Vehicle air conditioning system

Abstract

To provide a vehicle air conditioner attaining an appropriate heating operation in parallel with highly efficient defrosting of an outdoor heat exchanger.SOLUTION: A vehicle air conditioner 1 includes a refrigeration cycle 10 and a controlling device. The refrigeration cycle 10 includes a compressor 11, a heating part 35, an outside air heat exchanging part 29X, a heating expansion valve 20a, a cooling expansion valve 20c and a chiller 24. The control device includes: a compression control part and a pressure reduction control part which perform control when performing condensation heat defrosting and heating in an air-condition target space in parallel. The compression control part attains one refrigerant temperature of the refrigerant temperature required in a water-refrigerant heat exchanger 12 and the refrigerant temperature required in an outdoor heat exchanger 22 by controlling the operation of the compressor 11. The pressure reduction control part attains the other refrigerant temperature of the refrigerant temperature required in the water-refrigerant heat exchanger 12 and the refrigerant temperature required in the outdoor heat exchanger 22 by controlling the operation of the heating expansion valve 20a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle air conditioning system having a condenser that dissipates heat of a refrigerant to blown air, and an exterior heat exchanger that exchanges heat between outside air and the refrigerant. [Background technology]

[0002] In the past, various technologies have been developed for vehicle air conditioners that have a condenser that dissipates heat from the refrigerant to the blown air and an exterior heat exchanger that exchanges heat between the refrigerant and the outside air. In vehicle air conditioners, when the condenser heats the air-conditioned space, the exterior heat exchanger may cause frost to form when the refrigerant absorbs heat from the low-temperature outside air in the exterior heat exchanger.

[0003] When frost forms on the exterior heat exchanger, the heat exchange performance of the exterior heat exchanger is significantly reduced, which has a significant impact on the heating performance of the vehicle air conditioner, and therefore it is necessary to defrost the exterior heat exchanger, etc. When the exterior heat exchanger is being defrosted, the exterior heat exchanger is unable to absorb heat from the outside air to the refrigerant, but there is also an increasing need to heat the space to be air-conditioned at the same time as defrosting the exterior heat exchanger.

[0004] Known technology relating to such vehicle air conditioning systems is that described in Patent Document 1. For example, in Patent Document 1, hot gas is used to heat the space to be air-conditioned and to defrost the heat exchanger, thereby producing two different temperatures: one for defrosting and the other for heating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-203221 Summary of the Invention [Problem to be solved by the invention]

[0006] The vehicle air conditioner of Patent Document 1 employs a so-called accumulator cycle as a refrigeration cycle. Since hot gas defrosting cannot be performed in a receiver cycle, the configuration of the refrigeration cycle is limited in order to apply the technology of Patent Document 1.

[0007] Furthermore, as a method for defrosting the outdoor heat exchanger, condensation heat defrosting has been developed, which utilizes heat absorbed by an evaporator located on the low-pressure side of the refrigeration cycle. The hot gas defrosting described in Patent Document 1 is considered to have a lower defrosting capacity than condensation heat defrosting, because it uses heat equivalent to the compression work done by the compressor.

[0008] In other words, it is desirable to be able to flexibly respond to the difference between the amount of heat in the outdoor heat exchanger due to condensation heat defrosting and the amount of heat in the condenser to improve comfort, and to achieve both defrosting of the outdoor heat exchanger and heating of the space to be air-conditioned.

[0009] In view of the above, an object of the present disclosure is to provide a vehicle air conditioner that can achieve appropriate heating operation in parallel with efficient defrosting of an exterior heat exchanger. [Means for solving the problem]

[0010] A vehicle air conditioner according to one aspect of the present disclosure includes a refrigeration cycle (10) and a control unit (70). The refrigeration cycle includes a compressor (11), a heating unit (35), an outside air heat exchange unit (29X), a first expansion valve (20a), second expansion valves (20b, 20c), and evaporators (23, 24).

[0011] The compressor compresses and discharges the refrigerant. The heating section has a heating heat exchanger (12, 12X) and uses the refrigerant as a heat source to heat the air to be blown into the space to be air-conditioned. The heating heat exchanger condenses the refrigerant discharged from the compressor during heating operation to heat the space to be air-conditioned. The outdoor air heat exchange section has an outdoor air heat exchanger (22) that causes the refrigerant to absorb heat from outdoor air during heating operation.

[0012] The first expansion valve is disposed between the outlet of the heating heat exchanger and the inlet of the outdoor air heat exchanger and is configured to be able to reduce the pressure of the refrigerant flowing out from the heating heat exchanger. The second expansion valve is configured to be able to reduce the pressure of the refrigerant flowing out from at least one of the heating heat exchanger and the outdoor air heat exchanger. The evaporator causes the refrigerant decompressed by the second expansion valve to absorb heat and evaporate.

[0013] The control unit controls condensation heat defrosting, which uses heat absorbed by the refrigerant in the evaporator to melt and defrost frost that has adhered to the outdoor air heat exchanger, and heating of the air-conditioned space using heat released from the refrigerant in the heating heat exchanger.

[0014] The control unit includes a compression control unit (70d) and a pressure reduction control unit (70e) that perform control when condensation heat defrosting and heating of the space to be air-conditioned are performed in parallel. or pressure and the refrigerant temperature required for the outdoor air heat exchanger or pressure If different, the required refrigerant temperature in the heating heat exchanger or pressure and the required refrigerant temperature in the outdoor air heat exchanger or pressure The temperature of either of the refrigerants or pressure The pressure reduction control section controls the refrigerant temperature required by the heating heat exchanger. or pressure and the required refrigerant temperature in the outdoor air heat exchanger or pressure The temperature of the other refrigerant or pressure This is achieved by controlling the operation of the first expansion valve.

[0015] The vehicle air conditioning system uses a refrigeration cycle and a control unit to perform condensation heat defrosting, which uses heat absorbed by the refrigerant in the evaporator to melt and defrost frost that has adhered to the outside air heat exchanger, and heating, which uses heat released from the refrigerant in the heating heat exchanger, in parallel.

[0016] In addition, when condensation heat defrosting and heating of the air-conditioned space are performed in parallel, the refrigerant temperature required by the heating heat exchanger or pressure and the required refrigerant temperature in the outdoor air heat exchanger or pressureWhen the two different refrigerant temperatures are different, the compression control section and the pressure reduction control section or pressure That is, the operation of the compressor is controlled by the compression control unit, and the refrigerant temperature required for either the heating heat exchanger or the outside air heat exchanger can be realized. or pressure Furthermore, the pressure reduction control section controls the operation of the first expansion valve to reduce the pressure in either the heating heat exchanger or the outside air heat exchanger. On the other hand The required refrigerant temperature or pressure This can be achieved.

[0017] According to the vehicle air conditioning system, when condensation heat defrosting and heating of the air-conditioned space are performed in parallel, the amount of heat dissipated in the outdoor air heat exchanger related to condensation heat defrosting and the amount of heat dissipated in the heating heat exchanger related to heating can be controlled separately, and both can be achieved in an appropriate manner.

[0018] The symbols in parentheses for each means described in this section and in the claims indicate the correspondence with the specific means described in the embodiments to be described later. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an overall configuration diagram of a vehicle air conditioner according to a first embodiment. [Figure 2] 1 is a configuration diagram of an interior air conditioning unit in a vehicle air conditioning system; [Figure 3] 2 is a block diagram showing a control system of the vehicle air conditioner; FIG. [Figure 4] 1 is an overall configuration diagram showing the operation of a heating mode in a vehicle air conditioner according to a first embodiment; [Figure 5] 2 is an overall configuration diagram showing an example of operation in a condensation heat defrosting mode in the vehicle air conditioner of the first embodiment. FIG. [Figure 6] FIG. 1 is an explanatory diagram of an experimental formula for estimating the evaporation rate in dry defrosting using condensation heat defrosting. [Figure 7] 10 is a graph showing the relationship between the condensation temperature of the outdoor heat exchanger and the amount of evaporation from the outdoor heat exchanger and the wind speed. [Figure 8]10 is a graph showing the relationship between the compressor rotation speed and the condensation temperature and the wind speed. [Figure 9] 10 is a graph showing an operating condition area that can be achieved by the refrigeration cycle device in relation to the amount of evaporation from the outdoor unit and the wind speed. [Figure 10] FIG. 1 is a psychrometric chart showing criteria for the visibility of white mist in dry defrosting. [Figure 11] FIG. 1 is a psychrometric chart for calculating the allowable upper limit of evaporation per unit weight. [Figure 12] 10 is a graph showing the relationship between the outdoor unit evaporation amount and wind speed with respect to the condensation temperature, and the relationship between the outdoor unit evaporation amount and the allowable upper limit evaporation amount. [Figure 13] 10 is a graph showing a target area for sufficiently restoring the heat exchange performance of an outdoor heat exchanger while suppressing the visual observation of white mist during dry defrosting. [Figure 14] 10 is a graph showing a target area that can be achieved to sufficiently recover the heat exchange performance of the outdoor heat exchanger while suppressing the visual observation of white mist during dry defrosting. [Figure 15] FIG. 4 is a control characteristic diagram for determining a target condensation temperature in dry defrosting. [Figure 16] FIG. 10 is a control characteristic diagram for determining a target air velocity in dry defrosting. [Figure 17] FIG. 10 is an explanatory diagram showing an example of changes in air velocity, compressor rotation speed, and discharge pressure in a dry defrosting mode. [Figure 18] 1 is an overall configuration diagram showing an example of operation in a heating and defrosting mode in a vehicle air conditioner according to a first embodiment; [Figure 19] 5 is a flowchart showing the control content of a heating and defrosting mode in the vehicle air conditioner. [Figure 20] 10 is a flowchart showing control details of an efficiency priority mode in a heating and defrosting mode. [Figure 21] 10 is a flowchart showing the control content of a comfort priority mode in a heating and defrosting mode. [Figure 22] FIG. 10 is an overall configuration diagram of a vehicle air conditioner according to a second embodiment. [Figure 23]FIG. 10 is a configuration diagram of an indoor air conditioning unit according to a second embodiment. [Figure 24] FIG. 10 is an overall configuration diagram of a vehicle air conditioner according to a third embodiment. [Figure 25] FIG. 10 is an overall configuration diagram showing the operation of a heating mode in a vehicle air conditioner according to a third embodiment. [Figure 26] FIG. 11 is an overall configuration diagram showing an example of operation in a condensation heat defrosting mode in a vehicle air conditioner according to a third embodiment. [Figure 27] FIG. 11 is an overall configuration diagram showing an example of operation in a heating and defrosting mode in a vehicle air conditioner according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment may be assigned the same reference numerals, and duplicate descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0021] (First embodiment) First, a first embodiment of the present disclosure will be described with reference to the drawings. A vehicle air conditioner 1 according to the first embodiment is mounted on an electric vehicle, which is a vehicle that obtains driving force for traveling from an electric motor. The vehicle air conditioner 1 is an air conditioner that conditions the interior of the vehicle, which is the space to be air-conditioned, in the electric vehicle, and also has an in-vehicle equipment cooling function that cools a battery 75, which is an in-vehicle equipment.

[0022] Battery 75 is a secondary battery, such as a lithium-ion battery, that stores power to be supplied to on-board devices such as an electric motor. Battery 75 is a so-called assembled battery formed by stacking multiple battery cells and electrically connecting these battery cells in series or parallel.

[0023] This type of battery has limitations on input and output at low temperatures and is prone to a drop in output at high temperatures. For this reason, the battery temperature must be maintained within an appropriate temperature range (5°C or higher and 55°C or lower in this embodiment) that allows the battery's charge and discharge capacity to be fully utilized.

[0024] Furthermore, in this type of battery, the higher the battery temperature, the more likely the cells that make up the battery will deteriorate. In other words, by maintaining the battery temperature at a relatively low temperature, the progression of battery deterioration can be suppressed.

[0025] Therefore, in the vehicle air conditioner 1, the battery 75 can be cooled by the cold energy generated by the refrigeration cycle 10. Therefore, the object to be cooled in the refrigeration cycle 10 of this embodiment, which is different from the blown air, is the battery 75.

[0026] 1, the vehicle air conditioner 1 of the first embodiment includes a refrigeration cycle 10, a high-temperature side heat medium circuit 30, and a low-temperature side heat medium circuit 40. The refrigeration cycle 10 cools or heats the air to be blown into the vehicle cabin in the vehicle air conditioner 1. The refrigeration cycle 10 also cools a battery 75.

[0027] Therefore, the objects to be temperature-adjusted in the refrigeration cycle 10 are the blown air and the battery 75. The refrigeration cycle 10 is configured to be able to switch the refrigerant circuit in order to air-condition the vehicle interior and cool the battery 75.

[0028] The refrigeration cycle 10 uses an HFO refrigerant (specifically, R1234yf) as a refrigerant. The refrigeration cycle 10 constitutes a vapor compression subcritical refrigeration cycle in which the pressure of the high-pressure refrigerant discharged from the compressor 11 does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with refrigeration oil (specifically, PAG oil) for lubricating the compressor 11. A portion of the refrigeration oil circulates through the cycle together with the refrigerant.

[0029] The compressor 11 draws in, compresses, and discharges refrigerant in the refrigeration cycle 10. The compressor 11 is disposed in a drive unit compartment at the front of the vehicle interior. The drive unit compartment forms a space in which at least a portion of a drive unit (e.g., an electric motor) for outputting driving force for traveling is disposed.

[0030] The compressor 11 is an electric compressor that uses an electric motor to rotate a fixed-displacement compression mechanism with a fixed discharge capacity. The rotation speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from a control device 70, which will be described later.

[0031] The discharge port of the compressor 11 is connected to the refrigerant inlet side of the water-refrigerant heat exchanger 12. The water-refrigerant heat exchanger 12 has a refrigerant passage 12a through which the high-pressure refrigerant discharged from the compressor 11 flows, and a heat medium passage 12b through which the high-temperature side heat medium circulating in the high-temperature side heat medium circuit 30 flows.

[0032] The water-refrigerant heat exchanger 12 is a heating heat exchanger that exchanges heat between the high-pressure refrigerant flowing through the refrigerant passage 12a and the high-temperature heat medium flowing through the heat medium passage 12b to heat the high-temperature heat medium. The water-refrigerant heat exchanger 12 condenses the high-pressure refrigerant flowing through the refrigerant passage 12a by exchanging heat with the high-temperature heat medium, and is therefore an example of a heating heat exchanger.

[0033] An inlet side of a first three-way joint 13a, which has three inlet and outlet ports that communicate with each other, is connected to the outlet of the refrigerant passage 12a of the water-refrigerant heat exchanger 12. Such a three-way joint may be formed by joining multiple pipes or by providing multiple refrigerant passages in a metal block or a resin block.

[0034] Furthermore, as will be described later, the refrigeration cycle 10 is provided with a second three-way joint 13b to an eighth three-way joint 13h. The second three-way joint 13b to the eighth three-way joint 13h all have the same basic configuration as the first three-way joint 13a.

[0035] When one of the three inlet / outlets is used as an inlet and two are used as outlets, the first three-way joints 13a to eighth three-way joints 13h function as branching sections that branch the flow of refrigerant that has flowed in from one inlet. When two of the three inlet / outlets are used as inlet / outlets and one is used as an outlet, the first three-way joints 13a etc. function as merging sections that merge the flows of refrigerant that have flowed in from the two inlets.

[0036] In this embodiment, the first three-way joint 13a, the third three-way joint 13c, the sixth three-way joint 13f, and the seventh three-way joint 13g are connected to function as a branching section, and the second three-way joint 13b, the fourth three-way joint 13d, the fifth three-way joint 13e, and the eighth three-way joint 13h are connected to function as a merging section.

[0037] One outlet of the first three-way joint 13a is connected to the inlet side of the receiver 19 via a first on-off valve 16a and a fifth three-way joint 13e. The other outlet of the first three-way joint 13a is connected to the inlet side of a heating expansion valve 20a via a second on-off valve 16b and a second three-way joint 13b.

[0038] The first on-off valve 16a is a solenoid valve that opens and closes an inlet-side passage 27a that extends from one outlet of the first three-way joint 13a to the inlet of the receiver 19. The opening and closing operation of the first on-off valve 16a is controlled by a control voltage output from the control device 70.

[0039] The fifth three-way joint 13e has one inlet connected to the outlet of the first on-off valve 16a in the inlet-side passage 27a. Furthermore, one outlet of the fifth three-way joint 13e in the inlet-side passage 27a is connected to the inlet of the receiver 19.

[0040] The receiver 19 is a liquid storage unit having a gas-liquid separation function. That is, the receiver 19 separates the gas and liquid phases of the refrigerant flowing out from the heat exchange unit that functions as a condenser that condenses the refrigerant in the refrigeration cycle 10. The receiver 19 then allows a portion of the separated liquid-phase refrigerant to flow downstream and stores the remaining liquid-phase refrigerant as surplus refrigerant in the cycle.

[0041] The second on-off valve 16b is a solenoid valve that opens and closes the outside air passage 27c that runs from the other outlet of the first three-way joint 13a to one inlet of the second three-way joint 13b. The basic configuration of the second on-off valve 16b is the same as that of the first on-off valve 16a. The opening and closing operation of the second on-off valve 16b is also controlled by a control voltage output from the control device 70.

