40 will be described with reference to FIG. In the above-described embodiment, it is determined whether or not the refrigerant is allowed to flow through the injection circuit 40 by comparing the required heating capacity Qtgt and the heating capacity Qhp. In this embodiment, the determination is made based on the environmental conditions of the vehicle air conditioner 1. FIG. 13 shows an example of this, and a composite condition indicating deterioration of environmental conditions for performing gas injection from no injection (normal HP) without performing gas injection,
Outside air temperature Tam ≦ predetermined value (for example, −10 ° C.), and
Air volume in the air flow passage 3 ≧ predetermined value (for example, 150 m ³ / h), and
Target radiator temperature TCO−radiator temperature Tci (detected value of air temperature immediately after radiator 4 or estimated value of air temperature immediately after radiator 4) ≧ β, and
The discharge temperature of the compressor 2 ≧ D, and
Discharge pressure of compressor 2 ≧ E
When the above is established, the injection expansion valve 30 is opened, and the injection circuit 40 performs gas injection into the compressor 2. Subsequent valve opening control of the injection expansion valve 30 is the same as described above. Note that β, D, and E are predetermined values determined in advance through experiments or the like.

In addition, as a single condition indicating the deterioration of environmental conditions,
Outside air temperature Tam ≦ predetermined value (for example, −15 ° C. lower than the above) and / or
Vehicle interior temperature (for example, −20 ° C.) − Set temperature (for example, set temperature of vehicle interior temperature: 25 ° C.) ≦ A (for example, −35 deg)
Target radiator temperature TCO-radiator temperature Tci (detected value of air temperature immediately after radiator 4 or estimated value of air temperature immediately after radiator 4) ≧ γ (for example, 70 deg)
Gas injection is performed when any of the above holds.

As a compound condition when returning,
Outside air temperature Tam> predetermined value (for example, −10 ° C.), and
Air volume in the air flow passage 3 <predetermined value (for example, 150 m ³ / h), and
Target radiator temperature TCO-radiator temperature Tci (detected value of air temperature immediately after radiator 4 or estimated value of air temperature immediately after radiator 4) <α (predetermined value smaller than β)
When is established, the injection expansion valve 30 is closed to stop the gas injection.

As a single condition when returning,
Outside air temperature Tam> predetermined value (for example, lower than the above −5 ° C.) and / or
Set temperature-vehicle interior temperature <B (for example, 10 deg), and / or
Radiator temperature Tci (detected value of air temperature immediately after radiator 4 or estimated value of air temperature immediately after radiator 4) -target radiator temperature TCO> (for example, 5 deg), and / or
Target injection refrigerant superheat degree TGSH> D (for example, 50 deg)
Gas injection is stopped when any of the above holds.

  In addition, you may add target blowing temperature TAO> predetermined value (for example, 60 degreeC) to the outside air temperature Tam <= predetermined value of the said independent conditions. When the above single condition, for example, outside air temperature Tam ≦ predetermined value (and target blowing temperature TAO> predetermined value) is satisfied, gas injection is executed regardless of other conditions, and when the single condition is not satisfied, the controller 32 determines the composite condition.

  As described above, or without limitation, the controller 32 is configured such that the outside air temperature Tam, the air volume in the air flow passage 3, the difference between the target radiator temperature TCO and the radiator temperature Tci, the discharge refrigerant temperature of the compressor 2, and When it is determined whether or not the environmental condition in the heating mode has deteriorated based on the environmental condition determined from any of the indicators indicating the refrigerant pressure discharged from the compressor 2 or a combination thereof. In other words, the gas injection into the compressor 2 can be accurately controlled also by flowing the refrigerant through the injection circuit 40 by the injection expansion valve 30.

(7-1) Other example 1 of injection circuit
Next, FIG. 14 shows another configuration diagram of the vehicle air conditioner 1 of the present invention. In this embodiment, the injection circuit 40 includes a radiator outlet side heat exchanger 45 between the injection expansion valve 30 and the discharge side heat exchanger 35 in the injection circuit 40 in addition to the configuration of FIG. The heat exchanger outlet side heat exchanger 45 exchanges heat between the refrigerant decompressed by the injection expansion valve 30 and the refrigerant flowing out of the heat radiator 4 and flowing through the refrigerant pipe 13 </ b> E toward the outdoor expansion valve 6. Then, the refrigerant (injection refrigerant) output from the radiator outlet side heat exchanger 45 flows into the discharge side heat exchanger 35.

