Vehicle air conditioning device

Abstract

A vehicle air-conditioning device has a refrigeration cycle (10) and a control portion (70). The refrigeration cycle has a compressor (11), a heating portion (35), an outside air heat exchanger (29X), a first expansion valve (20a), second expansion valves (20b, 20c), and evaporators (23, 24). The control portion has a compression control portion (70d) and a pressure reduction control portion (70e) that control when condensation heat defrosting and heating of an air-conditioned space are performed in parallel. The compression control portion achieves the temperature or pressure of refrigerant of either one of the heating heat exchanger required temperature or pressure of refrigerant and the outside air heat exchanger required temperature or pressure of refrigerant by operation control of the compressor. The pressure reduction control portion achieves the temperature or pressure of refrigerant of the other one of the heating heat exchanger required temperature or pressure of refrigerant and the outside air heat exchanger required temperature or pressure of refrigerant by operation control of the first expansion valve.

Description

[0001] Cross-reference of related applications

[0002] This application is based on Japanese Patent Application No. 2021-092303, filed on June 1, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to an air conditioning unit for a vehicle, which has a condenser for dissipating heat from the refrigerant in the supply air and an outdoor heat exchanger for exchanging heat between the outside air and the refrigerant. Background Technology

[0004] Previously, various technologies have been developed related to vehicle air conditioning systems, which include a condenser that dissipates heat from the refrigerant into the supply air and an outdoor heat exchanger that exchanges heat between the outside air and the refrigerant. In vehicle air conditioning systems, when the condenser heats the space to be conditioned, frost may form on the outdoor heat exchanger if it absorbs heat from the cold outside air into the refrigerant.

[0005] When the outdoor heat exchanger frosts, its heat exchange performance is significantly reduced, greatly impacting the heating performance of the vehicle's air conditioning system. Therefore, defrosting of the outdoor heat exchanger is necessary. While defrosting the outdoor heat exchanger is in progress, it cannot absorb heat from the outside air into the refrigerant. However, the demand for simultaneously heating the air-conditioned space is increasing during outdoor heat exchanger defrosting.

[0006] As a technology related to such a vehicle air conditioning device, the technology described in Patent Document 1 is known. For example, in Patent Document 1, hot air is used to heat the air-conditioned space and defrost the heat exchanger, generating two different temperatures: heat for defrosting and heat for heating.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-203221

[0010] In the vehicle air conditioning system of Patent Document 1, a so-called receiver-of-coolant (ROC) cycle is used as the refrigeration cycle. Hot gas defrosting cannot be performed in the ROC cycle, therefore, the structure of the refrigeration cycle is limited in order to apply the technology of Patent Document 1.

[0011] In addition, as a method for defrosting outdoor heat exchangers, condensation heat defrosting utilizing heat absorbed by the evaporator located on the low-pressure side of the refrigeration cycle has been developed. Patent Document 1 describes hot gas defrosting that uses heat equivalent to the compression work done in the compressor; therefore, it is considered that the defrosting capacity of hot gas defrosting is lower than that of condensation heat defrosting.

[0012] In other words, the goal is to flexibly address the difference between the heat in the outdoor heat exchanger used for defrosting based on condensation heat and the heat in the condenser used to improve comfort, while simultaneously defrosting the outdoor heat exchanger and heating the air-conditioned space. Summary of the Invention

[0013] The purpose of this invention is to provide a vehicle air conditioning unit that, in view of the above-mentioned problems, can achieve appropriate heating operation in parallel with efficient defrosting of the outdoor heat exchanger.

[0014] One aspect of the present invention relates to a vehicle air conditioning unit having a refrigeration cycle and a control unit. The refrigeration cycle includes a compressor, a heating unit, an outside air heat exchange unit, a first expansion valve, a second expansion valve, and an evaporator.

[0015] The compressor compresses the refrigerant and then discharges it. The heating section has a heat exchanger for heating, which uses the refrigerant as a heat source to heat the supply air blown into the air-conditioned space. During heating operation, the heat exchanger condenses the refrigerant discharged from the compressor. The outdoor air heat exchange section has an outdoor air heat exchanger that allows the refrigerant to absorb heat from the outdoor air during heating operation.

[0016] A first expansion valve is disposed between the outlet of the heating heat exchanger and the inlet of the outdoor gas heat exchanger, configured to depressurize the refrigerant flowing out of the heating heat exchanger. A second expansion valve is configured to depressurize the refrigerant flowing out of at least one of the heating heat exchanger and the outdoor gas heat exchanger. The evaporator causes the refrigerant, after being depressurized by the second expansion valve, to absorb heat and evaporate.

[0017] The control unit performs controls related to condensing heat defrosting and heating of the air-conditioned space. The condensing heat defrosting uses the heat absorbed by the refrigerant in the evaporator to melt the frost attached to the outdoor air heat exchanger. The heating of the air-conditioned space uses the heat dissipation from the refrigerant in the heating heat exchanger.

[0018] Furthermore, the control unit includes a compression control unit and a pressure reduction control unit that control the operation of both condensation defrosting and heating of the air-conditioned space in parallel. When the temperature or pressure of the refrigerant required by the heating heat exchanger differs from that required by the outdoor gas heat exchanger, the compression control unit controls the operation of the compressor to achieve either the required temperature or pressure of the refrigerant for the heating heat exchanger or the required temperature or pressure of the refrigerant for the outdoor gas heat exchanger. The pressure reduction control unit controls the operation of the first expansion valve to achieve the other of the required temperature or pressure of the refrigerant for the heating heat exchanger and the required temperature or pressure of the refrigerant for the outdoor gas heat exchanger.

[0019] According to the vehicle air conditioning unit, condensation defrosting and heating can be performed in parallel using a refrigeration cycle and a control unit. The condensation defrosting uses the heat absorbed by the refrigerant in the evaporator to melt the frost attached to the outside air heat exchanger, and the heating uses the heat dissipation from the refrigerant in the heating heat exchanger.

[0020] Furthermore, when performing condensation defrosting and heating of the air-conditioned space in parallel, if the refrigerant temperature or pressure required by the heating heat exchanger differs from that required by the outdoor air heat exchanger, the compression control unit and the pressure reduction control unit can achieve the two different refrigerant temperatures or pressures. In other words, the compression control unit can control the operation of the compressor to achieve the refrigerant temperature or pressure required by either the heating heat exchanger or the outdoor air heat exchanger. Moreover, the pressure reduction control unit can control the operation of the first expansion valve to achieve the refrigerant temperature or pressure required by either the heating heat exchanger or the outdoor air heat exchanger.

[0021] According to the vehicle air conditioning system, when condensation defrosting and heating of the air-conditioned space are performed in parallel, the heat dissipation in the heat exchanger for the outside air involved in condensation defrosting and the heat dissipation in the heat exchanger for heating involved in heating can be controlled separately, and they can coexist in an appropriate manner. Attached Figure Description

[0022] The above-mentioned and other objects, features, and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings,

[0023] Figure 1 This is an overall structural diagram of the vehicle air conditioning unit according to the first embodiment.

[0024] Figure 2 This is a structural diagram of the interior air conditioning unit in a vehicle's air conditioning system.

[0025] Figure 3 This is a block diagram representing the control system of a vehicle's air conditioning unit.

[0026] Figure 4 This is an overall structural diagram illustrating the operation of the heating mode in the vehicle air conditioning system according to the first embodiment.

[0027] Figure 5 This is an overall structural diagram illustrating an example of the operation of the condensation heat defrosting mode in the vehicle air conditioning system according to the first embodiment.

[0028] Figure 6 This is an explanatory diagram of an experimental formula used to estimate the evaporation rate in dry defrosting using condensation-heat defrosting.

[0029] Figure 7 This is a graph showing the relationship between the outdoor unit's evaporation rate and wind speed relative to the outdoor heat exchanger's condensing temperature.

[0030] Figure 8 It is a graph showing the relationship between condensing temperature and fan speed relative to compressor speed.

[0031] Figure 9 It is a graph showing the range of operating conditions achievable in a refrigeration cycle unit under the relationship between outdoor unit evaporation rate and wind speed.

[0032] Figure 10 This is a baseline graph of moist air lines representing the relationship between visibility of white fog during dry defrosting.

[0033] Figure 11 It is a humid air curve graph related to the calculation of the maximum allowable evaporation per unit weight.

[0034] Figure 12 This is a graph showing the relationship between outdoor unit evaporation rate and wind speed relative to condensing temperature and the allowable upper limit of evaporation rate.

[0035] Figure 13 This is a diagram showing the target area used to suppress visible white fog during dry defrosting while fully restoring the heat exchange performance of the outdoor heat exchanger.

[0036] Figure 14 This is a diagram showing the achievable target area for fully restoring the heat exchange performance of the outdoor heat exchanger while visibly suppressing white fog during dry defrosting.

[0037] Figure 15 This is a control characteristic diagram used to determine the target condensation temperature during drying and defrosting.

[0038] Figure 16 This is a control characteristic diagram used to determine the target wind speed during drying and defrosting.

[0039] Figure 17 This is an explanatory diagram illustrating an example of the changes in fan speed, compressor speed, and discharge pressure during the drying and defrosting mode.

[0040] Figure 18 This is an overall structural diagram illustrating an example of the operation of the heating and defrosting mode in the vehicle air conditioning unit according to the first embodiment.

[0041] Figure 19 This is a flowchart illustrating the control functions of the heating and defrosting modes in a vehicle's air conditioning system.

[0042] Figure 20 This is a flowchart illustrating the control content of the efficiency-priority mode in the heating and defrosting system.

[0043] Figure 21 This is a flowchart illustrating the control content of the comfort-priority mode within the heating and defrosting modes.

[0044] Figure 22 This is an overall structural diagram of the vehicle air conditioning unit in the second embodiment.

[0045] Figure 23 This is a structural diagram of the indoor air conditioning unit in the second embodiment.

[0046] Figure 24 This is an overall structural diagram of the vehicle air conditioning unit according to the third embodiment.

[0047] Figure 25 This is an overall structural diagram illustrating the operation of the heating mode in the vehicle air conditioning system according to the third embodiment.

[0048] Figure 26 This is an overall structural diagram illustrating an example of the operation of the condensation heat defrosting mode in the vehicle air conditioning system according to the third embodiment.

[0049] Figure 27 This is an overall structural diagram illustrating an example of the operation of the heating and defrosting mode in the vehicle air conditioning unit according to the third embodiment. Detailed Implementation

[0050] Hereinafter, various embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In each embodiment, the same reference numerals are sometimes used to denote parts corresponding to matters described in previous embodiments, and repeated descriptions are omitted. Where only a part of the structure is described in each embodiment, other previously described embodiments can be applied to the other parts of the structure. Not only are the combinations of combinable parts specifically shown in each embodiment, but embodiments can also be partially combined with each other even if not explicitly shown, provided that the combination does not particularly hinder it.

[0051] (First Implementation)

[0052] First, refer to the appendix Figure 1 The first embodiment of the present invention will now be described. The vehicle air conditioning unit 1 according to the first embodiment is installed in an electric vehicle, which is a vehicle that obtains driving power from an electric motor. The vehicle air conditioning unit 1 is an air conditioning unit with a vehicle cooling function that regulates the air in the vehicle interior, which is the space to be air-conditioned, and cools the battery 75, which is a vehicle-mounted device.

[0053] Battery 75 is a secondary battery, such as a lithium-ion battery, that stores electricity to supply onboard equipment such as electric motors. Battery 75 is a so-called battery pack formed by stacking multiple battery cells and connecting these battery cells in series or parallel.

[0054] Such a battery imposes limitations on input and output if its temperature is low, and its output power tends to decrease if its temperature is high. Therefore, the battery temperature must always be maintained within an appropriate temperature range that allows full utilization of the battery's charge and discharge capacity (in this embodiment, 5°C or higher and 55°C or lower).

[0055] Furthermore, for this type of battery, the higher the battery temperature, the easier it is for the battery cells to deteriorate. In other words, by maintaining the battery temperature at a relatively low level, it is possible to suppress the progression of battery degradation.

[0056] Therefore, in the vehicle air conditioning unit 1, the battery 75 can be cooled using the heat generated by the refrigeration cycle 10. Thus, in this embodiment, the object being cooled in the refrigeration cycle 10 is the battery 75, which is different from the supplied air.

[0057] like Figure 1 As shown, the vehicle air conditioning unit 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 blown into the vehicle interior within the vehicle air conditioning unit 1. Furthermore, the refrigeration cycle 10 cools the battery 75.

[0058] Therefore, the objects of temperature regulation in the refrigeration cycle 10 are the supplied air and the battery 75. Furthermore, the refrigeration cycle 10 is configured to switch the refrigerant circuit for both air conditioning inside the vehicle and cooling of the battery 75.

[0059] In refrigeration cycle 10, an HFO-based refrigerant (specifically, R1234yf) is used as the refrigerant. Refrigeration cycle 10 constitutes a vapor compression subcritical refrigeration cycle where the pressure of the high-pressure refrigerant discharged from compressor 11 does not exceed the critical pressure of the refrigerant. Refrigeration oil (specifically PAG oil) for lubricating compressor 11 is mixed into the refrigerant. A portion of the refrigeration oil circulates in the cycle along with the refrigerant.

[0060] The compressor 11 draws in refrigerant, compresses it, and then discharges it in the refrigeration cycle 10. The compressor 11 is disposed in the drive unit compartment on the front side of the vehicle compartment. The drive unit compartment forms a space in which a drive device (e.g., an electric motor) for outputting driving force for driving is disposed.

[0061] Compressor 11 is an electric compressor that uses an electric motor to drive a fixed-capacity compressor mechanism with a fixed discharge capacity. The compressor 11 controls its speed (i.e., refrigerant discharge capacity) according to a control signal output from the control device 70 described later.

[0062] The refrigerant inlet side of a water refrigerant heat exchanger 12 is connected to the outlet of the compressor 11. The water refrigerant heat exchanger 12 has a refrigerant passage 12a through which high-pressure refrigerant discharged from the compressor 11 flows and a heat medium passage 12b through which high-temperature heat medium circulating in the high-temperature heat medium circuit 30 flows.

[0063] Furthermore, the water refrigerant heat exchanger 12 is a heating heat exchanger that heats the high-pressure refrigerant flowing in the refrigerant passage 12a by exchanging heat with the high-temperature side heat medium flowing in the heat medium passage 12b. Additionally, since the water refrigerant heat exchanger 12 condenses the high-pressure refrigerant flowing in the refrigerant passage 12a through heat exchange with the high-temperature side heat medium, it is equivalent to an example of a heating heat exchanger.

[0064] The outlet of the refrigerant passage 12a of the water refrigerant heat exchanger 12 is connected to the inlet side of a first tee fitting 13a having three interconnected inlet outlets. Such a tee fitting can be a fitting formed by joining multiple pipes or a fitting formed by setting multiple refrigerant passages in a metal block or resin block.

[0065] Furthermore, as described later, the refrigeration cycle 10 includes a second three-way connector 13b to an eighth three-way connector 13h. The basic structure of the second three-way connector 13b to the eighth three-way connector 13h is the same as that of the first three-way connector 13a.

[0066] When one of the three inflow and outflow outlets is used as an inflow inlet and two are used as outflow outlets, the first tee joint 13a to the eighth tee joint 13h function as a branch section for allowing the refrigerant flowing in from one inflow inlet to branch out. Furthermore, when two of the three inflow and outflow outlets are used as inflow inlets and one is used as an outflow outlet, the first tee joint 13a, etc., function as a merging section for allowing the refrigerant flows from the two inflow inlets to merge.

[0067] In this embodiment, the first tee connector 13a, the third tee connector 13c, the sixth tee connector 13f, and the seventh tee connector 13g are connected to function as branch sections. Additionally, the second tee connector 13b, the fourth tee connector 13d, the fifth tee connector 13e, and the eighth tee connector 13h are connected to function as confluence sections.

[0068] One outlet of the first three-way connector 13a is connected to the inlet side of the collector 19 via the first on / off valve 16a and the fifth three-way connector 13e. The other outlet of the first three-way connector 13a is connected to the inlet side of the heating expansion valve 20a via the second on / off valve 16b and the second three-way connector 13b.