[0042] The other inlet of the second three-way joint 13b is connected to the refrigerant outlet side of the receiver 19. A sixth three-way joint 13f and a third check valve 21c are arranged in an outlet-side passage 27b that connects the refrigerant outlet of the receiver 19 and the other inlet of the second three-way joint 13b.

[0043] The inlet of the sixth three-way joint 13f is connected to the refrigerant outlet side of the receiver 19 via the outlet-side passage 27b. The other inlet of the second three-way joint 13b is connected to one outlet of the sixth three-way joint 13f via the outlet-side passage 27b and the third check valve 21c. Furthermore, the other outlet of the sixth three-way joint 13f is connected to the inlet side of the seventh three-way joint 13g.

[0044] The outlet of the second three-way joint 13b is connected to the refrigerant inlet side of the outdoor heat exchanger 22 via a heating expansion valve 20a. The heating expansion valve 20a is a pressure reducing section that reduces the pressure of the refrigerant flowing out of the receiver 19 and adjusts the flow rate of the refrigerant flowing downstream at least when the refrigerant circuit is switched to a heating mode, which will be described later. The heating expansion valve 20a corresponds to an example of a first expansion valve.

[0045] The heating expansion valve 20a is an electrically operated variable throttle mechanism having a valve element configured to change the throttle opening and an electrically operated actuator (specifically, a stepping motor) that displaces the valve element. The operation of the heating expansion valve 20a is controlled by a control signal (specifically, a control pulse) output from the control device 70.

[0046] The heating expansion valve 20a has a fully open function, which functions as a simple refrigerant passageway with almost no flow rate adjustment or refrigerant pressure reduction action when the valve is fully open, and a fully closed function, which blocks the refrigerant passageway when the valve is fully closed.

[0047] 1, the refrigeration cycle 10 includes a cooling expansion valve 20b and a cooling expansion valve 20c. The cooling expansion valve 20b and the cooling expansion valve 20c have the same basic configuration as the heating expansion valve 20a. The cooling expansion valve 20b and the cooling expansion valve 20c correspond to an example of a second expansion valve.

[0048] The outdoor heat exchanger 22 is a heat exchanger that exchanges heat between the refrigerant flowing out from the heating expansion valve 20a and the outside air blown by the outside air fan 22a. The outdoor heat exchanger 22 is disposed on the front side of the drive unit compartment. Therefore, when the vehicle is traveling, the traveling wind can be applied to the outdoor heat exchanger 22. The outdoor heat exchanger 22 is an example of an outdoor air heat exchanger, and constitutes an outdoor air heat exchange section 29X.

[0049] The outdoor heat exchanger 22 functions as a radiator that radiates heat from the high-pressure refrigerant in a cooling mode, etc. In addition, in a heating mode, etc., the outdoor heat exchanger 22 functions as an evaporator that evaporates the low-pressure refrigerant decompressed by the heating expansion valve 20a.

[0050] The outdoor air fan 22a is disposed so as to blow outdoor air toward the outdoor heat exchanger 22. The outdoor air fan 22a is an electric blower whose rotation speed (i.e., air blowing capacity) is controlled by a control voltage output from the control device 70. That is, the outdoor air fan 22a can adjust the wind speed (air volume) of the outdoor air toward the outdoor heat exchanger 22.

[0051] The inlet side of a three-way valve 18 constituting the third three-way joint 13c is connected to the refrigerant outlet of the outdoor heat exchanger 22. The three-way valve 18 is an electric three-way flow control valve that has one inlet and two outlets and can continuously adjust the passage area ratio of the two outlets. The operation of the three-way valve 18 is controlled by a control signal output from the control device 70.

[0052] One outlet of the three-way valve 18 constituting the third three-way joint 13c is connected to one inlet side of the fourth three-way joint 13d via a first check valve 21a. The outlet of the fourth three-way joint 13d is connected to the suction port side of the compressor 11. The other outlet of the three-way valve 18 is connected to the other inlet side of the fifth three-way joint 13e via a second check valve 21b.

[0053] Therefore, the three-way valve 18 can continuously adjust the flow rate of the refrigerant that flows out of the outdoor heat exchanger 22 and flows into the receiver 19, and the flow rate of the refrigerant that flows directly into the compressor 11.

[0054] 1, the first check valve 21a is disposed in the suction passage 27d that extends from one outlet of the third three-way joint 13c to one inlet of the fourth three-way joint 13d. The first check valve 21a allows the refrigerant to flow from the refrigerant outlet side of the outdoor heat exchanger 22 to the suction side of the compressor 11 via the three-way valve 18, but prohibits the refrigerant from flowing from the suction side of the compressor 11 to the refrigerant outlet side of the outdoor heat exchanger 22.

[0055] The second check valve 21b is disposed in the refrigerant passage extending from the other outlet of the third three-way joint 13c to the other inlet of the fifth three-way joint 13e. The second check valve 21b allows the refrigerant to flow from the refrigerant outlet side of the outdoor heat exchanger 22 to the inlet side of the receiver 19 via the three-way valve 18, but prohibits the refrigerant from flowing from the receiver 19 to the refrigerant outlet side of the outdoor heat exchanger 22.

[0056] As described above, the other outlet of the sixth three-way joint 13f disposed in the outlet-side passage 27b is connected to the inlet side of the seventh three-way joint 13g. One outlet of the sixth three-way joint 13f is connected to the other inlet of the second three-way joint 13b via the third check valve 21c.

[0057] The third check valve 21c allows the refrigerant to flow from the refrigerant outlet side of the receiver 19 to the heating expansion valve 20a, and prohibits the refrigerant from flowing to the receiver 19 from the second three-way joint 13b side.

[0058] One outlet of the seventh three-way joint 13g is connected to the inlet side of the cooling expansion valve 20b, and the other outlet of the seventh three-way joint 13g is connected to the inlet side of the cooling expansion valve 20c.

[0059] The cooling expansion valve 20b is a pressure reducing part that reduces the pressure of the refrigerant flowing out from the receiver 19 and adjusts the flow rate of the refrigerant flowing downstream at least when the refrigerant circuit is switched to a cooling mode, which will be described later. When the cooling expansion valve 20b is performing its pressure reducing function, it corresponds to an example of a second expansion valve.

[0060] The outlet of the cooling expansion valve 20b is connected to the refrigerant inlet side of the indoor evaporator 23. As shown in Fig. 2, the indoor evaporator 23 is disposed inside a casing 61 of the indoor air-conditioning unit 60. The indoor evaporator 23 is an evaporation section that evaporates the low-pressure refrigerant decompressed by the cooling expansion valve 20b by heat exchange with the air blown from the blower 62.

[0061] The interior evaporator 23 is a blown air cooling section that cools the blown air by evaporating low-pressure refrigerant and exerting a heat absorption effect. Therefore, the interior evaporator 23 corresponds to an example of an evaporator. A refrigerant outlet of the interior evaporator 23 is connected to one inlet of the eighth three-way joint 13h via a fourth check valve 21d. The fourth check valve 21d allows refrigerant to flow from the refrigerant outlet side of the interior evaporator 23 to the eighth three-way joint 13h, but prohibits refrigerant from flowing from the eighth three-way joint 13h side to the interior evaporator 23.

[0062] The cooling expansion valve 20c is a pressure reducing section that reduces the pressure of the refrigerant flowing out from the receiver 19 and adjusts the flow rate of the refrigerant flowing downstream when the low-temperature side heat medium is cooled in the chiller 24. The cooling expansion valve 20c serves as an example of a second expansion valve by performing a pressure reducing function. The outlet of the cooling expansion valve 20c is connected to the inlet side of the refrigerant passage 24a of the chiller 24.

[0063] The chiller 24 has a refrigerant passage 24a through which the low-pressure refrigerant decompressed by the cooling expansion valve 20c flows, and a heat medium passage 24b through which the low-temperature heat medium circulating in the low-temperature heat medium circuit 40 flows. The chiller 24 is an evaporation section that performs heat exchange between the low-pressure refrigerant flowing in the refrigerant passage 24a and the low-temperature heat medium flowing in the heat medium passage 24b, thereby evaporating the low-pressure refrigerant and exerting a heat absorption effect. In other words, the chiller 24 corresponds to an example of an evaporator.

[0064] The other inlet of eighth three-way joint 13h is connected to the outlet of refrigerant passage 24a of chiller 24. The outlet of eighth three-way joint 13h is connected to the suction port side of compressor 11 via fourth three-way joint 13d.

[0065] As is clear from the above description, in the refrigeration cycle 10, the refrigerant circuit can be switched by opening and closing the refrigerant passage with the first on-off valve 16a, the second on-off valve 16b, and the three-way valve 18. Therefore, the first on-off valve 16a, the second on-off valve 16b, the three-way valve 18, etc. are included in the refrigerant circuit switching unit.

[0066] The first on-off valve 16a, the second on-off valve 16b, and the first three-way joint 13a guide the refrigerant flowing out of the water-refrigerant heat exchanger 12 to one of the receiver 19 side and the second three-way joint 13b side. The second three-way joint 13b guides at least one of the refrigerant flowing out of the first three-way joint 13a and the refrigerant flowing out of the receiver 19 to the heating expansion valve 20a side. The three-way valve 18 constituting the third three-way joint 13c guides the refrigerant flowing out of the outdoor heat exchanger 22 to one of the suction port side of the compressor 11 and the receiver 19 side.

[0067] Next, the high-temperature side heat medium circuit 30 will be described. The high-temperature side heat medium circuit 30 is a heat medium circulation circuit that circulates a high-temperature side heat medium. As the high-temperature side heat medium, ethylene glycol, dimethylpolysiloxane, a solution containing nanofluid, or antifreeze solution can be used. The high-temperature side heat medium circuit 30 is configured by connecting the heat medium passage 12b of the water-refrigerant heat exchanger 12, the high-temperature side pump 32, the heater core 33, the water heater 34, etc. via the high-temperature side heat medium flow path 31.

[0068] A water heater 34 is disposed on the outlet side of the heat medium passage 12b in the water-refrigerant heat exchanger 12. The water heater 34 is configured to be able to dissipate heat to the high-temperature side heat medium flowing out of the heat medium passage 12b of the water-refrigerant heat exchanger 12, and heats the high-temperature side heat medium.

[0069] A PTC heater having a PTC element (i.e., a positive temperature coefficient thermistor) can be used as the water heater 34. The heat generation amount of the water heater 34 is arbitrarily controlled by a control voltage output from the control device 70. The water heater 34 corresponds to an example of an auxiliary heating device.

[0070] The outlet side of the heat medium passage of the water heater 34 is connected to the suction port side of the high-temperature side pump 32. The high-temperature side pump 32 is a water pump that pumps the high-temperature side heat medium that has passed through the water heater 34 to the heat medium inlet side of the heater core 33. The high-temperature side pump 32 is an electric pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 70.

[0071] The heater core 33 is a heat exchanger that heats the blown air by exchanging heat between the high-temperature heat medium heated in the water-refrigerant heat exchanger 12 or the like and the blown air that has passed through the indoor evaporator 23. As shown in Fig. 2, the heater core 33 is disposed in a casing 61 of the indoor air-conditioning unit 60. The inlet side of the heat medium passage 12b of the water-refrigerant heat exchanger 12 is connected to the heat medium outlet of the heater core 33.

[0072] Therefore, in the high-temperature side heat medium circuit 30, the high-temperature side pump 32 adjusts the flow rate of the high-temperature side heat medium flowing into the heater core 33, thereby adjusting the amount of heat dissipated by the high-temperature side heat medium in the heater core 33 to the blown air (i.e., the amount of heat applied to the blown air in the heater core 33).

[0073] In other words, in this embodiment, the water-refrigerant heat exchanger 12 and the components of the high-temperature side heat medium circuit 30 form a heating section 35 that heats the blown air using the refrigerant discharged from the compressor 11 as a heat source.

[0074] Next, the low-temperature side heat medium circuit 40 will be described. The low-temperature side heat medium circuit 40 is a heat medium circulation circuit that circulates a low-temperature side heat medium. As the low-temperature side heat medium, the same fluid as the high-temperature side heat medium can be used.

[0075] As shown in FIG. 1, the low-temperature side heat medium circuit 40 is configured by connecting the heat medium passage 12b of the chiller 24, the low-temperature side pump 42, the battery heat exchanger 43, the electric heater 44, the low-temperature side reserve tank 45, etc. via the low-temperature side heat medium flow path 41.

[0076] The low-temperature side heat medium circuit 40 adjusts the temperature of the battery 75 by exchanging heat between the low-temperature side heat medium, the temperature of which has been adjusted by the refrigeration cycle 10 or the like, and the battery 75 in the battery heat exchange section 43. The low-temperature side heat medium circuit 40 adjusts the temperature of the battery 75 and can also be said to be a heat medium circuit for effectively utilizing waste heat from the battery 75 for various purposes.

[0077] As shown in Fig. 1, an electric heater 44 is disposed on the outlet side of the heat medium passage 24b of the chiller 24. The electric heater 44 is configured to be able to dissipate heat to the low-temperature side heat medium flowing out of the heat medium passage 24b of the chiller 24, and heats the low-temperature side heat medium. A PTC heater can be used as the electric heater 44. The amount of heat generated by the electric heater 44 is controlled as desired by a control voltage output from the control device 70.

[0078] The outlet side of the heat medium passage in the electric heater 44 is connected to the inlet side of the battery heat exchanger 43. The battery heat exchanger 43 is a heat exchanger for adjusting the temperature of the battery 75 by exchanging heat between the low-temperature heat medium flowing through the heat medium passage 43a and the battery cells.

[0079] The heat medium passage 43a in the battery heat exchanger 43 has a passage configuration in which multiple passages are connected in parallel inside a dedicated case. As a result, the heat medium passage 43a is formed so that it can absorb waste heat from the battery 75 evenly from the entire area of the battery 75. In other words, the refrigerant passage is formed so that it can absorb heat from all battery cells evenly and cool all battery cells evenly.

[0080] Such a battery heat exchanger 43 may be formed by arranging heat medium passages 43a between stacked battery cells. Alternatively, the battery heat exchanger 43 may be formed integrally with the battery 75. For example, the battery heat exchanger 43 may be formed integrally with the battery 75 by providing the heat medium passages 43a in a dedicated case that houses the stacked battery cells.

[0081] A low-temperature side reserve tank 45 is disposed at the outlet of the heat medium passage 43a in the battery heat exchange section 43. The low-temperature side reserve tank 45 is a storage section that stores surplus low-temperature side heat medium in the low-temperature side heat medium circuit 40.

[0082] The heat medium outlet side of the low-temperature side reserve tank 45 is connected to the suction port side of the low-temperature side pump 42. The low-temperature side pump 42 is a water pump that pumps the low-temperature side heat medium to the inlet side of the heat medium passage 43a in the chiller 24. The basic configuration of the low-temperature side pump 42 is similar to that of the high-temperature side pump 32.

[0083] Therefore, in the low-temperature side heat medium circuit 40, the low-temperature side pump 42 adjusts the flow rate of the low-temperature side heat medium flowing into the battery heat exchanger 43, thereby adjusting the amount of heat absorbed by the low-temperature side heat medium in the battery heat exchanger 43 from the battery 75. In addition, the amount of heat absorbed in the battery heat exchanger 43 can also be adjusted by adjusting the temperature difference between the battery 75 and the low-temperature side heat medium using the electric heater 44.

[0084] That is, according to this embodiment, the chiller 24 and the components of the low-temperature side heat medium circuit 40 form a cooling unit that evaporates the refrigerant that flows out from the cooling expansion valve 20c and cools the battery 75.

[0085] Next, the interior air conditioning unit 60 will be described with reference to Fig. 2. The interior air conditioning unit 60 is for blowing out the ventilation air, the temperature of which has been adjusted by the refrigeration cycle 10, into the vehicle interior. The interior air conditioning unit 60 is disposed inside the instrument panel at the front of the vehicle interior.

[0086] The interior air conditioning unit 60 accommodates a blower 62, the interior evaporator 23, the heater core 33, etc. in an air passage formed in a casing 61 that forms the outer shell of the unit. The casing 61 forms an air passage for the ventilation air to be blown into the vehicle cabin. The casing 61 is molded from a resin (e.g., polypropylene) that has a certain degree of elasticity and excellent strength.

[0087] An inside / outside air switching device 63 is disposed on the most upstream side of the blown air flow of the casing 61. The inside / outside air switching device 63 switches between introducing inside air (air inside the vehicle cabin) and outside air (air outside the vehicle cabin) into the casing 61.

[0088] The inside / outside air switching device 63 continuously adjusts the opening areas of the inside air inlet, which introduces inside air, and the outside air inlet, which introduces outside air, into the casing 61, using an inside / outside air switching door, thereby changing the ratio of the amount of inside air introduced to the amount of outside air introduced. The inside / outside air switching door is driven by an electric actuator for the inside / outside air switching door. The operation of this electric actuator is controlled by a control signal output from the control device 70.

[0089] A blower 62 is disposed downstream of the inside / outside air switching device 63 in the flow of blown air. The blower 62 blows the air drawn in through the inside / outside air switching device 63 toward the vehicle interior. The blower 62 is an electric blower that drives a centrifugal multi-blade fan with an electric motor. The rotation speed (i.e., the blowing capacity) of the blower 62 is controlled by a control voltage output from the control device 70.