  In this way, by providing the injection circuit 40 with the radiator outlet side heat exchanger 45 in addition to the discharge side heat exchanger 35, the compressor 2 is also in the middle of compression by heat exchange with the refrigerant exiting the radiator 4. The returned injection refrigerant can be evaporated. Thereby, the inconvenience which unnecessarily lowers the enthalpy of the refrigerant | coolant which flows in into the heat radiator 4 for gas injection can also be suppressed.

(7-2) Other example 2 of injection circuit
Next, FIG. 15 shows another configuration diagram of the vehicle air conditioner 1 of the present invention. In this embodiment, in addition to the configuration of FIG. 14, the injection circuit 40 has an outlet side of the radiator outlet side heat exchanger 45 in the injection circuit 40, that is, a radiator outlet side heat exchanger 45 and a discharge side heat exchanger 35. In the meantime, another injection expansion valve 70 (pressure reduction means) comprising an electric valve is provided. In this case, the controller 32 controls the valve opening degree of the injection expansion valve 30 based on the refrigerant superheat degree at the outlet of the radiator outlet side heat exchanger 45, and the refrigerant superheat degree on the outlet side of the discharge side heat exchanger 35. Based on this, the valve opening degree of the injection expansion valve 70 is controlled.

  With this configuration, it becomes possible to accurately control the evaporation of the refrigerant in each of the heat exchangers 45 and 35 in addition to the example of FIG. 14, and the enthalpy of the refrigerant flowing into the radiator 4 is reduced. Can be accurately controlled.

(7-3) Other example 3 of injection circuit
Next, FIG. 16 shows still another configuration diagram of the vehicle air conditioner 1 of the present invention. In this embodiment, in addition to the configuration of FIG. 14, the injection circuit 40 has a three-way valve 71 and a bypass pipe 72 (these constitute flow path control means on the outlet side of the heat exchanger outlet side heat exchanger 45 in the injection circuit 40. ). One outlet of the three-way valve 71 is connected to the discharge side heat exchanger 35, the other outlet is connected to the bypass pipe 72, and the bypass pipe 72 is connected to the refrigerant pipe 13K in parallel with the discharge side heat exchanger 35. Then, the discharge side heat exchanger 35 is bypassed.

  The three-way valve 71 is controlled by the controller 32. When performing gas injection to the compressor 2, the controller 32 usually causes the refrigerant exiting the heat exchanger outlet side heat exchanger 45 to flow through the bypass pipe 72 by the three-way valve 71, and for example, the heating capacity Qph of the heat radiator 4 described above is required. When the heating capacity Qtgt is insufficient, the three-way valve 71 is controlled so that the refrigerant discharged from the radiator outlet side heat exchanger 45 flows to the discharge side heat exchanger 35.

  The ph diagrams in this case are shown in FIGS. FIG. 17 shows a normal time, FIG. 18 shows a time when the heating capacity is insufficient, and the way of viewing the drawing is the same as in FIG. Thus, by controlling the inflow of the refrigerant to the discharge side heat exchanger 35 using the three-way valve 71 and the bypass pipe 72 during the gas injection, the heat with the discharge side heat exchanger 35 is only obtained when the heating capacity is insufficient. It becomes possible to use the exchange, and it is possible to accurately eliminate the disadvantage of lowering the enthalpy of the refrigerant flowing into the radiator 4 for gas injection, and to improve the operation efficiency while improving the heating capacity. become able to.

(7-4) Other example 4 of injection circuit
Next, FIG. 19 shows still another configuration diagram of the vehicle air conditioner 1 of the present invention. In the configuration of FIG. 15, the radiator outlet side heat exchanger 45 and the discharge side heat exchanger 35 are connected in series in the injection circuit 40, but in this embodiment, the radiator outlet side heat exchanger in the injection circuit 40. 45 and the discharge side heat exchanger 35 are connected in parallel, and the injection refrigerant flowing into each is decompressed by the injection expansion valves 30 and 70.