[0069] The first on / off valve 16a is a solenoid valve that opens and closes the inlet-side passage 27a from one outlet of the first three-way connector 13a to the inlet of the liquid collector 19. The opening and closing of the first on / off valve 16a is controlled by a control voltage output from the control device 70.

[0070] The fifth three-way connector 13e has one inlet in the inlet passage 27a connected to the outlet of the first on / off valve 16a. Furthermore, the fifth three-way connector 13e has one outlet in the inlet passage 27a connected to the inlet of the collector 19.

[0071] The liquid collector 19 is a liquid storage section with a gas-liquid separation function. That is, the liquid collector 19 separates the gas and liquid of the refrigerant flowing out from the heat exchange section that functions as a condenser in the refrigeration cycle 10 to condense the refrigerant. Furthermore, the liquid collector 19 causes a portion of the separated liquid refrigerant to flow downstream, and stores the remaining liquid refrigerant as surplus refrigerant in the cycle.

[0072] The second on / off valve 16b is a solenoid valve that opens and closes the external air passage 27c from the outlet on one side of the first three-way connector 13a to the inlet on one side of the second three-way connector 13b. The basic structure of the second on / off valve 16b is the same as that of the first on / off valve 16a. The second on / off valve 16b is also controlled by a control voltage output from the control device 70.

[0073] Furthermore, the refrigerant outlet side of the liquid collector 19 is connected to the inlet on the other side of the second three-way connector 13b. A sixth three-way connector 13f and a third check valve 21c are provided in the outlet-side passage 27b that connects the refrigerant outlet of the liquid collector 19 to the inlet on the other side of the second three-way connector 13b.

[0074] The inlet of the sixth three-way connector 13f is connected to the refrigerant outlet side of the collector 19 via the outlet-side passage 27b. The outlet of one side of the sixth three-way connector 13f is connected to the inlet of the other side of the second three-way connector 13b via the outlet-side passage 27b and the third check valve 21c. Furthermore, the outlet of the other side of the sixth three-way connector 13f is connected to the inlet side of the seventh three-way connector 13g.

[0075] Furthermore, the outlet of the second three-way connector 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, when the refrigerant circuit is switched to at least the heating mode described later, reduces the pressure of the refrigerant flowing out of the collector 19 and regulates the flow rate of the refrigerant flowing downstream. The heating expansion valve 20a is an example of the first expansion valve.

[0076] The heating expansion valve 20a is an electrically operated variable throttling mechanism having a valve core configured to change the throttling opening and an electric actuator (specifically a stepper motor) that displaces the valve core. The heating expansion valve 20a is controlled to operate by a control signal (specifically a control pulse) output from the control device 70.

[0077] The expansion valve 20a for heating has a fully open function and a fully closed function. The fully open function functions as a refrigerant passage with almost no flow regulation or refrigerant pressure reduction by keeping the valve fully open. The fully closed function closes the refrigerant passage by keeping the valve fully closed.

[0078] like Figure 1 As shown, the refrigeration cycle 10 includes a refrigeration expansion valve 20b and a cooling expansion valve 20c. The basic structure of the refrigeration expansion valve 20b and the cooling expansion valve 20c is the same as that of the heating expansion valve 20a. The refrigeration expansion valve 20b and the cooling expansion valve 20c are examples of a second expansion valve.

[0079] The outdoor heat exchanger 22 is a heat exchanger that allows the refrigerant flowing out from the heating expansion valve 20a to exchange heat with the outside air blown in from the outside air fan 22a. The outdoor heat exchanger 22 is located at the front of the drive unit compartment. Therefore, when the vehicle is in motion, the driving air can blow onto the outdoor heat exchanger 22. The outdoor heat exchanger 22 is an example of an outside air heat exchanger and constitutes an outside air heat exchange section 29X.

[0080] In cooling mode, the outdoor heat exchanger 22 functions as a radiator to dissipate heat from the high-pressure refrigerant. In heating mode, the outdoor heat exchanger 22 functions as an evaporator to evaporate the low-pressure refrigerant after it has been depressurized by the heating expansion valve 20a.

[0081] Furthermore, the outdoor air fan 22a is configured to blow outdoor air into the outdoor heat exchanger 22. The outdoor air fan 22a is an electric fan whose speed (i.e., air delivery 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 directed towards the outdoor heat exchanger 22.

[0082] The refrigerant outlet of the outdoor heat exchanger 22 is connected to the inlet side of a three-way valve 18, which constitutes a third three-way connector 13c. The three-way valve 18 is an electrically operated three-way flow regulating valve with one inlet and two outlets, capable of continuously adjusting the passage area ratio of the two outlets. The operation of the three-way valve 18 is controlled according to a control signal output from the control device 70.

[0083] The outlet of one of the three-way valves 18 constituting the third three-way connector 13c is connected to the inlet side of one of the four three-way connectors 13d via the first check valve 21a. The outlet of the fourth three-way connector 13d is connected to the suction port side of the compressor 11. Furthermore, the outlet of the other three-way valve 18 is connected to the inlet side of the other five three-way connectors 13e via the second check valve 21b.

[0084] Therefore, the three-way valve 18 can continuously regulate the flow rate of refrigerant flowing from the outdoor heat exchanger 22, which flows into the liquid collector 19 and which flows directly into the compressor 11.

[0085] like Figure 1 As shown, the first check valve 21a is disposed in the suction-side passage 27d from the outlet of one of the third three-way connectors 13c to the inlet of one of the fourth three-way connectors 13d. The first check valve 21a allows refrigerant to flow from the refrigerant outlet side of the outdoor heat exchanger 22 to the suction port side of the compressor 11 via the three-way valve 18, and prohibits refrigerant from flowing from the suction port side of the compressor 11 to the refrigerant outlet side of the outdoor heat exchanger 22.

[0086] Furthermore, the second check valve 21b is configured in the refrigerant passage from the outlet on the other side of the third three-way connector 13c to the inlet on the other side of the fifth three-way connector 13e. The second check valve 21b allows refrigerant to flow from the refrigerant outlet side of the outdoor heat exchanger 22 to the inlet side of the collector 19 via the three-way valve 18, and prohibits refrigerant from flowing from the collector 19 side to the refrigerant outlet side of the outdoor heat exchanger 22.

[0087] As described above, the outlet of the sixth tee connector 13f, which is located in the outlet passage 27b, is connected to the inlet side of the seventh tee connector 13g. The outlet of the sixth tee connector 13f is connected to the inlet of the second tee connector 13b via the third check valve 21c.

[0088] The third check valve 21c allows refrigerant to flow from the refrigerant outlet side of the collector 19 to the heating expansion valve 20a, and prohibits refrigerant from flowing from the second three-way connector 13b to the collector 19.

[0089] Furthermore, the outlet of the seventh three-way connector 13g is connected to the inlet side of the refrigeration expansion valve 20b. Additionally, the outlet of the seventh three-way connector 13g is connected to the inlet side of the cooling expansion valve 20c.

[0090] The expansion valve 20b for refrigeration is a pressure-reducing unit that, at least when the refrigerant circuit is switched to the refrigeration mode described later, reduces the pressure of the refrigerant flowing out of the collector 19 and regulates the flow rate of the refrigerant flowing downstream. When functioning as a pressure-reducing valve, the expansion valve 20b is equivalent to an example of a second expansion valve.

[0091] The outlet of the refrigeration expansion valve 20b is connected to the refrigerant inlet side of the indoor evaporator 23. For example... Figure 2 As shown, the indoor evaporator 23 is disposed inside the housing 61 of the indoor air conditioning unit 60. The indoor evaporator 23 is an evaporation section that causes the low-pressure refrigerant, after being depressurized by the refrigeration expansion valve 20b, to exchange heat with the supply air blown from the blower 62, thereby causing the low-pressure refrigerant to evaporate.

[0092] The indoor evaporator 23 is a cooling section for supply air that cools the supply air by absorbing heat through the evaporation of low-pressure refrigerant. Therefore, the indoor evaporator 23 is equivalent to an example of an evaporator. The refrigerant outlet of the indoor evaporator 23 is connected to the inlet of the eighth three-way connector 13h via a fourth check valve 21d. The fourth check valve 21d allows refrigerant to flow from the refrigerant outlet side of the indoor evaporator 23 to the eighth three-way connector 13h, and prohibits refrigerant from flowing from the eighth three-way connector 13h side to the indoor evaporator 23.

[0093] The cooling expansion valve 20c is a pressure-reducing unit that, when the chiller 24 cools the low-temperature side heat medium, reduces the pressure of the refrigerant flowing out of the collector 19 and regulates the flow rate of the refrigerant flowing downstream. The cooling expansion valve 20c functions as an example of a second expansion valve by performing this 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.

[0094] The chiller 24 has a refrigerant passage 24a through which low-pressure refrigerant, after being depressurized by the cooling expansion valve 20c, flows, and a heat medium passage 24b through which low-pressure heat medium circulating in the low-temperature heat medium circuit 40 flows. Furthermore, the chiller 24 is an evaporator that allows 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 causing the low-pressure refrigerant to evaporate and absorb heat. In other words, the chiller 24 is an example of an evaporator.

[0095] The outlet of the refrigerant passage 24a of the chiller 24 is connected to the inlet of the other side of the eighth three-way connector 13h. The outlet of the eighth three-way connector 13h is connected to the suction side of the compressor 11 via the fourth three-way connector 13d.

[0096] As is evident from the above description, in the refrigeration cycle 10, the refrigerant circuit can be switched by opening and closing the refrigerant passage through 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, and the three-way valve 18 are included in the refrigerant circuit switching unit.

[0097] Furthermore, the first on / off valve 16a, the second on / off valve 16b, and the first three-way connector 13a direct the refrigerant flowing from the water refrigerant heat exchanger 12 to either the liquid collector 19 side or the second three-way connector 13b side. Additionally, the second three-way connector 13b directs at least one of the refrigerant flowing from the first three-way connector 13a and the refrigerant flowing from the liquid collector 19 to the heating expansion valve 20a side. Furthermore, the three-way valve 18 constituting the third three-way connector 13c directs the refrigerant flowing from the outdoor heat exchanger 22 to either the compressor 11 suction port side or the liquid collector 19 side.

[0098] 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 the high-temperature side heat medium. As the high-temperature side heat medium, solutions containing ethylene glycol, dimethyl polysiloxane, or nanofluids, antifreeze, etc., can be used. The high-temperature side heat medium circuit 30 is constructed 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., through the high-temperature side heat medium flow path 31.

[0099] A water heater 34 is provided on the outlet side of the heat medium passage 12b in the water refrigerant heat exchanger 12. The water heater 34 is configured to dissipate heat from the high-temperature side heat medium flowing out of the heat medium passage 12b of the water refrigerant heat exchanger 12 and to heat the high-temperature side heat medium.

[0100] The water heater 34 can be a PTC heater with a PTC element (i.e., a positive characteristic thermistor). The heat output of the water heater 34 can be arbitrarily controlled by the control voltage output from the control device 70. The water heater 34 is equivalent to an example of an auxiliary heating device.

[0101] The outlet side of the hot medium passage of the water heater 34 is connected to the inlet side of the high-temperature side pump 32. The high-temperature side pump 32 is a water pump that delivers the high-temperature side hot medium after passing through the water heater 34 to the hot medium inlet side of the heater core 33. The high-temperature side pump 32 is an electric pump whose speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 70.

[0102] The heater core 33 is a heat exchanger that heats the supply air by exchanging heat between the high-temperature side heat medium heated by the water refrigerant heat exchanger 12 and the supply air after passing through the indoor evaporator 23. For example... Figure 2 As shown, the heater core 33 is disposed within the housing 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.

[0103] Therefore, in the high-temperature side heat medium circuit 30, the high-temperature side pump 32 can adjust the heat dissipation of the high-temperature side heat medium in the heater core 33 to the supply air by adjusting the flow rate of the high-temperature side heat medium flowing into the heater core 33 (i.e., the amount of heating of the supply air in the heater core 33).

[0104] In other words, in this embodiment, the heating unit 35, which heats the supply air by using the refrigerant discharged from the compressor 11 as a heat source, is constructed by the water refrigerant heat exchanger 12 and the high-temperature side heat medium circuit 30.

[0105] 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 the 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.

[0106] like Figure 1 As shown, the low-temperature side heat medium circuit 40 is configured to connect the heat medium passage 12b of the chiller 24, the low-temperature side pump 42, the battery heat exchange unit 43, the electric heater 44, the low-temperature side water storage tank 45, etc., through the low-temperature side heat medium flow path 41.

[0107] Furthermore, the low-temperature side heat transfer medium circuit 40 regulates the temperature of the battery 75 by exchanging heat between the low-temperature side heat transfer medium, which has been regulated by the refrigeration cycle 10, etc., and the battery 75 through the battery heat exchange section 43. The low-temperature side heat transfer medium circuit 40 can be described as a heat transfer medium circuit used for regulating the temperature of the battery 75 and effectively utilizing the waste heat from the battery 75 for various applications.

[0108] like Figure 1 As shown, an electric heater 44 is provided at the outlet side of the heat medium passage 24b in the chiller 24. The electric heater 44 is configured to dissipate heat from the low-temperature side heat medium flowing out of the heat medium passage 24b of the chiller 24 and to heat the low-temperature side heat medium. A PTC heater can be used as the electric heater 44. The heat output of the electric heater 44 can be arbitrarily controlled by the control voltage output from the control device 70.

[0109] 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 used to regulate the temperature of the battery 75 by exchanging heat between the low-temperature side heat medium flowing in the heat medium passage 43a and the battery cell.

[0110] Furthermore, the heat transfer medium passage 43a in the battery heat exchange section 43 is a passage structure in which multiple passages are connected in parallel inside the dedicated casing. Thus, the heat transfer medium passage 43a is configured to absorb the waste heat of the battery 75 evenly from the entire area of ​​the battery 75. In other words, the refrigerant passage is configured to absorb the heat possessed by all battery cells equally, thereby cooling all battery cells equally.

[0111] Such a battery heat exchange section 43 can be formed by providing heat transfer medium passages 43a between the stacked battery cells. Alternatively, the battery heat exchange section 43 can be integrally formed with the battery 75. For example, the battery heat exchange section 43 can be integrally formed with the battery 75 by providing heat transfer medium passages 43a in a dedicated case that houses the stacked battery cells.

[0112] A low-temperature side water tank 45 is provided at the outlet of the heat medium passage 43a in the battery heat exchange unit 43. The low-temperature side water tank 45 is a storage unit for storing the remaining low-temperature side heat medium in the low-temperature side heat medium circuit 40.

[0113] Furthermore, the suction port of the low-temperature side pump 42 is connected to the hot medium outlet side of the low-temperature side water tank 45. The low-temperature side pump 42 is a water pump that pressurizes the low-temperature side hot medium to the inlet side of the hot medium passage 43a of the chiller 24. The basic structure of the low-temperature side pump 42 is the same as that of the high-temperature side pump 32.

[0114] Therefore, in the low-temperature side heat medium circuit 40, the low-temperature side pump 42 can regulate the amount of heat absorbed by the low-temperature side heat medium in the battery heat exchange section 43 from the battery 75 by adjusting the flow rate of the low-temperature side heat medium flowing into the battery heat exchange section 43. Furthermore, the amount of heat absorbed in the battery heat exchange section 43 can also be regulated by using the electric heater 44 to adjust the temperature difference between the battery 75 and the low-temperature side heat medium.

[0115] In other words, according to this embodiment, a cooling section is constructed by means of the chiller 24 and the constituent devices of the low-temperature side heat medium circuit 40, which evaporate the refrigerant flowing out of the cooling expansion valve 20c to cool the battery 75.

[0116] Next, refer to Figure 2 The interior air conditioning unit 60 will be described below. The interior air conditioning unit 60 is a unit used to blow supply air, which has been regulated by the refrigeration cycle 10, into the vehicle interior. The interior air conditioning unit 60 is located inside the instrument panel (instrument panel) at the front of the vehicle interior.

[0117] The indoor air conditioning unit 60 houses a blower 62, an indoor evaporator 23, a heater core 33, etc., within an air passage formed inside the housing 61 that forms its outer shell. The housing 61 forms an air passage for the supply air blown into the vehicle interior. The housing 61 is molded from a resin (e.g., polypropylene) that has a certain degree of elasticity and excellent strength.