[0090] The interior evaporator 23 and the heater core 33 are arranged in this order with respect to the flow of air blown by the blower 62. In other words, the interior evaporator 23 is arranged upstream of the heater core 33 with respect to the flow of air blown.

[0091] A cool air bypass passage 65 is provided within the casing 61, which allows the blown air after passing through the interior evaporator 23 to bypass the heater core 33. An air mix door 64 is disposed within the casing 61 on the downstream side of the interior evaporator 23 in the blown air flow and on the upstream side of the heater core 33 in the blown air flow.

[0092] The air mix door 64 is an air volume ratio adjustment unit that adjusts the ratio of the volume of the blown air that passes through the heater core 33 side to the volume of the blown air that passes through the cool air bypass passage 65 after passing through the interior evaporator 23. The air mix door 64 is driven by an electric actuator for the air mix door. The operation of this electric actuator is controlled by a control signal output from the control device 70.

[0093] A mixing space is disposed downstream of the heater core 33 and the cold air bypass passage 65 in the casing 61 in the flow direction of the blown air. The mixing space is a space where the blown air heated by the heater core 33 and the blown air that has passed through the cold air bypass passage 65 and has not been heated are mixed.

[0094] Further, openings for blowing the blown air mixed in the mixing space (i.e., the conditioned air) into the vehicle cabin, which is the space to be air-conditioned, are arranged downstream in the flow of the blown air of the casing 61. These openings include a face opening, a foot opening, and a defroster opening (none of which are shown).

[0095] The face opening is an opening for blowing conditioned air toward the upper bodies of occupants in the vehicle cabin, the foot opening is an opening for blowing conditioned air toward the feet of occupants, and the defroster opening is an opening for blowing conditioned air toward the inside surface of the vehicle's front windshield.

[0096] These face opening holes, foot opening holes, and defroster opening holes are connected to face air outlets, foot air outlets, and defroster air outlets (none of which are shown) provided in the vehicle cabin via ducts that form air passages, respectively.

[0097] Therefore, the temperature of the conditioned air mixed in the mixing space is adjusted by the air mix door 64 adjusting the ratio of the air volume passing through the heater core 33 to the air volume passing through the cool air bypass passage 65. This adjusts the temperature of the blown air (conditioned air) blown into the vehicle cabin from each air outlet.

[0098] Additionally, a face door, a foot door, and a defroster door (none of which are shown) are disposed upstream of the face opening, foot opening, and defroster opening, respectively. The face door adjusts the opening area of the face opening. The foot door adjusts the opening area of the foot opening. The defroster door adjusts the opening area of the defroster opening.

[0099] The face door, foot door, and defroster door constitute an air outlet mode switching device that switches the air outlet mode. These doors are connected to an electric actuator for driving the air outlet mode doors via a link mechanism or the like, and are rotated in conjunction with each other. The operation of this electric actuator is also controlled by a control signal output from the control device 70.

[0100] Specific examples of the air outlet modes that can be switched by the air outlet mode switching device include a face mode, a bi-level mode, a foot mode, etc. The face mode is an air outlet mode in which the face air outlet is fully opened and air is blown out from the face air outlet toward the upper bodies of passengers in the vehicle interior.

[0101] The bi-level mode is an outlet mode in which both the face and foot outlets are open to blow air toward the upper bodies and feet of passengers in the vehicle, while the foot mode is an outlet mode in which the foot outlet is fully open and the defroster outlet is only slightly opened to blow air mainly from the foot outlet.

[0102] Furthermore, the occupant can manually switch to the defroster mode by operating the air outlet mode selector switch provided on the operation panel 71. The defroster mode is an air outlet mode in which the defroster air outlet is fully opened and air is blown out from the defroster air outlet onto the inner surface of the windshield.

[0103] Next, an overview of the electrical control unit of the vehicle air conditioner 1 will be explained using Figure 3. The control unit 70 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control unit 70 performs various calculations and processes based on an air conditioning control program stored in the ROM, and controls the operation of various controlled devices connected to the output side. The control unit 70 corresponds to an example of a control unit.

[0104] The various controlled devices include a compressor 11, a first on-off valve 16a, a second on-off valve 16b, a three-way valve 18, a heating expansion valve 20a, a cooling expansion valve 20b, a cooling expansion valve 20c, and an outdoor air fan 22a.Furthermore, the various controlled devices include a high-temperature side pump 32, a water heater 34, a low-temperature side pump 42, an electric heater 44, a blower 62, an inside / outside air switching device 63, an air mix door 64, etc.

[0105] 3, various control sensors are connected to the input side of the control device 70. The control sensors include an inside air temperature sensor 72a, an outside air temperature sensor 72b, a solar radiation sensor 72c, a high-pressure sensor 72d, and an air conditioning air temperature sensor 72e. The control sensors also include an evaporator temperature sensor 72f, an evaporator pressure sensor 72g, a chiller temperature sensor 72h, a chiller pressure sensor 72i, an outdoor unit temperature sensor 72j, an outdoor unit pressure sensor 72k, and a battery temperature sensor 72l.

[0106] The inside air temperature sensor 72a is an inside air temperature detector that detects the inside air temperature Tr, which is the temperature inside the vehicle cabin. The outside air temperature sensor 72b is an outside air temperature detector that detects the outside air temperature Tam, which is the temperature outside the vehicle cabin. The solar radiation sensor 72c is an solar radiation amount detector that detects the amount of solar radiation As irradiating into the vehicle cabin.

[0107] The high-pressure pressure sensor 72d is a high-pressure pressure detection unit that detects the high-pressure pressure Pd, which is the pressure of the high-pressure refrigerant discharged from the compressor 11. The conditioned air temperature sensor 72e is an conditioned air temperature detection unit that detects the temperature TAV of the air blown from the mixing space into the vehicle cabin.

[0108] The evaporator temperature sensor 72f is an evaporator temperature detection unit that detects the refrigerant evaporation temperature (evaporator temperature) Te in the interior evaporator 23. Specifically, the evaporator temperature sensor 72f in this embodiment detects the temperature of the refrigerant on the outlet side of the interior evaporator 23.

[0109] The evaporator pressure sensor 72g is an evaporator pressure detection unit that detects the refrigerant evaporation pressure Pe in the interior evaporator 23. Specifically, the evaporator pressure sensor 72g of the present embodiment detects the pressure of the refrigerant on the outlet side of the interior evaporator 23.

[0110] The chiller temperature sensor 72h is a chiller-side refrigerant temperature detection unit that detects the refrigerant evaporation temperature in the refrigerant passage 24a of the chiller 24. Specifically, the chiller temperature sensor 72h according to the present embodiment detects the temperature of the refrigerant on the outlet side in the refrigerant passage 24a of the chiller 24.

[0111] The chiller pressure sensor 72i is a chiller-side refrigerant pressure detection unit that detects the refrigerant evaporation pressure in the refrigerant passage 24a of the chiller 24. Specifically, the chiller pressure sensor 72i detects the pressure of the refrigerant on the outlet side in the refrigerant passage 24a of the chiller 24.

[0112] The outdoor unit temperature sensor 72j is an outdoor unit temperature detection unit that detects an outdoor unit refrigerant temperature T1, which is the temperature of the refrigerant flowing through the outdoor heat exchanger 22. Specifically, the outdoor unit temperature sensor 72j of the present embodiment detects the temperature of the refrigerant on the outlet side of the outdoor heat exchanger 22.

[0113] The outdoor unit pressure sensor 72k is an outdoor unit temperature detection unit that detects an outdoor unit refrigerant pressure P1, which is the pressure of the refrigerant flowing through the outdoor heat exchanger 22. Specifically, the outdoor unit pressure sensor 72k of the present embodiment detects the pressure of the refrigerant on the outlet side of the outdoor heat exchanger 22.

[0114] The battery temperature sensor 72l is a battery temperature detection unit that detects the battery temperature TB, which is the temperature of the battery 75. The battery temperature sensor 72l has multiple temperature detection units and detects the temperatures of multiple locations on the battery 75. This allows the control device 70 to detect the temperature difference between each location on the battery 75. Furthermore, the average value of the detection values of the multiple temperature sensors is used as the battery temperature TB.

[0115] Furthermore, a plurality of heat medium temperature sensors are connected to the input side of the control device 70 in order to detect the temperatures of the heat media in the high-temperature side heat medium circuit 30 and the low-temperature side heat medium circuit 40. The plurality of heat medium temperature sensors include a first heat medium temperature sensor 73a to a fifth heat medium temperature sensor 73e.

[0116] The first heat medium temperature sensor 73a is disposed at the outlet of the heat medium passage 12b in the water-refrigerant heat exchanger 12, and detects the temperature of the high-temperature side heat medium flowing out of the water-refrigerant heat exchanger 12. The second heat medium temperature sensor 73b is disposed at the outlet of the heater core 33, and detects the temperature of the high-temperature side heat medium passing through the heater core 33.

[0117] The third heat medium temperature sensor 73c is arranged at the outlet of the heat medium passage of the water heating heater 34, and detects the temperature of the high-temperature side heat medium flowing out from the water heating heater 34. The fourth heat medium temperature sensor 73d is arranged at the inlet of the heat medium passage of the chiller 24, and detects the temperature of the heat medium flowing into the chiller 24.

[0118] The fifth heat medium temperature sensor 73e is disposed at the outlet portion of the heat medium passage 43a of the battery heat exchanger 43, and detects the temperature of the low-temperature side heat medium flowing out from the heat medium passage 43a of the battery heat exchanger 43.

[0119] The vehicle air conditioner 1 switches the flow of the heat medium in the high temperature side heat medium circuit 30 and the low temperature side heat medium circuit 40 by referring to the detection results of the first to fifth heat medium temperature sensors 73a to 73e.

[0120] Furthermore, an operation panel 71 located near the instrument panel at the front of the vehicle interior is connected to the input side of the control device 70. Operation signals are input to the control device 70 from various operation switches provided on this operation panel 71.

[0121] The various operation switches provided on the operation panel 71 specifically include an auto switch, an air conditioner switch, an air volume setting switch, a temperature setting switch, etc. The auto switch is an operation switch that sets or cancels the automatic control operation of the refrigeration cycle 10.

[0122] The air conditioning switch is an operation switch that requests cooling of the blown air by the interior evaporator 23. The air volume setting switch is an operation switch that is operated to manually set the air volume of the blower 62. The temperature setting switch is an operation switch that sets the target temperature Tset in the vehicle interior.

[0123] A communication unit 74 is also connected to the control device 70. The communication unit 74 communicates and acquires various information via a network including the Internet, public line networks such as a mobile phone network, and base stations. Therefore, the control device 70 can acquire weather information and the like corresponding to the current location of the electric vehicle in which the automotive air conditioner 1 is installed.

[0124] The control device 70 of this embodiment is an integrated unit that controls various control target devices connected to its output side. Therefore, the configuration (i.e., hardware and software) that controls the operation of each control target device constitutes a control unit that controls the operation of each control target device.

[0125] For example, the component of the control device 70 that determines whether the amount of frost on the outdoor heat exchanger 22 has exceeded a predetermined standard constitutes a frost determination unit 70a. Also, the component of the control device 70 that determines whether all of the frost adhering to the outdoor heat exchanger 22 has melted by condensation heat defrosting constitutes a melting determination unit 70b. And, the component of the control device 70 that determines whether drying of the outdoor heat exchanger 22 by evaporation and removal of moisture generated as the frost melts has been completed in dry defrosting with condensation heat defrosting constitutes a drying completion determination unit 70c.

[0126] Furthermore, in the control device 70, in a heating / defrosting mode in which condensation heat defrosting and heating are performed in parallel, the refrigerant temperature required in the water-refrigerant heat exchanger 12 is or pressure and the refrigerant temperature required in the outdoor heat exchanger 22. or pressure Either temperature or pressure The control unit 70d controls the operation of the compressor to achieve the above. or pressure and the refrigerant temperature required in the outdoor heat exchanger 22. also is pressure Either the other temperature or pressure The configuration that realizes the above by controlling the operation of the heating expansion valve 20a constitutes a pressure reduction control section 70e.

[0127] Furthermore, the control device 70 includes a configuration that determines whether the efficiency priority mode, which prioritizes condensation heat defrosting over heating of the air-conditioned space, or the comfort priority mode, which prioritizes heating of the air-conditioned space over condensation heat defrosting, is more appropriate in the heating defrosting mode, and this configuration constitutes a mode determination unit 70f.The control device 70 includes a configuration that sets either the efficiency priority mode or the comfort priority mode in the heating defrosting mode based on the determination result of the mode determination unit 70f, and this configuration constitutes a mode setting unit 70g.

[0128] Next, a description will be given of the operation of the vehicle air conditioner according to the first embodiment. The vehicle air conditioner 1 is configured to be able to switch refrigerant circuits in order to air-condition the interior of the vehicle and cool the battery 75.

[0129] Specifically, the vehicle air conditioner 1 can switch between a heating mode refrigerant circuit, a cooling mode refrigerant circuit, a dehumidifying and heating mode refrigerant circuit, etc. to condition the air inside the vehicle cabin. The heating mode is an operating mode in which heated ventilation air is blown into the vehicle cabin. The cooling mode is an operating mode in which cooled ventilation air is blown into the vehicle cabin. The dehumidifying and heating mode is an operating mode in which cooled and dehumidified ventilation air is reheated and blown into the vehicle cabin.

[0130] These operating modes are switched by executing an air conditioning control program that is pre-stored in the control device 70. The air conditioning control program is executed when the auto switch on the operation panel 71 is turned on. The air conditioning control program switches the operating mode based on detection signals from various control sensors and operation signals from the operation panel.

[0131] The heating mode of the vehicle air conditioner 1 according to this embodiment will be described with reference to Fig. 4. In the heating mode, the control device 70 opens the first on-off valve 16a and closes the second on-off valve 16b. The control device 70 then operates the three-way valve 18 so that the refrigerant outlet side of the exterior heat exchanger 22 communicates with the inlet side of the first check valve 21a and the flow path to the fifth three-way joint 13e is closed. Furthermore, the control device 70 places the heating expansion valve 20a in a throttled state to exert a refrigerant decompression effect, and places the cooling expansion valve 20b and the cooling expansion valve 20c in a fully closed state.

[0132] The control device 70 also operates the high-temperature side pump 32 to pump the high-temperature side heat medium at a predetermined pumping capacity. In the heating mode, the control device 70 keeps the low-temperature side pump 42 stopped.

[0133] As a result, in the refrigeration cycle 10 in heating mode, as shown in FIG. 4, the refrigerant circulates through the compressor 11, the refrigerant passage 12a of the water-refrigerant heat exchanger 12, the receiver 19, the heating expansion valve 20a, the outdoor heat exchanger 22, the first check valve 21a, and the compressor 11 in that order.

[0134] With this circuit configuration, the control device 70 controls the operation of various controlled devices. For example, with respect to the compressor 11, the control device 70 controls the refrigerant discharge capacity so that the temperature of the high-temperature side heat medium in the heater core 33 approaches a target high-temperature side heat medium temperature.

[0135] The target high-temperature-side heat medium temperature is determined based on the target blowing temperature TAO by referring to a control map for the heating mode stored in advance in the control device 70. The target blowing temperature TAO is calculated using detection signals from various control sensors and operation signals from the operation panel. The refrigerant discharge capacity of the compressor 11 is controlled so that the high-pressure pressure Pd detected by the high-pressure pressure sensor 72d approaches the target high-pressure PdO determined based on the target high-temperature-side heat medium temperature.

[0136] As for the heating expansion valve 20a, the control device 70 controls the throttle opening so that the degree of superheat SH1 of the refrigerant on the outlet side of the outdoor heat exchanger 22 approaches a predetermined target degree of superheat KSH (5°C in this embodiment). The degree of superheat SH1 is calculated from the outdoor unit refrigerant temperature T1 detected by the outdoor unit temperature sensor 72j and the outdoor unit refrigerant pressure P1 detected by the outdoor unit pressure sensor 72k.

[0137] Furthermore, the control device 70 controls the opening of the air mix door 64 so that the blown air temperature TAV detected by the air conditioning air temperature sensor 72e approaches the target blown air temperature TAO. In the heating mode, the opening of the air mix door 64 may be controlled so that the entire volume of the blown air that has passed through the indoor evaporator 23 flows into the water-refrigerant heat exchanger 12.

[0138] In the refrigeration cycle 10, when the compressor 11 operates, high-pressure refrigerant discharged from the compressor 11 flows into the refrigerant passage 12a of the water-refrigerant heat exchanger 12. The refrigerant that has flowed into the water-refrigerant heat exchanger 12 dissipates heat to the high-temperature side heat medium flowing through the heat medium passage 12b and is condensed. As a result, the high-temperature side heat medium is heated in the water-refrigerant heat exchanger 12.

[0139] At this time, the high-temperature side heat medium is circulating in the high-temperature side heat medium circuit 30 due to the operation of the high-temperature side pump 32. Therefore, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 12 flows into the heater core 33 via the water heater 34 and the high-temperature side pump 32. The high-temperature side heat medium that has flowed into the heater core 33 exchanges heat with the blown air that has passed through the interior evaporator 23. As a result, the blown air that is blown into the vehicle cabin is heated using at least the high-pressure refrigerant as a heat source.