  And the valve opening degree of each injection expansion valve 30 and 70 is independently controlled by the refrigerant superheat degree on the outlet side of each heat exchanger 45, 35, and each expansion valve 30, 70 is independently set to the fully closed position. Thus, as shown in FIG. 16, it becomes possible to accurately and independently adjust the refrigerant inflow and the flow rate to each of the heat exchangers 45 and 35 according to the excess or deficiency of the capacity, and improve the heating capacity and the operation. Efficiency can be improved more effectively.

(7-5) Other example 5 of injection circuit
Next, FIG. 20 shows still another configuration diagram of the vehicle air conditioner 1 of the present invention. In this embodiment, the discharge side heat exchanger 35 is not provided in the injection circuit 40 as shown in FIG. In this example, the injection circuit 40 includes a water-refrigerant heat exchanger 75 instead of the discharge side heat exchanger 35 in the configuration of FIG. In this embodiment, a water circulation circuit 78 is provided in the vehicle air conditioner 1.

  The water circulation circuit 78 includes an electric heater 73 constituting heating means, a pump 74 constituting circulation means, and a water-air heat exchanger 76 provided on the air inflow side of the outdoor heat exchanger 7. Further, the water-refrigerant heat exchanger 75 of the injection circuit 40 is connected to the downstream side of the three-way valve 71 as in the case of FIG. 16, and the bypass pipe 72 bypasses the water-refrigerant heat exchanger 75. Reference numeral 77 denotes a check valve provided at the refrigerant outlet of the water-refrigerant heat exchanger 75.

  And the water which flows through the water circulation circuit 78 flows into this water-refrigerant heat exchanger 75, and it is set as the structure which heat-exchanges with an injection refrigerant | coolant. The electric heater 73 and the pump 74 are also controlled by the controller 32. The controller 32 generates heat in the electric heater 73 and heats the water in the water circulation circuit 78. The heated water (warm water) is fed to the water-refrigerant heat exchanger 75 by the pump 74, and the injection refrigerant is heated and evaporated.

  The water exiting the water-refrigerant heat exchanger 75 then flows into the water-air heat exchanger 76 and dissipates heat into the outside air. Since the outdoor heat exchanger 7 pumps up this heat radiation, it contributes to the improvement of the heating capacity, and the frost formation of the outdoor heat exchanger 7 is also suppressed by this heat radiation. The water-air heat exchanger 76 may be provided in the air flow passage 3 on the air downstream side of the radiator 4. If the air flow passage 3 is provided, the water-air heat exchanger 76 becomes a so-called heater core, which can supplement heating in the vehicle interior.

  Next, control of the injection circuit 40 by the controller 32 will be described with reference to FIG. In this figure, the horizontal axis is the outside air temperature Tam, the vertical axis is the heating capacity, the solid line (diagonal line) indicated by the HP capacity is the limit line of the heating capacity Qhp by the radiator 4 when the gas injection by the injection circuit 40 is not performed, INJ A broken line (diagonal line) indicated by the capacity indicates a limit line of the injection heating capacity Qinj when heat is exchanged by the heat exchanger outlet side heat exchanger 45 and gas injection is performed.

  Now, when the outside air temperature Tam = −20 ° C. in FIG. 22, the required heating capacity Qtgt is the required capacity 2 lower than the solid line of the HP capacity, that is, the heating when the required heating capacity Qtgt is not gas-injected. When the capacity Qhp is satisfied, the controller 32 sets the injection expansion valve 30 shown in FIGS. 20 and 21 to the fully closed position and does not perform gas injection.

  When the required heating capacity Qtgt is larger than Qhp and the required capacity 1 is smaller than the heating capacity Qinj by the gas injection using the radiator outlet side heat exchanger 45, the controller 32 opens the injection expansion valve 30 of FIGS. In addition, the reduced pressure refrigerant is caused to flow through the radiator outlet-side heat exchanger 45, and the refrigerant that has exited the radiator outlet-side heat exchanger 45 is caused to flow through the bypass pipe 72 by the three-way valve 71, and the gas injection is returned to the compressor 2 in the middle of compression. Do. Thus, the required heating capacity Qtgt (required capacity 1) is satisfied by increasing the heating capacity.

  On the other hand, when the required capacity Qtgt is the required capacity 3 larger than Qinj, the controller 32 energizes the electric heater 73 and the pump 74 of the water circulation circuit 78 to circulate the heated water (hot water) in the water circulation circuit 78 and The refrigerant that has exited the heat exchanger outlet side heat exchanger 45 by the valve 71 is caused to flow into the water-refrigerant heat exchanger 75 to exchange heat with water (hot water) flowing through the water circulation circuit 78, and then returned to the compressor 2 for gas injection. Do.

