Heat pump cycle device

Abstract

To provide a heat pump cycle device capable of improving stability in operation when a heated object is heated.SOLUTION: An air conditioning device 1 for a vehicle as a heat pump cycle device includes: a compressor 11; a first three-way joint 12a; an indoor condenser 13; an expansion valve for cooling 14c; a bypass passage 21a; a bypass-side flow rate adjustment valve 14d; a sixth three-way joint 12f; and a target high / low pressure difference determination portion S11. In a hot gas heating mode, an operation of at least one of the compressor 11, the expansion valve for cooling 14c, and the bypass-side flow rate adjustment valve 14d is controlled so that a high / low pressure difference ΔP obtained by subtracting a suction refrigerant pressure of a sucked refrigerant sucked to the compressor, from a discharged refrigerant pressure of a discharged refrigerant discharged from the compressor 11 approaches a target high / low pressure difference ΔPO determined by the target high / low pressure difference determination portion S11.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a heat pump cycle device that heats an object to be heated by using heat generated by the work of a compressor. [Background technology]

[0002] Patent Document 1 discloses a heat pump cycle device applied to a vehicle air conditioner. In the heat pump cycle device of Patent Document 1, the refrigerant circuit is switched to a hot gas heater circuit in a heating mode for heating the vehicle interior. In the hot gas heater circuit of Patent Document 1, the refrigerant discharged from the compressor is circulated through a fixed throttle, an indoor heat exchanger, and the intake side of the compressor in this order.

[0003] In the heat pump cycle device of Patent Document 1, in the heating mode, the indoor heat exchanger exchanges heat between the refrigerant decompressed by the fixed throttle and the air blown into the vehicle cabin to heat the air. In other words, in the heating mode, the heat pump cycle device of Patent Document 1 heats the air to be heated, using heat generated by the work of the compressor, without using heat absorbed from the outside air, etc.

[0004] Furthermore, in the heat pump cycle device of Patent Document 1, in the heating mode, the discharge refrigerant pressure, which is the pressure of the refrigerant discharged from the compressor, is controlled so as to approach a target high pressure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-260645 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the heat pump cycle device of Patent Document 1, it is difficult to adjust the heating capacity of the blown air in the indoor heat exchanger in heating mode. The reason is that in the heat pump cycle device of Patent Document 1, the discharged refrigerant, which has been pressurized to approach a target high pressure, is depressurized using a fixed throttle, making it difficult to change the high-low pressure difference in the cycle.

[0007] Here, the heating capacity of the blown air in the indoor heat exchanger can be defined as the product of the enthalpy difference obtained by subtracting the enthalpy of the refrigerant on the outlet side of the indoor heat exchanger from the enthalpy of the refrigerant on the inlet side of the indoor heat exchanger and the flow rate (mass flow rate) of the refrigerant circulating through the indoor heat exchanger.

[0008] Therefore, in an operation mode in which the heat generated by the compressor's work is used to heat the blown air, such as the heating mode of Patent Document 1, the amount of work done by the compressor is the heating capacity of the blown air in the indoor heat exchanger. Furthermore, the enthalpy difference of the refrigerant in the indoor heat exchanger is determined by the high-low pressure difference of the cycle. Therefore, if it is difficult to change the high-low pressure difference of the cycle, it becomes difficult to change the heating capacity of the blown air.

[0009] In response to this, it is conceivable to adopt a variable throttle mechanism instead of the fixed throttle of the heat pump cycle device of Patent Document 1. Then, by changing the throttle opening of the variable throttle mechanism, it is conceivable to adjust the high-low pressure difference in the cycle and thereby adjust the heating capacity of the blown air in the indoor heat exchanger.

[0010] However, in the heat pump cycle device of Patent Document 1, even if a variable throttling mechanism is adopted, it is difficult to operate the cycle stably unless the workload of the compressor can be adjusted to an appropriate amount of heat for heating the blown air.

[0011] For example, in the heat pump cycle apparatus of Patent Document 1, which employs a variable throttle mechanism, the refrigerant discharge capacity of the compressor is increased to increase the heating capacity of the blown air in the indoor heat exchanger. Increasing the refrigerant discharge capacity of the compressor increases the discharge refrigerant pressure. Therefore, it is conceivable to increase the throttle opening of the variable throttle mechanism in order to bring the discharge refrigerant pressure closer to the target high pressure.

[0012] However, increasing the throttle opening of the variable throttle mechanism increases the pressure of the refrigerant flowing into the indoor heat exchanger, reducing the pressure difference between the high and low levels. This prevents the indoor heat exchanger from adequately increasing its heating capacity for the air being blown in. As a result, the compressor's refrigerant discharge capacity must be further increased, making it impossible to operate the cycle stably.

[0013] In view of the above, an object of the present invention is to provide a heat pump cycle device that improves the stability of operation when heating an object to be heated. [Means for solving the problem]

[0014] To achieve the above object, a heat pump cycle apparatus according to a first aspect of the present invention includes a compressor (11), a branching section (12a), a heating section (13), a heating section-side pressure reducing section (14c), a bypass passage (21a), a bypass-side flow rate adjusting section (14d), a mixing section (12f), and a target high-low pressure difference determining section (S11).

[0015] The compressor compresses and discharges the refrigerant. The branching section branches the flow of the discharged refrigerant discharged from the compressor. The heating section uses one of the discharged refrigerants branched at the branching section as a heat source to heat an object to be heated. The heating section side decompression section decompresses the refrigerant flowing out from the heating section. The bypass passage leads the other of the discharged refrigerant branched at the branching section to the suction port side of the compressor. The bypass side flow rate adjustment section adjusts the flow rate of the refrigerant flowing through the bypass passage. The mixing section mixes the refrigerant flowing out from the bypass side flow rate adjustment section and the refrigerant flowing out from the heating section side decompression section, and causes the mixed refrigerant to flow out to the suction port side of the compressor. The target high-low pressure difference determination section determines a target high-low pressure difference (ΔP0), which is a target value of the high-low pressure difference (ΔP), obtained by subtracting the suction refrigerant pressure (Ps) of the suction refrigerant drawn into the compressor from the discharge refrigerant pressure (Pd) of the discharged refrigerant.

[0016] and, In an operation mode in which the refrigerant flowing out from the bypass-side flow rate adjustment unit and the refrigerant flowing out from the heating unit-side pressure reduction unit are directly mixed in the mixing unit, The operation of at least one of the compressor, the heating unit side pressure reducing unit, and the bypass side flow rate adjusting unit is controlled so that the high-low pressure difference (ΔP) approaches the target high-low pressure difference (ΔPO). At the same time, the operation of at least one of the remaining compressor, the heating unit side pressure reducing unit, and the bypass side flow rate adjusting unit is controlled so that the suction refrigerant pressure (Ps) approaches the target suction refrigerant pressure (PSO1), and further, the suction refrigerant is converted into a gas phase refrigerant. do.

[0017] According to this, the operation of at least one of the compressor (11), the heating section-side decompressor (14c), and the bypass-side flow rate adjuster (14d) is controlled so that the high-low pressure difference (ΔP) approaches the target high-low pressure difference (ΔP0). Therefore, by appropriately determining the target high-low pressure difference (ΔP0), the workload of the compressor (11) can be adjusted to a heat quantity that can appropriately heat the object to be heated.

[0018] As a result, according to the heat pump cycle device of claim 1, it is possible to improve the stability of operation when heating an object to be heated.

[0019] Also, claims 4 The heat pump cycle apparatus described in the above item (1) comprises a compressor (11), a branching section (12a), a heating section (13), a heating section-side pressure reducing section (14c), a bypass passage (21a), a bypass-side flow rate adjusting section (14d), a mixing section (12f), a target high-low pressure difference determining section (S11), and a bypass-side control section (60c). , and is equipped with.

[0020] The compressor compresses and discharges the refrigerant. The branching unit branches the flow of refrigerant discharged from the compressor. The heating unit heats an object to be heated using one of the discharged refrigerants branched at the branching unit as a heat source. The heating unit-side decompression unit decompresses the refrigerant flowing out from the heating unit. The bypass passage guides the other of the discharged refrigerant branched at the branching unit to the suction port side of the compressor. The bypass-side flow rate adjustment unit adjusts the flow rate of refrigerant flowing through the bypass passage. The mixing unit mixes the refrigerant flowing out from the bypass-side flow rate adjustment unit and the refrigerant flowing out from the heating unit-side decompression unit, and causes the mixed refrigerant to flow out to the suction port side of the compressor. The target high-low pressure difference determination unit determines a target high-low pressure difference (ΔP0), which is a target value of the high-low pressure difference (ΔP), obtained by subtracting the suction refrigerant pressure (Ps) of the suction refrigerant drawn into the compressor from the discharge refrigerant pressure (Pd) of the discharged refrigerant. The bypass-side control unit (60c) controls the operation of the bypass-side flow rate adjustment unit.