[0140] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the receiver 19 via the first three-way joint 13a and the inlet-side passage 27a. The refrigerant flowing into the receiver 19 is separated into gas and liquid in the receiver 19. A portion of the liquid-phase refrigerant separated in the receiver 19 flows into the heating expansion valve 20a via the outlet-side passage 27b and the second three-way joint 13b. The remaining liquid-phase refrigerant separated in the receiver 19 is stored in the receiver 19 as surplus refrigerant.

[0141] The refrigerant flowing into the heating expansion valve 20a is decompressed to a low-pressure refrigerant. At this time, the throttle opening of the heating expansion valve 20a is controlled so that the superheat degree SH1 approaches the target superheat degree KSH. In the heating mode, the superheat degree of the refrigerant on the outlet side of the outdoor heat exchanger 22 is essentially controlled so that it approaches the target superheat degree KSH.

[0142] The low-pressure refrigerant decompressed by the heating expansion valve 20a flows into the outdoor heat exchanger 22. The refrigerant that flows into the outdoor heat exchanger 22 exchanges heat with outside air blown by the outside air fan 22a, absorbing heat from the outside air and evaporating. The refrigerant that flows out of the outdoor heat exchanger 22 is drawn into the compressor 11 via the third three-way joint 13c, the suction side passage 27d, and the fourth three-way joint 13d, and is compressed again.

[0143] Therefore, in the heating mode, the air heated by the heater core 33 is blown into the vehicle compartment, thereby heating the vehicle compartment.

[0144] As described above, in the heating mode of the vehicle air conditioner 1 according to this embodiment, heat is absorbed from the outside air by the exterior heat exchanger 22, and the heat absorbed from the outside air is used to heat the vehicle interior. Here, when the outside air is at a low temperature and has high humidity, frost forms on the surface of the exterior heat exchanger 22, which reduces the heat exchange performance of the exterior heat exchanger 22.

[0145] In other words, in the heating mode, if frost forms on the exterior heat exchanger 22, the amount of heat absorbed from the outside air by the exterior heat exchanger 22 decreases, which results in a decrease in the heating performance of the vehicle air conditioner 1.

[0146] For this reason, the vehicle air conditioner 1 according to this embodiment performs a defrosting operation to deal with frosting on the exterior heat exchanger 22. The defrosting operation according to this embodiment has a condensation heat defrosting mode as an operating mode. The condensation heat defrosting mode, which is one of the operating modes of the defrosting operation, will be described with reference to FIG. 5 .

[0147] The condensation heat defrosting mode is an operation mode in which the outdoor heat exchanger 22 is defrosted by utilizing heat absorbed by the indoor evaporator 23 from the blown air in the indoor air conditioning unit 60 and heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40. The heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40 includes heat radiated from the battery 75 to the low-temperature side heat medium and heat added by the electric heater 44 to the low-temperature side heat medium.

[0148] As an example of the condensation heat defrosting mode, a case will be described below in which the outdoor heat exchanger 22 is defrosted using heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40. The condensation heat defrosting mode in this case is executed, for example, when the outdoor heat exchanger 22 is defrosted while the battery 75 of an electric vehicle is being charged and there is heat capacity in the vehicle cabin. When the battery 75 is being charged, it is expected that a large amount of heat will be generated in the battery 75, and therefore the heat generated in the battery 75 due to charging can be effectively used to defrost the outdoor heat exchanger 22.

[0149] In this condensation heat defrost mode, the control device 70 closes the first on-off valve 16a and opens the second on-off valve 16b. The control device 70 then operates the three-way valve 18 so that the refrigerant outlet of the outdoor heat exchanger 22 communicates with the flow path on the fifth three-way joint 13e side and closes the flow path on the first check valve 21a side. Furthermore, the control device 70 fully opens the heating expansion valve 20a and throttles the cooling expansion valve 20c. The control device 70 then fully closes the cooling expansion valve 20b.

[0150] The control device 70 also operates the low-temperature side pump 42 to pump the low-temperature side heat medium at a predetermined pumping capacity. The control device 70 then keeps the high-temperature side pump 32 of the high-temperature side heat medium circuit 30 stopped.

[0151] As a result, a vapor compression refrigeration cycle is configured in the condensation heat defrost mode of the refrigeration cycle 10. The refrigerant circulates through the compressor 11, water-refrigerant heat exchanger 12, second on-off valve 16b, heating expansion valve 20a, outdoor heat exchanger 22, three-way valve 18, receiver 19, cooling expansion valve 20c, chiller 24, and compressor 11 in this order.

[0152] With this circuit configuration, the control device 70 controls the operation of various controlled devices. For example, with respect to the compressor 11, the control device 70 controls the refrigerant discharge capacity so that the temperature of the low-temperature side heat medium in the chiller 24 approaches a target low-temperature side heat medium temperature. The target low-temperature side heat medium temperature is determined so that the battery temperature approaches an appropriate temperature range.

[0153] The control device 70 controls the throttle opening of the cooling expansion valve 20c so that the superheat of the refrigerant on the outlet side of the refrigerant passage 24a in the chiller 24 approaches a predetermined reference chiller-side superheat. The superheat of the refrigerant on the outlet side of the chiller 24 is calculated from the temperature of the refrigerant on the outlet side detected by the chiller temperature sensor 72h and the pressure of the refrigerant on the outlet side detected by the chiller pressure sensor 72i. The reference chiller-side superheat is set to a temperature of the low-temperature side heat medium that allows the battery temperature TB to be maintained within an appropriate temperature range for the battery 75.

[0154] 5, in the refrigeration cycle 10, high-pressure refrigerant discharged from the compressor 11 passes through the refrigerant passage 12a of the water-refrigerant heat exchanger 12. The high-pressure refrigerant flowing out of the water-refrigerant heat exchanger 12 passes through the second on-off valve 16b and the outdoor air-side passage 27c, passes through the heating expansion valve 20a which is fully open, and flows into the outdoor heat exchanger 22.

[0155] Therefore, the high-pressure refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 22 with almost no heat dissipation. Therefore, the heat of the high-pressure refrigerant can be added to the outdoor heat exchanger 22, and the outdoor heat exchanger 22 can be defrosted.

[0156] The refrigerant flowing out from the outdoor heat exchanger 22 flows into the receiver 19 via the three-way valve 18, the second check valve 21b, and the fifth three-way joint 13e, where it is separated into gas and liquid. A portion of the liquid-phase refrigerant separated in the receiver 19 flows into the cooling expansion valve 20c via the sixth three-way joint 13f and the seventh three-way joint 13g, where it is decompressed, and flows into the refrigerant passage 24a of the chiller 24. As a result, the low-pressure refrigerant that has flowed into the chiller 24 absorbs heat from the low-temperature side heat medium that has absorbed heat from the battery 75, and evaporates. The refrigerant flowing out from the chiller 24 is guided to the suction port of the compressor 11, where it is compressed again and discharged.

[0157] In this case, in the condensation heat defrosting mode, the heat generated in the battery 75 and absorbed by the chiller 24 is pumped up by the refrigeration cycle 10 and can be used to defrost the outdoor heat exchanger 22.

[0158] The condensation heat defrosting operation of the exterior heat exchanger 22 in the vehicle air conditioner 1 according to this embodiment is performed when the amount of frost on the exterior heat exchanger 22 exceeds a predetermined standard. In the condensation heat defrosting mode, the frost on the exterior heat exchanger 22 is melted, and then the moisture produced by the melting is evaporated and removed.

[0159] Specifically, in the condensation heat defrosting mode, defrosting is performed, which aims to melt the frost that has adhered to the outdoor heat exchanger 22, and dry defrosting is performed, which aims to evaporate and remove the moisture generated by the defrosting.

[0160] Here, even if the frost adhering to the outdoor heat exchanger 22 is melted by defrosting the outdoor heat exchanger 22, if the outdoor air temperature is low, such as 0°C or below, the moisture produced by the melting (hereinafter also referred to as residual moisture) will refreeze, reducing the heat exchange performance of the outdoor heat exchanger 22.

[0161] A decrease in the heat exchange performance of the exterior heat exchanger 22 can lead to a decrease in the air conditioning performance of the vehicle air conditioner 1, so it is necessary to prevent the refreezing of the moisture generated by defrosting. One method for preventing the refreezing of the moisture generated by defrosting is to evaporate the moisture generated by defrosting and remove it from the surface of the exterior heat exchanger 22. In the condensation heat defrosting mode, dry defrosting is implemented to prevent the refreezing of the melted moisture.

[0162] It is believed that there are efficient conditions for evaporating and removing moisture from the exterior heat exchanger 22 during condensation heat defrosting in the vehicle air conditioner 1. Therefore, in order to identify useful conditions for evaporating and removing moisture from the exterior heat exchanger 22 from the viewpoints of energy efficiency and the quality of the vehicle air conditioner 1, the evaporation of moisture in the exterior heat exchanger 22 will be considered.

[0163] First, we will explain the prerequisites for considering the evaporation of water in the outdoor heat exchanger 22. Based on the trends of past actual measurement results, we assume that the frost that has adhered to the outdoor heat exchanger 22 melts into water within 1 to 2 minutes after the start of defrosting operation, and that all of the adhered frost has melted.

[0164] It is assumed that there is no distribution on the evaporation surface of the residual moisture on the surface of the outdoor heat exchanger 22. The refrigerant temperature in the outdoor heat exchanger is uniform at the condensation temperature. The wind speed on the evaporation surface of the residual moisture in the outdoor heat exchanger 22 is uniform. In the evaporation removal of the residual moisture, changes over time, such as transient changes in the surface area of the water, are ignored.

[0165] The evaporation temperature of the residual moisture on the surface of the outdoor heat exchanger 22 is defined as satisfying the following relationship: The value obtained by subtracting the evaporation temperature of the residual moisture from the refrigerant condensation temperature of the outdoor heat exchanger 22 is multiplied by the conductivity of water and the evaporation surface area, and divided by the thickness of the residual moisture, is equal to the value obtained by subtracting the refrigerant condensation temperature of the outdoor heat exchanger 22 from the outdoor air temperature, multiplied by the thermal conductivity of water to air and the evaporation surface area.

[0166] Regarding the water retention state of the residual moisture in the air passage of the outdoor heat exchanger 22, the inside of the fins that separate the air passage are assumed to be not filled with residual moisture, and in this case, the evaporation surface area of the outdoor heat exchanger 22 is assumed to be a predetermined value.

[0167] Under the above-mentioned preconditions, the evaporation rate per unit area Va is considered using several empirical formulas shown in Figure 6. Specifically, an empirical formula for the diffusion coefficient D, an empirical formula for the Reynolds number Re, an empirical formula for the Schmidt number Sc, an empirical formula for the Sherwood number Sh, and an empirical formula for the evaporation rate per unit area Va are used.

[0168] From these empirical formulas shown in Figure 6, it can be seen that as the wind speed Vc increases, the evaporation rate Va per unit area tends to increase. Also, as the evaporation water temperature of the residual moisture increases, the evaporation rate Va per unit area tends to increase. The evaporation water temperature of the residual moisture increases as the refrigerant condensation temperature increases, and increases as the wind speed Vc decreases. If the wind speed Vc is increased at the same refrigerant condensation temperature, the evaporation rate Va per unit area will be affected by both factors that increase and factors that decrease it.

[0169] Figure 7 shows the results of calculating the relationship between the outdoor unit evaporation rate and wind speed Vc when the refrigerant condensation temperature is different, using the empirical formula shown in Figure 6. Eta in Figure 7 shows the relationship between the outdoor unit evaporation rate and wind speed when the refrigerant condensation temperature is 20°C.

[0170] Similarly, Etb indicates the relationship between the outdoor unit evaporation rate and wind speed when the refrigerant condensation temperature is 30°C, Etc indicates the relationship between the outdoor unit evaporation rate and wind speed when the refrigerant condensation temperature is 40°C, Etd indicates the relationship between the outdoor unit evaporation rate and wind speed when the refrigerant condensation temperature is 50°C, and Ete indicates the relationship between the outdoor unit evaporation rate and wind speed when the refrigerant condensation temperature is 60°C.

[0171] 7, it can be seen that the outdoor unit evaporation rate tends to increase due to an increase in the evaporative water temperature of the residual moisture associated with an increase in the air velocity Vc. Furthermore, it can be seen that the outdoor unit evaporation rate tends to increase due to an increase in the evaporative water temperature of the residual moisture associated with an increase in the refrigerant condensation temperature. In other words, by appropriately adjusting the refrigerant condensation temperature and the air velocity Vc of the outdoor air fan 22a, which can be controlled by the vehicle air conditioner 1, it is possible to more efficiently evaporate and remove the residual moisture in the outdoor heat exchanger 22.

[0172] Here, in the vehicle air conditioning system 1 according to this embodiment, when evaporating and removing moisture in the exterior heat exchanger 22, the refrigeration cycle 10 needs to operate in order to achieve the above-mentioned refrigerant condensation temperature and wind speed Vc.

[0173] The relationship between the refrigerant condensation temperature and the wind speed within the range that can be achieved in a typical refrigeration cycle will be examined. Figure 8 is a graph showing the relationship between the refrigerant condensation temperature and the wind speed when the refrigerant discharge capacity of the compressor and the heat absorption amount of the chiller 24 are set as conditions.

[0174] 8, Tcdh indicates the relationship between the refrigerant condensation temperature and wind speed when the rotation speed of the compressor 11 and the heat absorption amount of the chiller 24 are maximum. Tcdl indicates the relationship between the refrigerant condensation temperature and wind speed when the rotation speed of the compressor 11 and the heat absorption amount of the chiller 24 are minimum. Tcds indicates the relationship between the refrigerant condensation temperature and wind speed when the rotation speed of the compressor 11 and the heat absorption amount of the chiller 24 are standard values.

[0175] The graph shown in Fig. 9 is created using the graphs shown in Fig. 7 and Fig. 8. In Fig. 9, Edh shows the relationship between the outdoor unit evaporation amount and wind speed when the rotation speed of the compressor 11 and the heat absorption amount of the chiller 24 are at their maximums. Edl shows the relationship between the outdoor unit evaporation amount and wind speed when the rotation speed of the compressor 11 and the heat absorption amount of the chiller 24 are their minimums. And Wds shows the relationship between the outdoor unit evaporation amount and wind speed when the rotation speed of the compressor 11 and the heat absorption amount of the chiller 24 are at their standard values.

[0176] 9, it is possible to identify an operating condition area Af that can be achieved by the refrigeration cycle depending on the wind speed. By operating the refrigeration cycle under the outdoor unit evaporation rate and wind speed Vc included in this operating condition area Af, it is possible to at least achieve evaporation and removal of residual moisture in the outdoor heat exchanger 22 in a relatively short period of time.

[0177] Evaporating and removing residual moisture in the outdoor heat exchanger 22 means that water vapor resulting from the residual moisture is generated. When the outdoor temperature is low and water vapor is generated from the outdoor heat exchanger 22 in the drive unit compartment, the outside will recognize a white mist-like gas as being generated from the drive unit compartment, which may lead to the misconception that white smoke is being generated from the equipment in the drive unit compartment.

[0178] For this reason, when evaporating and removing the residual moisture in the outdoor heat exchanger 22, it is necessary to promote the evaporation and removal of the residual moisture while suppressing the visibility of the white mist. A method using a psychrometric chart is known as a standard for the visibility of the white mist.

[0179] Figure 10 is an explanatory diagram of a psychrometric chart. In this diagram, the horizontal axis represents temperature, the vertical axis represents absolute humidity, and the diagonal curve in the diagram represents relative humidity ψ. The line where relative humidity ψ is 100% is specifically called the saturation line Lsa. The area to the left of the saturation line Lsa represents a state where moisture is completely liquefied. The area to the right of the saturation line Lsa represents a state where water vapor and other gases (air, etc.) are mixed. In gas in this state, the higher the relative humidity ψ, the more moisture condenses and is more likely to be visible as a white mist.

[0180] Here, it is assumed that when residual moisture is evaporated and removed in the outdoor heat exchanger 22, water vapor is mistakenly recognized as a white mist at the stage where mixing of the outside air with the air that has passed through the outdoor heat exchanger 22 is complete. Once mixing of the outside air with the air that has passed through the outdoor heat exchanger 22 is complete, a relationship based on the mixing ratio of the two is finally reached.

[0181] Therefore, although heat diffusion is faster than the diffusion of substances, whether or not the visible white mist becomes a problem can be defined from empirical knowledge as a state in which substance mixing is complete, and it is thought that this can be determined by the mixing ratio of outside air and air that has passed through the outdoor heat exchanger 22.

[0182] In addition, the state of the air at the air outlet side of the outdoor air heat exchanger includes not only the state of the air after passing through the outdoor heat exchanger 22, but also the state in which the air after passing through the outdoor heat exchanger 22 has completed mixing of substances with the outdoor air.