  The controller 32 controls the opening degree of the injection expansion valve 30 in these cases based on the degree of superheat of the refrigerant before flowing into the compressor 2 (the refrigerant pipe 13K on the downstream side of the bypass pipe 72). In the water-refrigerant heat exchanger 75, the refrigerant absorbs heat from water (hot water) and actively evaporates. Therefore, the controller 32 increases the valve opening of the injection expansion valve 30 and returns the amount of gas injection returned to the compressor 2. increase.

  As described above, the injection circuit 40 is further provided with the three-way valve 71 and the bypass pipe 72 for controlling the flow of the refrigerant to the heat exchangers 35, 45, and 75 in the injection circuit 40, and the controller 32 is controlled by the three-way valve 71. When the refrigerant decompressed by the injection expansion valve 30 is always evaporated by the heat exchanger outlet-side heat exchanger 45 and the heating capacity by the heat radiation of the radiator 4 is insufficient, the water circulation circuit 78 is operated to activate the water-refrigerant heat. The heated water in the water circulation circuit 78 of the compressor 2 is used only when the heating capacity is insufficient by evaporating in the exchanger 75 and increasing the refrigerant flow rate in the injection circuit 40 by the injection expansion valve 30. Will be able to. As a result, the problem of unnecessarily lowering the enthalpy of the refrigerant flowing into the radiator 4 for gas injection can be eliminated, and the operation efficiency can be improved.

(8) Frost suppression of outdoor heat exchanger by injection circuit Next, frost suppression control of the outdoor heat exchanger 7 by the controller 32 will be described. In the heating mode, as described above, the outdoor heat exchanger 7 absorbs heat from the outside air and becomes a low temperature. Therefore, moisture in the outside air adheres to the outdoor heat exchanger 7 as frost. When this frost grows, heat exchange between the outdoor heat exchanger 7 and the outside air to be ventilated is significantly hindered, and air conditioning performance deteriorates. When frost forms on the outdoor heat exchanger 7, the controller 32 opens the above-described electromagnetic valve 23 to execute the defrosting mode of the outdoor heat exchanger 7, but before that, the injection circuit 40 is used. The frost formation on the outdoor heat exchanger 7 is suppressed.

  The injection circuit 40 diverts a part of the refrigerant from the radiator 4, and in FIG. 1 heat-exchanges with the discharge-side heat exchanger 35 and gasifies it, and then returns to the middle of compression of the compressor 2. Since the discharge pressure (high pressure side pressure) of the compressor 2 is increased by this gas injection, the refrigerant pressure of the outdoor heat exchanger 7 that is the low pressure side pressure of the refrigerant circuit R is also increased, so that frost formation is suppressed. Because.

(8-1) Estimation of Frost of Outdoor Heat Exchanger Specifically, the controller 32 first estimates the frost formation state of the outdoor heat exchanger 7. Next, the estimation example of the frost formation state of the outdoor heat exchanger 7 is demonstrated using FIG. When the controller 32 first satisfies (i) of the following frost formation state estimation permission conditions and any one of (ii) to (iv) holds, the frost formation state of the outdoor heat exchanger 7 Allow estimation of.

[Frosting condition estimation permission condition]
(I) The operation mode is the heating mode.
(Ii) The high pressure has converged to the target value. Specifically, for example, the state where the absolute value of the difference (PCO− Pci ) between the target radiator pressure PCO and the radiator pressure Pci is not more than a predetermined value A continues for a predetermined time t1 (sec). It is done.
(Iii) The predetermined time t2 (sec) has elapsed after the transition to the heating mode.
(Iv) The vehicle speed fluctuation is not more than a predetermined value (the vehicle acceleration / deceleration is not more than a predetermined value). The acceleration / deceleration of the vehicle is, for example, a difference (VSP−VSPz) between the current vehicle speed VSP and the vehicle speed VSPz one second before.
The conditions (ii) and (iii) are conditions for eliminating an erroneous estimation that occurs in the transition period of the operating state. Further, the above condition (iv) is added because erroneous estimation occurs even when the vehicle speed fluctuation is large.