[0021] and, The bypass side control unit controls the operation of the bypass side flow rate adjustment unit so that the high-low pressure difference (ΔP) approaches the target high-low pressure difference (ΔPO), and the bypass side control unit estimates the throttle passage area (Ab) of the bypass side flow rate adjustment unit using the target high-low pressure difference (ΔPO) and controls the operation of the bypass side flow rate adjustment unit by feedforward control.

[0022] According to this, The same effect as that of the invention described in claim 1 can be obtained.

[0029] The symbols in parentheses for each means described in this section and in the claims are examples showing the correspondence with the specific means described in the embodiments to be described later. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic overall configuration diagram of a vehicle air conditioner according to a first embodiment. [Figure 2] 1 is a schematic configuration diagram of an indoor air conditioning unit according to a first embodiment. [Figure 3] 2 is a block diagram showing an electric control unit of the vehicle air conditioner of the first embodiment. FIG. [Figure 4] 4 is a flowchart of a main routine of a control program according to the first embodiment. [Figure 5] 4 is a flowchart of a subroutine of a control program according to the first embodiment. [Figure 6] 1 is a schematic overall configuration diagram showing the flow of refrigerant in a hot gas heating mode of a heat pump cycle of a first embodiment. FIG. [Figure 7] FIG. 3 is a Mollier diagram showing changes in the state of a refrigerant in a hot gas heating mode of the heat pump cycle of the first embodiment. [Figure 8] 1 is a schematic overall configuration diagram showing the flow of refrigerant in a hot gas dehumidification heating mode of a heat pump cycle of a first embodiment. FIG. [Figure 9] FIG. 3 is a Mollier diagram showing changes in the state of a refrigerant in a hot gas dehumidification heating mode of the heat pump cycle of the first embodiment. [Figure 10] 1 is a schematic overall configuration diagram showing a flow of refrigerant in a single warm-up mode of a heat pump cycle of a first embodiment. FIG. [Figure 11] FIG. 3 is a Mollier diagram showing changes in the state of a refrigerant in the heat pump cycle of the first embodiment in a single warm-up mode. [Figure 12] 1 is a schematic overall configuration diagram showing the flow of refrigerant in a defrosting mode of a heat pump cycle of a first embodiment. FIG. [Figure 13] FIG. 3 is a Mollier diagram showing changes in the state of a refrigerant in a defrosting mode of the heat pump cycle of the first embodiment. [Figure 14] FIG. 10 is a schematic overall configuration diagram of an air conditioner according to a second embodiment. [Figure 15] FIG. 10 is a schematic overall configuration diagram of an air conditioner according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, several embodiments for carrying out the present invention will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicate explanations may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination. Of the embodiments described below, the first embodiment is an embodiment of the present invention, and the second and third embodiments are shown as reference examples.

[0032] (First embodiment) A first embodiment of a heat pump cycle device according to the present invention will be described with reference to Figures 1 to 13. In this embodiment, the heat pump cycle device according to the present invention is applied to a vehicle air conditioner 1 mounted on an electric vehicle. An electric vehicle is a vehicle that obtains driving power for traveling from an electric motor. The vehicle air conditioner 1 conditions the air inside the vehicle cabin, which is the space to be air-conditioned, and also adjusts the temperature of on-board equipment. Therefore, the vehicle air conditioner 1 can be called an air conditioner with an on-board equipment temperature adjustment function, or an on-board equipment temperature adjustment device with an air conditioning function.

[0033] Specifically, the vehicle air conditioner 1 adjusts the temperature of a battery 70 as an in-vehicle device. The battery 70 is a secondary battery that stores power to be supplied to a plurality of electrically operated in-vehicle devices. The battery 70 is an assembled battery formed by electrically connecting a plurality of stacked battery cells in series or parallel. The battery cells in this embodiment are lithium-ion batteries.

[0034] The battery 70 generates heat during operation (i.e., during charging and discharging). The output of the battery 70 is likely to decrease at low temperatures, and deterioration is likely to progress at high temperatures. For this reason, the temperature of the battery 70 needs to be maintained within an appropriate temperature range (in this embodiment, 15°C or higher and 55°C or lower). Therefore, in the electric vehicle of this embodiment, the temperature of the battery 70 is adjusted using the vehicle air conditioner 1. Of course, the on-board equipment whose temperature is adjusted by the vehicle air conditioner 1 is not limited to the battery 70.

[0035] The vehicle air conditioner 1 includes a heat pump cycle 10, a low-temperature side heat medium circuit 30, an interior air conditioning unit 50, a control device 60, and the like.

[0036] First, the heat pump cycle 10 will be described. The heat pump cycle 10 is a vapor compression refrigeration cycle that adjusts the temperature of the air blown into the vehicle cabin and the low-temperature side heat medium circulating through the low-temperature side heat medium circuit 30. The heat pump cycle 10 is configured to be able to switch the refrigerant circuit according to various operation modes described below for air conditioning the vehicle cabin and cooling on-board devices.

[0037] The heat pump cycle 10 employs an HFO refrigerant (specifically, R1234yf) as a refrigerant. The heat pump cycle 10 constitutes a subcritical refrigeration cycle in which the pressure of the high-pressure side refrigerant does not exceed the critical pressure of the refrigerant. Refrigerant oil is mixed with the refrigerant to lubricate the compressor 11. The refrigerant oil is PAG oil (i.e., polyalkylene glycol oil) that is compatible with liquid-phase refrigerants. A portion of the refrigerant oil circulates through the heat pump cycle 10 together with the refrigerant.

[0038] The compressor 11 draws in, compresses, and discharges refrigerant in the heat pump cycle 10. The compressor 11 is an electric compressor that uses an electric motor to rotate a fixed-displacement compression mechanism with a fixed discharge capacity. The rotation speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from a control device 60, which will be described later.

[0039] The compressor 11 is disposed in a drive unit compartment formed at the front side of the vehicle interior. The drive unit compartment forms a space in which at least some of the devices used to generate and adjust the driving force for running the vehicle (for example, an electric motor for running) are disposed.

[0040] The inlet side of a first three-way joint 12a is connected to the discharge port of the compressor 11. The first three-way joint 12a has three inlet and outlet ports that communicate with each other. The first three-way joint 12a can be a joint formed by joining multiple pipes or a joint formed by providing multiple refrigerant passages in a metal block or a resin block.

[0041] Furthermore, as will be described later, the heat pump cycle 10 includes a second three-way joint 12b to a sixth three-way joint 12f. The second three-way joint 12b to the sixth three-way joint 12f have the same basic configuration as the first three-way joint 12a.

[0042] These three-way joints branch the refrigerant flow when one of the three inlet / outlet ports is used as an inlet and the remaining two are used as outlet ports. Furthermore, when two of the three inlet / outlet ports are used as inlet ports and the remaining one is used as an outlet port, the refrigerant flows are merged. The first three-way joint 12a is a branching section that branches the flow of the refrigerant discharged from the compressor 11.

[0043] One outlet of the first three-way joint 12a is connected to the refrigerant inlet side of the indoor condenser 13. The other outlet of the first three-way joint 12a is connected to one inlet side of a sixth three-way joint 12f. The refrigerant passage extending from the other outlet of the first three-way joint 12a to one inlet of the sixth three-way joint 12f is a bypass passage 21a. A bypass-side flow control valve 14d is disposed in the bypass passage 21a.

[0044] The bypass-side flow rate control valve 14d is a pressure reducing part on the bypass passage side that reduces the pressure of the discharged refrigerant flowing out from the other outlet of the first three-way joint 12a (i.e., the other discharged refrigerant branched at the first three-way joint 12a) in a hot gas heating mode, etc., which will be described later. The bypass-side flow rate control valve 14d is a bypass-side flow rate control part that adjusts the flow rate (mass flow rate) of the refrigerant flowing through the bypass passage 21a.

[0045] The bypass-side flow rate adjustment valve 14d is an electric variable throttle mechanism having a valve element that changes the throttle opening and an electric actuator (specifically, a stepping motor) that displaces the valve element. The operation of the bypass-side flow rate adjustment valve 14d is controlled by control pulses output from the control device 60.

[0046] The bypass-side flow control valve 14d has a full-open function that functions simply as a refrigerant passage by fully opening the valve and exerts almost no refrigerant pressure reduction or flow rate adjustment action, and a full-close function that closes the refrigerant passage by fully closing the valve.