[0183] With reference to Figure 10, the determination of the visibility of white mist using a psychrometric chart will be explained using an example where the outside air temperature is 0°C. First, a tangent line Ltan to the saturation line Lsa is found from the saturation point at the outside air temperature on the psychrometric chart. The tangent line Ltan indicates the visibility limit at which water vapor is recognized as white mist. In the case shown in Figure 10, a tangent line Ltan passing through the saturation point P when the outside air temperature is 0°C is found.

[0184] 10, the region below the tangent line Ltan corresponds to the visibility suppression region Aa, where water vapor generated from the outdoor heat exchanger 22 is not recognized as white mist. On the other hand, the region below the saturation line Lsa and above the tangent line Ltan corresponds to the visibility region Ab, where water vapor generated from the outdoor heat exchanger 22 is recognized as white mist, which poses a problem.

[0185] Whether water vapor is visible as a white mist can be determined depending on whether the state of the air at the stage when mixing of the outside air and the air after passing through the outdoor heat exchanger 22 is complete falls into the visibility suppression region Aa or the visibility region Ab. Therefore, by controlling the refrigerant condensation temperature and air velocity Vc in the outdoor heat exchanger 22 so that the state of the air at the stage when mixing of the outside air and the air after passing through the outdoor heat exchanger 22 is complete falls into the visibility suppression region Aa, rapid dry defrosting can be achieved while suppressing visibility as a white mist.

[0186] Furthermore, by defining the state of the air at the stage where mixing of the outside air and the air after passing through the outdoor heat exchanger 22 is completed as being in the visibility suppression region Aa using the tangent line Ltan on the psychrometric chart as a reference, the state of the air does not belong to the visibility region Ab. Therefore, visibility as a white mist can be sufficiently suppressed until mixing of the outside air and the air after passing through the outdoor heat exchanger 22 is completed.

[0187] Assuming that the refrigerant capacity and air capacity in the refrigeration cycle are balanced, the air-side specific enthalpy Sep is calculated for the refrigerant-side outdoor unit capacity at the refrigeration cycle balance point (i.e., the refrigerant discharge capacity and heat absorption amount) that creates an arbitrary air speed Vc and refrigerant condensation temperature. From the air-side specific enthalpy Sep, the specific enthalpy line Lse corresponding to the air-side specific enthalpy Sep is identified on the psychrometric chart.

[0188] For example, assuming a certain system, when the outside air temperature is 0°C, the wind speed Vc is 0.5 m / s, and the refrigerant condensation temperature is 35°C, the air-side specific enthalpy is calculated to be 33 kJ / kg. Then, on the psychrometric chart shown in Fig. 11, the specific enthalpy line Lse corresponding to the calculated 33 kJ / kg is identified.

[0189] Next, the intersection Pc of the tangent line Ltan and the specific enthalpy line Lse is identified. Here, the allowable upper limit evaporation rate Em per unit passing air weight is calculated by subtracting the absolute humidity Aha at the intersection Pc from the absolute humidity Aht at the saturation point P of the outdoor air temperature. The allowable upper limit evaporation rate Em per unit passing air weight indicates the amount of water vapor that is allowable for air per unit weight after passing through the outdoor heat exchanger 22 until saturation occurs.

[0190] The allowable upper limit evaporation rate Em per unit passing air weight calculated in this way was calculated by changing various conditions, such as the air speed Vc and the refrigerant condensation temperature. The allowable upper limit evaporation rate Em per unit passing air weight under various conditions is summarized as the allowable upper limit evaporation rate line Emx in Figure 12. In Figure 12, if the outdoor unit evaporation rate and air speed Vc are in a range lower than the allowable upper limit evaporation rate line Emx, residual moisture can be efficiently evaporated and removed without being visually recognized as white mist.

[0191] Here, in the condensation heat defrosting in the vehicle air conditioner 1, it is assumed that the heating operation at low outdoor temperatures causes the maximum allowable amount of frost to adhere to the outdoor heat exchanger 22. Therefore, in this embodiment, the required amount of water evaporation En that needs to be evaporated and removed from the outdoor heat exchanger 22 is calculated by subtracting the amount of water that drops from the outdoor heat exchanger 22 due to melting of frost from the maximum allowable amount of frost.

[0192] 13, the operating conditions for quickly restoring the heat exchange performance of the outdoor heat exchanger 22 without causing visible white mist when evaporating and removing residual moisture from the outdoor heat exchanger 22 are defined by the target area Ao. The target area Ao is determined so that it is greater than the wind speed Vc associated with the allowable upper limit evaporation rate line Emx and so that the outdoor heat exchanger evaporation rate is greater than the required moisture evaporation rate En.

[0193] The considerations made using Figures 6 to 13 can be summarized in the graph shown in Figure 14. The graph in Figure 14 is a combination of the graph shown in Figure 9 and the graph shown in Figure 13. The target area At shown in the graph in Figure 14 indicates operating conditions for evaporative removal of residual moisture that are achievable in the refrigeration cycle and that quickly restore the heat exchange performance of the outdoor heat exchanger 22 without making white mist visible. Specifically, the target area At is defined by the overlapping range between the operating condition area Af in Figure 9 and the target area Ao in Figure 13.

[0194] As shown in Figure 14, the target area At includes points Px, Pz, and Pz. Point Px indicates the intersection of the allowable upper limit evaporation rate line Emx and the required water evaporation rate En. Point Py indicates the intersection of the allowable upper limit evaporation rate line Emx and curve Edh, which represents the outdoor unit evaporation rate when the rotation speed of the compressor 11 and the heat absorption rate of the chiller 24 are at their maximums. Point Pz indicates the intersection of curve Edh and the required water evaporation rate En.

[0195] The minimum value of the wind speed Vc in the target area At is the wind speed at point Px, which is 0.12 m / s, and the maximum value of the wind speed Vc in the target area At is the wind speed at point Pz, which is 1.2 m / s.

[0196] Therefore, when evaporating and removing residual moisture from the outdoor heat exchanger 22 during defrosting operation, the wind speed of the outdoor air fan 22a can be adjusted within the range of 0.12 m / s to 1.2 m / s, thereby enabling the residual moisture to be quickly evaporated and removed without causing visible white mist.

[0197] The minimum value of the outdoor unit evaporation rate in the target area At is determined based on the outdoor unit evaporation rates at points Px and Pz, and corresponds to the required water evaporation rate En. Since the refrigerant condensation temperature can be determined from the outdoor unit evaporation rate, the minimum value of the refrigerant condensation temperature in the target area At is determined to be 15°C.

[0198] The maximum value of the outdoor unit evaporation rate in the target area At is determined based on the outdoor unit evaporation rate at point Py. The maximum value of the refrigerant condensation temperature in the target area At is determined to be 70°C, calculated from the outdoor unit evaporation rate at point Py.

[0199] Therefore, when evaporating and removing residual moisture from the outdoor heat exchanger 22 during defrosting operation, by supplying the outdoor heat exchanger 22 with an amount of heat adjusted so that the refrigerant condensation temperature is 15°C to 70°C, the residual moisture can be quickly evaporated and removed without causing visible white mist.

[0200] Here, control in the dry defrost mode can be performed using a defrost condition coefficient DCC as an operating condition related to the evaporation and removal of residual moisture from the outdoor heat exchanger 22. The defrost condition coefficient DCC is a parameter determined by multiplying the air speed Vc supplied to the outdoor heat exchanger 22 by the outdoor air fan 22a by the refrigerant condensation temperature in the outdoor heat exchanger 22. When calculating the defrost condition coefficient DCC, Celsius is used as the unit of the refrigerant condensation temperature in the outdoor heat exchanger 22. This is because the melting point of water is used as a reference and the temperature difference from the melting point is an important factor when discussing dry defrosting phenomena.

[0201] When the defrost condition coefficient DCC is used, the defrost condition coefficient DCC for the target area At is set to 1.8 to 35. The value "1.8" for the defrost condition coefficient DCC is a value for point Px, and is obtained by multiplying 0.12 m / s by 15°C. The value "35" for the defrost condition coefficient DCC is a value for point Py, and is obtained by multiplying 0.5 m / s by 70°C.

[0202] Therefore, when evaporating and removing residual moisture from the outdoor heat exchanger 22, by adjusting the wind speed Vc and the refrigerant condensation temperature so that the defrost condition coefficient DCC is 1.8 to 35, the residual moisture can be evaporated and removed quickly without making the white mist visible.

[0203] Here, dry defrosting in condensation heat defrosting will be described. In dry defrosting, which evaporates and removes residual moisture resulting from melted frost, the operation of the vehicle air conditioner 1 is controlled using parameters such as the air velocity Vc and the refrigerant condensation temperature determined as described above.

[0204] At this time, the control device 70 controls the refrigerant discharge capacity of the compressor 11 so that the refrigerant condensation temperature in the outdoor heat exchanger 22 approaches the target condensation temperature TCO. The target condensation temperature TCO is determined by referring to a control map stored in advance in the control device 70.

[0205] In this embodiment, the target condensing temperature TCO is determined to increase as the outside air temperature increases, as shown in the control characteristics diagram of Fig. 15. As a result, the refrigerant condensing temperature in dry defrosting is adjusted to decrease as the outside air temperature decreases, within the range of 15°C to 70°C.

[0206] For the air conditioning expansion valve 20b and the cooling expansion valve 20c, the control device 70 controls the throttle opening so that the superheat of the refrigerant on the outlet side of the refrigerant passage 24a in the chiller 24 approaches a predetermined reference chiller side superheat (e.g., 10°C).

[0207] The rotation speed of the outdoor air fan 22a, which corresponds to the amount of outdoor air supplied to the outdoor heat exchanger 22, is controlled so as to approach the target air speed VaO. The target air speed VaO is determined by referring to a control map stored in advance in the control device 70.

[0208] In this embodiment, as shown in the control characteristics diagram of Fig. 16, the target air speed VaO is determined to decrease with a decrease in the refrigerant condensation temperature of the outdoor heat exchanger 22. As described above, the target condensation temperature TCO is set lower as the outdoor air temperature decreases, and therefore the target air speed VaO is also set smaller as the outdoor air temperature decreases.

[0209] In the control characteristics diagram shown in Fig. 16, the target air speed VaO is set to be greater than the limit visibility air speed Vl when the outdoor air fan 22a is operating. The limit visibility air speed Vl indicates the upper limit of the air speed Vc at which water vapor is visible as white mist in dry defrosting based on the refrigerant condensation temperature of the outdoor heat exchanger 22. Thus, by setting the target air speed VaO in dry defrosting in accordance with the control characteristics diagram shown in Fig. 16, it is possible to promote evaporation and removal of residual moisture from the outdoor heat exchanger 22 while suppressing the visibility of the white mist.

[0210] When determining the target air speed of the outdoor air fan 22a, if the outdoor air temperature is lower than a low-temperature reference temperature (for example, -15°C), the target air speed is set to 0.12 m / s or less. When the outdoor air temperature is lower than the low-temperature reference temperature, it is thought that water vapor generated in the dry defrost mode is rapidly cooled and turns into ice particles. In this case, it is thought that there is little possibility that the water vapor will be mistaken for white smoke, so the target air speed VaO is set to 0.12 m / s or less.

[0211] When the outdoor air temperature is lower than the low temperature reference temperature, the target air speed of 0.12 m / s can be achieved by stopping the outdoor air fan 22a. Alternatively, a shutter device disposed on the air flow path to the outdoor heat exchanger 22 may be used to block the supply of air to the outdoor heat exchanger 22.

[0212] The condensation heat defrosting mode ends when dry defrosting is completed. Completion of dry defrosting is determined when the remaining moisture on the surface of the outdoor heat exchanger 22 has evaporated and been removed from the surface of the outdoor heat exchanger 22.

[0213] In the condensation heat defrosting mode, dry defrosting is performed after the completion of the defrosting process, as shown in Fig. 17. It is believed that the residual moisture evaporated in the dry defrosting process originates from the melting of frost in the defrosting process, and therefore there is a strong correlation between the amount of energy input in the defrosting process and the amount of energy required in the dry defrosting process.

[0214] In this embodiment, whether or not dry defrosting is complete is determined by utilizing the relationship between the amount of energy input during defrosting and the amount of energy required during dry defrosting. First, the amount of melted water, which indicates the total amount of frost melted during defrosting, is estimated. The amount of melted water is estimated by dividing the total amount of energy input to melt the frost during defrosting by the heat of melting of ice per unit weight.

[0215] Specifically, the total amount of energy input to melting the frost during melting defrosting is calculated by subtracting the heat radiation loss due to wind speed, etc. from the sum of the work load of the compressor 11 and the heat absorption amount in the chiller 24, and then cumulatively adding the result. The calculated total amount of energy corresponds to an example of the amount of input energy. The heat radiation loss due to wind speed, etc. corresponds to the amount of heat radiation energy during melting defrosting.

[0216] The amount of heat radiation energy during melting and defrosting is determined using a control table obtained by experimentally determining the heat radiation loss to air from the relationship between wind speed and outside air temperature. The control table specifies that the amount of heat radiation energy increases as the outside air temperature decreases. The control table also specifies that the amount of heat radiation energy increases as the wind speed increases.

[0217] Then, by dividing the calculated total energy amount by the heat of fusion of ice per unit weight (for example, approximately 334 kJ / kg), the amount of melted water, which is the total amount of frost melted during defrosting, is estimated.

[0218] Next, the required work amount is calculated using the calculated amount of melted water. The required work amount means the amount of energy required to evaporate the residual water equivalent to the amount of melted water in dry defrosting, and corresponds to an example of the required energy amount. Specifically, the required work amount is calculated by multiplying the estimated amount of melted water by the latent heat of vaporization of water per unit weight (for example, approximately 2400 kJ / kg).

[0219] Next, it is determined whether the dry input work amount, which is the integrated value of the energy input during the dry defrosting, is equal to or greater than the required work amount (i.e., whether or not it is equal to or greater than the required energy amount). The dry input work amount corresponds to an example of the dry input energy amount.

[0220] When determining the amount of dry input energy, the amount of heat dissipation energy during dry defrosting is subtracted from the total value of the workload of the compressor 11 and the amount of heat absorbed by the chiller 24. The amount of heat dissipation energy during dry defrosting means the heat loss dissipated into the air during dry defrosting. Therefore, by referring to the control table described above and using the air speed and outside air temperature during dry defrosting, the amount of heat dissipation energy during dry defrosting can be determined.

[0221] When the dry input workload is equal to or greater than the required workload, it is considered that all of the residual moisture generated by the melting and defrosting has evaporated during the dry defrosting, and it is determined that the dry defrosting is complete.When the dry input workload is less than the required workload, it is determined that the dry defrosting is not complete.

[0222] By determining the completion of dry defrosting in this manner, the vehicle air conditioner 1 can reliably remove residual moisture from the exterior heat exchanger 22. Furthermore, by taking into account the amount of heat radiation energy during melting and defrosting and during dry defrosting, the accuracy of determining whether the removal of residual moisture has been completed can be improved. Furthermore, because the amount of heat radiation energy is determined using wind speed and outside air temperature, it is appropriately determined according to the environment during melting and defrosting and during dry defrosting. This also improves the accuracy of determining whether dry defrosting has been completed.

[0223] The vehicle air conditioner 1 according to the first embodiment has a heating and defrosting mode in order to simultaneously perform the heating of the air-conditioned space (vehicle interior) and the condensation heat defrosting of the exterior heat exchanger 22. The heating and defrosting mode in the vehicle air conditioner 1 will be described with reference to FIG.

[0224] In the heating and defrosting mode, in order to improve comfort by heating the air-conditioned space (vehicle interior), a heating capacity is required such that the refrigerant temperature in the water-refrigerant heat exchanger 12 becomes, for example, 40°C to 70°C.

[0225] On the other hand, for condensation heat defrosting in the heating defrost mode, a defrosting capacity is required such that the refrigerant temperature of the outdoor heat exchanger 22 becomes, for example, around 30°C. From the viewpoint of defrosting the outdoor heat exchanger 22, a higher refrigerant temperature is considered preferable, but if the refrigerant temperature is too high, the visibility of white mist generated by evaporation of water increases, increasing the possibility that it will be mistaken for white smoke or the like. For this reason, the defrosting capacity of the outdoor heat exchanger 22 also needs to be controlled by the operation of the refrigeration cycle 10.

[0226] In the heating / defrosting mode, the control device 70 closes the first on-off valve 16a and opens the second on-off valve 16b. The control device 70 then operates the three-way valve 18 so that the refrigerant outlet of the outdoor heat exchanger 22 communicates with the flow path on the fifth three-way joint 13e side and closes the flow path on the first check valve 21a side. Furthermore, the control device 70 throttles the heating expansion valve 20a and the cooling expansion valve 20c. The control device 70 then fully closes the cooling expansion valve 20b.

[0227] The control device 70 also controls the high-temperature side pump 32 in the high-temperature side heat medium circuit 30 to pump the high-temperature side heat medium at a predetermined pumping capacity. The control device 70 controls the water heater 34 in the high-temperature side heat medium circuit 30 to generate heat in accordance with predetermined conditions to heat the high-temperature side heat medium. The control device 70 also controls the low-temperature side pump 42 in the low-temperature side heat medium circuit 40 to pump the low-temperature side heat medium at a predetermined pumping capacity.