  When the frosting state estimation permission condition is satisfied and the frosting state estimation is permitted, the controller 32 obtains the current refrigerant evaporation temperature TXO of the outdoor heat exchanger 7 obtained from the outdoor heat exchanger pressure sensor 56 and the outside air. However, the frosting state of the outdoor heat exchanger 7 is estimated based on the refrigerant evaporation temperature TXObase of the outdoor heat exchanger 7 when no frost is formed on the outdoor heat exchanger 7 in a low humidity environment. In this case, the controller 32 determines the refrigerant evaporation temperature TXObase of the outdoor heat exchanger 7 at the time of non-frosting using the following formula (IV).

TXObase = f (Tam, NC, BLV, VSP)
= K1 x Tam + k2 x NC + k3 x BLV + k4 x VSP (IV)

  Here, Tam, which is a parameter of formula (IV), is the outside air temperature obtained from the outside air temperature sensor 33, NC is the rotation speed of the compressor 2, BLV is the blower voltage of the indoor blower 27, and VSP is the vehicle speed obtained from the vehicle speed sensor 52. K1 to k4 are coefficients, which are obtained in advance by experiments.

The outside air temperature Tam is an index indicating the intake air temperature of the outdoor heat exchanger 7. The lower the outside air temperature Tam (the intake air temperature of the outdoor heat exchanger 7), the lower the TXObase. Therefore, the coefficient k1 is a positive value. The index indicating the intake air temperature of the outdoor heat exchanger 7 is not limited to the outdoor air temperature Tam.
The rotational speed NC of the compressor 2 is an index indicating the refrigerant flow rate in the refrigerant circuit R. The higher the rotational speed NC (the higher the refrigerant flow rate), the lower the TXObase. Therefore, the coefficient k2 is a negative value.
The blower voltage BLV is an index indicating the amount of air passing through the radiator 4. The higher the blower voltage BLV (the larger the amount of air passing through the radiator 4), the lower the TXObase. Therefore, the coefficient k3 is a negative value. The index indicating the amount of air passing through the radiator 4 is not limited to this and may be the blower air amount of the indoor blower 27 or the air mix damper 28 opening SW.
The vehicle speed VSP is an index indicating the passing air speed of the outdoor heat exchanger 7. The lower the vehicle speed VSP (the lower the passing air speed of the outdoor heat exchanger 7), the lower the TXObase. Therefore, the coefficient k4 is a positive value. The index indicating the passing air speed of the outdoor heat exchanger 7 is not limited to this, and the voltage of the outdoor blower 15 may be used.

  In the embodiment, the outdoor temperature Tam, the rotational speed NC of the compressor 2, the blower voltage BLV of the indoor blower 27, and the vehicle speed VSP are used as parameters of the formula (IV). One load may be added as a parameter. As an index indicating this load, the target blowout temperature TAO, the rotational speed NC of the compressor 2, the blower air volume of the indoor blower 27, the inlet air temperature of the radiator 4 and the radiator temperature Tci of the radiator 4 can be considered. The larger the value, the lower the PXObase. Furthermore, you may add the aged deterioration (the number of driving years and the frequency | count of driving | operation) of a vehicle to a parameter. Further, the parameters of the formula (IV) are not limited to all of the above, and any one of them or a combination thereof may be used.

  Next, the controller 32 calculates the difference ΔTXO (ΔTXO = TXObase−TXO) between the refrigerant evaporation temperature TXObase at the time of no frosting obtained by substituting the current values of the respective parameters into the formula (IV) and the current refrigerant evaporation temperature TXO. The refrigerant evaporation temperature TXO is lower than the refrigerant evaporation temperature TXObase when there is no frost formation, and the state in which the difference ΔTXO is equal to or higher than the predetermined frost detection threshold value 1 continues for a predetermined time t1 (sec) or longer. In this case, it is determined that frost formation is occurring in the outdoor heat exchanger 7.