[0118] An internal / external air switching device 63 is disposed on the upstream side of the air supply flow of the housing 61. The internal / external air switching device 63 switches the introduction of internal air (indoor air) and external air (outdoor air) into the housing 61.

[0119] The internal / external air switching device 63 continuously adjusts the opening areas of the internal air inlet (for introducing internal air into the housing 61) and the external air inlet (for introducing external air into the housing 61) via an internal / external air switching gate, thereby changing the ratio of the introduced internal air volume to the introduced external air volume. The internal / external air switching gate is driven by an electric actuator. This electric actuator controls its operation according to a control signal output from the control device 70.

[0120] A blower 62 is disposed downstream of the airflow from the internal / external air switching device 63. The blower 62 blows the air drawn in by the internal / external air switching device 63 into the vehicle interior. The blower 62 is an electric blower that uses an electric motor to drive a centrifugal multi-bladed fan. The speed (i.e., airflow capacity) of the blower 62 is controlled by a control voltage output from the control device 70.

[0121] Downstream of the supply airflow from the blower 62, an indoor evaporator 23 and a heater core 33 are arranged sequentially relative to the supply airflow. That is, the indoor evaporator 23 is positioned upstream of the supply airflow compared to the heater core 33.

[0122] A cold air bypass passage 65 is provided inside the housing 61, allowing the supply air after passing through the indoor evaporator 23 to flow around the heater core 33. In addition, an air mixing door 64 is provided inside the housing 61 on the downstream side of the supply air flow of the indoor evaporator 23 and the upstream side of the supply air flow of the heater core 33.

[0123] The air mixing door 64 is an airflow ratio regulating unit that adjusts the airflow ratio between the supply air passing through the heater core 33 side and the supply air passing through the cold air bypass passage 65 in the supply air after passing through the indoor evaporator 23. The air mixing door 64 is driven by an electric actuator for the air mixing door. This electric actuator controls its operation according to a control signal output from the control device 70.

[0124] A mixing space is provided downstream of the supply air flow of the heater core 33 and the cold air bypass passage 65 within the housing 61. The mixing space is a space in which the supply air heated by the heater core 33 is mixed with the supply air that has not been heated by passing through the cold air bypass passage 65.

[0125] Furthermore, an opening is provided downstream of the airflow in the housing 61, which is used to blow the mixed airflow (i.e., air conditioning air) into the vehicle interior, which is the target space for air conditioning. This opening includes a face opening, a foot opening, and a defrost opening (none shown).

[0126] The face opening is for directing air conditioning air towards the upper body of the occupants inside the vehicle. The foot opening is for directing air conditioning air towards the occupants' feet. The defrost opening is for directing air conditioning air towards the inside of the front windshield.

[0127] These face openings, foot openings, and defrost openings are connected to face air vents, foot air vents, and defrost air vents (not shown) located inside the vehicle interior via ducts that form air passages.

[0128] Therefore, the air mixing door 64 adjusts the airflow ratio between the airflow through the heater core 33 and the airflow through the cold air bypass passage 65, thereby regulating the temperature of the air conditioning air mixed in the mixing space. As a result, the temperature of the supply air (air conditioning air) blown into the vehicle interior from each outlet is regulated.

[0129] In addition, a face panel, a foot panel, and a defrost door (not shown) are respectively installed upstream of the airflow from the face opening, foot opening, and defrost opening. The face panel adjusts the opening area of ​​the face opening. The foot panel adjusts the opening area of ​​the foot opening. The defrost door adjusts the opening area of ​​the defrost opening.

[0130] These face panels, foot panels, and defrost doors constitute a blowout mode switching device for switching blowout modes. These doors are rotated in conjunction with an electric actuator for driving the blowout mode doors via a linkage mechanism, etc. The electric actuator is also controlled by a control signal output from the control device 70.

[0131] Specifically, the air outlet modes, which are switched by the air outlet mode switching device, include face mode, dual mode, and foot mode. The face mode is an air outlet mode in which the face air outlet is set to be fully open and air is blown from the face air outlet toward the upper body of the passenger in the vehicle.

[0132] The dual-mode airflow mode opens both the face and foot airflow outlets, blowing air towards the upper body and feet of the occupants inside the vehicle. The foot mode sets the foot airflow outlets to full open and the defrost airflow outlets to only a small opening, with air mainly blowing out from the foot airflow outlets.

[0133] Furthermore, occupants can also manually switch to defrost mode by operating the blowout mode switch located on the control panel 71. Defrost mode is a blowout mode in which the defrost blowout is set to fully open, blowing air from the defrost blowout to the inner surface of the front window glass.

[0134] Next, use Figure 3 The electrical control unit of the vehicle air conditioning system 1 will be described in general. The control unit 70 consists of a well-known microcomputer including a CPU, ROM, and RAM, and its peripheral circuitry. The control unit 70 performs various calculations and processes based on the air conditioning control program stored in the ROM, and controls the operation of various controllable devices connected to the output side. The control unit 70 is an example of a control unit.

[0135] 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 also 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 indoor / outdoor air switching device 63, and an air mixing gate 64.

[0136] And, as Figure 3As shown, various control sensors are connected to the input side of the control device 70. These control sensors include an indoor air temperature sensor 72a, an outdoor air temperature sensor 72b, a sunlight sensor 72c, a high-pressure sensor 72d, and an air conditioning fan temperature sensor 72e. Other control sensors 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.

[0137] Interior air temperature sensor 72a is an interior air temperature detection unit that detects the interior air temperature Tr, which is the temperature inside the vehicle. Outside air temperature sensor 72b is an outside air temperature detection unit that detects the outside air temperature Tam, which is the temperature outside the vehicle. Sunlight sensor 72c is a sunlight intensity detection unit that detects the amount of sunlight As shining into the vehicle interior.

[0138] The high-pressure sensor 72d is a high-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 air conditioning air temperature sensor 72e is an air conditioning air temperature detection unit that detects the temperature TAV of the air blown from the mixing space into the vehicle interior.

[0139] The evaporator temperature sensor 72f is an evaporator temperature detection unit that detects the refrigerant evaporation temperature (evaporator temperature) Te in the indoor evaporator 23. Specifically, in this embodiment, the evaporator temperature sensor 72f detects the temperature of the refrigerant on the outlet side of the indoor evaporator 23.

[0140] The evaporator pressure sensor 72g is an evaporator pressure detection unit that detects the refrigerant evaporation pressure Pe in the indoor evaporator 23. Specifically, the evaporator pressure sensor 72g of this embodiment detects the pressure of the refrigerant on the outlet side of the indoor evaporator 23.

[0141] 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 this embodiment detects the temperature of the refrigerant on the outlet side in the refrigerant passage 24a of the chiller 24.

[0142] 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 of the refrigerant passage 24a of the chiller 24.

[0143] The outdoor unit temperature sensor 72j is an outdoor unit temperature detection unit that detects the outdoor unit refrigerant temperature T1, which is the temperature of the refrigerant flowing in the outdoor heat exchanger 22. Specifically, in this embodiment, the outdoor unit temperature sensor 72j detects the temperature of the refrigerant on the outlet side of the outdoor heat exchanger 22.

[0144] The outdoor unit pressure sensor 72k is an outdoor unit pressure detection unit that detects the outdoor unit refrigerant pressure P1, which is the pressure of the refrigerant flowing in the outdoor heat exchanger 22. Specifically, in this embodiment, the outdoor unit pressure sensor 72k detects the pressure of the refrigerant on the outlet side of the outdoor heat exchanger 22.

[0145] 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, detecting the temperature of multiple parts of the battery 75. Therefore, the control device 70 can also detect the temperature difference between different parts of the battery 75. Furthermore, the battery temperature TB is the average value of the detection values ​​from multiple temperature sensors.

[0146] In addition, in order to detect the temperature of each heat medium in the high-temperature side heat medium circuit 30 and the low-temperature side heat medium circuit 40, multiple heat medium temperature sensors are connected to the input side of the control device 70. Among the multiple heat medium temperature sensors are the first heat medium temperature sensor 73a to the fifth heat medium temperature sensor 73e.

[0147] 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 to detect 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 to detect the temperature of the high-temperature side heat medium passing through the heater core 33.

[0148] The third heat medium temperature sensor 73c is disposed at the outlet of the heat medium passage in the water heater 34 to detect the temperature of the high-temperature side heat medium flowing out of the water heater 34. The fourth heat medium temperature sensor 73d is disposed at the inlet of the heat medium passage in the chiller 24 to detect the temperature of the heat medium flowing into the chiller 24.

[0149] Furthermore, the fifth heat medium temperature sensor 73e is disposed in the outlet portion of the heat medium passage 43a of the battery heat exchange unit 43, and detects the temperature of the low-temperature side heat medium flowing out from the heat medium passage 43a of the battery heat exchange unit 43.

[0150] The vehicle air conditioning unit 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 heat medium temperature sensor 73a to the fifth heat medium temperature sensor 73e.

[0151] 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 from various operation switches provided on the operation panel 71 are input to the control device 70.

[0152] The various operating switches provided on the control panel 71 specifically include an automatic switch, an air conditioning switch, an airflow setting switch, and a temperature setting switch. The automatic switch is an operating switch that sets or deactivates the automatic control operation of the cooling cycle 10.

[0153] The air conditioning switch is an operating switch that requires cooling of the supplied air in the indoor evaporator 23. The airflow setting switch is an operating switch operated when manually setting the airflow of the blower 62. The temperature setting switch is an operating switch for setting the target temperature Tset inside the vehicle.

[0154] Furthermore, a communication unit 74 is connected to the control device 70. The communication unit 74 obtains various information through communication via public network networks including the Internet, mobile phone networks, and base stations. Therefore, the control device 70 can obtain weather information and other information corresponding to the current location of the electric vehicle equipped with the vehicle air conditioning unit 1.

[0155] Furthermore, the control device 70 of this embodiment is integrally configured with a control unit that controls various controllable devices connected to its output side. Therefore, the structure (i.e., hardware and software) that controls the operation of each controllable device constitutes the control unit that controls the operation of each controllable device.

[0156] For example, the control device 70 includes a frosting determination unit 70a that determines whether the amount of frost on the outdoor heat exchanger 22 exceeds a predetermined benchmark. Additionally, the control device 70 includes a melting determination unit 70b that determines whether all the frost adhering to the outdoor heat exchanger 22 has melted through condensation-heat defrosting. Furthermore, the control device 70 includes a drying completion determination unit 70c that determines whether the drying of the outdoor heat exchanger 22, which involves evaporating to remove moisture generated as the frost melts during condensation-heat defrosting, is complete.

[0157] Furthermore, the control device 70 includes a compression control unit 70d that, in the heating defrosting mode where condensation defrosting and heating are performed in parallel, controls the operation of the compressor to achieve the temperature or pressure of either the refrigerant required by the water refrigerant heat exchanger 12 or the refrigerant required by the outdoor heat exchanger 22. Additionally, the control device 70 includes a pressure reduction control unit 70e that, in the heating defrosting mode, controls the operation of the heating expansion valve 20a to achieve the temperature or pressure of either the refrigerant required by the water refrigerant heat exchanger 12 or the refrigerant required by the outdoor heat exchanger 22.

[0158] Furthermore, the control device 70 includes a mode determination unit 70f that determines which mode is appropriate in the heating defrosting mode: an efficiency-priority mode that prioritizes defrosting with condensation heat over heating of the air-conditioned space, and a comfort-priority mode that prioritizes heating of the air-conditioned space over defrosting with condensation heat. Additionally, the control device 70 includes a mode setting unit 70g that sets one of the efficiency-priority mode and the comfort-priority mode based on the determination result of the mode determination unit 70f in the heating defrosting mode.

[0159] Next, the operation of the vehicle air conditioning unit according to the first embodiment will be described. The vehicle air conditioning unit 1 is configured to switch the refrigerant circuit for air conditioning inside the vehicle and cooling the battery 75.

[0160] Specifically, the vehicle air conditioning unit 1 includes a refrigerant circuit that can switch between heating mode, cooling mode, and dehumidification / heating mode for air conditioning inside the vehicle. Heating mode is an operating mode that blows heated air into the vehicle interior. Cooling mode is an operating mode that blows cooled air into the vehicle interior. Dehumidification / heating mode is an operating mode that reheats cooled and dehumidified air before blowing it into the vehicle interior.

[0161] These operating modes are switched by executing an air conditioning control program pre-stored in the control device 70. The air conditioning control program is executed when the automatic switch on the operation panel 71 is turned on. In the air conditioning control program, the operating mode is switched based on the detection signals of various control sensors and the operation signals of the operation panel.

[0162] Reference Figure 4The heating mode of the vehicle air conditioning unit 1 according to this embodiment will be described. In the heating mode, the control device 70 opens the first on / off valve 16a and closes the second on / off valve 16b. Furthermore, the control device 70 operates the three-way valve 18 in such a way that the refrigerant outlet side of the outdoor heat exchanger 22 is connected to the inlet side of the first check valve 21a, and the flow path to the fifth three-way connector 13e is closed. Further, the control device 70 sets the heating expansion valve 20a to a throttling state to exert refrigerant pressure reduction, and sets the cooling expansion valve 20b and the cooling expansion valve 20c to a fully closed state.

[0163] Additionally, the control device 70 activates the high-temperature side pump 32 to pressurize the high-temperature side heat medium at a predetermined pressure delivery capacity. Furthermore, in heating mode, the control device 70 remains in a state where the low-temperature side pump 42 is stopped.

[0164] Therefore, in the cooling cycle 10 of the heating mode, such as Figure 4 As shown, the refrigerant circulates in the following order: compressor 11, refrigerant passage 12a of water refrigerant heat exchanger 12, liquid collector 19, heating expansion valve 20a, outdoor heat exchanger 22, first check valve 21a, and compressor 11.

[0165] In this circuit structure, the control device 70 controls the operation of various controlled devices. For example, for 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 is close to the target high-temperature side heat medium temperature.

[0166] The target high-temperature side heat medium temperature is determined based on the target outlet temperature TAO, referring to the control mapping for the heating mode pre-stored in the control device 70. The target outlet 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 Pd detected by the high-pressure sensor 72d is close to the target high-pressure PdO determined based on the target high-temperature side heat medium temperature.

[0167] Furthermore, for the heating expansion valve 20a, the control device 70 controls the throttling opening so that the superheat SH1 of the refrigerant on the outlet side of the outdoor heat exchanger 22 is close to a predetermined target superheat KSH (5°C in this embodiment). The superheat SH1 is calculated based on the outdoor refrigerant temperature T1 detected by the outdoor unit temperature sensor 72j and the outdoor refrigerant pressure P1 detected by the outdoor unit pressure sensor 72k.

[0168] Additionally, for the air mixing door 64, the control device 70 controls the opening degree so that the blow-out air temperature TAV detected by the air conditioning air temperature sensor 72e is close to the target blow-out temperature TAO. In heating mode, the opening degree of the air mixing door 64 can also be controlled so that all the airflow after passing through the indoor evaporator 23 flows into the water refrigerant heat exchanger 12.

[0169] In the refrigeration cycle 10, when the compressor 11 operates, the high-pressure refrigerant discharged from the compressor 11 flows into the refrigerant passage 12a of the water refrigerant heat exchanger 12. The refrigerant flowing into the water refrigerant heat exchanger 12 dissipates heat and condenses on the high-temperature side heat medium flowing in the heat medium passage 12b. Thus, the high-temperature side heat medium is heated in the water refrigerant heat exchanger 12.

[0170] At this time, in the high-temperature side heat medium circuit 30, the high-temperature side heat medium circulates through the operation of the high-temperature side pump 32. Therefore, the high-temperature side heat medium, heated by 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 flowing into the heater core 33 exchanges heat with the supply air after passing through the indoor evaporator 23. Thus, the supply air blown into the vehicle interior is heated by at least the high-pressure refrigerant as a heat source.

[0171] Refrigerant flowing from the water refrigerant heat exchanger 12 flows into the liquid collector 19 via the first tee connector 13a and the inlet-side passage 27a. The refrigerant flowing into the liquid collector 19 undergoes gas-liquid separation. A portion of the liquid refrigerant separated from the liquid collector 19 flows into the heating expansion valve 20a via the outlet-side passage 27b and the second tee connector 13b. The remaining liquid refrigerant separated from the liquid collector 19 is stored as surplus refrigerant in the liquid collector 19.