[0047] Furthermore, as will be described later, the heat pump cycle 10 includes a heating expansion valve 14a, a cooling expansion valve 14b, a cooling expansion valve 14c, and a defrosting flow control valve 14e. The heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the defrosting flow control valve 14e have the same basic configuration as the bypass-side flow control valve 14d.

[0048] The heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, the bypass side flow rate adjustment valve 14d, and the defrosting flow rate adjustment valve 14e can switch the refrigerant circuit by performing the fully closing function described above. Therefore, the heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, the bypass side flow rate adjustment valve 14d, and the defrosting flow rate adjustment valve 14e also function as a refrigerant circuit switching unit.

[0049] Of course, the heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, the bypass side flow rate adjustment valve 14d, and the defrosting flow rate adjustment valve 14e may be formed by combining a variable throttle mechanism that does not have a full-closing function with an on-off valve that opens and closes the throttle passage. In this case, each on-off valve serves as a refrigerant circuit switching unit.

[0050] The indoor condenser 13 is disposed in an air conditioning case 51 of the indoor air conditioning unit 50, which will be described later. The indoor condenser 13 is a heating heat exchanger that exchanges heat between the discharged refrigerant flowing out from one outlet of the first three-way joint 12a (i.e., one of the discharged refrigerant branches at the first three-way joint 12a) and the blown air that has passed through an indoor evaporator 18, which will be described later. Indoor condenser 13 In this case, the heat of the discharged refrigerant is dissipated into the blown air, thereby heating the blown air.

[0051] Therefore, the interior condenser 13 is a heating section that heats the blown air, which is an object to be heated, using one of the discharged refrigerants branched at the first three-way joint 12a as a heat source.

[0052] The inlet side of the second three-way joint 12b is connected to the outlet of the indoor condenser 13. The inlet side of the heating expansion valve 14a is connected to one outlet of the second three-way joint 12b. The inlet side of one of the four-way joints 12x is connected to the other outlet of the second three-way joint 12b. The refrigerant passage that runs from the other outlet of the second three-way joint 12b to one of the inlets of the four-way joint 12x is the dehumidification passage 21b.

[0053] A dehumidification on-off valve 22a is disposed in the dehumidification passage 21b. The dehumidification on-off valve 22a is an on-off valve that opens and closes the dehumidification passage 21b. The dehumidification on-off valve 22a is an electromagnetic valve whose opening and closing operation is controlled by a control voltage output from the control device 60. The dehumidification on-off valve 22a can switch the refrigerant circuit by opening and closing the dehumidification passage 21b. Therefore, the dehumidification on-off valve 22a is a refrigerant circuit switching unit.

[0054] The four-way joint 12x is a joint part having four inlet / outlet ports that communicate with each other. A joint part formed in the same manner as the above-mentioned three-way joint can be used as the four-way joint 12x. Alternatively, a joint formed by combining two three-way joints can be used as the four-way joint 12x.

[0055] The heating expansion valve 14a is a pressure reducing unit on the outdoor heat exchanger side that reduces the pressure of the refrigerant flowing into the outdoor heat exchanger 15 during a heating mode, which will be described later. Furthermore, the heating expansion valve 14a is a flow rate adjusting unit on the outdoor heat exchanger side that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the outdoor heat exchanger 15.

[0056] The outlet of the heating expansion valve 14a is connected to the refrigerant inlet side of the outdoor heat exchanger 15. The outdoor heat exchanger 15 is an outdoor heat exchanger that exchanges heat between the refrigerant flowing out of the heating expansion valve 14a and outside air blown by an outside air fan (not shown). The outdoor heat exchanger 15 is located on the front side of the drive unit compartment. Therefore, when the vehicle is traveling, the traveling air that flows into the drive unit compartment through the grill can be directed against the outdoor heat exchanger 15.

[0057] An inlet side of a third three-way joint 12c is connected to a refrigerant outlet of the outdoor heat exchanger 15. Another inlet side of a four-way joint 12x is connected to one outlet side of the third three-way joint 12c via a first check valve 16a. One inlet side of a fourth three-way joint 12d is connected to the other outlet side of the third three-way joint 12c. The refrigerant passage extending from the other outlet side of the third three-way joint 12c to one inlet side of the fourth three-way joint 12d is a heating passage 21c.

[0058] A defrosting flow control valve 14e is disposed in the heating passage 21c. The defrosting flow control valve 14e is a pressure reducing unit on the heating passage side that reduces the pressure of the refrigerant flowing out from the exterior heat exchanger 15 during a defrosting mode, which will be described later. The defrosting flow control valve 14e is a flow control unit on the heating passage side that adjusts the flow rate (mass flow rate) of the refrigerant flowing through the heating passage 21c.

[0059] The first check valve 16a allows the refrigerant to flow from the third three-way joint 12c side to the four-way joint 12x side, and prohibits the refrigerant from flowing from the four-way joint 12x side to the third three-way joint 12c side.

[0060] One outlet of the four-way joint 12x is connected to the refrigerant inlet side of the indoor evaporator 18 via a cooling expansion valve 14b. The cooling expansion valve 14b is a pressure reducing unit on the indoor evaporator side that reduces the pressure of the refrigerant flowing out from one outlet of the four-way joint 12x during a cooling mode, which will be described later. Furthermore, the cooling expansion valve 14b is a flow rate adjusting unit on the indoor evaporator side that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the indoor evaporator 18.

[0061] The interior evaporator 18 is disposed in an air conditioning case 51 of the interior air conditioning unit 50. The interior evaporator 18 is an evaporative part for cooling that exchanges heat between the low-pressure refrigerant decompressed by the air conditioning expansion valve 14b and the blown air blown into the vehicle interior from the interior blower 52. The interior evaporator 18 evaporates the low-pressure refrigerant to exert a heat absorption effect, thereby cooling the blown air.

[0062] A refrigerant outlet of the indoor evaporator 18 is connected to one inlet side of a fifth three-way joint 12e via an evaporation pressure regulating valve 19 and a second check valve 16b.

[0063] The evaporation pressure regulating valve 19 is a variable throttle mechanism that maintains the refrigerant evaporation temperature in the indoor evaporator 18 at a temperature (1°C in this embodiment) or higher that can suppress frost formation on the indoor evaporator 18. The evaporation pressure regulating valve 19 is configured with a mechanical mechanism that increases the valve opening degree as the pressure of the refrigerant on the refrigerant outlet side of the indoor evaporator 18 increases.

[0064] The second check valve 16b allows the refrigerant to flow from the outlet side of the evaporation pressure adjustment valve 19 to the fifth three-way joint 12e side, and prohibits the refrigerant from flowing from the fifth three-way joint 12e side to the evaporation pressure adjustment valve 19 side.

[0065] Another outlet of the four-way joint 12x is connected to the other inlet side of a sixth three-way joint 12f via a cooling expansion valve 14c. The outlet of the sixth three-way joint 12f is connected to the inlet side of the refrigerant passage of the chiller 20.

[0066] The cooling expansion valve 14c is a chiller-side pressure reducing unit that reduces the pressure of the refrigerant flowing into the chiller 20, such as in a hot gas heating mode (described later). Furthermore, the cooling expansion valve 14c is a chiller-side flow rate adjusting unit that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the chiller 20.

[0067] The chiller 20 is a cooling evaporation section that evaporates the low-pressure refrigerant by exchanging heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14c and the low-temperature side heat medium circulating in the low-temperature side heat medium circuit 30. The chiller 20 evaporates the low-pressure refrigerant to exert a heat absorption effect, thereby cooling the low-temperature side heat medium.

[0068] The other inlet side of fourth three-way joint 12d is connected to the outlet of the refrigerant passage of chiller 20. The other inlet side of fifth three-way joint 12e is connected to the outlet of fourth three-way joint 12d.

[0069] The outlet of the fifth three-way joint 12e is connected to the inlet side of the accumulator 23. The accumulator 23 is a low-pressure gas-liquid separator that separates the refrigerant that flows into it into gas and liquid phases and stores excess liquid-phase refrigerant in the cycle. The outlet of the accumulator 23 is connected to the suction port side of the compressor 11.

[0070] Next, the low-temperature side heat medium circuit 30 will be described. The low-temperature side heat medium circuit 30 is a heat medium circuit that circulates a low-temperature side heat medium. The low-temperature side heat medium circuit 30 uses an ethylene glycol aqueous solution as the low-temperature side heat medium. As shown in FIG. 1 , the low-temperature side heat medium circuit 30 is connected to a low-temperature side pump 31, a coolant passage 70a of a battery 70, a heat medium passage of a chiller 20, etc.