[0228] As a result, in the heating / defrosting mode, a vapor compression refrigeration cycle is formed in the refrigeration cycle 10. The refrigerant circulates by flowing through the compressor 11, water-refrigerant heat exchanger 12, second on-off valve 16b, heating expansion valve 20a, outdoor heat exchanger 22, three-way valve 18, receiver 19, cooling expansion valve 20c, chiller 24, and compressor 11 in this order.

[0229] With this circuit configuration, the control device 70 controls the operation of various control target devices. For example, the refrigerant discharge capacity (i.e., rotation speed) of the compressor 11, the throttle opening of the heating expansion valve 20a, the throttle opening of the cooling expansion valve 20c, the heat generation amount of the water heater 34, etc. are controlled according to a heating / defrosting control program described later. The heating / defrosting control program will be described in detail later.

[0230] Note that, like the condensation heat defrosting mode described above, the condensation heat defrosting in the heating defrosting mode includes melting-off frost and dry defrosting. Therefore, during dry defrosting, the air speed Vc supplied to the outdoor heat exchanger 22 by the outdoor air fan 22a and the refrigerant condensation temperature in the outdoor heat exchanger 22 are determined to fall within the target area At shown in Fig. 14 and are controlled to reach the determined target values.

[0231] 18, in the refrigeration cycle 10, high-pressure refrigerant discharged from the compressor 11 flows into the refrigerant passage 12a of the water-refrigerant heat exchanger 12. The refrigerant that has flowed into the water-refrigerant heat exchanger 12 dissipates heat to the high-temperature side heat medium flowing through the heat medium passage 12b and is condensed. As a result, the high-temperature side heat medium is heated in the water-refrigerant heat exchanger 12.

[0232] At this time, the high-temperature side heat medium is circulating in the high-temperature side heat medium circuit 30 due to the operation of the high-temperature side pump 32. Therefore, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 12 flows into the heater core 33 via the water heater 34 and the high-temperature side pump 32. The high-temperature side heat medium that has flowed into the heater core 33 exchanges heat with the blown air that has passed through the interior evaporator 23. As a result, in the heating and defrosting mode, the blown air that is blown into the vehicle cabin is heated using at least the high-pressure refrigerant as a heat source.

[0233] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the heating expansion valve 20a via the second on-off valve 16b and the outdoor air side passage 27c, and is decompressed to an intermediate-pressure refrigerant according to the throttle opening of the heating expansion valve 20a. The intermediate-pressure refrigerant decompressed by the heating expansion valve 20a flows into the outdoor heat exchanger 22.

[0234] Therefore, the intermediate-pressure refrigerant that has flowed out from the heating expansion valve 20a flows into the outdoor heat exchanger 22, and the heat of the intermediate-pressure refrigerant can be added to the outdoor heat exchanger 22. That is, in the heating defrosting mode, condensation heat defrosting of the outdoor heat exchanger 22 can be performed using the heat of the intermediate-pressure refrigerant.

[0235] The refrigerant that flows out of the outdoor heat exchanger 22 passes through the three-way valve 18, the second check valve 21b, and the fifth three-way joint 13e and flows into the receiver 19, where it is separated into gas and liquid. A portion of the liquid-phase refrigerant separated in the receiver 19 flows through the sixth three-way joint 13f and the seventh three-way joint 13g into the cooling expansion valve 20c, where it is decompressed, and then flows into the refrigerant passage 24a of the chiller 24.

[0236] As a result, the low-pressure refrigerant that has flowed into chiller 24 evaporates by absorbing heat from the low-temperature side heat medium that has absorbed heat from battery 75. The refrigerant that has flowed out of chiller 24 is guided to the intake port of compressor 11, compressed again, and discharged.

[0237] In this case, in the heating / defrosting mode, the heat generated in the battery 75, which is absorbed by the chiller 24, is pumped up by the refrigeration cycle 10 and can be used to heat the space to be air-conditioned and to defrost the outdoor heat exchanger 22 using condensation heat.

[0238] Next, the control details in the heating / defrosting mode of the vehicle air conditioner 1 will be described with reference to Fig. 19 to Fig. 21. The heating / defrosting operation of the vehicle air conditioner 1 is realized by the control device 70 executing a heating / defrosting control program stored in the ROM. This heating / defrosting control program is executed simultaneously when the vehicle air conditioner 1 is powered on.

[0239] As described above, in the heating and defrosting mode, in parallel with the heating of the air-conditioned space, condensation heat defrosting is performed on the outdoor heat exchanger 22. Condensation heat defrosting includes melting and defrosting and dry defrosting, so there are two states: one in which the air-conditioned space is heated and the outdoor heat exchanger 22 is melted and defrosted, and the other in which the air-conditioned space is heated and the outdoor heat exchanger 22 is dry defrosted.

[0240] As shown in FIG. 19, first, in step S1, it is determined whether or not there is a heating instruction for the operation of the vehicle air conditioner 1. A heating instruction is issued when, in conjunction with the execution of the air conditioning control program, a request is made to heat the air-conditioned space based on detection signals from various control sensors and operation signals from the operation panel. If there is a heating instruction, the process proceeds to step S2. On the other hand, if there is no heating instruction, the heating / defrosting control program is terminated. In this case, air conditioning operation related to another operation mode or cooling operation of the battery 75 is performed.

[0241] In step S2, it is determined whether or not frost has formed on the exterior heat exchanger 22. The determination process in step S2 is made based on whether or not the amount of frost adhering to the exterior heat exchanger 22 exceeds a predetermined standard. If it is determined that the amount of frost has exceeded the standard and that the exterior heat exchanger 22 has frost, the process proceeds to step S3. If it is determined that the exterior heat exchanger 22 has not frosted, the heating / defrosting control program is terminated. In this case, the vehicle air conditioner 1 performs heating operation.

[0242] When the process proceeds to step S3, the operation mode of the vehicle air conditioner 1 is set to the heating / defrosting mode. In the heating / defrosting mode, heating of the air-conditioned space and defrosting of the exterior heat exchanger 22 by condensation heat are performed in parallel, but when both are performed in parallel, it is expected that the capacity of the refrigeration cycle 10 will be insufficient.

[0243] For this reason, the vehicle air conditioner 1 has, as heating and defrosting modes, an efficiency priority mode in which condensation heat defrosting of the exterior heat exchanger 22 is prioritized over heating of the air-conditioned space, and a comfort priority mode in which heating of the air-conditioned space is prioritized over condensation heat defrosting of the exterior heat exchanger 22.

[0244] In step S3, a process is performed to determine whether to give priority to heating of the air-conditioned space or defrosting using condensation heat of the outdoor heat exchanger 22. Specifically, it is determined based on the detection signals of various control sensors and the operation signals of the operation panel whether or not an efficiency priority condition is met under which the efficiency priority mode is assumed to be more suitable than the comfort priority mode.

[0245] An example of the efficiency priority condition is when an operation signal indicating that the efficiency priority mode has been selected is output as an operation signal from the operation panel 71. In other words, when the efficiency priority mode has been selected by a user operation, it is determined that the efficiency priority condition is met.

[0246] Furthermore, an example of an efficiency-priority condition is when it is determined from the detection signals of various control sensors that the heating load of the space to be air-conditioned is smaller than a reference value. If the heating load is smaller than the reference value, it is determined that the efficiency-priority condition is met.

[0247] If the efficiency priority condition is met, the process proceeds to step S4, where control relating to the efficiency priority mode of the heating and dehumidifying mode is performed. The control details relating to the efficiency priority mode of step S4 will be described later with reference to the drawings. When control relating to the efficiency priority mode of the heating and dehumidifying mode is completed, the process proceeds to step S6.

[0248] On the other hand, if the efficiency priority condition is not satisfied, the process proceeds to step S5, where control relating to the comfort priority mode of the heating and dehumidifying mode is performed. The control details relating to the comfort priority mode of step S5 will be explained later with reference to the drawings. When control relating to the comfort priority mode of the heating and dehumidifying mode is completed, the process proceeds to step S6.

[0249] In step S6, since the condensation heat defrosting of the exterior heat exchanger 22 has been completed at the time of completing steps S4 and S5, the operation mode of the vehicle air conditioner 1 is switched from the heating / defrosting mode to the heating mode. After switching to the heating mode, the heating / defrosting control program is terminated.

[0250] Next, the control details regarding the efficiency priority mode of the heating defrost mode will be described with reference to Fig. 20. When the efficiency priority mode is started in step S4, as shown in Fig. 20, first, defrosting capacity control is performed in step 11.

[0251] In the defrosting capacity control in step S11, the refrigerant discharge capacity (rotation speed) of the compressor 11 is controlled so that the refrigerant condensation temperature in the outdoor heat exchanger 22 becomes the target condensing temperature. In dry defrosting in the heating defrosting mode, the target condensing temperature TCO is determined in accordance with the control characteristics diagram shown in Fig. 15, as described in the condensing heat defrosting mode. In addition, the refrigeration cycle 10 There is a strong correlation between the refrigerant temperature and pressure. The target refrigerant pressure corresponding to the refrigerant pressure in the outdoor heat exchanger 22 can be determined. It is also possible to carry out the process using a standard refrigerant pressure.

[0252] That is, when the refrigerant condensation temperature of the outdoor heat exchanger 22 is higher than the target condensation temperature, the rotation speed of the compressor 11 is controlled to be lower than the current speed, and when the refrigerant condensation temperature is lower than the target condensation temperature, the rotation speed of the compressor 11 is controlled to be higher than the current speed. This makes it possible to control the amount of heat released by the refrigerant in the outdoor heat exchanger 22 to a state suitable for condensation heat defrosting.

[0253] In step S12, it is determined whether the refrigerant condensing temperature of the outdoor heat exchanger 22 is lower than the target condensing temperature. That is, it is determined whether the capacity generated by the refrigeration cycle 10 is insufficient for condensation heat defrosting of the outdoor heat exchanger 22. If the refrigerant condensing temperature is lower than the target condensing temperature, the process proceeds to step S14. If the refrigerant condensing temperature is not lower than the target condensing temperature, the process proceeds to step S13.

[0254] In step S13, heating capacity control is performed because a predetermined capacity is ensured for condensation heat defrosting of the outdoor heat exchanger 22. In the heating capacity control in step S13, the opening of the heating expansion valve 20a is controlled so that the blown air temperature TAV becomes the target blown air temperature TAO. The refrigerant temperature corresponding to the target outlet temperature TAO can be identified. There is a strong correlation between the temperature and pressure of the refrigerant in the refrigeration cycle 10 . Therefore, it is possible to specify the target refrigerant pressure corresponding to the target outlet temperature TAO, and the water-refrigerant heat exchange The processing is performed using the target refrigerant pressure corresponding to the refrigerant pressure in the converter 12 and the blown air temperature TAV. It is also possible to do this.

[0255] In other words, when the blown air temperature TAV is higher than the target blown air temperature TAO, the opening of the heating expansion valve 20a is controlled to be larger than the current opening, and when the blown air temperature TAV is lower than the target blown air temperature TAO, the opening of the heating expansion valve 20a is controlled to be smaller than the current opening.

[0256] This allows the amount of heat dissipated in the water-refrigerant heat exchanger 12 to be controlled to an arbitrary value lower than the amount of heat dissipated in the exterior heat exchanger 22. That is, it is possible to create different refrigerant temperatures, namely, the refrigerant temperature required for condensation heat defrosting of the exterior heat exchanger 22 and the refrigerant temperature required for heating the passenger compartment, and each can be appropriately controlled.

[0257] In step S14, defrosting capacity improvement control is performed because it is determined in the determination process of step S12 that the condensation heat defrosting of the outdoor heat exchanger 22 is insufficient relative to a predetermined capacity. In the defrosting capacity improvement control of step S14, the opening degree of the heating expansion valve 20a is fully opened to reduce the temperature of the refrigerant flowing through the water-refrigerant heat exchanger 12 and suppress the amount of heat radiation, thereby increasing the amount of heat radiation in the outdoor heat exchanger 22.

[0258] As a result, even if the refrigerant condensation temperature cannot be adjusted to be higher than the target condensation temperature by simply controlling the operation of the compressor 11, a state in which the refrigerant condensation temperature is higher than the target condensation temperature can be created by controlling the opening of the heating expansion valve 20a.

[0259] In step S15, it is determined whether the outlet air temperature TAV is lower than the target outlet temperature TAO. That is, it is determined whether the amount of heat dissipated in the water-refrigerant heat exchanger 12 is insufficient for the required heating capacity. If the outlet air temperature TAV is lower than the target outlet temperature TAO, the process proceeds to step S16. On the other hand, if the outlet air temperature TAV is not lower than the target outlet temperature TAO, the process proceeds to step S17.

[0260] In step S16, auxiliary heating control is executed because the blown air temperature TAV is lower than the target blown air temperature TAO and the heating capacity of the refrigeration cycle 10 is insufficient relative to the target. In auxiliary heating control, the heat generation amount of the water heater 34 is controlled so that the blown air temperature TAV becomes the target blown air temperature TAO. In other words, the heating capacity of the water heater 34 compensates for the shortage of the heating capacity of the refrigeration cycle 10 relative to the target value, thereby ensuring comfort in the air-conditioned space.

[0261] In step S17, liquid backflow prevention control is performed. In the liquid backflow prevention control, the opening degree of the cooling expansion valve 20c is controlled so as to prevent liquid backflow, in which the liquid phase refrigerant is supplied to the suction port of the compressor 11. The opening degree of the cooling expansion valve 20c is controlled so that the degree of superheat of the refrigerant on the suction port side of the compressor 11 becomes a predetermined reference value. This makes it possible to prevent damage to the compressor 11 due to the liquid phase refrigerant flowing in from the suction port of the compressor 11.

[0262] In step S18, it is determined whether condensation heat defrosting of the outdoor heat exchanger 22 has been completed. As described above, condensation heat defrosting is performed in the order of melting and defrosting, and then dry defrosting. Therefore, in step S18, it is determined whether moisture generated by melting and defrosting has been evaporated and removed from the outdoor heat exchanger 22 by dry defrosting. If condensation heat defrosting has been completed, control related to the efficiency priority mode of the heating defrosting mode is terminated. If condensation heat defrosting has not been completed, the process returns to step S11, and control related to the efficiency priority mode is restarted.

[0263] 20, in the efficiency priority mode, in step S11, the heating capacity required for condensation heat defrosting of the outdoor heat exchanger 22 is realized by controlling the refrigerant discharge capacity of the compressor 11. Then, in step S13, the heating capacity required for heating the space to be air-conditioned is realized by controlling the opening of the heating expansion valve 20a.

[0264] As a result, in the cycle configuration in the heating defrost mode, the defrosting capacity required for condensation heat defrosting of the outdoor heat exchanger 22 and the heating capacity required for heating the space to be air-conditioned can be controlled separately, thereby achieving different refrigerant condensation temperatures.

[0265] In the efficiency priority mode, when the refrigerant condensation temperature is lower than the target condensation temperature, defrosting capacity improvement control is performed and the opening of the heating expansion valve 20a is adjusted to the fully open state. As a result, the refrigeration cycle 10 operates to satisfy the amount of heat radiation required for condensation heat defrosting of the outdoor heat exchanger 22, with priority given to ensuring the amount of heat radiation required for heating the air-conditioned space. Therefore, condensation heat defrosting can be achieved with priority given to heating the air-conditioned space.

[0266] Furthermore, in the efficiency priority mode of the heating and defrosting mode, if the heating capacity of the space to be air-conditioned by the operation of the refrigeration cycle 10 is insufficient (step S15), the high temperature side heat medium is heated by the water heater 34 under auxiliary heating control.

[0267] As a result, even if the heating capacity of the refrigeration cycle 10 is insufficient for heating the air-conditioned space in the heating defrost mode, this can be compensated for by using the water heater 34, which is a heat source different from the refrigeration cycle 10, thereby ensuring comfort.

[0268] Next, the control details regarding the comfort priority mode of the heating and defrosting mode will be described with reference to Fig. 21. When the comfort priority mode is started in step S5, as shown in Fig. 21, first, heating capacity control is performed in step S21.

[0269] In the heating capacity control in step S21, the refrigerant discharge capacity (rotation speed) of the compressor 11 is controlled so that the blown air temperature TAV becomes the target blown air temperature TAO. The target blown air temperature TAO in the heating defrost mode is determined in the same way as in the heating mode.

[0270] That is, when the blown air temperature TAV is higher than the target blown air temperature TAO, the rotation speed of the compressor 11 is controlled to be lower than the current speed, and when the blown air temperature TAV is lower than the target blown air temperature TAO, the rotation speed of the compressor 11 is controlled to be higher than the current speed. This ensures the amount of heat dissipation from the water-refrigerant heat exchanger 12 required for heating the air-conditioned space, and enables the air-conditioned space to be heated in an appropriate manner.

[0271] In step S22, it is determined whether the blown air temperature TAV is lower than the target blown air temperature TAO. That is, it is determined whether the amount of heat dissipated in the water-refrigerant heat exchanger 12 is insufficient for the required heating capacity. If the blown air temperature TAV is lower than the target blown air temperature TAO, the process proceeds to step S23. On the other hand, if the blown air temperature TAV is not lower than the target blown air temperature TAO, the process proceeds to step S24.