[0172] The refrigerant flowing into the heating expansion valve 20a is depressurized to become a low-pressure refrigerant. At this time, the throttling opening of the heating expansion valve 20a is controlled so that the superheat SH1 is close to the target superheat KSH. In heating mode, the throttling opening of the heating expansion valve 20a is essentially controlled so that the superheat of the refrigerant on the outlet side of the outdoor heat exchanger 22 is close to the target superheat KSH.

[0173] Low-pressure refrigerant, depressurized by the heating expansion valve 20a, flows into the outdoor heat exchanger 22. The refrigerant flowing into the outdoor heat exchanger 22 exchanges heat with the outside air blown in by the outdoor fan 22a, absorbing heat from the outside air and evaporating. The refrigerant flowing out of the outdoor heat exchanger 22 is drawn into the compressor 11 via the third three-way connector 13c, the suction-side passage 27d, and the fourth three-way connector 13d, and is compressed again.

[0174] Therefore, in heating mode, heating of the vehicle interior can be achieved by blowing the heated air from the heater core 33 into the vehicle interior.

[0175] As described above, in the heating mode of the vehicle air conditioning unit 1 according to this embodiment, the outdoor heat exchanger 22 absorbs heat from the outside air and uses the heat absorbed from the outside air for heating inside the vehicle. Here, when the outside air is cold and humid, frost forms on the surface of the outdoor heat exchanger 22, reducing the heat exchange performance of the outdoor heat exchanger 22.

[0176] In other words, if frost forms on the outdoor heat exchanger 22 in the heating mode, the amount of heat absorbed from the outside air in the outdoor heat exchanger 22 decreases, which in turn becomes the main reason for the reduced heating performance of the vehicle air conditioning unit 1.

[0177] Therefore, the vehicle air conditioning unit 1 according to this embodiment performs defrosting operation to cope with frost formation on the outdoor heat exchanger 22. As the defrosting operation mode in this embodiment, a condensation heat defrosting mode is included. (Refer to...) Figure 5 The condensation heat defrosting mode, one of the defrosting operation modes, is explained.

[0178] The condensing heat defrosting mode operates as follows: defrosting of the outdoor heat exchanger 22 is performed using heat absorbed by the indoor evaporator 23 from the supply 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 dissipated from the battery 75 to the low-temperature side heat medium and heat applied to the low-temperature side heat medium by the electric heater 44.

[0179] The following describes a case where the outdoor heat exchanger 22 is defrosted using heat absorbed from the low-temperature side heat medium circuit 40 in the chiller 24, as an example of a condensation heat defrosting mode. This condensation heat defrosting mode is performed, for example, during the defrosting of the outdoor heat exchanger 22 when the battery 75 of an electric vehicle is being charged and the vehicle interior has heat capacity. Since the battery 75 is charging, it is conceivable that a large amount of heat is generated in the battery 75, thus the heat generated in the battery 75 due to charging can be effectively utilized for defrosting the outdoor heat exchanger 22.

[0180] In the condensing defrost mode under this condition, the control device 70 closes the first on / off valve 16a and opens the second on / off valve 16b. Furthermore, the control device 70 operates the three-way valve 18 in such a way that it connects the refrigerant outlet of the outdoor heat exchanger 22 to the flow path on the side of the fifth three-way connector 13e and closes the flow path on the side of the first check valve 21a. Further, the control device 70 sets the heating expansion valve 20a to the fully open state and the cooling expansion valve 20c to the throttling state. And the control device 70 sets the cooling expansion valve 20b to the fully closed state.

[0181] Additionally, the control device 70 operates the cryogenic side pump 42 to pressurize the cryogenic side heat medium at a predetermined pressurization capacity. Furthermore, the control device 70 maintains the high-temperature side heat medium circuit 30 in a state where the high-temperature side pump 32 is stopped.

[0182] Thus, in the refrigeration cycle 10 under the condensing heat defrosting mode, a vapor compression refrigeration cycle is formed. The refrigerant circulates in the following order: compressor 11, water refrigerant heat exchanger 12, second on / off valve 16b, heating expansion valve 20a, outdoor heat exchanger 22, three-way valve 18, liquid collector 19, cooling expansion valve 20c, chiller 24, and compressor 11.

[0183] In this circuit structure, the control device 70 controls the operation of various controlled devices. For example, for 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 is close to the target low-temperature side heat medium temperature. The target low-temperature side heat medium temperature is determined to make the battery temperature close to an appropriate temperature range.

[0184] Furthermore, for the cooling expansion valve 20c, the control device 70 controls the throttling opening so that the superheat of the refrigerant on the outlet side of the refrigerant passage 24a in the chiller 24 is close to a predetermined reference chiller-side superheat. The superheat of the refrigerant on the outlet side in the chiller 24 is calculated based on 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. In addition, the reference chiller-side superheat is set to the temperature of the low-temperature heat medium that can be maintained within an appropriate temperature range of the battery 75 at the battery temperature TB.

[0185] like Figure 5 As shown, in the refrigeration cycle 10, the 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 flows into the outdoor heat exchanger 22 after passing through the second on / off valve 16b and the outside air passage 27c and the fully open heating expansion valve 20a.

[0186] Therefore, the high-pressure refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 22 with almost no heat loss. Thus, the heat from the high-pressure refrigerant can be applied to the outdoor heat exchanger 22, enabling defrosting of the outdoor heat exchanger 22.

[0187] The refrigerant flowing from the outdoor heat exchanger 22 flows through the three-way valve 18, the second check valve 21b, and the fifth three-way connector 13e into the liquid collector 19 for gas-liquid separation. A portion of the liquid refrigerant separated from the liquid collector 19 flows through the sixth three-way connector 13f and the seventh three-way connector 13g into the cooling expansion valve 20c to be depressurized, and then flows into the refrigerant passage 24a of the chiller 24. Thus, the low-pressure refrigerant flowing 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 of the chiller 24 is guided to the suction port of the compressor 11, where it is compressed again and discharged.

[0188] In the condensing heat defrosting mode under this condition, the refrigeration cycle 10 can absorb the heat generated by the battery 75 absorbed in the chiller 24 and use this heat for defrosting of the outdoor heat exchanger 22.

[0189] The condensing heat defrosting operation of the outdoor heat exchanger 22 in the vehicle air conditioning unit 1 according to this embodiment is performed when the amount of frost adhering to the outdoor heat exchanger 22 exceeds a predetermined benchmark. In the condensing heat defrosting mode, after the frost adhering to the outdoor heat exchanger 22 is melted, the moisture generated by the melting is evaporated and removed.

[0190] Specifically, in the condensing heat defrosting mode, melting defrosting is performed to melt the frost attached to the outdoor heat exchanger 22, and drying defrosting is performed to evaporate and remove the moisture generated by melting defrosting.

[0191] Here, during the defrosting of the outdoor heat exchanger 22, even if the frost attached to the outdoor heat exchanger 22 is melted, the moisture generated by the melting (hereinafter also referred to as residual moisture) will freeze again at a low temperature when the outside air temperature is below 0°C, which will reduce the heat exchange performance of the outdoor heat exchanger 22.

[0192] The reduction in heat exchange performance of the outdoor heat exchanger 22 is a major cause of the reduction in air conditioning performance in the vehicle air conditioning unit 1, therefore it is necessary to prevent the refreezing of moisture generated during defrosting. As a method to prevent the refreezing of moisture generated during defrosting, it is advisable to evaporate the moisture generated during defrosting and remove it from the surface of the outdoor heat exchanger 22. In the condensation heat defrosting mode, dry defrosting is introduced to prevent the refreezing of the melted moisture.

[0193] Furthermore, it is believed that there are favorable conditions for the efficient removal of moisture from the outdoor heat exchanger 22 during defrosting using the condensation heat in the vehicle air conditioning unit 1. Therefore, regarding the removal of moisture from the outdoor heat exchanger 22 by evaporation, in order to determine useful conditions from the viewpoint of energy efficiency and the quality of the vehicle air conditioning unit 1, the evaporation of moisture in the outdoor heat exchanger 22 is examined.

[0194] First, the preconditions for investigating the evaporation of moisture in the outdoor heat exchanger 22 will be explained. Based on the tendency of past measurement results, it is assumed that the frost attached to the outdoor heat exchanger 22 melts into water within 1 to 2 minutes after the defrosting operation starts, and it is assumed that all the attached frost has melted.

[0195] It is assumed that there is no distribution of residual moisture on the evaporation surface of the outdoor heat exchanger 22. It is assumed that the refrigerant temperature in the outdoor heat exchanger is uniform at the condensation temperature. It is assumed that the wind speed on the evaporation surface of the residual moisture in the outdoor heat exchanger 22 is uniform throughout. Changes in the surface area of ​​the water over time, such as transient changes, are neglected during the evaporation and removal of residual moisture.

[0196] Regarding the evaporation temperature of residual moisture on the surface of the outdoor heat exchanger 22, the following relationship holds: The value obtained by subtracting the evaporation temperature of residual moisture from the refrigerant condensation temperature of the outdoor heat exchanger 22, multiplying it by the water conductivity and evaporation surface area, and then dividing 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 outside air temperature, multiplying it by the thermal conductivity from water to air and the evaporation surface area.

[0197] Furthermore, regarding the water retention state of residual moisture in the air passage of the outdoor heat exchanger 22, it is assumed that the interior of the fins that divide the air passage is not filled with residual moisture, and it is assumed that the evaporation surface area of ​​the outdoor heat exchanger 22 under this condition is a predetermined value.

[0198] Under the aforementioned preconditions, use Figure 6 Several experimental formulas are shown to investigate the evaporation rate Va per unit area. Specifically, experimental formulas related to the diffusion coefficient D, the Reynolds number Re, the Schmidt number Sc, the Sherwood number Sh, and the evaporation rate Va per unit area are used.

[0199] From these Figure 6The experimental results show that the evaporation rate Va per unit area tends to increase as the wind speed Vc increases. Furthermore, it shows that the evaporation rate Va per unit area tends to increase as the temperature of the residual moisture evaporating increases. The temperature of the residual moisture evaporating increases with increasing refrigerant condensation temperature and increases with decreasing wind speed Vc. When the wind speed Vc is increased at the same refrigerant condensation temperature, both factors that increase and factors that decrease the evaporation rate Va per unit area are observed.

[0200] exist Figure 7 Showing the use Figure 6 The experimental formula shown is the result of calculating the relationship between the outdoor unit evaporation rate and the wind speed Vc under different refrigerant condensation temperatures. Figure 7 In this context, Eta represents the relationship between the outdoor unit's evaporation rate and the wind speed when the refrigerant condensation temperature is 20°C.

[0201] Similarly, Etb represents the relationship between outdoor unit evaporation rate and wind speed when the refrigerant condensing temperature is 30°C, and Etc represents the relationship when the refrigerant condensing temperature is 40°C. Furthermore, Etd represents the relationship between outdoor unit evaporation rate and wind speed when the refrigerant condensing temperature is 50°C, and Ete represents the relationship when the refrigerant condensing temperature is 60°C.

[0202] from Figure 7 As shown in the graphs, the outdoor unit evaporation rate tends to increase due to the rise in the evaporation temperature of residual moisture associated with the increase in wind speed Vc. Furthermore, it is evident that the outdoor unit evaporation rate also tends to increase due to the rise in the evaporation temperature of residual moisture associated with the increase in refrigerant condensation temperature. In other words, by appropriately adjusting the refrigerant condensation temperature, which can be controlled by the vehicle air conditioning unit 1, and the wind speed Vc of the outdoor fan 22a, the evaporation and removal of residual moisture in the outdoor heat exchanger 22 can be achieved more efficiently.

[0203] In the vehicle air conditioning unit 1 according to this embodiment, in order to achieve the above-mentioned refrigerant condensation temperature and wind speed Vc, the refrigeration cycle 10 needs to operate when the moisture in the outdoor heat exchanger 22 is evaporated and removed.

[0204] The relationship between refrigerant condensation temperature and air velocity is studied within a range achievable in a typical refrigeration cycle. Figure 8 It is a graph showing the relationship between refrigerant condensation temperature and air velocity under the condition that the refrigerant discharge capacity of the compressor and the heat absorption of the chiller 24 are determined.

[0205] In addition, Figure 8In the diagram, Tcdh represents the relationship between refrigerant condensing temperature and fan speed when the compressor 11 speed and the heat absorption of the chiller 24 are at their maximum. Tcdl represents the relationship between refrigerant condensing temperature and fan speed when the compressor 11 speed and the heat absorption of the chiller 24 are at their minimum. Furthermore, Tcds represents the relationship between refrigerant condensing temperature and fan speed when the compressor 11 speed and the heat absorption of the chiller 24 are at their standard values.

[0206] use Figure 7 , Figure 8 The chart shown is formed Figure 9 The chart shown. Figure 9 In the diagram, Edh represents the relationship between the outdoor unit's evaporation rate and the fan speed when the compressor 11's speed and the chiller 24's heat absorption are at their maximum. Edl represents the relationship between the outdoor unit's evaporation rate and the fan speed when the compressor 11's speed and the chiller 24's heat absorption are at their minimum. Wds represents the relationship between the outdoor unit's evaporation rate and the fan speed when the compressor 11's speed and the chiller 24's heat absorption are at their standard values.

[0207] according to Figure 9 The diagram shown indicates that the operating condition zone Af achievable in the refrigeration cycle can be determined based on the wind speed. By operating the refrigeration cycle at the outdoor unit evaporation rate and wind speed Vc contained in this operating condition zone Af, the evaporation and removal of residual moisture in the outdoor heat exchanger 22 can be achieved at least for a relatively short period of time.

[0208] The evaporation and removal of residual moisture in the outdoor heat exchanger 22 means that water vapor from the residual moisture is generated. When the outside air temperature is low, when water vapor is generated from the outdoor heat exchanger 22 in the drive unit room, it is perceived from the outside as white mist gas being generated from the drive unit room, and therefore it is possible to mistakenly believe that white smoke is being generated from the equipment in the drive unit room.

[0209] Therefore, when removing residual moisture from the outdoor heat exchanger 22 by evaporation, it is necessary to simultaneously suppress the visual recognition of white fog and promote the evaporation of residual moisture. As a reference for the visual recognition of white fog, a method using a moisture profile is known.

[0210] Figure 10 This is an explanation of a humidity curve. In this graph, the horizontal axis represents temperature, the vertical axis represents absolute humidity, and the sloping curve represents relative humidity ψ. The line where the 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 has been completely liquefied. The area to the right of the saturation line Lsa represents a state where water vapor and other gases (such as air) are mixed. In this state, the higher the relative humidity ψ, the more moisture condenses and the more easily it is visually perceived as fog.

[0211] Here, it is assumed that during the evaporation and removal of residual moisture in the outdoor heat exchanger 22, the water vapor is mistakenly perceived as white fog during the stage when the outside air and the air after passing through the outdoor heat exchanger 22 are mixed. Furthermore, if the mixing of the outside air and the air after passing through the outdoor heat exchanger 22 is completed, a relationship based on the mixing ratio of the two will eventually be achieved.

[0212] Therefore, although heat diffuses faster than matter diffuses, whether the result of white fog being visually recognized is a question. Based on empirical insights, it can be defined as a state in which matter has been fully mixed, and it is believed that this can be determined based on the mixing ratio of the outside air and the air after passing through the outdoor heat exchanger 22.

[0213] Furthermore, the state of the air at the air outlet side of the outdoor heat exchanger includes not only the state of the air after passing through the outdoor heat exchanger 22, but also the state after the air after passing through the outdoor heat exchanger 22 is mixed with the substances of the outdoor air.

[0214] While referring to Figure 10 The following example illustrates the determination of the visual recognition of white fog using a humid air graph, assuming an outside air temperature of 0°C. First, the tangent line Ltan relative to the saturation line Lsa is calculated based on the saturation point at the outside air temperature in the humid air graph. The tangent line Ltan represents the visual recognition threshold by which water vapor is identified as white fog. Figure 10 The tangent line Ltan through the saturation point P when the outside air temperature is 0℃ was obtained from the case shown.

[0215] exist Figure 10 In the humid air profile, the region below the tangent Ltan corresponds to the visually suppressed region Aa, where water vapor generated from the outdoor heat exchanger 22 is not identified as white fog. On the other hand, in the humid air profile, the region below the saturation line Lsa and above the tangent Ltan corresponds to the visually suppressed region Ab, where water vapor generated from the outdoor heat exchanger 22 is identified as white fog and thus becomes a problem.