[0071] The low-temperature side pump 31 is a pumping unit that pumps the low-temperature side heat medium that flows out from the cooling water passage 70a of the battery 70 to the inlet side of the heat medium passage of the chiller 20. The low-temperature side pump 31 is an electric water pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60. The outlet side of the heat medium passage of the chiller 20 is connected to the inlet side of the cooling water passage 70a of the battery 70.

[0072] The cooling water passage 70a of the battery 70 is formed inside a battery case that houses multiple stacked battery cells. The cooling water passage 70a is configured with multiple passages connected in parallel inside the battery case. This allows the cooling water passage 70a to cool all battery cells evenly. The outlet of the cooling water passage 70a is connected to the suction port side of the low-temperature side pump 31.

[0073] Next, the interior air conditioning unit 50 will be described. The interior air conditioning unit 50 is a unit that integrates multiple components to blow out air adjusted to an appropriate temperature to appropriate locations within the vehicle cabin for air conditioning. The interior air conditioning unit 50 is located inside the instrument panel at the front of the vehicle cabin.

[0074] 2, the indoor air conditioning unit 50 is formed by accommodating an indoor fan 52, an indoor evaporator 18, an indoor condenser 13, etc. in an air conditioning case 51 that forms an air passage for the blown air. The air conditioning case 51 is molded from a resin (for example, polypropylene) that has a certain degree of elasticity and excellent strength.

[0075] An inside / outside air switching device 53 is disposed on the most upstream side of the blown air flow of the air conditioning case 51. The inside / outside air switching device 53 switches between introducing inside air (i.e., air inside the vehicle cabin) and outside air (i.e., air outside the vehicle cabin) into the air conditioning case 51. The operation of the inside / outside air switching device 53 is controlled by a control signal output from the control device 60.

[0076] An interior blower 52 is disposed downstream of the inside / outside air switching device 53 in the flow of blown air. The interior blower 52 blows the air drawn in through the inside / outside air switching device 53 toward the vehicle interior. The rotation speed (i.e., blowing capacity) of the interior blower 52 is controlled by a control voltage output from the control device 60.

[0077] The indoor evaporator 18 and the indoor condenser 13 are arranged downstream in the flow of air blown by the indoor blower 52. The indoor evaporator 18 is arranged upstream in the flow of air blown from the indoor condenser 13. A cool air bypass passage 55 is formed in the air conditioning case 51, which allows the blown air that has passed through the indoor evaporator 18 to bypass the indoor condenser 13.

[0078] An air mix door 54 is disposed downstream of the indoor evaporator 18 in the air conditioning case 51 in the flow of blown air, and upstream of the indoor condenser 13 and the cold air bypass passage 55 in the flow of blown air.

[0079] The air mix door 54 adjusts the ratio of the volume of the blown air that passes through the indoor condenser 13 side to the volume of the blown air that passes through the cool air bypass passage 55 after passing through the indoor evaporator 18. The operation of the actuator for driving the air mix door 54 is controlled by a control signal output from the control device 60.

[0080] A mixing space 56 is disposed downstream of the indoor condenser 13 and the cold air bypass passage 55 in the flow direction of the blown air. The mixing space 56 is a space where the blown air heated by the indoor condenser 13 and the blown air that has passed through the cold air bypass passage 55 and has not been heated are mixed.

[0081] Therefore, in the interior air conditioning unit 50, by adjusting the opening degree of the air mix door 54, it is possible to adjust the temperature of the blown air (that is, the conditioned air) that is mixed in the mixing space 56 and blown into the vehicle interior.

[0082] A plurality of openings (not shown) for blowing conditioned air toward various locations in the vehicle cabin are formed at the most downstream portion of the airflow of the air-conditioning case 51. A blowout mode door (not shown) for opening and closing each of the openings is disposed in each opening. The operation of the actuator for driving the blowout mode door is controlled by a control signal output from the control device 60.

[0083] Therefore, in the interior air conditioning unit 50, by switching the opening holes that the blow-out mode door opens and closes, conditioned air that has been adjusted to an appropriate temperature can be blown out to an appropriate location in the vehicle interior.

[0084] Next, the electrical control unit of this embodiment will be described. The control device 60 has a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 60 performs various calculations and processes based on control programs stored in the ROM. Then, based on the results of the calculations and processes, the control device 60 controls the operation of various control target devices 11, 14a to 14e, 22a, 31, 52, 53, etc. connected to the output side.

[0085] As shown in the block diagram of FIG. 3, a group of control sensors are connected to the input side of the control device 60, including an inside air temperature sensor 61a, an outside air temperature sensor 61b, a solar radiation sensor 61c, a discharge refrigerant temperature and pressure sensor 62a, a high-pressure side refrigerant temperature and pressure sensor 62b, an outdoor unit side refrigerant temperature and pressure sensor 62c, an evaporator side refrigerant temperature and pressure sensor 62d, a chiller side refrigerant temperature and pressure sensor 62e, an intake refrigerant temperature and pressure sensor 62f, a low-temperature side heat medium temperature sensor 63a, a battery temperature sensor 64, and an air conditioning air temperature sensor 65.

[0086] The inside air temperature sensor 61a is an inside air temperature detector that detects the temperature inside the vehicle cabin (inside air temperature) Tr. The outside air temperature sensor 61b is an outside air temperature detector that detects the temperature outside the vehicle cabin (outside air temperature) Tam. The solar radiation sensor 61c is an solar radiation amount detector that detects the amount of solar radiation As irradiating into the vehicle cabin.

[0087] The discharge refrigerant temperature and pressure sensor 62 a is a discharge refrigerant temperature and pressure detection unit that detects the discharge refrigerant temperature Td and the discharge refrigerant pressure Pd of the refrigerant discharged from the compressor 11 .

[0088] The high-pressure side refrigerant temperature and pressure sensor 62b is a high-pressure side refrigerant temperature and pressure detection unit that detects the high-pressure side refrigerant temperature T1 and high-pressure side refrigerant pressure P1 of the refrigerant flowing out from the indoor condenser 13.

[0089] The outdoor unit side refrigerant temperature and pressure sensor 62c is an outdoor unit side refrigerant temperature and pressure detection unit that detects the outdoor unit side refrigerant temperature T2 and outdoor unit side refrigerant pressure P2 of the refrigerant flowing out from the outdoor heat exchanger 15.

[0090] The evaporator-side refrigerant temperature and pressure sensor 62d is an evaporator-side refrigerant temperature and pressure detection unit that detects the evaporator-side refrigerant temperature Te and evaporator-side refrigerant pressure Pe of the refrigerant flowing out from the interior evaporator .

[0091] The chiller-side refrigerant temperature and pressure sensor 62e is a chiller-side refrigerant temperature and pressure detection unit that detects the chiller-side refrigerant temperature Tc and chiller-side refrigerant pressure Pc of the refrigerant flowing out from the refrigerant passage of the chiller 20.

[0092] The intake refrigerant temperature and pressure sensor 62f is a intake refrigerant temperature and pressure detection unit that detects the intake refrigerant temperature Ts and the intake refrigerant pressure Ps of the intake refrigerant that is drawn into the compressor 11.

[0093] In addition, in this embodiment, a detection unit in which a pressure detection unit and a temperature detection unit are integrated is used as the refrigerant temperature pressure sensor, but of course, a pressure detection unit and a temperature detection unit that are each configured as separate units may also be used.

[0094] The low-temperature side heat medium temperature sensor 63a is a low-temperature side heat medium temperature detection unit that detects the low-temperature side heat medium temperature TWL, which is the temperature of the low-temperature side heat medium flowing into the coolant passage a of the battery .

[0095] The battery temperature sensor 64 is a battery temperature detection unit that detects the battery temperature TB, which is the temperature of the battery 70. The battery temperature sensor 64 has multiple temperature sensors and detects the temperature at multiple locations on the battery 70. This allows the control device 60 to detect the temperature difference and temperature distribution among the battery cells that make up the battery 70. Furthermore, the average value of the detection values of the multiple temperature sensors is used as the battery temperature TB.

[0096] The conditioned air temperature sensor 65 is an conditioned air temperature detection unit that detects the temperature TAV of the air blown from the mixing space 56 into the vehicle interior.

[0097] Furthermore, an operation panel 69 located near the instrument panel at the front of the vehicle interior is connected to the input side of the control device 60, as shown in Fig. 3. Operation signals are input to the control device 60 from various operation switches provided on the operation panel 69.

[0098] The various operation switches provided on the operation panel 69 specifically include an auto switch, an air conditioner switch, an air volume setting switch, a temperature setting switch, and the like.