[0272] In step S23, auxiliary heating control is executed because the blown air temperature TAV is lower than the target blown air temperature TAO and the heating capacity of the refrigeration cycle 10 is insufficient relative to the target. In auxiliary heating control, the heat generation amount of the water heater 34 is controlled so that the blown air temperature TAV becomes the target blown air temperature TAO. In other words, the heating capacity of the water heater 34 compensates for the shortage of the heating capacity of the refrigeration cycle 10 relative to the target value, thereby ensuring comfort in the air-conditioned space.

[0273] When the process proceeds to step S24, defrosting capacity control in the heating defrost mode is performed. In the defrosting capacity control in step S24, the opening of the heating expansion valve 20a is controlled so that the refrigerant condensation temperature in the outdoor heat exchanger 22 becomes a target condensing temperature. In dry defrosting in the heating defrost mode, the target condensing temperature TCO is determined in accordance with the control characteristics diagram shown in Fig. 15, as described in the condensing heat defrost mode.

[0274] That is, when the refrigerant condensation temperature of the outdoor heat exchanger 22 is higher than the target condensation temperature, the opening degree of the heating expansion valve 20a is controlled to be lower than the current opening degree, and when the refrigerant condensation temperature is lower than the target condensation temperature, the opening degree of the heating expansion valve 20a is controlled to be higher than the current opening degree. This makes it possible to control the amount of heat released by the refrigerant in the outdoor heat exchanger 22 to a state suitable for condensation heat defrosting.

[0275] In step S25, it is determined whether the refrigerant condensation temperature of the outdoor heat exchanger 22 is higher than the target condensation temperature. Here, in the condensation heat defrosting of the outdoor heat exchanger 22, the target condensation temperature is set to be within the target area At shown in Fig. 14, so a state where the condensation temperature is higher than the target condensation temperature is considered to be a state where there is a high possibility that water evaporated by the condensation heat defrosting will be visible as white mist.

[0276] That is, in step S25, it is determined whether or not the evaporated water is likely to be visible as a white mist, from the viewpoint of the amount of heat added in the condensation heat defrosting. If the refrigerant condensation temperature is higher than the target condensation temperature, the process proceeds to step S26. If the refrigerant condensation temperature is not higher than the target condensation temperature, the process proceeds to step S27.

[0277] In step S26, since it is determined that the evaporated water is likely to be visible as white mist in terms of the amount of heat added in the condensation heat defrosting, the condensation heat defrosting of the exterior heat exchanger 22 in the heating defrosting mode is stopped. This makes it possible to prevent the white mist resulting from the water evaporating in the condensation heat defrosting from being mistaken for white smoke. When the processing of step S26 ends, the control related to the comfort-priority mode in the heating defrosting mode ends. As a result, in step S6 of FIG. 19, the operation mode of the vehicle air conditioner 1 is switched to the heating mode.

[0278] In step S27, liquid backflow prevention control is performed. In the liquid backflow prevention control in step S27, similar to step S17, the opening of the cooling expansion valve 20c is controlled so as to prevent liquid backflow, which is the supply of liquid-phase refrigerant to the suction port of the compressor 11. This makes it possible to prevent damage to the compressor 11 due to the inflow of liquid-phase refrigerant from the suction port of the compressor 11.

[0279] In step S28, it is determined whether condensation heat defrosting of the outdoor heat exchanger 22 has been completed. The contents of the determination process in step S28 are the same as those in step S17. If condensation heat defrosting has been completed, control related to the comfort priority mode of the heating defrost mode is terminated. If condensation heat defrosting has not been completed, the process returns to step S21, and control related to the comfort priority mode is restarted.

[0280] 21, in the comfort-priority mode, in step S21, the heating capacity required for heating the air-conditioned space is realized by controlling the refrigerant discharge capacity of the compressor 11. Then, in step S24, the defrosting capacity required for condensation heat defrosting of the outdoor heat exchanger 22 is realized by controlling the opening of the heating expansion valve 20a.

[0281] As a result, in the cycle configuration in the heating defrost mode, the defrosting capacity required for condensation heat defrosting of the outdoor heat exchanger 22 and the heating capacity required for heating the space to be air-conditioned can be controlled separately, thereby achieving different refrigerant condensation temperatures.

[0282] Furthermore, if it is determined in step S25 that the evaporated water is likely to be visible as white mist, in view of the amount of heat added in the condensation heat defrosting, the condensation heat defrosting in the heating defrosting mode is stopped and the mode is switched to the heating mode, thereby preventing the water vapor generated by the condensation heat defrosting from being mistaken for white mist.

[0283] In the comfort priority mode, as described above, the heating of the air-conditioned space continues, but if the conditions of step S25 etc. are satisfied, the condensation heat defrosting is stopped. That is, in the comfort priority mode, the heating of the air-conditioned space can be given priority over the condensation heat defrosting of the outdoor heat exchanger 22.

[0284] Furthermore, in the comfort priority mode of the heating and defrosting mode, if the heating capacity of the air-conditioned space due to the operation of the refrigeration cycle 10 is insufficient (step S22), the high-temperature side heat medium is heated by the water heater 34 under auxiliary heating control.

[0285] As a result, even if the heating capacity of the refrigeration cycle 10 is insufficient for heating the air-conditioned space in the heating defrost mode, this can be compensated for by using the water heater 34, which is a heat source different from the refrigeration cycle 10, thereby ensuring comfort.

[0286] As described above, the vehicle air conditioning system 1 according to the first embodiment can be operated in a heating / defrosting mode using the refrigeration cycle 10 and the control device 70, in which condensation heat defrosting of the outdoor heat exchanger 22 and heating of the space to be air-conditioned are performed in parallel.

[0287] In addition, in the heating / defrosting mode, the temperature of the refrigerant required by the water-refrigerant heat exchanger 12 or pressure and the refrigerant temperature required in the outdoor heat exchanger 22 or pressure When the two different refrigerant temperatures are different, the operation control of the compressor 11 and the heating expansion valve 20a is performed. or pressure Achieve this.

[0288] That is, the operation of the compressor 11 is controlled by the compression control unit 70d to adjust the refrigerant temperature required in either the water-refrigerant heat exchanger 12 or the outdoor heat exchanger 22. or pressure Furthermore, the pressure reduction control section 70e controls the operation of the heating expansion valve 20a to achieve the refrigerant temperature required for either the water-refrigerant heat exchanger 12 or the outdoor heat exchanger 22. or pressure This can be achieved.

[0289] According to the vehicle air conditioning system 1, in the heating defrost mode, the amount of heat released from the exterior heat exchanger 22 related to condensation heat defrosting and the amount of heat released from the water-refrigerant heat exchanger 12 related to heating can be controlled separately, and both can be achieved in an appropriate manner.

[0290] Condensation heat defrosting in the vehicle air conditioner 1 involves dry defrosting, which uses heat absorbed by the refrigerant to evaporate the moisture produced by melting and defrosting. By performing dry defrosting with condensation heat defrosting, it is possible to suppress refreezing of the moisture produced by melting the frost, and to prevent a decrease in the heat exchange performance of the exterior heat exchanger 22 and a decrease in the heating performance of the vehicle air conditioner 1 due to refreezing.

[0291] Furthermore, in dry defrosting of condensation heat defrosting, the target condensation temperature TCO required in the outdoor heat exchanger 22 is set to be located within the target area At in Fig. 14, and in dry defrosting, the refrigerant condensation temperature in the outdoor heat exchanger 22 is controlled to approach the target condensation temperature. This reduces the possibility that water vapor derived from melted moisture will be visible as white mist during dry defrosting, and prevents it from being mistaken for white smoke or the like.

[0292] In dry defrosting using condensation heat defrosting, the wind speed of the outside air blown by the outside air fan 22a toward the outdoor heat exchanger 22 is set so that it is within the target area At in Fig. 14, and in dry defrosting, the operation of the outside air fan 22a is controlled so that the wind speed becomes the set value. This reduces the possibility that water vapor derived from melted moisture will be visible as white mist during dry defrosting, preventing it from being mistaken for white smoke or the like.

[0293] 20, in the efficiency priority mode of the heating defrost mode, the operation of the compressor 11 is controlled in the defrosting capacity control of step S11 so that the refrigerant condensation temperature becomes the target condensing temperature TCO. Then, in the heating capacity control of step S13, the opening of the heating expansion valve 20a is controlled so that the blown air temperature TAV becomes the target blown air temperature TAO.

[0294] As a result, in the cycle configuration in the heating defrost mode, the defrosting capacity required for condensation heat defrosting of the outdoor heat exchanger 22 and the heating capacity required for heating the space to be air-conditioned can be controlled separately, thereby achieving different refrigerant condensation temperatures.

[0295] In the efficiency priority mode, when the refrigerant condensation temperature is lower than the target condensation temperature, defrosting capacity improvement control is performed and the opening of the heating expansion valve 20a is adjusted to the fully open state. As a result, the refrigeration cycle 10 operates to satisfy the amount of heat radiation required for condensation heat defrosting of the outdoor heat exchanger 22, with priority given to ensuring the amount of heat radiation required for heating the air-conditioned space. Therefore, condensation heat defrosting can be achieved with priority given to heating the air-conditioned space.

[0296] 21, in the comfort-priority mode of the heating / defrosting mode, in step S21, the heating capacity required for heating the air-conditioned space is realized by controlling the refrigerant discharge capacity of the compressor 11. Then, in step S24, the defrosting capacity required for condensation heat defrosting of the outdoor heat exchanger 22 is realized by controlling the opening of the heating expansion valve 20a.

[0297] As a result, in the cycle configuration in the heating defrost mode, the defrosting capacity required for condensation heat defrosting of the outdoor heat exchanger 22 and the heating capacity required for heating the space to be air-conditioned can be controlled separately, thereby achieving different refrigerant condensation temperatures.

[0298] Furthermore, in the heating defrosting mode, if the heating capacity of the space to be air-conditioned due to the operation of the refrigeration cycle 10 is insufficient (steps S15, S22), the high-temperature side heat medium is heated by the water heater 34 through auxiliary heating control (steps S16, S23).

[0299] As a result, even if the heating capacity of the refrigeration cycle 10 is insufficient for heating the air-conditioned space in the heating defrost mode, this can be compensated for by using the water heater 34, which is a heat source different from the refrigeration cycle 10, thereby ensuring comfort.

[0300] Furthermore, if it is determined in step S25 that the evaporated water is likely to be visible as white mist, in view of the amount of heat added in the condensation heat defrosting, the condensation heat defrosting in the heating defrosting mode is stopped and the mode is switched to the heating mode, thereby preventing the water vapor generated by the condensation heat defrosting from being mistaken for white mist.

[0301] In the comfort priority mode, as described above, the heating of the air-conditioned space continues, but if the conditions of step S25 etc. are satisfied, the condensation heat defrosting is stopped. That is, in the comfort priority mode, the heating of the air-conditioned space can be given priority over the condensation heat defrosting of the outdoor heat exchanger 22.

[0302] Furthermore, in the comfort priority mode of the heating and defrosting mode, if the heating capacity of the air-conditioned space due to the operation of the refrigeration cycle 10 is insufficient (step S22), the high-temperature side heat medium is heated by the water heater 34 under auxiliary heating control.

[0303] As a result, even if the heating capacity of the refrigeration cycle 10 is insufficient for heating the air-conditioned space in the heating defrost mode, this can be compensated for by using the water heater 34, which is a heat source different from the refrigeration cycle 10, thereby ensuring comfort.

[0304] 19, in step S3, depending on whether or not the efficiency priority condition is satisfied, either the efficiency priority mode or the comfort priority mode is set in the heating / dehumidifying mode. Whether or not the efficiency priority condition is satisfied is determined by an operation instruction from the user, the operating environment surrounding the automotive air conditioner 1, and the like. In other words, the automotive air conditioner 1 can realize the heating / defrosting mode in a manner that corresponds to the user's intention and the environment surrounding the automotive air conditioner 1.

[0305] (Second embodiment) Next, a second embodiment, which differs from the above-described embodiment, will be described with reference to Figures 22 and 23. In the second embodiment, the configuration of the heating unit 35 and the device employed as the auxiliary heating device are different from those of the above-described embodiment. Other basic configurations are the same as those of the above-described embodiment, so repeated description will be omitted.

[0306] First, the heating section 35 of the vehicle air conditioner 1 according to the second embodiment is composed of the interior condenser 12X. The heating section 35 according to the first embodiment is composed of the water-refrigerant heat exchanger 12 and the high-temperature side heat medium circuit 30.

[0307] As shown in Fig. 22, the indoor condenser 12X is disposed between the discharge port of the compressor 11 and the inlet port of the first three-way joint 13a, and is a condenser that condenses the high-pressure refrigerant discharged from the compressor 11. As shown in Fig. 23, the indoor condenser 12X is disposed in the casing 61 of the indoor air-conditioning unit 60 at the position of the heater core 33 in the first embodiment.

[0308] Therefore, the indoor condenser 12X condenses the high-pressure refrigerant discharged from the compressor 11 through heat exchange with the blown air that has passed through the indoor evaporator 23, thereby heating the blown air. That is, the indoor condenser 12X corresponds to an example of a heating heat exchanger.

[0309] 23, the air heater 34X is disposed inside the casing 61 of the indoor air-conditioning unit 60, downstream of the indoor condenser 12X in the flow of blown air. The air heater 34X is configured to be able to radiate heat to the blown air that has passed through the indoor condenser 12X, and heats the blown air.

[0310] A PTC heater having a PTC element (i.e., a positive temperature coefficient thermistor) can be used as the air heater 34X. The heat generation amount of the air heater 34X is arbitrarily controlled by a control voltage output from the control device 70. The air heater 34X corresponds to an example of an auxiliary heating device.

[0311] 22, the vehicle air conditioner 1 according to the second embodiment has the same configuration as that of the first embodiment described above, except for the configuration of the heating unit 35 and the arrangement of the air heater 34X. Therefore, a summary of condensation heat defrosting and control details related to the heating defrosting mode will not be described again.

[0312] As a result, with the vehicle air conditioner 1 according to the second embodiment, even if the configuration of the heating unit 35 is changed from that of the first embodiment, it is possible to achieve both condensation heat defrosting of the exterior heat exchanger 22 and passenger compartment heating in the heating and defrosting mode. The compression control unit 70d and the decompression control unit 70e can create and control two different refrigerant temperatures for condensation heat defrosting of the exterior heat exchanger 22 and passenger compartment heating, respectively.

[0313] As described above, according to the vehicle air conditioning device 1 of the second embodiment, even if the configuration of the heating section 35, etc. is changed, the same effects as those of the above-mentioned embodiment can be obtained from the same configuration as those of the above-mentioned embodiment.

[0314] (Third embodiment) Next, a third embodiment, which is different from the above-described embodiments, will be described with reference to Figs. 24 to 27. In the above-described embodiments, the cycle configuration of the refrigeration cycle 10 is a so-called receiver cycle, but the refrigeration cycle 10 in the third embodiment is configured as an accumulator cycle, which is different. In Figs. 24 to 27, the same reference numerals are used to designate the same or equivalent parts as those in the above-described embodiments. This also applies to the following drawings.

[0315] 24, the vehicle air conditioner 1 according to the third embodiment includes a refrigeration cycle 10, a high-temperature side heat medium circuit 30, a low-temperature side heat medium circuit 40, and an interior air conditioning unit 60. The high-temperature side heat medium circuit 30, the low-temperature side heat medium circuit 40, the interior air conditioning unit 60, and the control device 70 according to the third embodiment have the same configurations as those of the above-described embodiments.

[0316] The refrigeration cycle 10 of the third embodiment is connected to a compressor 11, a water-refrigerant heat exchanger 12, a heating expansion valve 20a, a cooling expansion valve 20b, a cooling expansion valve 20c, an outdoor heat exchanger 22, an indoor evaporator 23, a chiller 24, etc.

[0317] The discharge port of the compressor 11 according to the third embodiment is connected to the inlet side of the refrigerant passage 12a of the water-refrigerant heat exchanger 12. The water-refrigerant heat exchanger 12 has the same configuration as in the above-described embodiments. The water-refrigerant heat exchanger 12 corresponds to an example of a heating heat exchanger, and together with the high-temperature side heat medium circuit 30, constitutes a heating section 35.

[0318] An inlet side of a first connection part 14a having a three-way joint structure having three inlet and outlet ports that communicate with each other is connected to an outlet of a refrigerant passage 12a of the water-refrigerant heat exchanger 12. The refrigeration cycle 10 of the third embodiment is provided with second to sixth connection parts 14b to 14f that are configured similarly to the first connection part 14a.

[0319] An inlet side of a heating expansion valve 20a is connected to one outlet of the first connection part 14a. The heating expansion valve 20a corresponds to an example of a first expansion valve. An inlet side of a second connection part 14b is connected to the other outlet of the first connection part 14a via a refrigerant bypass passage 28a. A dehumidification on-off valve 17a is arranged in the refrigerant bypass passage 28a.

[0320] The dehumidification on-off valve 17a is a solenoid valve that opens and closes a refrigerant passage that connects the other outlet side of the first connection part 14a and one inlet side of the second connection part 14b. Furthermore, the refrigeration cycle 10 includes a heating on-off valve 17b, as will be described later. The heating on-off valve 17b has a basic configuration similar to that of the dehumidification on-off valve 17a. The dehumidification on-off valve 17a and the heating on-off valve 17b can switch the refrigerant circuit for each operation mode by opening and closing the refrigerant passage.