[0216] Based on whether the air state during the mixing stage of the outside air and the air after passing through the outdoor heat exchanger 22 belongs to either the visual recognition suppression zone Aa or the visual recognition zone Ab, it can be determined whether water vapor is visually recognized as fog. Therefore, by controlling the refrigerant condensation temperature and wind speed Vc in the outdoor heat exchanger 22 so that the air state during the mixing stage of the outside air and the air after passing through the outdoor heat exchanger 22 belongs to the visual recognition suppression zone Aa, rapid drying and defrosting can be achieved while suppressing the visibility of fog.

[0217] Furthermore, in the humid air diagram, the air state at the stage where the mixing of outside air and air after passing through the outdoor heat exchanger 22 is completed, based on the tangent Ltan, is defined as the visual recognition suppression region Aa. Therefore, the air state will not fall within the visual recognition region Ab. Thus, the visibility of white fog can be sufficiently suppressed during the process until the mixing of outside air and air after passing through the outdoor heat exchanger 22 is complete.

[0218] Here, assuming that the refrigerant-side capacity and air-side capacity are balanced in the refrigeration cycle, the air-side enthalpy Sep relative to the refrigerant-side outdoor unit capacity is calculated at any fan speed Vc and the refrigeration cycle equilibrium point (i.e., refrigerant discharge capacity and heat absorption) at which the refrigerant condensation temperature is generated. Based on the air-side enthalpy Sep, the enthalpy line Lse corresponding to the air-side enthalpy Sep is determined in the humid air curve diagram.

[0219] For example, taking an arbitrary system as an example, with an outside air temperature of 0°C, a wind speed Vc of 0.5 m / s, and a refrigerant condensation temperature of 35°C, the air-side specific enthalpy is calculated to be 33 kJ / kg. Then, in Figure 11 In the humid air curve diagram shown, the specific enthalpy line Lse corresponding to the calculated 33 kJ / kg is determined.

[0220] Next, the intersection point Pc of the tangent line Ltan and the specific enthalpy line Lse is determined. Here, the permissible upper limit of evaporation per unit weight of air is calculated by subtracting the absolute humidity Aha at the intersection point Pc from the absolute humidity Aht at the saturation point P of the outside air temperature. The permissible upper limit of evaporation per unit weight of air represents the amount of water vapor allowed per unit weight of air after passing through the outdoor heat exchanger 22 until saturation.

[0221] This calculation is performed by varying the allowable upper limit of evaporation per unit of air weight (Em) under different conditions such as wind speed (Vc) and refrigerant condensing temperature. If the allowable upper limit of evaporation per unit of air weight (Em) for each condition is summed, it becomes... Figure 12 The allowable upper limit of evaporation, Emx, is shown in the figure. Figure 12 In areas where the outdoor unit's evaporation rate and wind speed Vc are lower than the allowable upper limit evaporation rate line Emx, residual moisture can be efficiently evaporated and removed without being visually recognized as white fog.

[0222] Here, in the condensation heat defrosting of the vehicle air conditioning unit 1, it is assumed that the maximum permissible amount of frost adheres to the outdoor heat exchanger 22 due to heating operation at low outside air temperatures. Therefore, in this embodiment, the necessary amount of moisture evaporation En that needs to be evaporated from the outdoor heat exchanger 22 is calculated by subtracting the amount of water falling from the outdoor heat exchanger 22 due to the melting of frost from the maximum permissible amount of frost.

[0223] like Figure 13 As shown, the operating conditions for rapidly restoring the heat exchange performance of the outdoor heat exchanger 22 without visually detecting white fog during the evaporation and removal of residual moisture from the outdoor heat exchanger 22 are specified by the target area Ao. Furthermore, the target area Ao is determined to be greater than the wind speed Vc involved in the allowable upper limit evaporation line Emx and the outdoor unit evaporation rate is greater than the necessary moisture evaporation rate En.

[0224] use Figures 6 to 13 The investigation was able to use Figure 14 The charts shown summarize the main points. Figure 14 The chart is to Figure 9 The charts and Figure 13 The chart shown summarizes the contents. Figure 14 The target area At shown in the diagram represents the operating conditions under which the outdoor heat exchanger 22 can quickly recover its heat exchange performance without visually detecting white fog during the evaporation and removal of residual moisture in the refrigeration cycle. Specifically, the target area At is defined by... Figure 9 The operating condition region Af and Figure 13 The overlapping range of the object region Ao in the specification.

[0225] like Figure 14 As shown, the target region At contains points Px, Py, and Pz. Point Px represents the intersection of the allowable upper limit evaporation line Emx and the necessary moisture evaporation En. Point Py represents the intersection of the allowable upper limit evaporation line Emx and the curve Edh, which represents the outdoor unit evaporation rate under the condition that the compressor 11 speed and the heat absorption of the chiller 24 are at their maximum. Point Pz represents the intersection of curve Edh and the necessary moisture evaporation En.

[0226] The minimum wind speed Vc in the target area At is the wind speed at point Px, which is 0.12 m / s. The maximum wind speed Vc in the target area At is the wind speed at point Pz, which is 1.2 m / s.

[0227] Therefore, when the residual moisture is evaporated and removed from the outdoor heat exchanger 22 by defrosting, the residual moisture can be quickly evaporated and removed without the white fog being visually detected by adjusting the wind speed of the outdoor air fan 22a to the range of 0.12m / s to 1.2m / s.

[0228] Furthermore, the minimum outdoor unit evaporation rate in the target area At is determined based on the outdoor unit evaporation rates at points Px and Pz, which is equivalent to the necessary moisture evaporation rate En. Since the refrigerant condensation temperature can be determined based on the outdoor unit evaporation rate, the minimum refrigerant condensation temperature in the target area At is determined to be 15°C.

[0229] Furthermore, the maximum outdoor unit evaporation rate in target area At is determined based on the outdoor unit evaporation rate at point Py. The maximum refrigerant condensation temperature in target area At is calculated based on the outdoor unit evaporation rate at point Py and is set to 70°C.

[0230] Therefore, when the residual moisture is evaporated from the outdoor heat exchanger 22 through defrosting operation, heat that is adjusted to a refrigerant condensation temperature of 15°C to 70°C is supplied to the outdoor heat exchanger 22, thereby enabling the residual moisture to be evaporated quickly without visually detecting white fog.

[0231] Here, the defrost condition coefficient DCC is used to control the operation in the dry defrost mode, as it relates 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 velocity 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. When calculating the defrost condition coefficient DCC, Celsius is used as the unit for the refrigerant condensation temperature in the outdoor heat exchanger 22. This is because, in discussing the phenomenon of dry defrost, the temperature difference between the melting point of water and the melting point is an important factor.

[0232] With the use of the defrost condition coefficient DCC, the defrost condition coefficient DCC for the target area At was determined to be between 1.8 and 35. The value of "1.8" in the defrost condition coefficient DCC is a value related to point Px, obtained by multiplying 0.12 m / s by 15°C. The value of "35" in the defrost condition coefficient DCC is a value related to point Py, obtained by multiplying 0.5 m / s by 70°C.

[0233] Therefore, when the residual moisture is evaporated and removed from the outdoor heat exchanger 22, the defrosting condition coefficient DCC is adjusted to 1.8 to 35 by adjusting the wind speed Vc and the refrigerant condensation temperature, so that the residual moisture can be quickly evaporated and removed without being visually detected as white fog.

[0234] Here, the dry defrosting method in condensation defrosting will be explained. In dry defrosting, which removes residual moisture caused by the melting frost by evaporation, parameters such as the wind speed Vc and the refrigerant condensation temperature, as determined above, are used to control the operation of the vehicle air conditioning unit 1.

[0235] At this time, the control device 70 controls the refrigerant discharge capacity of the compressor 11 so that the refrigerant condensing temperature in the outdoor heat exchanger 22 is close to the target condensing temperature TCO. The target condensing temperature TCO is determined with reference to the control mapping pre-stored in the control device 70.

[0236] In this embodiment, such as Figure 15 As shown in the control characteristic diagram, the target condensing temperature (TCO) increases with the increase of the outside air temperature. Therefore, the refrigerant condensing temperature during defrosting is adjusted to be lower within the range of 15°C to 70°C, with the temperature decreasing as the outside air temperature decreases.

[0237] Furthermore, for the refrigeration expansion valve 20b and the cooling expansion valve 20c, the control device 70 controls the throttling opening so that the superheat of the refrigerant on the outlet side of the refrigerant passage 24a in the chiller 24 is close to a predetermined reference chiller side superheat (e.g., 10°C).

[0238] Furthermore, for the outdoor air fan 22a corresponding to the amount of outdoor air supplied to the outdoor heat exchanger 22, the rotational speed of the outdoor air fan 22a is controlled to approach the target wind speed VaO. The target wind speed VaO is determined with reference to the control mapping pre-stored in the control device 70.

[0239] In this embodiment, such as Figure 16 As shown in the control characteristic diagram, the target wind speed VaO is determined to decrease as the refrigerant condensing temperature of the outdoor heat exchanger 22 decreases. As mentioned above, the lower the outside air temperature, the lower the target condensing temperature TCO is determined; therefore, the target wind speed VaO is also determined to be smaller as the outside air temperature decreases.

[0240] exist Figure 16 In the control characteristic diagram shown, the target wind speed VaO is determined to be greater than the visual recognition limit wind speed Vl when the outdoor fan 22a is operating. The visual recognition limit wind speed Vl represents the upper limit of the wind speed Vc at which water vapor is visually recognized as white fog during the dry defrosting process of the outdoor heat exchanger 22 based on the refrigerant condensation temperature. Therefore, by... Figure 16 The control characteristic diagram shown sets the target wind speed VaO during drying and defrosting, thereby suppressing the visual recognition of white fog while promoting the evaporation and removal of residual moisture from the outdoor heat exchanger 22.

[0241] Furthermore, when determining the target wind speed of the external air fan 22a, if the external air temperature is lower than the low-temperature side reference temperature (e.g., -15°C), the target wind speed is set to 0.12 m / s or less. Under the condition that the external air temperature is lower than the low-temperature side reference temperature, it is assumed that the water vapor generated during the drying defrosting mode is rapidly cooled and becomes ice particles. In this case, the possibility of it being mistaken for white smoke is considered low, therefore the target wind speed VaO is set to 0.12 m / s or less.

[0242] When the outside air temperature is lower than the low-temperature reference temperature, the outside air fan 22a can be stopped as a way to achieve the target wind speed of 0.12 m / s. Alternatively, the supply of air to the outdoor heat exchanger 22 can be hindered by a damper device configured in the air supply path relative to the outdoor heat exchanger 22.

[0243] Furthermore, the condensation defrosting mode ends upon completion of dry defrosting. Dry defrosting is considered complete when residual moisture on the surface of the outdoor heat exchanger 22 has evaporated and been removed from the surface of the outdoor heat exchanger 22.

[0244] like Figure 17 As shown, in the condensation defrosting mode, after melting defrosting is completed, drying defrosting is performed. Since it is assumed that the residual moisture evaporated during drying defrosting comes from the melting of frost during melting defrosting, it is believed that there is a strong correlation between the energy invested in melting defrosting and the energy required for drying defrosting.

[0245] In this embodiment, the determination of whether defrosting is complete is based on the relationship between the energy invested during melting defrosting and the energy required for drying defrosting. First, the amount of water melted is estimated, which represents the total amount of frost melted by melting defrosting. The amount of water melted is estimated by dividing the total energy invested in melting the frost during melting defrosting by the heat of melting per unit weight of ice.

[0246] Specifically, the total energy invested in melting the frost during defrosting is calculated by subtracting heat loss due to factors such as wind speed from the total work done by compressor 11 and heat absorbed in chiller 24. The calculated total energy represents one example of the energy invested. Heat loss due to factors such as wind speed represents the heat dissipation energy during defrosting.

[0247] The heat dissipation energy during defrosting is determined, for example, using a control table derived experimentally from the relationship between wind speed and outside air temperature to measure heat loss from the air. This control table specifies that the lower the outside air temperature, the greater the heat dissipation energy. Furthermore, the control table also specifies that the greater the wind speed, the greater the heat dissipation energy.

[0248] Then, by dividing the calculated total energy by the heat of melting per unit weight of ice (e.g., about 334 kJ / kg), the amount of melted water, which is the total amount of frost melted during defrosting, is estimated.

[0249] Next, the calculated amount of melted water is used to calculate the required work. The required work refers to the energy required in the drying defrosting process to evaporate residual water equivalent to the amount of melted water; it is an example of the necessary energy. Specifically, the required work is calculated by multiplying the estimated amount of melted water by the latent heat of vaporization per unit weight of water (e.g., approximately 2400 kJ / kg).

[0250] Next, it is determined whether the cumulative value of the energy input in the drying defrosting process is greater than or equal to the necessary work (i.e., whether it is greater than or equal to the necessary energy). The drying work input is equivalent to an example of the drying energy input.

[0251] When determining the energy input for drying, the heat dissipation energy during drying defrost is pre-calculated by removing the total work done by compressor 11 and the heat absorbed by chiller 24. The heat dissipation energy during drying defrost refers to the heat loss due to air cooling during the drying defrost process. Therefore, the heat dissipation energy during drying defrost can be determined by referring to the control table described above and using the air velocity and outside air temperature during drying defrost.

[0252] If the amount of work required for drying exceeds the necessary amount, it can be assumed that all residual moisture generated during the melting defrost process has evaporated during the drying defrost process, and therefore the drying defrost process is considered complete. If the amount of work required for drying is less than the necessary amount, the drying defrost process is considered incomplete.

[0253] By determining the completion of drying defrosting in this way, the vehicle air conditioning unit 1 can reliably remove residual moisture from the outdoor heat exchanger 22. Furthermore, by considering the heat dissipation energy during both melting defrosting and drying defrosting, the accuracy of determining whether residual moisture removal has been completed can be improved. Moreover, since the heat dissipation energy utilizes wind speed and outside air temperature, it can be appropriately determined based on the environment during melting defrosting and drying defrosting. From this perspective, the accuracy of determining the completion of drying defrosting can also be improved.

[0254] In the vehicle air conditioning unit 1 according to the first embodiment, a heating and defrosting mode is provided in order to perform heating of the air-conditioned target space (vehicle interior) and condensation heat defrosting of the outdoor heat exchanger 22 in parallel. (Refer to...) Figure 18 Explanation of the heating and defrosting modes in vehicle air conditioning unit 1

[0255] In the heating and defrosting mode, in order to improve comfort by heating the air-conditioned space (inside the vehicle), a heating capacity of, for example, 40°C to 70°C is required as the temperature of the refrigerant in the water refrigerant heat exchanger 12.

[0256] On the other hand, regarding condensation-based defrosting in the heating defrosting mode, a defrosting capability of approximately 30°C is required, based on the refrigerant temperature of the outdoor heat exchanger 22. From the perspective of defrosting the outdoor heat exchanger 22, a higher refrigerant temperature is generally considered better. However, if the refrigerant temperature is too high, the visibility of white mist generated by moisture evaporation increases, making it more likely to be mistaken for white smoke. Therefore, the defrosting capability of the outdoor heat exchanger 22 also needs to be controlled through the operation of the refrigeration cycle 10.

[0257] In heating and defrosting mode, control device 70 closes the first on / off valve 16a and opens the second on / off valve 16b. Furthermore, control device 70 operates the three-way valve 18 in such a way that it connects the refrigerant outlet of the outdoor heat exchanger 22 to the flow path on the side of the fifth three-way connector 13e and closes the flow path on the side of the first check valve 21a. Further, control device 70 sets the heating expansion valve 20a and the cooling expansion valve 20c to a throttling state. And control device 70 sets the cooling expansion valve 20b to a fully closed state.

[0258] Furthermore, regarding the high-temperature side heat medium circuit 30, the control device 70 operates the high-temperature side pump 32 to pressurize the high-temperature side heat medium at a predetermined pressurization capacity. The control device 70 also causes the water heater 34 in the high-temperature side heat medium circuit 30 to heat the high-temperature side heat medium according to predetermined conditions. And, regarding the low-temperature side heat medium circuit 40, the control device 70 operates the low-temperature side pump 42 to pressurize the low-temperature side heat medium at a predetermined pressurization capacity.