[0099] The auto switch is an operation switch that sets or cancels automatic control operation of the vehicle air conditioner 1. The air conditioner switch is an operation switch that requests cooling of the blown air by the interior evaporator 18. The air volume setting switch is an operation switch that manually sets the air volume of the interior blower 52. The temperature setting switch is an operation switch that sets the set temperature Tset in the vehicle interior.

[0100] The control device 60 of this embodiment is an integrated unit that controls various control target devices connected to its output side. Therefore, the configuration (hardware and software) that controls the operation of each control target device constitutes the control unit that controls the operation of each control target device.

[0101] For example, in the control device 60, the configuration that controls the refrigerant discharge capacity (specifically, the rotation speed) of the compressor 11 constitutes a discharge capacity control section 60a. The configuration that controls the operation of the cooling expansion valve 14c constitutes a heating section side control section 60b. The configuration that controls the operation of the bypass side flow rate adjustment valve 14d constitutes a bypass side control section 60c.

[0102] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. The vehicle air conditioner 1 of this embodiment switches between various operation modes to condition the air inside the vehicle cabin and adjust the temperature of the battery 70. The operation mode is switched by executing a control program stored in advance in the control device 60.

[0103] The control program is executed not only when the so-called IG switch is turned on and the vehicle system is running, but also when the battery 70 is being charged from an external power source. The main routine of the control program will be described using the flowchart of Figure 4. Each control step shown in the flowchart of Figure 4 etc. is a part that realizes various functions of the control device 60.

[0104] First, in step S1 of Fig. 4, initialization of flags, timers, etc., and initial positioning of electric actuators, etc. are performed. Next, in step S2, detection signals from the control sensors and operation signals from the operation panel 69 are read. Next, in step S3, a target blown-out temperature TAO is determined. The target blown-out temperature TAO is the target temperature of the air blown into the passenger compartment. Therefore, step S3 is a target temperature determination unit.

[0105] Specifically, in step S3, the target blown-out temperature TAO is determined using the following formula F1. TAO=Kset×Tset-Kr×Tr-Kam×Tam-Ks×As+C…(F1) Tset is the target temperature inside the vehicle cabin set by the temperature setting switch. Tr is the inside air temperature detected by the inside air temperature sensor 61a. Tam is the outside air temperature detected by the outside air temperature sensor 61b. As is the amount of solar radiation detected by the solar radiation sensor 61c. Furthermore, Kset, Kr, Kam, and Ks are control gains, and C is a correction constant.

[0106] Next, in step S4, an operation mode is selected using the detection signal and operation signal read in step S2 and the target blow-out temperature TAO determined in step S3. Next, in step S5, the operation of various controlled devices is controlled so that the operation mode selected in step S4 is executed.

[0107] Next, in step S6, it is determined whether or not a predetermined termination condition for the automotive air conditioner 1 is satisfied. If it is determined in step S6 that the termination condition is not satisfied, the program returns to step S2. If it is determined in step S6 that the termination condition is satisfied, the program is terminated.

[0108] Here, the termination condition in this embodiment is met when the IG switch is turned off while the battery 70 is not being charged from the external power source. Alternatively, the termination condition is met when charging of the battery 70 from the external power source is completed while the IG switch is turned off. The detailed operation of each operation mode selected in step S4 will be described below.

[0109] (a) Cooling mode The cooling mode is an operating mode in which cooled air is blown into the vehicle cabin to cool the interior of the vehicle. In the control program of this embodiment, the cooling mode is selected when the outside air temperature Tam is relatively high (25°C or higher in this embodiment), such as in summer.

[0110] The cooling modes include a single cooling mode in which the vehicle cabin is cooled without cooling the battery 70, and a cooled cooling mode in which the vehicle cabin is cooled while cooling the battery 70. In the control program of this embodiment, when the battery temperature TB becomes equal to or higher than a predetermined reference upper limit temperature KTBH, an operation mode in which the battery 70, which is an in-vehicle device, is cooled, is executed.

[0111] (a-1) Single cooling mode In the heat pump cycle 10 in the cooling only mode, the control device 60 fully opens the heating expansion valve 14a, throttles the cooling expansion valve 14b to reduce the refrigerant pressure, fully closes the cooling expansion valve 14c, fully closes the bypass flow control valve 14d, and fully closes the defrosting flow control valve 14e. The control device 60 also closes the dehumidification on-off valve 22a.

[0112] Therefore, in the heat pump cycle 10 in the cooling-only mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a fully open state, the outdoor heat exchanger 15, the cooling expansion valve 14b which is in a throttled state, the indoor evaporator 18, the evaporation pressure control valve 19, the accumulator 23, and the intake port of the compressor 11.

[0113] In addition, in the indoor air conditioning unit 50 in the single cooling mode, the control device 60 adjusts the opening degree of the air mix door 54 so that the blowing air temperature TAV detected by the air conditioning air temperature sensor 65 approaches the target blowing temperature TAO. The control device 60 also controls the operation of the inside / outside air switching device 53 and the blowing mode door based on the target blowing temperature TAO. The control device 60 also controls the operation of other control target devices as appropriate.

[0114] Therefore, in the heat pump cycle 10 in the cooling-only mode, the indoor condenser 13 and the outdoor heat exchanger 15 function as condensers that condense the refrigerant by dissipating heat, and the indoor evaporator 18 functions as an evaporator that evaporates the refrigerant, forming a vapor compression refrigeration cycle.

[0115] In the interior air conditioning unit 50 in the single cooling mode, the air blown from the interior blower 52 is cooled by the interior evaporator 18. The air cooled by the interior evaporator 18 is reheated by the interior condenser 13 so as to approach the target outlet temperature TAO depending on the opening degree of the air mix door 54. The temperature-adjusted air is then blown into the vehicle cabin, thereby cooling the vehicle cabin.

[0116] (a-2) Cooling mode In the heat pump cycle 10 in the cooling / air-cooling mode, the control device 60 throttles the cooling expansion valve 14c in comparison with the single cooling mode.

[0117] Therefore, in the heat pump cycle 10 in the cooling / cooling mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the stand-alone cooling mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a fully open state, the outdoor heat exchanger 15, the cooling expansion valve 14c which is in a throttled state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit in which they are connected in parallel with respect to the flow of the refrigerant.

[0118] In addition, in the low-temperature side heat medium circuit 30 in the cooling / air-cooling mode, the control device 60 operates the low-temperature side pump 31 so as to exert a predetermined reference pumping capacity. Therefore, in the low-temperature side heat medium circuit 30, the low-temperature side heat medium pumped by the low-temperature side pump 31 circulates through the heat medium passage of the chiller 20, the coolant passage 70a of the battery 70, and the suction port of the low-temperature side pump 31 in that order.

[0119] In the indoor air conditioning unit 50 in the cooling / air-conditioning mode, the control device 60 controls the air blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0120] Therefore, in the heat pump cycle 10 in the cooling / air-conditioning mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 and the outdoor heat exchanger 15 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators.

[0121] In the low-temperature side heat medium circuit 30 in the cooling / air-conditioning mode, the low-temperature side heat medium pumped from the low-temperature side pump 31 flows into the chiller 20 and is cooled. Then, the low-temperature side heat medium cooled in the chiller 20 flows through the coolant passage 70a of the battery 70, thereby cooling the battery 70.

[0122] In the interior air conditioning unit 50 in the cooling / air-conditioning mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby cooling the vehicle compartment, as in the single cooling mode.

[0123] (b) Series dehumidifying and heating mode The series dehumidifying and heating mode is an operating mode in which cooled and dehumidified ventilation air is reheated and blown into the passenger compartment to dehumidify and heat the passenger compartment. In the control program of this embodiment, the series dehumidifying and heating mode is selected when the outside air temperature Tam is within a predetermined medium-to-high temperature range (in this embodiment, 10°C or higher and lower than 25°C).

[0124] The series dehumidifying and heating modes include a single series dehumidifying and heating mode in which the vehicle interior is dehumidified and heated without cooling the battery 70, and a cooling series dehumidifying and heating mode in which the battery 70 is cooled and the vehicle interior is dehumidified and heated.

[0125] (b-1) Single series dehumidifying and heating mode In the heat pump cycle 10 in the single-series dehumidifying and heating mode, the control device 60 throttles the heating expansion valve 14a, throttles the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, fully closes the bypass-side flow control valve 14d, and fully closes the defrosting flow control valve 14e. The control device 60 also closes the dehumidifying on-off valve 22a.

[0126] Therefore, in the heat pump cycle 10 in the single-series dehumidifying and heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a throttling state, the outdoor heat exchanger 15, the cooling expansion valve 14b which is in a throttling state, the indoor evaporator 18, the evaporation pressure control valve 19, the accumulator 23, and the intake port of the compressor 11.