  The solid line in FIG. 23 shows the change in the refrigerant evaporation temperature TXO of the outdoor heat exchanger 7, and the broken line shows the change in the refrigerant evaporation temperature TXObase when there is no frost formation. At the beginning of operation, the refrigerant evaporating temperature TXO of the outdoor heat exchanger 7 is high and exceeds the refrigerant evaporating temperature TXObase when there is no frost formation. As the heating mode progresses, the temperature in the passenger compartment is warmed and the load on the vehicle air conditioner 1 is reduced. Therefore, the refrigerant flow rate and the amount of air passing through the radiator 4 are also reduced. The calculated TXObase (broken line in FIG. 23) rises. On the other hand, when frost formation starts in the outdoor heat exchanger 7, the heat exchange performance with the outside air deteriorates little by little, so the refrigerant evaporation temperature TXO (solid line) gradually decreases and eventually falls below TXObase. Then, when the refrigerant evaporation temperature TXO further decreases and the difference ΔTXO (TXObase−TXO) becomes the frost detection threshold 1 or more and the state continues for the predetermined time t1 or more, the controller 32 performs the frost formation estimation first stage. Is determined.

(8-2) Frost suppression operation to the outdoor heat exchanger If the controller 32 determines that the frosting state of the outdoor heat exchanger 7 is the first stage of frosting state estimation, it will frost on the outdoor heat exchanger 7 in the future. It is determined that there is a high risk of occurrence of a frost, and a predetermined frost suppression operation is executed. The frosting suppression operation is a reduction in the refrigerant subcooling degree of the radiator 4 due to a decrease in the rotational speed of the compressor 2, a decrease in the amount of air passing through the radiator 4 by the indoor fan 27, and a reduction in the valve opening degree of the outdoor expansion valve 6. Ascending, etc., and combinations thereof are conceivable. As a result, the refrigerant evaporation pressure of the outdoor heat exchanger 7, which is the low-pressure side pressure, increases, so that frost formation on the outdoor heat exchanger 7 is suppressed.

(8-3) Frost Suppression by Injection Circuit Frost detection to the outdoor heat exchanger 7 also proceeds by such frost suppression operation, and the difference ΔTXO (TXObase-TXO) is greater than the frost detection threshold 1 When the threshold value is 2 or more and the state continues for a predetermined time t2 or more, the controller 32 determines that the frosting state estimation second stage. When the controller 32 determines that the frosting state of the outdoor heat exchanger 7 is the second stage of frosting state estimation, the controller 32 determines that frosting on the outdoor heat exchanger 7 is predicted, and sets the injection expansion valve 30. Opened and the gas injection into the compressor 2 is executed by the injection circuit 40. Subsequent control of the injection amount by the valve opening control of the injection expansion valve 30 is the same as described above.

  Such gas injection increases the low pressure side pressure as described above, so that frost formation on the outdoor heat exchanger 7 is suppressed. Moreover, the heating capacity in the passenger compartment is also improved by gas injection.

  When the water circulation circuit 78 similar to that shown in FIG. 21 is also provided in the configuration diagram of FIG. 1, the controller 32 causes the water circulation when the heating capacity Qhp is less than the required heating capacity Qtgt even by gas injection. It is assumed that the circuit 78 is operated, heating supplementation by the water-air heat exchanger 76 is performed, and the heating capacity of the vehicle interior is maintained.

(8-4) Defrosting mode of outdoor heat exchanger Frosting to the outdoor heat exchanger 7 also proceeds by gas injection by the injection circuit 40, and the difference ΔTXO (TXObase-TXO) is greater than the frosting detection threshold 2. When the large frost detection threshold value is 3 or more and the state continues for a predetermined time t3 or more, the controller 32 determines that the frost state estimation final stage. When the controller 32 determines that the frost state of the outdoor heat exchanger 7 is the final stage of frost state estimation, the controller 32 shifts to the defrost mode. In this defrosting mode, the controller 32 opens the solenoid valve 23 and the solenoid valve 21, closes the solenoid valve 22 and the solenoid valve 17, and operates the compressor 2. Thus, the high-temperature and high-pressure gas refrigerant (hot gas) discharged from the compressor 2 passes through the refrigerant valve 13H through the electromagnetic valve 23, and directly flows into the outdoor heat exchanger 7 from the refrigerant pipe 13I through the check valve 24. It becomes a state to do. Thereby, since the outdoor heat exchanger 7 is heated, frost formation is thawed and removed.

  The refrigerant exiting the outdoor heat exchanger 7 enters the refrigerant pipe 13D from the refrigerant pipe 13A through the electromagnetic valve 21, and is sucked into the compressor 2 through the refrigerant pipe 13B. And when predetermined time passes since the start of defrost mode, controller 32 complete | finishes defrost mode and returns to heating mode. The state from frost formation state estimation to a defrost mode which concerns on the timing chart of FIG. 24 is shown.