[0259] Thus, in the refrigeration cycle 10 under the heating and defrosting mode, a vapor compression refrigeration cycle is formed. The refrigerant circulates in the following order: compressor 11, water refrigerant heat exchanger 12, second on / off valve 16b, heating expansion valve 20a, outdoor heat exchanger 22, three-way valve 18, liquid collector 19, cooling expansion valve 20c, chiller 24, and compressor 11.

[0260] In this circuit structure, the control device 70 controls the operation of various controlled devices. For example, it controls the refrigerant discharge capacity (i.e., speed) of the compressor 11, the throttling opening of the heating expansion valve 20a, the throttling opening of the cooling expansion valve 20c, and the heat output of the water heater 34, according to the heating defrosting control program described later. Details of the heating defrosting control program will be described later.

[0261] Furthermore, the condensation defrosting mode in the heating defrosting mode, like the aforementioned condensation defrosting mode, includes both melt defrosting and dry defrosting. Therefore, during dry defrosting, the air velocity Vc supplied by the outdoor fan 22a to the outdoor heat exchanger 22 and the refrigerant condensation temperature in the outdoor heat exchanger 22 are determined to be within the range of... Figure 14The target area At shown is controlled to reach a predetermined target value.

[0262] like Figure 18 As shown, in the refrigeration cycle 10, the high-pressure refrigerant discharged from the compressor 11 flows into the refrigerant passage 12a of the water refrigerant heat exchanger 12. The refrigerant flowing into the water refrigerant heat exchanger 12 dissipates heat and condenses on the high-temperature side heat medium flowing in the heat medium passage 12b. Thus, the high-temperature side heat medium is heated in the water refrigerant heat exchanger 12.

[0263] At this time, in the high-temperature side heat medium circuit 30, the high-temperature side heat medium circulates through the operation of the high-temperature side pump 32. Therefore, the high-temperature side heat medium, heated by 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 flowing into the heater core 33 exchanges heat with the supply air after passing through the indoor evaporator 23. Thus, in the heating and defrosting mode, the supply air blown into the vehicle interior is heated by at least the high-pressure refrigerant as a heat source.

[0264] The refrigerant flowing from the water refrigerant heat exchanger 12 flows into the heating expansion valve 20a via the second on / off valve 16b and the outside air passage 27c, where it is depressurized to intermediate pressure refrigerant according to the throttling opening of the heating expansion valve 20a. The intermediate pressure refrigerant after being depressurized by the heating expansion valve 20a flows into the outdoor heat exchanger 22.

[0265] Therefore, the intermediate-pressure refrigerant flowing from the heating expansion valve 20a flows into the outdoor heat exchanger 22, thus applying the heat possessed by the intermediate-pressure refrigerant to the outdoor heat exchanger 22. That is, in the heating defrosting mode, condensation heat defrosting of the outdoor heat exchanger 22 using the heat possessed by the intermediate-pressure refrigerant can be performed.

[0266] The refrigerant flowing from the outdoor heat exchanger 22 flows through the three-way valve 18, the second check valve 21b, and the fifth three-way connector 13e into the liquid collector 19 for gas-liquid separation. A portion of the liquid refrigerant separated from the liquid collector 19 flows through the sixth three-way connector 13f and the seventh three-way connector 13g into the cooling expansion valve 20c to be depressurized, and then flows into the refrigerant passage 24a of the chiller 24.

[0267] As a result, the low-pressure refrigerant flowing 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 of the chiller 24 is guided to the suction port of the compressor 11, where it is compressed again and then discharged.

[0268] In the heating and defrosting mode under this condition, the refrigeration cycle 10 can absorb the heat generated by the battery 75 absorbed by the chiller 24 and use this heat for heating the air-conditioned space and defrosting the outdoor heat exchanger 22 using condensation heat.

[0269] Next, refer to Figures 19-21 The control functions of the vehicle air conditioning unit 1 in heating and defrosting mode are explained below. The heating and defrosting operation of the vehicle air conditioning unit 1 is achieved by the control device 70 executing a heating and defrosting control program stored in the ROM. This heating and defrosting control program is executed simultaneously with the power supply to the vehicle air conditioning unit 1.

[0270] As described above, in the heating defrosting mode, condensation defrosting of the outdoor heat exchanger 22 is performed in parallel with the heating of the air-conditioned space. Condensation defrosting includes melting defrosting and drying defrosting, thus creating a state where heating of the air-conditioned space and melting defrosting of the outdoor heat exchanger 22 are performed, and a state where heating of the air-conditioned space and drying defrosting of the outdoor heat exchanger 22 are performed.

[0271] like Figure 19 As shown, firstly, in step S1, it is determined whether a heating indication is present regarding the operation of the vehicle air conditioning unit 1. The heating indication is generated when the air conditioning target space is requested to be heated based on detection signals from various control sensors and operation signals from the operation panel during the execution of the air conditioning control program. If a heating indication is present, the process proceeds to step S2. On the other hand, if no heating indication is present, the heating defrost control program ends. In this case, air conditioning operation and battery 75 cooling operation, which are related to other operating modes, are performed.

[0272] In step S2, it is determined whether the outdoor heat exchanger 22 is frosted. The determination in step S2 is based on whether the amount of frost adhering to the outdoor heat exchanger 22 exceeds a predetermined threshold. If the amount of frost exceeds the threshold and the outdoor heat exchanger 22 is determined to be frosted, the process proceeds to step S3. If the outdoor heat exchanger 22 is determined not to be frosted, the heating defrosting control procedure ends. In this case, heating operation is performed in the vehicle air conditioning unit 1.

[0273] When transitioning to step S3, the operating mode of the vehicle air conditioning unit 1 is set to heating and defrosting mode. In heating and defrosting mode, heating of the air-conditioned space and defrosting of the outdoor heat exchanger 22 by condensation heat are performed in parallel, but it is assumed that the capacity of the refrigeration cycle 10 is insufficient when both are performed in parallel.

[0274] Therefore, in the vehicle air conditioning unit 1, as a heating and defrosting mode, there are two modes: an efficiency priority mode that prioritizes defrosting the outdoor heat exchanger 22 based on condensation heat compared to heating the air-conditioned space, and a comfort priority mode that prioritizes heating the air-conditioned space based on condensation heat compared to defrosting the outdoor heat exchanger 22.

[0275] In step S3, a process is performed to determine whether to prioritize heating of the air-conditioned space or defrosting of the outdoor heat exchanger 22 using condensation heat. Specifically, based on detection signals from various control sensors and operation signals from the control panel, a determination is made as to whether an efficiency-priority mode is more suitable than a comfort-priority mode.

[0276] As an example of the efficiency-first condition, one could exemplify the case where the operation signal indicating that the efficiency-first mode has been selected is used as the operation signal for the operation panel 71. In other words, if the efficiency-first mode is selected through user operation, the efficiency-first condition is deemed met.

[0277] Furthermore, as an efficiency-priority criterion, one example is the situation where the heating load of the air-conditioned space is determined to be less than a baseline based on detection signals from various control sensors. When the heating load is less than the baseline, the efficiency-priority criterion is deemed met.

[0278] If the efficiency priority condition is met, proceed to step S4 to perform control related to the efficiency priority mode of the heating and dehumidification mode. The control content related to the efficiency priority mode in step S4 will be explained later with reference to the accompanying drawings. When the control related to the efficiency priority mode of the heating and dehumidification mode ends, the process proceeds to step S6.

[0279] On the other hand, if the efficiency priority condition is not met, the process proceeds to step S5 to perform controls related to the comfort priority mode of the heating and dehumidification mode. The control content related to the comfort priority mode in step S5 will be explained later with reference to the accompanying drawings. When the control related to the comfort priority mode of the heating and dehumidification mode ends, the process proceeds to step S6.

[0280] In step S6, since the condensation defrosting of the outdoor heat exchanger 22 was completed at the end of steps S4 and S5, the operating mode of the vehicle air conditioning unit 1 is switched from heating defrosting mode to heating mode. After switching to heating mode, the heating defrosting control program ends.

[0281] Next, refer to Figure 20 The control parameters related to the efficiency-priority mode of the heating and defrosting mode are explained. When transitioning to step S4 to start the efficiency-priority mode, as... Figure 20 As shown, firstly, defrosting capability control is performed in step S11.

[0282] In the defrosting capacity control of step S11, the refrigerant discharge capacity (speed) of compressor 11 is controlled so that the refrigerant condensing temperature in outdoor heat exchanger 22 is the target condensing temperature. During dry defrosting in heating defrosting mode, the target condensing temperature TCO is determined as described in condensing heat defrosting mode. Figure 15 The control characteristic diagram shown is used to determine this.

[0283] Furthermore, a strong correlation was found between the refrigerant temperature and refrigerant pressure in refrigeration cycle 10. Therefore, the target refrigerant pressure equivalent to the target condensing temperature TCO can be determined, and processing can also be performed using the refrigerant pressure in the outdoor heat exchanger 22 and the target refrigerant pressure.

[0284] In other words, control is performed as follows: when the refrigerant condensing temperature of the outdoor heat exchanger 22 is higher than the target condensing temperature, the speed of the compressor 11 is reduced compared to the current speed; when the refrigerant condensing temperature is lower than the target condensing temperature, the speed of the compressor 11 is increased compared to the current speed. This allows the heat dissipation of the refrigerant in the outdoor heat exchanger 22 to be controlled to a state suitable for condensation heat defrosting.

[0285] 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 the condensing 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.

[0286] In step S13, heating capacity control is performed because the condensation heat defrosting of the outdoor heat exchanger 22 ensures the predetermined capacity. In the heating capacity control of step S13, the opening degree of the heating expansion valve 20a is controlled so that the blown air temperature TAV is the target blown air temperature TAO.

[0287] Furthermore, the refrigerant temperature corresponding to the target outlet temperature TAO can be determined, and a strong correlation between the refrigerant temperature and refrigerant pressure in the refrigeration cycle 10 is confirmed. Therefore, the target refrigerant pressure corresponding to the target outlet temperature TAO can be determined, and processing can also be performed using the refrigerant pressure in the water refrigerant heat exchanger 12 and the target refrigerant pressure corresponding to the outlet air temperature TAV.

[0288] In other words, the control is performed as follows: when the blow-out air temperature TAV is higher than the target blow-out temperature TAO, the opening degree of the heating expansion valve 20a is greater than the current opening degree; when the blow-out air temperature TAV is lower than the target blow-out temperature TAO, the opening degree of the heating expansion valve 20a is smaller than the current opening degree.

[0289] Therefore, the heat dissipation in the water refrigerant heat exchanger 12 can be controlled to any value lower than the heat dissipation in the outdoor heat exchanger 22. That is, different refrigerant temperatures can be generated, such as the refrigerant temperature required for defrosting the condensation heat of the outdoor heat exchanger 22 and the refrigerant temperature required for heating the vehicle interior, and each refrigerant temperature can be appropriately controlled.

[0290] In step S14, since the determination process in step S12 indicates that the defrosting capacity of the outdoor heat exchanger 22 is insufficient relative to a predetermined capacity, defrosting capacity enhancement control is performed. In the defrosting capacity enhancement control of step S14, the temperature of the refrigerant flowing in the water-cooled refrigerant heat exchanger 12 is lowered by fully opening the heating expansion valve 20a, thereby suppressing heat dissipation and increasing the heat dissipation in the outdoor heat exchanger 22.

[0291] Therefore, even if the refrigerant condensing temperature cannot be adjusted to be higher than the target condensing temperature by controlling the operation of the compressor 11 alone, a state higher than the target condensing temperature can be generated by controlling the opening of the heating expansion valve 20a.

[0292] When proceeding to step S15, it is determined whether the outlet air temperature TAV is lower than the target outlet air temperature TAO. In other words, it is determined whether the heat dissipation in the water refrigerant heat exchanger 12 is insufficient relative to the required heating capacity. If the outlet air temperature TAV is lower than the target outlet air 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 air temperature TAO, the process proceeds to step S17.

[0293] In step S16, 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. Therefore, auxiliary heating control is executed. In the auxiliary heating control, the heat output of the water heater 34 is controlled so that the blown air temperature TAV is equal to the target blown air temperature TAO. That is, by utilizing the heating capacity of the water heater 34 to compensate for the deficiency of the heating capacity of the refrigeration cycle 10 relative to the target value, the comfort of the air-conditioned space is ensured.

[0294] In step S17, liquid return prevention control is performed. In this control, the opening of the cooling expansion valve 20c is controlled to prevent liquid refrigerant from being supplied to the suction port of the compressor 11, thus preventing liquid return. The opening of the cooling expansion valve 20c is controlled such that the superheat of the refrigerant at the suction port of the compressor 11 is a predetermined reference value. This prevents compressor 11 malfunctions caused by liquid refrigerant flowing into the suction port of the compressor 11.

[0295] In step S18, it is determined whether condensation defrosting of the outdoor heat exchanger 22 has been completed. As described above, condensation defrosting is performed in the order of melt defrosting and dry defrosting. Therefore, in step S18, it is determined whether the moisture generated in melt defrosting has been evaporated and removed from the outdoor heat exchanger 22 by dry defrosting. If condensation defrosting is completed, the control related to the efficiency priority mode of the heating defrosting mode ends. If condensation defrosting is not completed, the process returns to step S11, and the control related to the efficiency priority mode starts again.

[0296] like Figure 20 As shown, in efficiency-priority mode, in step S11, the heating capacity required for defrosting the outdoor heat exchanger 22 by controlling the refrigerant discharge capacity of the compressor 11 is achieved. Furthermore, in step S13, the heating capacity required for heating the air-conditioned space is achieved by controlling the opening degree of the heating expansion valve 20a.

[0297] Therefore, in the circulation structure of the heating and defrosting mode, the defrosting capacity required by the condensation heat of the outdoor heat exchanger 22 and the heating capacity required by the air-conditioned space can be controlled separately, and different refrigerant condensation temperatures can be achieved.

[0298] Furthermore, in efficiency-priority mode, when the refrigerant condensing temperature is lower than the target condensing temperature, defrosting capacity enhancement control is implemented by adjusting the opening of the heating expansion valve 20a to the fully open state. As a result, the refrigeration cycle 10 operates in such a way that the heat dissipation required for condensation heat defrosting of the outdoor heat exchanger 22 is satisfied, prioritizing the heat dissipation required for heating the target space. Therefore, condensation heat defrosting can be achieved prioritizing heating of the target space.

[0299] Furthermore, in the efficiency priority mode of the heating and defrosting mode, when the heating capacity of the air-conditioned target space generated 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 in the auxiliary heating control.

[0300] Therefore, in the heating and defrosting mode, even if the heating capacity of the cooling cycle 10 is insufficient, the water heater 34, which is a different heat source from the cooling cycle 10, can be used to supplement the heating of the air-conditioned space, thus ensuring comfort.

[0301] Next, refer to Figure 21 The control settings related to the comfort-priority mode of the heating and defrosting mode are explained. When transitioning to step S5 to activate the comfort-priority mode, as... Figure 21 As shown, firstly, heating capacity control is performed in step S21.

[0302] In the heating capacity control of step S21, the refrigerant discharge capacity (speed) of compressor 11 is controlled so that the blow-out air temperature TAV is the target blow-out temperature TAO. The target blow-out temperature TAO in the heating defrost mode is determined in the same way as in the heating mode.

[0303] In other words, control is performed as follows: when the outlet air temperature TAV is higher than the target outlet air temperature TAO, the compressor speed 11 is reduced compared to the current speed, and when the outlet air temperature TAV is lower than the target outlet air temperature TAO, the compressor speed 11 is increased compared to the current speed. This ensures that the heat dissipation in the water-cooled refrigerant heat exchanger 12, required for heating the air-conditioned space, is adequately utilized to heat the air-conditioned space.

[0304] 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 heat dissipation in the water refrigerant heat exchanger 12 is insufficient relative to 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.

[0305] In step S23, 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. Therefore, auxiliary heating control is executed. In the auxiliary heating control, the heat output of the water heater 34 is controlled so that the blown air temperature TAV is equal to the target blown air temperature TAO. That is, by utilizing the heating capacity of the water heater 34 to compensate for the deficiency of the heating capacity of the refrigeration cycle 10 relative to the target value, the comfort of the air-conditioned space is ensured.