[0127] In the indoor air-conditioning unit 50 in the standalone series dehumidifying and heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the standalone cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0128] Therefore, in the heat pump cycle 10 in the single series dehumidifying and heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the indoor evaporator 18 functions as an evaporator.

[0129] Furthermore, in the single-series dehumidifying and heating mode, when the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam, the outdoor heat exchanger 15 functions as a condenser. When the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is lower than the outdoor air temperature Tam, the outdoor heat exchanger 15 functions as an evaporator.

[0130] In the interior air conditioning unit 50 in the single-series dehumidifying and heating mode, the air blown from the interior blower 52 is cooled and dehumidified in the interior evaporator 18. The air cooled and dehumidified in the interior evaporator 18 is reheated in the interior condenser 13 to approach the target outlet temperature TAO depending on the opening degree of the air mix door 54. The temperature-adjusted air is then blown into the vehicle cabin, thereby achieving dehumidifying and heating the vehicle cabin.

[0131] (b-2) Cooling series dehumidification heating mode In the heat pump cycle 10 in the cooling series dehumidifying heating mode, the control device 60 throttles the cooling expansion valve 14c in comparison with the single series dehumidifying heating mode.

[0132] Therefore, in the heat pump cycle 10 in the cooling series dehumidifying and heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single series dehumidifying and heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a in a throttling state, the outdoor heat exchanger 15, the cooling expansion valve 14c in a throttling state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit connected in parallel with respect to the refrigerant flow.

[0133] In the low-temperature side heat medium circuit 30 in the cooling series dehumidifying heating mode, the control device 60 controls the operation of the low-temperature side pump 31 in the same way as in the cooling cooling mode. Therefore, in the low-temperature side heat medium circuit 30 in the cooling series dehumidifying heating mode, the low-temperature side heat medium circulates in the same way as in the cooling cooling mode.

[0134] In the indoor air-conditioning unit 50 in the cooling series dehumidifying heating mode, the control device 60 controls the air blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0135] Therefore, in the heat pump cycle 10 in the cooling series dehumidifying heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the indoor evaporator 18 and chiller 20 function as evaporators.

[0136] Furthermore, in the cooling series dehumidifying and heating mode, as in the single series dehumidifying and heating mode, when the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam, the outdoor heat exchanger 15 functions as a condenser. When the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is lower than the outdoor air temperature Tam, the outdoor heat exchanger 15 functions as an evaporator.

[0137] In the low-temperature side heat medium circuit 30 in the cooling series dehumidifying heating mode, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70, thereby cooling the battery 70, as in the cooling air-conditioning mode.

[0138] In the interior air conditioning unit 50 in the cooling series dehumidifying and heating mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the single series dehumidifying and heating mode, thereby realizing dehumidifying and heating the vehicle compartment.

[0139] (c) Parallel dehumidifying and heating mode The parallel dehumidifying and heating mode is an operating mode in which cooled and dehumidified blown air is reheated with a heating capacity higher than that in the series dehumidifying and heating mode and blown into the passenger compartment to dehumidify and heat the passenger compartment. In the control program of this embodiment, the parallel dehumidifying and heating mode is selected when the outside air temperature Tam is within a predetermined low-to-medium temperature range (in this embodiment, 0°C or higher and lower than 10°C).

[0140] The parallel dehumidifying and heating modes include a standalone parallel dehumidifying and heating mode in which the vehicle interior is dehumidified and heated without cooling the battery 70, and a cooling parallel dehumidifying and heating mode in which the battery 70 is cooled and the vehicle interior is dehumidified and heated.

[0141] (c-1) Single parallel dehumidifying and heating mode In the heat pump cycle 10 in the single-parallel dehumidifying and heating mode, the control device 60 throttles the heating expansion valve 14a, throttles the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, fully closes the bypass-side flow control valve 14d, and fully opens the defrosting flow control valve 14e. The control device 60 also opens the dehumidifying on-off valve 22a.

[0142] Therefore, in the heat pump cycle 10 in the single-parallel dehumidifying and heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: the indoor condenser 13, the heating expansion valve 14a in the throttled state, the outdoor heat exchanger 15, the heating passage 21c, the accumulator 23, and the suction port of the compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: the indoor condenser 13, the dehumidifying passage 21b, the cooling expansion valve 14b in the throttled state, the indoor evaporator 18, the evaporation pressure control valve 19, the accumulator 23, and the suction port of the compressor 11. In other words, the outdoor heat exchanger 15 and the indoor evaporator 18 are switched to a refrigerant circuit connected in parallel with respect to the refrigerant flow.

[0143] In the indoor air conditioning unit 50 in the single parallel dehumidifying and heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0144] Therefore, in the heat pump cycle 10 in the single parallel dehumidifying heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser, and the outdoor heat exchanger 15 and the indoor evaporator 18 function as evaporators.

[0145] In the interior air conditioning unit 50 in the single-parallel dehumidifying and heating mode, the air blown from the interior blower 52 is cooled and dehumidified in the interior evaporator 18. The air cooled and dehumidified in the interior evaporator 18 is reheated in the interior condenser 13 to approach the target outlet temperature TAO depending on the opening degree of the air mix door 54. The temperature-adjusted air is then blown into the vehicle cabin, thereby achieving dehumidification and heating of the vehicle cabin.

[0146] Furthermore, in the heat pump cycle 10 in the single-parallel dehumidifying and heating mode, the opening degree of the heating expansion valve 14a can be reduced below the opening degree of the cooling expansion valve 14b, thereby reducing the refrigerant evaporation temperature in the outdoor heat exchanger 15 to a temperature lower than the refrigerant evaporation temperature in the indoor evaporator 18.

[0147] Therefore, in the single-parallel dehumidifying and heating mode, the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 15 can be increased more than in the single-series dehumidifying and heating mode, and the amount of heat released from the refrigerant to the blown air in the indoor condenser 13 can be increased. As a result, in the single-parallel dehumidifying and heating mode, the heating capacity of the blown air in the indoor condenser 13 can be improved more than in the single-series dehumidifying and heating mode.

[0148] (c-2) Cooling parallel dehumidifying heating mode In the heat pump cycle 10 in the cooling-parallel dehumidifying-heating mode, the control device 60 throttles the cooling expansion valve 14c in comparison with the single-parallel dehumidifying-heating mode.

[0149] Therefore, in the heat pump cycle 10 in the cooling-parallel dehumidifying-heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single-parallel dehumidifying-heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates, in order, through the indoor condenser 13, the dehumidifying passage 21b, the cooling expansion valve 14c in a throttled state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the refrigerant circuit is switched to one in which the outdoor heat exchanger 15, the indoor evaporator 18, and the chiller 20 are connected in parallel with respect to the refrigerant flow.

[0150] In the low-temperature side heat medium circuit 30 in the cooling parallel dehumidifying heating mode, the control device 60 controls the operation of the low-temperature side pump 31 in the same way as in the cooling cooling mode. Therefore, in the low-temperature side heat medium circuit 30 in the cooling series dehumidifying heating mode, the low-temperature side heat medium circulates in the same way as in the cooling cooling mode.

[0151] In the indoor air-conditioning unit 50 in the cooling parallel dehumidifying heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0152] Therefore, in the heat pump cycle 10 in the cooling parallel dehumidifying heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser, and the outdoor heat exchanger 15, the indoor evaporator 18, and the chiller 20 function as evaporators.

[0153] In the low-temperature side heat medium circuit 30 in the cooling parallel dehumidifying heating mode, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70, thereby cooling the battery 70, as in the cooling air conditioning mode.

[0154] In the interior air conditioning unit 50 in the cooling-parallel dehumidifying-heating mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the single-parallel dehumidifying-heating mode, thereby realizing dehumidifying and heating the vehicle compartment.

[0155] (d) Heating mode The heating mode is an operation mode in which heated air is blown into the vehicle cabin to heat the interior of the vehicle. In the control program of this embodiment, the heating mode is selected when the outside air temperature Tam is relatively low (below 0°C in this embodiment), such as in winter.

[0156] The heating mode includes a single heating mode in which the vehicle interior is heated without cooling the battery 70, and a cooling and heating mode in which the battery 70 is cooled and the vehicle interior is heated.

[0157] (d-1) Standalone heating mode In the heat pump cycle 10 in the single heating mode, the control device 60 throttles the heating expansion valve 14a, fully closes the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, fully closes the bypass flow control valve 14d, and fully opens the defrosting flow control valve 14e. The control device 60 also closes the dehumidification on-off valve 22a.

[0158] Therefore, in the heat pump cycle 10 in the single heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a throttled state, the outdoor heat exchanger 15, the heating passage 21c, the accumulator 23, and the intake port of the compressor 11.