  In the above embodiment, the refrigerant evaporating temperature TXO of the outdoor heat exchanger 7 is taken to estimate the frosting state. However, the present invention is not limited to this, and the present state of the outdoor heat exchanger 7 obtained from the outdoor heat exchanger temperature sensor 54 is not limited. Of the outdoor heat exchanger 7 based on the refrigerant evaporation pressure PXO of the outdoor heat exchanger 7 when the outside air is not frosted in the low humidity environment and the outdoor heat exchanger 7 is not frosted. The frost state may be estimated.

  Further, the frosting state estimating means is not limited to these, and the controller 32 is configured to use the outdoor heat exchanger 7 based on the dew point temperature detected by the outdoor temperature sensor 33 and the outdoor air humidity sensor 34 and the refrigerant evaporation temperature of the outdoor heat exchanger 7. The frost formation state may be estimated.

  Thus, the frost formation state of the outdoor heat exchanger 7 is estimated, and when frost formation is predicted, the injection circuit 40 performs gas injection to the compressor 2 to suppress frost formation on the outdoor heat exchanger 7. It becomes possible to do. Thereby, it becomes possible to avoid the deterioration of the air conditioning in the vehicle interior due to the defrosting and to improve the heating capacity by the radiator 4.

  In addition, since the controller 32 executes an operation for suppressing frost formation of the outdoor heat exchanger 7 before the injection circuit 40 is operated, defrosting is avoided as much as possible, and deterioration of the air conditioning in the vehicle interior is effective. Will be able to avoid.

  In the embodiment, the present invention is applied to the vehicle air conditioner 1 that switches between the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode, and the cooling mode. However, the present invention is not limited thereto, and only the heating mode is performed. In addition, the present invention is effective.

  In the embodiment, the high-temperature refrigerant gas is allowed to flow through the outdoor heat exchanger 7 for defrosting. However, the defrosting means is not limited to this, but by reversing the refrigerant flow, an electric heater, or the like. The present invention is also effective for a device that is defrosted by simply ventilating.

  Further, the configuration and each numerical value of the refrigerant circuit R described in the above embodiment are not limited thereto, and needless to say, can be changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 2 Compressor 3 Air flow path 4 Radiator 6 Outdoor expansion valve 7 Outdoor heat exchanger 8 Indoor expansion valve 9 Heat absorber 11 Evaporation capacity control valve 17, 20, 21, 22 Solenoid valve 23 Solenoid valve ( Defrosting means)
26 Suction Switching Damper 27 Indoor Blower (Blower Fan)
28 Air Mix Damper 32 Controller (Control Unit)
30, 70 Expansion valve 40 Injection circuit 35 Discharge side heat exchanger 45 Radiator outlet side heat exchanger 75 Water-refrigerant heat exchanger 76 Water-air heat exchanger 78 Water circulation circuit R Refrigerant circuit

Claims (8)