[0306] When transitioning to step S24, defrost capacity control in heating defrost mode is performed. In the defrost capacity control of step S24, the opening degree of the heating expansion valve 20a is controlled so that the refrigerant condensing temperature in the outdoor heat exchanger 22 is the target condensing temperature. During dry defrosting in heating defrost mode, the target condensing temperature TCO is determined as described in the condensing heat defrost mode, based on... Figure 15 The control characteristic diagram shown is used to determine this.

[0307] In other words, control is performed as follows: when the refrigerant condensing temperature of the outdoor heat exchanger 22 is higher than the target condensing temperature, the opening degree of the heating expansion valve 20a is reduced compared to the current opening degree; when the refrigerant condensing temperature is lower than the target condensing temperature, the opening degree of the heating expansion valve 20a is increased compared to the current opening degree. Thus, the heat dissipation of the refrigerant in the outdoor heat exchanger 22 can be controlled to a state suitable for condensation heat defrosting.

[0308] In step S25, it is determined whether the refrigerant condensing temperature of the outdoor heat exchanger 22 is higher than the target condensing temperature. Here, in the condensation defrosting of the outdoor heat exchanger 22, the target condensing temperature is determined to be within... Figure 14 Within the target area At shown, it is therefore believed that a state with a temperature higher than the target condensation temperature is a state in which the moisture evaporated during condensation heat defrosting is more likely to be visually identified as white fog.

[0309] In other words, in step S25, from the viewpoint of the heat applied in the condensation defrosting, it is determined whether the evaporated moisture is highly likely to be visually identified as white fog. 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.

[0310] In step S26, based on the viewpoint of the heat applied in the condensation defrosting, it is determined that the evaporated moisture is highly likely to be visually perceived as white mist, therefore the condensation defrosting of the outdoor heat exchanger 22 in the heating defrosting mode is stopped. This suppresses the possibility of white mist from the moisture evaporated in the condensation defrosting being mistaken for white smoke. When the process of step S26 ends, the control related to the comfort priority mode of the heating defrosting mode is terminated. As a result, in Figure 19 In step S6, the operating mode of the vehicle air conditioning unit 1 is switched to heating mode.

[0311] In step S27, liquid return prevention control is performed. In step S27, similar to step S17, the opening of the cooling expansion valve 20c is controlled to prevent liquid return from being supplied to the suction port of the compressor 11 by refrigerant in a liquid phase. This prevents compressor 11 malfunctions caused by liquid refrigerant flowing into the suction port of the compressor 11.

[0312] In step S28, it is determined whether the condensation defrosting of the outdoor heat exchanger 22 is complete. The determination process in step S28 is the same as in step S17. If condensation defrosting is complete, the control related to the comfort priority mode of the heating defrosting mode ends. If condensation defrosting is not complete, the process returns to step S21, and the control related to the comfort priority mode starts again.

[0313] like Figure 21 As shown, in the comfort-first mode, in step S21, the required heating capacity for heating the target space is achieved by controlling the refrigerant discharge capacity of the compressor 11. Furthermore, in step S24, the required defrosting capacity for defrosting the outdoor heat exchanger 22's condensation heat is achieved by controlling the opening degree of the heating expansion valve 20a.

[0314] Therefore, in the circulation structure of the heating and defrosting mode, the defrosting capacity required by the condensation heat of the outdoor heat exchanger 22 and the heating capacity required by the air-conditioned space can be controlled separately, and different refrigerant condensation temperatures can be achieved.

[0315] Furthermore, if the judgment process in step S25 determines, from the perspective of the heat applied in condensing defrost, that there is a high probability that the evaporated water will be visually identified as white mist, then the condensing defrost mode in heating defrost mode is stopped, and the system is switched to heating mode. This prevents water vapor generated in condensing defrost from being mistaken for white smoke.

[0316] Furthermore, in the comfort-priority mode, as described above, heating of the air-conditioned space continues, but condensation heat defrosting is stopped when conditions such as step S25 are met. That is, in the comfort-priority mode, heating of the air-conditioned space is prioritized over condensation heat defrosting of the outdoor heat exchanger 22.

[0317] Furthermore, in the comfort priority mode of the heating and defrosting mode, when the heating capacity of the air-conditioned target space generated by the operation of the refrigeration cycle 10 is insufficient (step S22), the high-temperature side heat medium is heated by the water heater 34 in the auxiliary heating control.

[0318] Therefore, in the heating and defrosting mode, even if the heating capacity of the cooling cycle 10 is insufficient, the water heater 34, which is a different heat source from the cooling cycle 10, can be used to supplement the heating of the air-conditioned space, thus ensuring comfort.

[0319] As explained above, the vehicle air conditioning unit 1 according to the first embodiment can operate in a heating defrosting mode by using the refrigeration cycle 10 and the control device 70 to perform condensation heat defrosting of the outdoor heat exchanger 22 and heating of the air-conditioned space in parallel.

[0320] In addition, in the heating defrosting mode, when the temperature or pressure of the refrigerant required by the water refrigerant heat exchanger 12 is different from the temperature or pressure of the refrigerant required by the outdoor heat exchanger 22, the two different refrigerant temperatures or pressures are achieved through the operation control of the compressor 11 and the operation control of the heating expansion valve 20a.

[0321] In other words, the operation of the compressor 11 can be controlled by the compression control unit 70d to achieve the refrigerant temperature or pressure required by either the water refrigerant heat exchanger 12 or the outdoor heat exchanger 22. Furthermore, the operation of the heating expansion valve 20a can be controlled by the pressure reduction control unit 70e to achieve the refrigerant temperature or pressure required by either the water refrigerant heat exchanger 12 or the outdoor heat exchanger 22.

[0322] According to the vehicle air conditioning unit 1, in the heating and defrosting mode, the heat dissipation in the outdoor heat exchanger 22 involved in condensation heat defrosting and the heat dissipation in the water refrigerant heat exchanger 12 involved in heating can be controlled separately, and they can coexist in an appropriate manner.

[0323] Furthermore, in the condensation heat defrosting of the vehicle air conditioning unit 1, a dry defrosting process is performed by using the heat absorbed by the refrigerant to evaporate the moisture generated during the melting defrosting. By using condensation heat defrosting for dry defrosting, the refreezing of moisture generated by the melting of frost can be suppressed, and the reduction in heat exchange performance of the outdoor heat exchanger 22 and the reduction in heating performance of the vehicle air conditioning unit 1 due to refreezing can be prevented.

[0324] In addition, in the dry defrosting of condensing heat defrosting, the target condensing temperature TCO required by the outdoor heat exchanger 22 is determined to be located at... Figure 14 Within the target area At, during dry defrosting, the refrigerant condensing temperature in the outdoor heat exchanger 22 is controlled to be close to the target condensing temperature. Therefore, during dry defrosting, the likelihood of water vapor from melted moisture being visually perceived as white fog is reduced, preventing it from being mistaken for white smoke, etc.

[0325] Furthermore, in the dry defrosting process of condensation heat defrosting, the wind speed of the outside air blown by the outside air fan 22a to the outside heat exchanger 22 is determined to be located at... Figure 14Within the target area At, during the drying and defrosting process, the operation of the external air fan 22a is controlled to achieve a predetermined airflow speed. This reduces the likelihood of water vapor from melted moisture being visually perceived as white fog during drying and defrosting, preventing it from being mistaken for white smoke.

[0326] like Figure 20 As shown, in the efficiency-priority mode of the heating defrosting mode, in the defrosting capacity control of step S11, the operation of the compressor 11 is controlled so that the refrigerant condensing temperature is the target condensing temperature TCO. Furthermore, in the heating capacity control of step S13, the opening degree of the heating expansion valve 20a is controlled so that the blow-out air temperature TAV is the target blow-out temperature TAO.

[0327] Therefore, in the circulation structure of the heating and defrosting mode, the defrosting capacity required by the condensation heat of the outdoor heat exchanger 22 and the heating capacity required by the air-conditioned space can be controlled separately, and different refrigerant condensation temperatures can be achieved.

[0328] Furthermore, in efficiency-priority mode, when the refrigerant condensing temperature is lower than the target condensing temperature, defrosting capacity enhancement control is implemented by adjusting the opening of the heating expansion valve 20a to the fully open state. As a result, the refrigeration cycle 10 operates in such a way that the heat dissipation required for condensation heat defrosting of the outdoor heat exchanger 22 is satisfied, prioritizing the heat dissipation required for heating the target space. Therefore, condensation heat defrosting can be achieved prioritizing heating of the target space.

[0329] like Figure 21 As shown, in the comfort-priority mode of the heating and defrosting mode, in step S21, the heating capacity required for heating the air-conditioned space is achieved by controlling the refrigerant discharge capacity of the compressor 11. Furthermore, in step S24, the defrosting capacity required for defrosting the outdoor heat exchanger 22 due to condensation heat is achieved by controlling the opening degree of the heating expansion valve 20a.

[0330] Therefore, in the circulation structure of the heating and defrosting mode, the defrosting capacity required by the condensation heat of the outdoor heat exchanger 22 and the heating capacity required by the air-conditioned space can be controlled separately, and different refrigerant condensation temperatures can be achieved.

[0331] Furthermore, in the heating defrosting mode, when the heating capacity of the air-conditioned space generated by the operation of the refrigeration cycle 10 is insufficient (steps S15 and S22), the high-temperature side heat medium is heated by the water heater 34 in the auxiliary heating control (steps S16 and S23).

[0332] Therefore, in the heating and defrosting mode, even if the heating capacity of the cooling cycle 10 is insufficient, the water heater 34, which is a different heat source from the cooling cycle 10, can be used to supplement the heating of the air-conditioned space, thus ensuring comfort.

[0333] Furthermore, if the judgment process in step S25 determines, from the perspective of the heat applied in condensing defrost, that there is a high probability that the evaporated water will be visually identified as white mist, then the condensing defrost mode in heating defrost mode is stopped, and the system is switched to heating mode. This prevents water vapor generated in condensing defrost from being mistaken for white smoke.

[0334] Furthermore, in the comfort-priority mode, as described above, heating of the air-conditioned space continues, but condensation heat defrosting is stopped when conditions such as step S25 are met. That is, in the comfort-priority mode, heating of the air-conditioned space is prioritized over condensation heat defrosting of the outdoor heat exchanger 22.

[0335] Furthermore, in the comfort priority mode of the heating and defrosting mode, when the heating capacity of the air-conditioned target space generated by the operation of the refrigeration cycle 10 is insufficient (step S22), the high-temperature side heat medium is heated by the water heater 34 in the auxiliary heating control.

[0336] Therefore, in the heating and defrosting mode, even if the heating capacity of the cooling cycle 10 is insufficient, the water heater 34, which is a different heat source from the cooling cycle 10, can be used to supplement the heating of the air-conditioned space, thus ensuring comfort.

[0337] In addition, such as Figure 19 As shown, in step S3, based on the result of determining whether the efficiency priority condition is met, either the efficiency priority mode or the comfort priority mode in the heating and dehumidification mode is set. Whether the efficiency priority condition is met is determined by the user's operation instructions, the operating environment surrounding the vehicle air conditioning unit 1, etc. In other words, the heating and defrosting mode can be implemented in a manner that corresponds to the user's intention and the surrounding environment of the vehicle air conditioning unit 1, according to the vehicle air conditioning unit 1.

[0338] (Second Implementation)

[0339] Next, refer to Figure 22 , Figure 23 A second embodiment, different from the embodiment described above, will be described. In the second embodiment, the structure of the heating unit 35 and the device used as an auxiliary heating device differ from those in the embodiment described above. Other basic structures are the same as in the embodiment described above, so further description is omitted.

[0340] First, the heating section 35 of the vehicle air conditioning unit 1 according to the second embodiment is composed of an indoor condenser 12X. The heating section 35 according to the first embodiment is composed of a water refrigerant heat exchanger 12 and a high-temperature side heat medium circuit 30.

[0341] like Figure 22 As shown, the indoor condenser 12X is positioned between the discharge port of the compressor 11 and the inlet of the first tee joint 13a, and is a condenser that condenses the high-pressure refrigerant discharged from the compressor 11. Figure 23 As shown, the indoor condenser 12X is disposed in the housing 61 of the indoor air conditioning unit 60 at the position of the heater core 33 in the first embodiment.

[0342] Therefore, the indoor condenser 12X enables the high-pressure refrigerant discharged from the compressor 11 to exchange heat with the supply air after passing through the indoor evaporator 23, thereby condensing the refrigerant and heating the supply air. In other words, the indoor condenser 12X is equivalent to an example of a heat exchanger for heating.

[0343] And, as Figure 23 As shown, the air heater 34X is disposed inside the housing 61 of the indoor air conditioning unit 60, downstream of the supply airflow relative to the indoor condenser 12X. The air heater 34X is configured to dissipate heat from the supply air after it passes through the indoor condenser 12X, thereby heating the supply air.

[0344] As the air heater 34X, a PTC heater with a PTC element (i.e., a positive characteristic thermistor) can be used. The heat output of the air heater 34X can be arbitrarily controlled by the control voltage output from the control device 70. The air heater 34X is equivalent to an example of an auxiliary heating device.

[0345] like Figure 22 As shown, the vehicle air conditioning unit 1 according to the second embodiment has the same structure as the first embodiment described above, except for the structure of the heating unit 35 and the configuration of the air heater 34X. Therefore, a further explanation of the overview of condensation defrosting and the control contents related to the heating defrosting mode is omitted.

[0346] Therefore, according to the vehicle air conditioning unit 1 according to the second embodiment, even if the structure of the heating unit 35 is changed from the first embodiment, the condensation heat defrosting of the outdoor heat exchanger 22 and the heating of the vehicle interior can be achieved simultaneously in the heating defrosting mode. By means of the compression control unit 70d and the pressure reduction control unit 70e, two different refrigerant temperatures related to the condensation heat defrosting of the outdoor heat exchanger 22 and the heating of the vehicle interior can be generated and controlled separately.

[0347] As explained above, the vehicle air conditioning device 1 according to the second embodiment can achieve the same effect as the above embodiment even if the structure of the heating section 35 is changed.

[0348] (Third Implementation)

[0349] Next, refer to Figures 24-27 A third embodiment, different from the embodiments described above, will be described. In the embodiments described above, the circulation structure of the refrigeration cycle 10 was set as a so-called liquid collector cycle, but in the third embodiment, the refrigeration cycle 10 is configured as a liquid reservoir cycle, which is different. Furthermore, in Figures 24-27 In this document, parts that are the same as or equivalent to the embodiments described above are labeled with the same symbols. This is also true in the following figures.

[0350] like Figure 24 As shown, the vehicle air conditioning unit 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 indoor air conditioning unit 60. The structures of the high-temperature side heat medium circuit 30, the low-temperature side heat medium circuit 40, the indoor air conditioning unit 60, and the control device 70 according to the third embodiment are the same as those in the above-described embodiment.

[0351] The refrigeration cycle 10 in 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.

[0352] In the third embodiment, the outlet of the compressor 11 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 structure as in the embodiment described above. The water refrigerant heat exchanger 12 is an example of a heat exchanger for heating, and together with the high-temperature side heat medium circuit 30, it forms the heating section 35.

[0353] The outlet of the refrigerant passage 12a of the water refrigerant heat exchanger 12 is connected to the inlet side of a first connecting portion 14a, which has a tee fitting structure with three interconnected inlet and outlet ports. In the third embodiment, the refrigeration cycle 10 is equipped with second connecting portions 14b to sixth connecting portions 14f, which are configured in the same way as the first connecting portion 14a.

[0354] The outlet of one of the first connection portions 14a is connected to the inlet side of a heating expansion valve 20a. The heating expansion valve 20a is an example of the first expansion valve. The outlet of the other of the first connection portion 14a is connected to the inlet side of one of the second connection portions 14b via a refrigerant bypass passage 28a. A dehumidification on / off valve 17a is disposed in the refrigerant bypass passage 28a.

[0355] The dehumidification on / off valve 17a is a solenoid valve that opens and closes the refrigerant passage connecting the outlet side of the first connection 14a to the inlet side of one of the second connection 14b. Furthermore, as described later, the refrigeration cycle 10 includes a heating on / off valve 17b. The basic structure of the heating on / off valve 17b is the same as that of the dehumidification on / off valve 17a. The dehumidification on / off valve 17a and the heating on / off valve 17b allow the refrigerant circuit to switch between different operating modes by opening and closing the refrigerant passage.