[0159] In the indoor air conditioning unit 50 in the single heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0160] Therefore, in the heat pump cycle 10 in the single heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the outdoor heat exchanger 15 functions as an evaporator.

[0161] In the interior air conditioning unit 50 in the single heating mode, the air blown from the interior blower 52 passes through the interior evaporator 18. The air that has passed through the interior evaporator 18 is heated by the interior condenser 13 so as to approach the target outlet temperature TAO according to the opening degree of the air mix door 54. The temperature-adjusted air is then blown into the vehicle cabin, thereby heating the vehicle cabin.

[0162] (d-2) Cooling and heating mode In the heat pump cycle 10 in the cooling and heating mode, the controller 60 throttles the cooling expansion valve 14c in comparison with the single heating mode, and also opens the dehumidifying on-off valve 22a.

[0163] Therefore, in the heat pump cycle 10 in the cooling and heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the dehumidification passage 21b, the cooling expansion valve 14c in a throttled state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the refrigerant circuit is switched to one in which the outdoor heat exchanger 15 and the chiller 20 are connected in parallel with respect to the refrigerant flow.

[0164] In the low-temperature side heat medium circuit 30 in the cooling and heating mode, the control device 60 controls the operation of the low-temperature side pump 31 in the same way as in the cooling and cooling mode. Therefore, in the low-temperature side heat medium circuit 30 in the cooling series dehumidifying and heating mode, the low-temperature side heat medium circulates in the same way as in the cooling and cooling mode.

[0165] In the indoor air conditioning unit 50 in the cooling / heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, just as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0166] Therefore, in the heat pump cycle 10 in the cooling / heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the outdoor heat exchanger 15 and the chiller 20 function as evaporators.

[0167] In the low-temperature side heat medium circuit 30 in the cooling / heating mode, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70, thereby cooling the battery 70, as in the cooling / air-conditioning mode.

[0168] In the interior air conditioning unit 50 in the cooling / heating mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby heating the vehicle compartment, as in the single heating mode.

[0169] (e) Hot gas heating mode The hot gas heating mode is an operating mode that heats the vehicle interior when the outside air temperature Tam is extremely low (below -10°C in this embodiment). In the control program of this embodiment, the hot gas heating mode is selected when the outside air temperature Tam is extremely low and the air conditioner switch is not turned on (OFF).

[0170] In the hot gas heating mode, high-low pressure difference control is executed as shown in the flowchart of Fig. 5. The flowchart shown in Fig. 5 is a control process executed as a subroutine in step S5 when an operation mode in which high-low pressure difference control is executed is selected in step S4 of the main routine.

[0171] 5, a target high-low pressure difference ΔP0, which is a target value of the high-low pressure difference ΔP, is determined according to the selected operation mode. The high-low pressure difference ΔP is a value obtained by subtracting the suction refrigerant pressure Ps detected by the suction refrigerant temperature and pressure sensor 62f from the discharge refrigerant pressure Pd detected by the discharge refrigerant temperature and pressure sensor 62a. Therefore, step S11 is a target high-low pressure difference determination unit.

[0172] In step S11 of the hot gas heating mode, the target high-low pressure difference ΔP0 is determined based on the target blow-out temperature TAO and by referring to a control map stored in advance in the control device 60. The control map for the hot gas heating mode determines the target high-low pressure difference ΔP0 to increase as the target blow-out temperature TAO increases.

[0173] Next, in step S12, the operating state of each controlled device is determined according to each operation mode. Next, in step S13, a control signal is output from the control device 60 to each controlled device so that the controlled device is in the operating state determined in step S12, and the process returns to the main routine.

[0174] In the heat pump cycle 10 in the hot gas heating mode, the control device 60 fully closes the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, throttles the bypass-side flow control valve 14d, and fully closes the defrosting flow control valve 14e. The control device 60 also opens the dehumidification on-off valve 22a.

[0175] 6, in the heat pump cycle 10 in the hot gas heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: first three-way joint 12a, indoor condenser 13, dehumidification passage 21b, four-way joint 12x, cooling expansion valve 14c in the throttled state, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of the compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: first three-way joint 12a, bypass-side flow control valve 14d arranged in bypass passage 21a in the throttled state, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of the compressor 11.

[0176] Therefore, in the hot gas heating mode, cooling expansion valve 14c serves as a heating section-side decompression section that decompresses the refrigerant flowing out from indoor condenser 13. In addition, in the hot gas heating mode, sixth three-way joint 12f serves as a mixing section that mixes the refrigerant flowing out from bypass-side flow control valve 14d and the refrigerant flowing out from cooling expansion valve 14c.

[0177] Furthermore, the control device 60 appropriately controls the operation of other controlled devices. Specifically, with regard to the compressor 11, the control device 60 controls the refrigerant discharge capacity (i.e., the rotation speed) of the compressor 11 so that the suction refrigerant pressure Ps approaches the first target suction refrigerant pressure PSO1. More specifically, the control device 60 controls the refrigerant discharge capacity of the compressor 11 using a feedback control method based on proportional-integral control.

[0178] Controlling the suction refrigerant pressure Ps to approach a predetermined value is effective for stabilizing the discharge flow rate Gr (mass flow rate) of the compressor 11. More specifically, by setting the suction refrigerant pressure Ps to a saturated gas-phase refrigerant at a constant pressure, the density of the suction refrigerant becomes constant. Therefore, controlling the suction refrigerant pressure Ps to approach a constant pressure makes it easier to stabilize the discharge flow rate Gr of the compressor 11 at the same rotation speed.

[0179] The control device 60 also adjusts the throttle opening of the cooling expansion valve 14c so that the degree of subcooling SC1 of the refrigerant flowing out from the indoor condenser 13 approaches the first target degree of subcooling SCO1. The degree of subcooling SC1 can be calculated from the high-pressure side refrigerant temperature T1 and the high-pressure side refrigerant pressure P1 detected by the high-pressure side refrigerant temperature and pressure sensor 62b. 。

[0180] Furthermore, the control device 60 adjusts the throttle opening of the bypass-side flow rate adjustment valve 14d so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. More specifically, the control device 60 controls the operation of the bypass-side flow rate adjustment valve 14d using a feedforward control method based on the target high-low pressure difference ΔP.

[0181] Here, a feedforward control method used by the control device 60 to control the operation of the bypass-side flow control valve 14d will be described. As described above, in the hot gas heating mode, the refrigerant discharge capacity of the compressor 11 is controlled so that the suction refrigerant pressure Ps approaches the first target suction refrigerant pressure PSO1. As a result, the density ρ and the discharge flow rate Gr of the suction refrigerant of the compressor 11 approach constant values.

[0182] Therefore, in the hot gas heating mode, the following formula F2 is used to estimate the throttle passage area Ab of the bypass side flow rate adjustment valve 14d at which the high-low pressure difference ΔP becomes the target high-low pressure difference ΔPO. Gr = ρ × Ab × (2 × ΔPO / ρ) 0.5 …(F2) Here, Gr is the discharge flow rate of the compressor 11, and is used as a constant value (const) when calculating the throttle passage area Ab. Then, the operation of the bypass-side flow rate adjustment valve 14d is controlled so that the throttle passage area Ab estimated using formula F2 is obtained.

[0183] Therefore, when the current high-low pressure difference ΔP is increased, the throttle opening of the bypass-side flow rate adjustment valve 14d is decreased. On the other hand, when the current high-low pressure difference ΔP is decreased, the throttle opening of the bypass-side flow rate adjustment valve 14d is increased.

[0184] Furthermore, in the low-temperature side heat medium circuit 30 in the hot gas heating mode, the control device 60 stops the low-temperature side pump 31.

[0185] In the indoor air conditioning unit 50 in the hot gas heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, and the operation of the blowing mode door, as in the single cooling mode. In the hot gas heating mode, the control device 60 often controls the opening degree of the air mix door 54 so that almost the entire volume of the air blown from the indoor blower 52 passes through the indoor condenser 13.

[0186] The control device 60 also controls the operation of the inside / outside air switching device 53 so as to introduce inside air into the air conditioning case 51 .

[0187] Therefore, in the heat pump cycle 10 in the hot gas heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0188] That is, the flow of the refrigerant discharged from the compressor 11 (point a7 in FIG. 7) is branched at the first three-way joint 12a. One of the refrigerant branches at the first three-way joint 12a flows into the indoor condenser 13 and dissipates heat into the blown air that has passed through the indoor evaporator 18 (from point a7 to point b7 in FIG. 7). This heats the blown air.