A compressor for compressing the refrigerant;
An air flow passage through which air to be supplied into the passenger compartment flows;
A radiator that is provided in the air flow passage to dissipate the refrigerant;
A heat absorber provided in the air flow passage to absorb the refrigerant;
An outdoor heat exchanger that is provided outside the vehicle cabin to dissipate or absorb heat from the refrigerant;
Control means,
At least the control means causes the refrigerant discharged from the compressor to radiate heat by the radiator, decompresses the radiated refrigerant, and then performs a heating mode in which heat is absorbed by the outdoor heat exchanger. In the device
An injection circuit that diverts a part of the refrigerant that has exited the radiator and returns it to the middle of compression of the compressor;
The injection circuit includes a decompression unit, a discharge-side heat exchanger that exchanges heat between the refrigerant decompressed by the decompression unit and the refrigerant before being discharged from the compressor and flowing into the radiator, and the decompression unit or separately A heat exchanger outlet-side heat exchanger for exchanging heat between the refrigerant decompressed by another decompression means provided and the refrigerant exiting the radiator, and the flow of the refrigerant to each heat exchanger in the injection circuit Having flow path control means for controlling,
The control means evaporates the refrigerant depressurized by the pressure reducing means by the flow path control means by the heat exchanger outlet side heat exchanger, and when the heat radiation of the radiator is insufficient, the discharge side heat exchange. The vehicle air conditioner is characterized by evaporating with a vessel and increasing the refrigerant flow rate in the injection circuit by the pressure reducing means . A compressor for compressing the refrigerant;
An air flow passage through which air to be supplied into the passenger compartment flows;
A radiator that is provided in the air flow passage to dissipate the refrigerant;
A heat absorber provided in the air flow passage to absorb the refrigerant;
An outdoor heat exchanger that is provided outside the vehicle cabin to dissipate or absorb heat from the refrigerant;
Control means,
At least the control means causes the refrigerant discharged from the compressor to radiate heat by the radiator, decompresses the radiated refrigerant, and then performs a heating mode in which heat is absorbed by the outdoor heat exchanger. In the device
An injection circuit for diverting a part of the refrigerant that has exited the radiator and returning it to the middle of compression of the compressor;
A water circulation circuit for circulating the water heated by the heating means by the circulation means,
The injection circuit includes a decompression unit, a water-refrigerant heat exchanger that exchanges heat between the refrigerant decompressed by the decompression unit and water flowing in the water circulation circuit, and the refrigerant decompressed by the decompression unit and the radiator. A heat exchanger outlet-side heat exchanger for exchanging heat with the refrigerant that has exited, and a flow path control means for controlling the flow of refrigerant to each heat exchanger in the injection circuit,
The control means evaporates the refrigerant depressurized by the pressure reducing means by the flow path control means by the heat exchanger outlet side heat exchanger, and if the heat radiation of the radiator is insufficient, the water-refrigerant heat A vehicle air conditioner characterized by evaporating with an exchanger and increasing the refrigerant flow rate in the injection circuit by the pressure reducing means .   The vehicle air conditioner according to claim 2, wherein the water circulation circuit includes a water-air heat exchanger provided on an air inflow side of the outdoor heat exchanger or in the air flow passage. The control means compares the required heating capacity Qtgt, which is the required heating capacity of the radiator, with the heating capacity Qhp generated by the radiator, and if the heating capacity Qhp is less than the required heating capacity Qtgt, The vehicle air conditioner according to any one of claims 1 to 3, wherein a refrigerant is caused to flow through the injection circuit by a decompression unit. The control means is any one of an index indicating the temperature of the air flowing into the radiator, the temperature of the air flowing out of the radiator, and the amount of air passing through the radiator, or a combination thereof And calculating the required heating capacity Qtgt based on the specific heat of the air flowing into the radiator and an index indicating the density of the air,
Outside air temperature, refrigerant flow rate, air volume in the air flow path, vehicle speed, temperature of the heat absorber, rotation speed of the compressor, refrigerant pressure at the radiator outlet, refrigerant temperature at the radiator outlet, refrigerant temperature at the radiator inlet 5. The vehicle according to claim 4, wherein the heating capacity Qhp is calculated based on any one of an index indicating a refrigerant pressure and a refrigerant temperature at the radiator inlet, or a combination thereof. Air conditioning equipment. The control means includes an outside air temperature, an air volume in the air flow path, a difference between a target radiator temperature and an actual radiator temperature, a discharge refrigerant temperature of the compressor, and a discharge refrigerant pressure of the compressor. When the environmental condition in the heating mode deteriorates based on an environmental condition determined from any one of the indicators or a combination thereof, the depressurization unit causes the refrigerant to flow through the injection circuit. The vehicle air conditioner according to any one of claims 1 to 3. The control means includes a difference between a required heating capacity Qtgt which is a required heating capacity of the radiator and a heating capacity Qhp generated by the radiator, a difference between a target radiator temperature and a temperature of the radiator, a target radiator pressure. And controlling the amount of refrigerant returned from the injection circuit to the compressor by the decompression means based on any one of a difference in pressure between the radiator and the target blow temperature to the passenger compartment, or a combination thereof. The vehicle air conditioner according to any one of claims 4 to 6, characterized in that A water circulation circuit for circulating the water heated by the heating means by the circulation means,
The water circulation circuit has a water-air heat exchanger provided in the air flow passage,
The control means circulates the water heated by the heating means to the water-air heat exchanger when the heating capacity of the radiator is insufficient even by flowing a refrigerant through the injection circuit. The vehicle air conditioner according to any one of claims 4 to 7.

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