[0321] The outlet of the heating expansion valve 20a is connected to the refrigerant inlet side of the outdoor heat exchanger 22. As in the first embodiment, the outdoor heat exchanger 22 is an example of an outdoor air heat exchanger and constitutes an outdoor air heat exchange section 29X. The outdoor air fan 22a is arranged to blow outdoor air to the outdoor heat exchanger 22.

[0322] An inlet side of the third connection part 14c is connected to a refrigerant outlet of the outdoor heat exchanger 22. One outlet side of the third connection part 14c is connected to one inlet side of the fourth connection part 14d via a heating passage 28b. A heating on-off valve 17b that opens and closes this refrigerant passage is arranged in the heating passage 28b.

[0323] The other outlet of the third connecting portion 14c is connected to the other inlet side of the second connecting portion 14b. A first check valve 21a is disposed in a refrigerant passage connecting the other outlet side of the third connecting portion 14c and the other inlet side of the second connecting portion 14b.

[0324] The outlet of the second connecting portion 14b is connected to the inlet side of the fifth connecting portion 14e. The inlet side of the cooling expansion valve 20b is connected to one outlet of the fifth connecting portion 14e. The inlet side of the cooling expansion valve 20c is connected to the other outlet of the fifth connecting portion 14e. As in the first embodiment, the cooling expansion valve 20b and the cooling expansion valve 20c correspond to examples of second expansion valves.

[0325] The outlet of the cooling expansion valve 20b is connected to the refrigerant inlet side of the indoor evaporator 23. As in the first embodiment, the indoor evaporator 23 is an example of an evaporator. The outlet of the cooling expansion valve 20c is connected to the inlet side of the refrigerant passage 24a of the chiller 24. The chiller 24 corresponds to an example of an evaporator. The other inlet side of the sixth connecting part 14f is connected to the outlet of the refrigerant passage 24a of the chiller 24.

[0326] The inlet side of an evaporation pressure regulating valve 25 is connected to the refrigerant outlet of the indoor evaporator 23. The evaporation pressure regulating valve 25 functions to maintain the refrigerant evaporation pressure in the indoor evaporator 23 at or above a predetermined reference pressure in order to suppress frost formation on the indoor evaporator 23. The evaporation pressure regulating valve 25 is configured as a mechanical variable throttle mechanism that increases the valve opening as the pressure of the refrigerant on the outlet side of the indoor evaporator 23 increases.

[0327] As a result, the evaporation pressure regulating valve 25 maintains the refrigerant evaporation temperature in the indoor evaporator 23 at or above a frost suppression temperature (1°C in this embodiment) that can suppress frost formation on the indoor evaporator 23. One inlet side of the sixth connecting part 14f is connected to an outlet of the evaporation pressure regulating valve 25. The other inlet side of the fourth connecting part 14d is connected to an outlet of the sixth connecting part 14f.

[0328] The outlet of the fourth connecting portion 14d is connected to the inlet side of the accumulator 26. The accumulator 26 is a gas-liquid separator that separates the refrigerant that flows into it into gas and liquid phases and stores excess liquid-phase refrigerant in the cycle. The gas-phase refrigerant outlet of the accumulator 26 is connected to the suction port side of the compressor 11.

[0329] According to the refrigeration cycle 10 of the third embodiment, various refrigerant circuits can be switched by controlling the operation of the heating on-off valve 17b, the cooling expansion valve 20b, the cooling expansion valve 20c, the dehumidification on-off valve 17a, and the heating on-off valve 17b. That is, the vehicle air conditioner 1 of the third embodiment can switch between a refrigerant circuit for a heating mode, a refrigerant circuit for a cooling mode, a refrigerant circuit for a dehumidification and heating mode, etc.

[0330] Next, the heating mode of the vehicle air conditioner 1 according to the third embodiment will be described with reference to Fig. 25. In the heating mode according to the third embodiment, the control device 70 closes the dehumidifying on-off valve 17a and opens the heating on-off valve 17b. The control device 70 then throttles the heating expansion valve 20a and fully closes the cooling expansion valve 20b and the cooling expansion valve 20c.

[0331] The control device 70 also operates the high-temperature side pump 32 to pump the high-temperature side heat medium at a predetermined pumping capacity. In the heating mode, the control device 70 keeps the low-temperature side pump 42 stopped.

[0332] As a result, a vapor compression refrigeration cycle is formed in the heating mode refrigeration cycle 10. As shown in Fig. 25, in the heating mode, the refrigerant circulates by flowing through the compressor 11, the water-refrigerant heat exchanger 12, the heating expansion valve 20a, the outdoor heat exchanger 22, the heating on-off valve 17b, the accumulator 26, and the compressor 11 in this order.

[0333] That is, in the refrigeration cycle 10 in the heating mode, the low-pressure refrigerant absorbs heat from the outside air in the outdoor heat exchanger 22, and the heat of the high-pressure refrigerant discharged from the compressor 11 is dissipated to the high-temperature side heat medium in the water-refrigerant heat exchanger 12. By circulating the high-temperature side heat medium in the high-temperature side heat medium circuit 30, the blown air passing through the heater core 33 is heated by the heat of the high-temperature side heat medium.

[0334] Therefore, in the heating mode according to the third embodiment, the air heated by the heater core 33 is blown into the vehicle compartment, thereby heating the vehicle compartment.

[0335] Here, also in the third embodiment, if the outside air is at a low temperature and has a high humidity during heating operation, frost will form on the exterior heat exchanger 22. The vehicle air conditioner 1 according to the third embodiment has a condensation heat defrosting mode as an operating mode of the defrosting operation.

[0336] Next, the condensation heat defrosting mode in the third embodiment will be described with reference to Fig. 26. The condensation heat defrosting mode in the third embodiment is an operation mode in which heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40 is used to defrost the outdoor heat exchanger 22, as in the first embodiment.

[0337] In the condensation heat defrosting mode, the control device 70 closes the dehumidifying on-off valve 17a and the heating on-off valve 17b. The control device 70 then fully opens the heating expansion valve 20a and throttles the cooling expansion valve 20c. The cooling expansion valve 20b is fully closed.

[0338] Furthermore, the control device 70 operates the low-temperature side pump 42 in the low-temperature side heat medium circuit 40 to pump the low-temperature side heat medium at a predetermined pumping capacity. In the condensation heat defrosting mode, the control device 70 stops the high-temperature side pump 32 in the high-temperature side heat medium circuit 30.

[0339] As a result, in the refrigeration cycle 10 in the condensation heat defrost mode, the refrigerant circulates by flowing through the compressor 11, water-refrigerant heat exchanger 12, heating expansion valve 20a, outdoor heat exchanger 22, first check valve 21a, cooling expansion valve 20c, chiller 24, accumulator 26, and compressor 11 in that order. With this circuit configuration, the control device 70 controls the operation of various controlled devices.

[0340] In other words, in the refrigeration cycle 10 in the condensation heat defrost mode, the heat generated in the battery 75, which is absorbed by the chiller 24, is pumped up by the refrigeration cycle 10 and applied to the outdoor heat exchanger 22, thereby defrosting the outdoor heat exchanger 22.

[0341] Note that melting defrosting and dry defrosting are also performed in the condensation heat defrosting according to the third embodiment. The same methods as those in the first embodiment can be employed for controlling the melting defrosting and dry defrosting.

[0342] Next, the heating and defrosting mode according to the third embodiment will be described with reference to Fig. 27. In the third embodiment as well, the heating and defrosting mode is an operation mode in which heating of the air-conditioned space and condensation heat defrosting of the outdoor heat exchanger 22 are performed in parallel. The condensation heat defrosting in this case also includes melting-off frost and dry defrosting.

[0343] In the heating and defrosting mode, the control device 70 closes the dehumidifying on-off valve 17a and the heating on-off valve 17b. Then, the control device 70 throttles the heating expansion valve 20a and the cooling expansion valve 20c, respectively, and fully closes the cooling expansion valve 20b.

[0344] The control device 70 also operates the low-temperature side pump 42 in the low-temperature side heat medium circuit 40 to pump the low-temperature side heat medium at a predetermined pumping capacity. In the heating / defrosting mode, the control device 70 also operates the high-temperature side pump 32 in the high-temperature side heat medium circuit 30 to pump the high-temperature side heat medium at a predetermined pumping capacity.

[0345] As a result, in the refrigeration cycle 10 in the heating / defrosting mode, the refrigerant circulates by flowing through the compressor 11, water-refrigerant heat exchanger 12, heating expansion valve 20a, outdoor heat exchanger 22, first check valve 21a, cooling expansion valve 20c, chiller 24, accumulator 26, and compressor 11 in that order. With this circuit configuration, the control device 70 controls the operation of various control target devices.

[0346] In other words, in the refrigeration cycle 10 in the condensation heat defrost mode, the heat generated in the battery 75 that has absorbed heat in the chiller 24 is pumped up by the refrigeration cycle 10 and can be used to heat the air-conditioned space via the heating section 35 and for condensation heat defrosting of the outdoor heat exchanger 22.

[0347] In the heating and defrosting mode according to the third embodiment, the control aspects of the components of the vehicle air conditioner 1 and the control details related to the efficiency priority mode and the comfort priority mode can be similar to those of the first embodiment. Therefore, a detailed description of the specific control aspects of the heating and defrosting mode will be omitted.

[0348] In the heating defrost mode of the third embodiment, when the refrigerant temperature required by the water-refrigerant heat exchanger 12 differs from the refrigerant temperature required by the outdoor heat exchanger 22, two different refrigerant temperatures are realized by controlling the operation of the compressor 11 and the heating expansion valve 20a.

[0349] That is, the operation of the compressor 11 is controlled by the compression control unit 70d to adjust the refrigerant temperature required in either the water-refrigerant heat exchanger 12 or the outdoor heat exchanger 22. or pressure Furthermore, the pressure reduction control section 70e controls the operation of the heating expansion valve 20a to achieve the refrigerant temperature required for either the water-refrigerant heat exchanger 12 or the outdoor heat exchanger 22. or pressure This can be achieved.

[0350] As described above, according to the vehicle air conditioning device 1 of the third embodiment, even if an accumulator cycle is adopted as the refrigeration cycle 10, the same effects as those of the above-mentioned embodiments can be obtained from the same configuration as those of the above-mentioned embodiments.

[0351] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications can be made as follows without departing from the spirit of the present invention. Furthermore, the means disclosed in each of the above-described embodiments may be combined as appropriate within the scope of feasibility.

[0352] (a) In the above-described embodiment, condensation heat defrosting is performed by performing melting / defrosting and dry defrosting, but if it is considered that the water produced by melting will not refreeze after melting / defrosting is performed, dry defrosting may be omitted. For example, if weather information corresponding to the current location of the electric vehicle is acquired by the communication unit 74 and the outside air temperature is expected to be higher than 0°C for a predetermined period of time in the future, dry defrosting may be omitted.

[0353] (b) Furthermore, in the condensation heat defrosting in the above-described embodiment, as an example, heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40 is utilized, but the present invention is not limited to this. As long as heat absorbed by the evaporator arranged on the low-pressure side can be utilized to defrost the outdoor heat exchanger 22, the heat absorption target is not limited. As a condensation heat defrosting embodiment, for example, heat can be absorbed from the air inside the indoor air-conditioning unit 60 by the indoor evaporator 23, or heat can be absorbed by both the indoor evaporator 23 and the chiller 24.

[0354] (c) In the heating / defrosting mode when the heating unit 35 of the vehicle air conditioner 1 is configured with the water-refrigerant heat exchanger 12 and the high-temperature side heat medium circuit 30, it is also possible to initially set the comfort priority mode out of the efficiency priority mode and the comfort priority mode. In this case, in the comfort priority mode, if the defrosting capacity of the exterior heat exchanger 22 is insufficient, the condensation heat defrosting may be terminated. [Explanation of symbols]

[0355] 1. Vehicle air conditioning system 10 Refrigeration cycle 11 Compressor 12 Water refrigerant heat exchanger 20a Heating expansion valve 20c Refrigerant expansion valve 22 Outdoor heat exchanger 24 Chiller 70 Control device

Claims

1. a heating section (35) that uses the refrigerant as a heat source to heat air to be blown into the air-conditioned space, the heating section (35) including a heating heat exchanger (12, 12X) that condenses the refrigerant discharged from the compressor during a heating operation for heating the air-conditioned space, the heating section (35) including an outdoor air heat exchanger (22) that causes the refrigerant to absorb heat from outdoor air during the heating operation, a first expansion valve (20a) that is arranged between an outlet of the heating heat exchanger and an inlet of the outdoor air heat exchanger and is configured to be able to reduce the pressure of the refrigerant flowing out from the heating heat exchanger, second expansion valves (20b, 20c) that are configured to be able to reduce the pressure of the refrigerant flowing out from at least one of the heating heat exchanger and the outdoor air heat exchanger, and an evaporator (23, 24) that causes the refrigerant decompressed by the second expansion valve to absorb heat and evaporate; a control unit (70) that controls condensation heat defrosting for melting and defrosting frost attached to the outside air heat exchanger using heat absorbed by the refrigerant in the evaporator, and heating of the air-conditioned space using heat radiated from the refrigerant in the heating heat exchanger, When the condensation heat defrosting and the heating of the air-conditioned space are performed in parallel, if the temperature or pressure of the refrigerant required in the heating heat exchanger is different from the temperature or pressure of the refrigerant required in the outdoor air heat exchanger, a compression control unit (70d) that realizes either the temperature or pressure of the refrigerant required in the heating heat exchanger or the temperature or pressure of the refrigerant required in the outside air heat exchanger by controlling the operation of the compressor; a pressure reduction control unit (70e) that realizes the other of the temperature or pressure of the refrigerant required in the heating heat exchanger and the temperature or pressure of the refrigerant required in the outside air heat exchanger by controlling the operation of the first expansion valve.

2. 2. The vehicle air conditioner according to claim 1, wherein the condensation heat defrosting evaporates moisture produced by melting the frost from the outside air heat exchanger using heat absorbed by the refrigerant.

3. 3. The vehicle air conditioning system according to claim 2, wherein the control unit determines the temperature or pressure of the refrigerant required in the outside air heat exchanger during the condensation heat defrosting so as to reduce visibility when moisture generated by defrosting of the outside air heat exchanger evaporates.

4. an outside air fan (22a) that blows the outside air to the outside air heat exchanger during the condensation heat defrosting; 4. The vehicle air conditioning system according to claim 2, wherein the control unit, in the condensation heat defrosting, determines a wind speed of the outside air blown by the outside air fan so as to reduce visibility when moisture generated by defrosting of the outside air heat exchanger evaporates.

5. In the case of an efficiency priority mode in which the condensation heat defrosting and the heating of the air-conditioned space are performed in parallel and the condensation heat defrosting is prioritized over the heating of the air-conditioned space, the compression control unit controls the operation of the compressor so as to achieve a temperature or pressure of the refrigerant required in the outside air heat exchanger, 5. The vehicle air conditioning system according to claim 1, wherein the pressure reduction control unit controls the operation of the first expansion valve so as to achieve a temperature or pressure of the refrigerant required in the heating heat exchanger.

6. In the efficiency priority mode, when the temperature or pressure of the refrigerant in the outdoor air heat exchanger is lower than the temperature or pressure of the refrigerant required in the outdoor air heat exchanger and the defrosting capacity related to the condensation heat defrosting is insufficient, The vehicle air conditioning system according to claim 5, wherein the pressure reduction control unit increases the opening degree of the first expansion valve to reduce the amount of heat radiation in the heating heat exchanger.

7. In a comfort priority mode in which the condensation heat defrosting and the heating of the air-conditioned space are performed in parallel and the heating of the air-conditioned space is prioritized over the condensation heat defrosting, the compression control unit controls the operation of the compressor to achieve a temperature or pressure of the refrigerant required in the heating heat exchanger, 7. The vehicle air conditioning system according to claim 1, wherein the pressure reduction control unit controls the operation of the first expansion valve so as to achieve a temperature or pressure of the refrigerant required in the outside air heat exchanger.

8. an auxiliary heating device (34, 34X) capable of heating the air to be blown into the air-conditioned space by using a heat source different from that of the refrigeration cycle; 8. The vehicle air conditioning system according to claim 1, wherein when the condensation heat defrosting and the heating of the air-conditioned space are performed in parallel, if the temperature or pressure of the refrigerant in the heating heat exchanger is insufficient for the heating capacity required for heating the air-conditioned space, the control unit compensates for the heating capacity by operating the auxiliary heating device.

9. the control unit includes a mode determination unit (70f) that determines whether an efficiency priority mode that prioritizes the condensation heat defrosting over the heating of the air-conditioned space or a comfort priority mode that prioritizes the heating of the air-conditioned space over the condensation heat defrosting is appropriate when the condensation heat defrosting and the heating of the air-conditioned space are performed in parallel; 9. The vehicle air conditioning system according to claim 1, further comprising a mode setting unit (70g) that sets either the efficiency priority mode or the comfort priority mode based on a determination result of the mode determination unit.

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