[0356] The outlet of the heating expansion valve 20a is connected to the refrigerant inlet side of the outdoor heat exchanger 22. The outdoor heat exchanger 22, like in the first embodiment, is an example of an outdoor air heat exchanger and constitutes an outdoor air heat exchange section 29X. Furthermore, the outdoor air fan 22a is configured to blow outdoor air onto the outdoor heat exchanger 22.

[0357] The refrigerant outlet of the outdoor heat exchanger 22 is connected to the inlet side of the third connection 14c. The outlet of one side of the third connection 14c is connected to the inlet side of one side of the fourth connection 14d via the heating passage 28b. A heating on / off valve 17b is provided in the heating passage 28b to open and close the refrigerant passage.

[0358] The outlet of the third connection 14c is connected to the inlet of the second connection 14b. A first check valve 21a is provided in the refrigerant passage connecting the outlet of the third connection 14c and the inlet of the second connection 14b.

[0359] The outlet of the second connection 14b is connected to the inlet side of the fifth connection 14e. The outlet of one side of the fifth connection 14e is connected to the inlet side of the refrigeration expansion valve 20b. The outlet of the other side of the fifth connection 14e is connected to the inlet side of the cooling expansion valve 20c. The refrigeration expansion valve 20b and the cooling expansion valve 20c are examples of the second expansion valve, similar to those in the first embodiment.

[0360] The outlet of the refrigeration expansion valve 20b is connected to the refrigerant inlet side of the indoor evaporator 23. The indoor evaporator 23 is an example of an evaporator, similar to that in the first embodiment. Furthermore, 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 is an example of an evaporator. The outlet of the refrigerant passage 24a of the chiller 24 is connected to the inlet side of the other end of the sixth connection portion 14f.

[0361] Furthermore, an evaporating pressure regulating valve 25 is connected to the inlet side of the refrigerant outlet of the indoor evaporator 23. To suppress frosting on the indoor evaporator 23, the evaporating pressure regulating valve 25 maintains the refrigerant evaporation pressure in the indoor evaporator 23 above a predetermined reference pressure. The evaporating pressure regulating valve 25 is a mechanical variable throttling mechanism that increases the valve opening as the refrigerant pressure at the outlet side of the indoor evaporator 23 increases.

[0362] Therefore, the evaporating pressure regulating valve 25 maintains the refrigerant evaporation temperature in the indoor evaporator 23 at or above the frosting suppression temperature (1°C in this embodiment) that can suppress frosting in the indoor evaporator 23. The outlet of the evaporating pressure regulating valve 25 is connected to the inlet side of one of the sixth connection portions 14f. Furthermore, the outlet of the sixth connection portion 14f is connected to the inlet side of the other of the fourth connection portions 14d.

[0363] The inlet side of the receiver 26 is connected to the outlet of the fourth connection 14d. The receiver 26 is a gas-liquid separator that separates the gas and liquid phases of the refrigerant flowing into it and stores the remaining liquid phase refrigerant in the cycle. The suction port side of the compressor 11 is connected to the gas phase refrigerant outlet of the receiver 26.

[0364] 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 conditioning unit 1 of the third embodiment can be switched to a refrigerant circuit in heating mode, a refrigerant circuit in cooling mode, a refrigerant circuit in dehumidification and heating mode, etc.

[0365] Next, refer to Figure 25 The heating mode of the vehicle air conditioning unit 1 according to the third embodiment will be described. In the heating mode according to the third embodiment, the control device 70 closes the dehumidification on / off valve 17a and opens the heating on / off valve 17b. Furthermore, the control device 70 sets the heating expansion valve 20a to a throttling state and sets the cooling expansion valve 20b and the cooling expansion valve 20c to a fully closed state.

[0366] Additionally, the control device 70 activates the high-temperature side pump 32 to pressurize the high-temperature side heat medium at a predetermined pressure delivery capacity. Furthermore, in heating mode, the control device 70 remains in a state where the low-temperature side pump 42 is stopped.

[0367] Therefore, in the refrigeration cycle 10 of the heating mode, a vapor compression refrigeration cycle is constituted. For example... Figure 25 As shown, in heating mode, the refrigerant circulates in the following order: compressor 11, water refrigerant heat exchanger 12, heating expansion valve 20a, outdoor heat exchanger 22, heating on / off valve 17b, receiver 26, and compressor 11.

[0368] In other words, in the refrigeration cycle 10 of the heating mode, the low-pressure refrigerant absorbs heat from the outside air at the outdoor heat exchanger 22, and the heat from the high-pressure refrigerant discharged from the compressor 11 is dissipated to the high-temperature side heat medium at the water refrigerant heat exchanger 12. By circulating the high-temperature side heat medium in the high-temperature side heat medium circuit 30, the heat of the high-temperature side heat medium is used to heat the air supplied through the heater core 33.

[0369] Therefore, in the heating mode of the third embodiment, heating of the vehicle interior can be achieved by blowing the air heated by the heater core 33 into the vehicle interior.

[0370] In this third embodiment, when the outside air is cold and humid during heating operation, frost will also form on the outdoor heat exchanger 22. The vehicle air conditioning unit 1 according to the third embodiment has a condensation heat defrosting mode as its defrosting operation mode.

[0371] Next, refer to Figure 26 The condensation heat defrosting mode in the third embodiment will be described. The condensation heat defrosting mode in the third embodiment is the same as that in the first embodiment, which uses the heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40 to defrost the outdoor heat exchanger 22.

[0372] In the condensing defrost mode, the control device 70 closes the dehumidification on / off valve 17a and the heating on / off valve 17b. Furthermore, the control device 70 sets the heating expansion valve 20a to the fully open state and the cooling expansion valve 20c to the throttling state. The cooling expansion valve 20b is set to the fully closed state.

[0373] Furthermore, regarding the low-temperature side heat medium circuit 40, the control device 70 operates the low-temperature side pump 42 to pressurize the low-temperature side heat medium at a predetermined pressurization capacity. Additionally, in the condensation defrosting mode, the control device 70 maintains the high-temperature side heat medium circuit 30 in a state where the high-temperature side pump 32 is stopped.

[0374] Therefore, in the refrigeration cycle 10 under the condensing hot defrosting mode, the refrigerant circulates in the following order: 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, liquid receiver 26, and compressor 11. In this circuit structure, the control device 70 controls the operation of various controlled devices.

[0375] In other words, in the refrigeration cycle 10 of the condensing heat defrosting mode, the refrigeration cycle 10 absorbs the heat generated by the battery 75 absorbed by the chiller 24 and applies it to the outdoor heat exchanger 22, thereby enabling the outdoor heat exchanger 22 to be defrosted.

[0376] Furthermore, in the condensation defrosting according to the third embodiment, both melt defrosting and dry defrosting are performed. The control methods for melt defrosting and dry defrosting can be the same as those in the first embodiment.

[0377] Next, refer to Figure 27 The heating defrosting mode according to the third embodiment will be described. In the third embodiment, the heating defrosting mode is also an operation mode in which heating of the air-conditioned target space and condensation defrosting of the outdoor heat exchanger 22 are performed in parallel. In this case, condensation defrosting also includes melting defrosting and drying defrosting.

[0378] In the heating defrosting mode, the control device 70 closes the dehumidification on / off valve 17a and the heating on / off valve 17b. Furthermore, the control device 70 sets the heating expansion valve 20a and the cooling expansion valve 20c to a throttling state, and sets the cooling expansion valve 20b to a fully closed state.

[0379] Furthermore, regarding the low-temperature side heat medium circuit 40, the control device 70 activates the low-temperature side pump 42 to pressurize the low-temperature side heat medium at a predetermined pressurization capacity. Also, in the heating defrosting mode, regarding the high-temperature side heat medium circuit 30, the control device 70 activates the high-temperature side pump 32 to pressurize the high-temperature side heat medium at a predetermined pressurization capacity.

[0380] Thus, in the refrigeration cycle 10 under heating and defrosting mode, the refrigerant circulates in the following order: 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, receiver 26, and compressor 11. In this circuit structure, the control device 70 controls the operation of various controlled devices.

[0381] In other words, in the refrigeration cycle 10 of the condensing heat defrosting mode, the refrigeration cycle 10 can absorb the heat generated by the battery 75 absorbed by the chiller 24 and use it for heating the air-conditioned target space via the heating unit 35 and for condensing heat defrosting of the outdoor heat exchanger 22.

[0382] Furthermore, in the heating and defrosting mode according to the third embodiment, the control methods, efficiency-priority mode, and comfort-priority mode of each component of the vehicle air conditioning unit 1 can be implemented using the same methods as in the first embodiment described above. Therefore, further explanation regarding the specific control methods of the heating and defrosting mode is omitted.

[0383] In the heating and defrosting mode of the third embodiment, when the temperature of the refrigerant required by the water refrigerant heat exchanger 12 is different from the temperature of the refrigerant required by the outdoor heat exchanger 22, the two different refrigerant temperatures are achieved by controlling the operation of the compressor 11 and the operation of the heating expansion valve 20a.

[0384] In other words, the operation of the compressor 11 can be controlled by the compression control unit 70d to achieve the refrigerant temperature or pressure required by either the water refrigerant heat exchanger 12 or the outdoor heat exchanger 22. Furthermore, the operation of the heating expansion valve 20a can be controlled by the pressure reduction control unit 70e to achieve the refrigerant temperature or pressure required by either the water refrigerant heat exchanger 12 or the outdoor heat exchanger 22.

[0385] As explained above, the vehicle air conditioning unit 1 according to the third embodiment can achieve the same effect as the above embodiment from the same structure, even when a liquid reservoir circulation is used as the refrigeration cycle 10.

[0386] The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention as follows.

[0387] In the above-described embodiment, the structure performs both melting defrosting and drying defrosting as condensation-heat defrosting. However, if it is assumed that the moisture generated by melting after melting defrosting will not freeze again, drying defrosting can be omitted. For example, if meteorological information corresponding to the current location of the electric vehicle is obtained using the communication unit 74, and the outside air temperature is higher than 0°C for a specified period in the future, drying defrosting can also be omitted.

[0388] Furthermore, in the condensation heat defrosting method described above, for example, heat absorbed by the chiller 24 from the low-temperature side heat medium circuit 40 is utilized, but this method is not limited. The heat absorption object is not limited as long as the heat absorbed by the evaporator located on the low-pressure side can be used for defrosting the outdoor heat exchanger 22. For example, as a condensation heat defrosting method, 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.

[0389] Furthermore, in the heating and defrosting mode where the heating unit 35 of the vehicle air conditioning unit 1 is composed of a water refrigerant heat exchanger 12 and a high-temperature side heat medium circuit 30, the comfort priority mode between the efficiency priority mode and the comfort priority mode can be set as the initial setting. In the comfort priority mode in this case, it can also be configured to terminate condensation heat defrosting if the defrosting capacity of the outdoor heat exchanger 22 is insufficient.

[0390] This invention has been described based on embodiments, but it should be understood that the invention is not limited to these embodiments or constructions. The invention also includes various modifications and variations within the same scope. Furthermore, various combinations, methods, and even other combinations and methods comprising only one element, more than one element, or less than one element are also included within the scope and spirit of this invention.

Claims

1. A vehicle air conditioning unit, characterized in that, It has a refrigeration cycle and a control unit, wherein, The refrigeration cycle includes: a compressor that compresses and discharges refrigerant; a heating unit having a heating heat exchanger that condenses the refrigerant discharged from the compressor during heating operation to heat the air-conditioned space, and uses the refrigerant as a heat source to heat the supply air blown into the air-conditioned space; an outside air heat exchanger having an outside air heat exchanger that allows the refrigerant to absorb heat from the outside air during heating operation; a first expansion valve disposed between the outlet of the heating heat exchanger and the inlet of the outside air heat exchanger, configured to depressurize the refrigerant flowing out of the heating heat exchanger; a second expansion valve configured to depressurize the refrigerant flowing out of at least one of the heating heat exchanger and the outside air heat exchanger; and an evaporator that evaporates the refrigerant after it has been depressurized by the second expansion valve by absorbing heat. The control unit performs controls related to condensation defrosting and heating of the air-conditioned space. Condensation defrosting utilizes the heat absorbed by the refrigerant in the evaporator to melt the frost adhering to the outdoor air heat exchanger. Heating of the air-conditioned space utilizes heat dissipation from the refrigerant in the heating heat exchanger. The control unit includes a compression control unit and a decompression control unit. When the condensation defrosting and heating of the air-conditioned space are performed in parallel, if the temperature or pressure of the refrigerant required by the heating heat exchanger differs from the temperature or pressure of the refrigerant required by the outdoor air heat exchanger, The compression control unit controls the operation of the compressor to achieve either the refrigerant temperature or pressure required by the heating heat exchanger or the refrigerant temperature or pressure required by the outdoor gas heat exchanger. The pressure reduction control unit achieves the temperature or pressure of the refrigerant required by the heating heat exchanger and the temperature or pressure of the refrigerant required by the outdoor gas heat exchanger through the operation control of the first expansion valve.

2. The vehicle air conditioning unit according to claim 1, characterized in that, In the condensation defrosting process, heat that causes the refrigerant to absorb heat is used to evaporate the moisture generated from the melting of the frost from the outside air via a heat exchanger.

3. The vehicle air conditioning unit according to claim 2, characterized in that, The control unit determines the temperature or pressure of the refrigerant required by the outdoor gas heat exchanger during the condensation defrosting process to reduce the visibility of the moisture generated during the defrosting of the outdoor gas heat exchanger.

4. The vehicle air conditioning unit according to claim 2, characterized in that, It has an external air fan that blows the outside air through a heat exchanger during the condensation defrosting process. The control unit determines the wind speed of the outside air generated by the outside air fan during the condensation defrosting process to reduce the visibility of the moisture generated during the defrosting of the outside air heat exchanger.

5. The vehicle air conditioning unit according to claim 1, characterized in that, In an efficiency-priority mode where the condensation defrosting and heating of the air-conditioned space are performed in parallel, and the condensation defrosting takes priority over the heating of the air-conditioned space, The compression control unit controls the operation of the compressor to achieve the required temperature or pressure of the refrigerant for the external gas heat exchanger. The pressure reduction control unit controls the operation of the first expansion valve to achieve the required temperature or pressure of the refrigerant for the heating heat exchanger.

6. The vehicle air conditioning unit according to claim 5, characterized in that, In the efficiency-priority mode, if the temperature or pressure of the refrigerant in the outdoor gas heat exchanger is lower than the temperature or pressure of the refrigerant required by the outdoor gas heat exchanger, and the defrosting capacity involved in the condensation heat defrosting is insufficient, The pressure reduction control unit increases the opening of the first expansion valve, thereby reducing the heat dissipation in the heating heat exchanger.

7. The vehicle air conditioning unit according to any one of claims 1 to 6, characterized in that, In a comfort-priority mode where the condensation defrosting and heating of the air-conditioned space are performed in parallel, and the heating of the air-conditioned space takes priority over the condensation defrosting, The compression control unit controls the operation of the compressor to achieve the required temperature or pressure of the refrigerant for the heating heat exchanger. The pressure reduction control unit controls the operation of the first expansion valve to achieve the required temperature or pressure of the refrigerant for the external gas heat exchanger.

8. The vehicle air conditioning unit according to any one of claims 1 to 6, characterized in that, It has an auxiliary heating device that can use a heat source different from the refrigeration cycle to heat the supply air blown into the air-conditioned space. When the condensation defrosting and 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 relative to the heating capacity required for heating the air-conditioned space, the control unit supplements the heating capacity by operating the auxiliary heating device.

9. The vehicle air conditioning unit according to any one of claims 1 to 6, characterized in that, The control unit includes a mode determination unit that, when the condensation defrosting and the heating of the air-conditioned target space are performed in parallel, determines which of the following is appropriate: an efficiency priority mode that prioritizes the condensation defrosting over the heating of the air-conditioned target space and a comfort priority mode that prioritizes the heating of the air-conditioned target space over the condensation defrosting. as well as The mode setting unit sets one of the efficiency priority mode and the comfort priority mode based on the determination result of the mode determination unit.

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