[0189] The refrigerant flowing out from the indoor condenser 13 flows into the dehumidification passage 21b. Because the cooling expansion valve 14b is fully closed, the refrigerant that has flowed into the dehumidification passage 21b flows into the cooling expansion valve 14c and is reduced in pressure (from point b7 to point c7 in FIG. 7). The refrigerant with a relatively low enthalpy that has flowed out from the cooling expansion valve 14c flows into the other inlet of the sixth three-way joint 12f.

[0190] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21a. The refrigerant that has flowed into the bypass passage 21a is flow-regulated and decompressed by the bypass-side flow control valve 14d (from point a7 to point d7 in FIG. 7). The refrigerant with a relatively high enthalpy that has been decompressed by the bypass-side flow control valve 14d flows into one inlet of the sixth three-way joint 12f.

[0191] The refrigerant flowing out from bypass-side flow control valve 14d and the refrigerant flowing out from cooling expansion valve 14c are mixed at sixth three-way joint 12f. The refrigerant flowing out from sixth three-way joint 12f flows into chiller 20. In hot gas heating mode, low-temperature side pump 31 is stopped, so the refrigerant flowing into chiller 20 is mixed homogeneously in chiller 20 without exchanging heat with the low-temperature side heat medium as it flows through the refrigerant passage (point e7 in Figure 7).

[0192] The refrigerant flowing out from the refrigerant passage of chiller 20 flows into accumulator 23. The gas phase refrigerant separated in accumulator 23 is drawn into compressor 11 and compressed again.

[0193] In the interior air conditioning unit 50 in the hot gas heating mode, the blown air that has passed through the interior evaporator 18 is heated by the interior condenser 13 and blown into the vehicle interior, thereby realizing heating of the vehicle interior.

[0194] Here, the hot gas heating mode is an operation mode that is executed when the outdoor air temperature Tam is extremely low. Therefore, if the refrigerant that flows out from the indoor condenser 13 flows into the outdoor heat exchanger 15, there is a possibility that the refrigerant will release heat to the outdoor air in the outdoor heat exchanger 15. Furthermore, if the low-temperature side pump 31 is operating, there is a possibility that the refrigerant will release heat to the low-temperature side heat medium in the chiller 20.

[0195] Then, if the refrigerant releases heat to the outside air or the low-temperature heat medium, the amount of heat that the refrigerant releases to the blown air in the indoor condenser 13 decreases, and the heating capacity of the blown air decreases.

[0196] In contrast, in the hot gas heating mode of this embodiment, the refrigerant circuit is configured to prevent the refrigerant flowing out from the indoor condenser 13 from flowing into the outdoor heat exchanger 15, thereby preventing the refrigerant from releasing heat to the outside air in the outdoor heat exchanger 15. Furthermore, by stopping the low-temperature side pump 31, the refrigerant is prevented from releasing heat to the low-temperature side heat medium in the chiller 20.

[0197] Therefore, in the hot gas heating mode, the heat generated by the work of the compressor 11 can be effectively used to heat the blown air. As a result, even if the outside air temperature Tam is extremely low, the decrease in the blown air heating capacity can be suppressed.

[0198] (f) Hot gas dehumidifying heating mode The hot gas dehumidifying heating mode is an operating mode that dehumidifies and heats the vehicle cabin when the outside air temperature Tam is extremely low. In the control program of this embodiment, the hot gas dehumidifying heating mode is selected when the outside air temperature Tam is extremely low (less than -10°C) and the air conditioner switch is turned on.

[0199] The hot gas dehumidifying and heating mode is an operating mode that dehumidifies and heats the vehicle cabin when the outside air temperature Tam is low. In the control program of this embodiment, the hot gas dehumidifying and heating mode is selected when the outside air temperature Tam is low (in this embodiment, above 0°C and below 10°C) and the air conditioner switch is turned on.

[0200] In the hot gas dehumidifying heating mode, similarly to the hot gas heating mode, the high-low pressure difference control described with reference to Fig. 5 is executed. In step S11 of the hot gas dehumidifying heating mode, similarly to the hot gas heating mode, the target high-low pressure difference ΔPO is determined based on the target blown air temperature TAO by referring to a control map stored in advance in the control device 60.

[0201] In the control map for the hot gas dehumidifying heating mode, the target high-low pressure difference ΔP0 is determined to increase as the target outlet temperature TAO increases. Furthermore, the target high-low pressure difference ΔP0 determined by the control map for the hot gas dehumidifying heating mode is equal to or greater than the target high-low pressure difference ΔP0 determined by the control map for the hot gas heating mode when the same target outlet temperature TAO is maintained.

[0202] In the heat pump cycle 10 in the hot gas dehumidifying heating mode, the control device 60 fully closes the heating expansion valve 14a, throttles the cooling expansion valve 14b, throttles the cooling expansion valve 14c, throttles the bypass-side flow control valve 14d, and fully closes the defrosting flow control valve 14e. The control device 60 also opens the dehumidifying on-off valve 22a.

[0203] Therefore, in the heat pump cycle 10 in the hot gas dehumidifying heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the hot gas heating mode, as shown by the solid arrows in Fig. 8. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates through the first three-way joint 12a, the indoor condenser 13, the dehumidifying passage 21b, the four-way joint 12x, the cooling expansion valve 14b in the throttled state, the indoor evaporator 18, the evaporation pressure control valve 19, the accumulator 23, and the intake port of the compressor 11 in this order.

[0204] Therefore, in the hot gas dehumidifying heating mode, the cooling expansion valve 14c serves as a heating section side decompression section that decompresses the refrigerant flowing out from the heating section, the indoor condenser 13. In addition, in the hot gas dehumidifying heating mode, the sixth three-way joint 12f serves as a mixing section that mixes the refrigerant flowing out from the bypass side flow control valve 14d and the refrigerant flowing out from the cooling expansion valve 14c.

[0205] Furthermore, the control device 60 appropriately controls the operation of other controlled devices. Specifically, for the compressor 11, the control device 60 controls the refrigerant discharge capacity (i.e., rotation speed) of the compressor 11, similarly to the hot gas heating mode, so that the suction refrigerant pressure Ps approaches the second target suction refrigerant pressure PSO2. The second target suction refrigerant pressure PSO2 is set to a value equal to or lower than the first target suction refrigerant pressure PSO1 to ensure reliable dehumidification.

[0206] In addition, the control device 60 adjusts the throttle opening of the cooling expansion valve 14c so that the degree of supercooling SC1 of the refrigerant flowing out from the indoor condenser 13 approaches the second target degree of supercooling SCO2. 。

[0207] Furthermore, the control device 60 adjusts the throttle opening of the cooling expansion valve 14b so that it becomes a predetermined throttle opening for the hot gas dehumidifying heating mode.

[0208] As in the hot gas heating mode, the control device 60 also uses a feedforward control method to adjust the throttle opening of the bypass-side flow rate adjustment valve 14d so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO.

[0209] Furthermore, in the low-temperature side heat medium circuit 30 in the hot gas dehumidifying heating mode, the control device 60 stops the low-temperature side pump 31.

[0210] In addition, in the indoor air conditioning unit 50 in the hot gas dehumidifying heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the hot gas heating mode.

[0211] Therefore, in the heat pump cycle 10 in the hot gas dehumidifying heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0212] That is, the flow of the refrigerant discharged from the compressor 11 (point a9 in FIG. 9) is branched at the first three-way joint 12a. One of the refrigerant branches at the first three-way joint 12a flows into the indoor condenser 13 and dissipates heat into the blown air that has been cooled and dehumidified in the indoor evaporator 18 (from point a9 to point b9 in FIG. 9). This reheats the blown air.

[0213] The refrigerant that flows out from the interior condenser 13 passes through the dehumidification passage 21b and flows into one inlet of the four-way joint 12x.

[0214] The refrigerant that flows out from one outlet of the four-way joint 12x flows into the cooling expansion valve 14b and is decompressed (from point b9 to point f9 in FIG. 9). The refrigerant that has been decompressed by the cooling expansion valve 14b flows into the indoor evaporator 18. The refrigerant that flows into the indoor evaporator 18 evaporates through heat exchange with air (indoor air in this embodiment) blown from the indoor blower 52 (from point f9 to point e9 in FIG. 9). As a result, the air blown from the indoor blower 52 is cooled and dehumidified.

[0215] The refrigerant that flows out from the indoor evaporator 18 passes through the evaporation pressure regulating valve 19 and the second check valve 16b and flows into the fifth three-way joint 12e.

[0216] The refrigerant flowing out from another outlet of four-way joint 12x flows into cooling expansion valve 14c and is decompressed (from point b9 to point c9 in Figure 9), similar to the hot gas heating mode. The refrigerant decompressed by cooling expansion valve 14c flows into the other inlet of sixth three-way joint 12f, similar to the hot gas heating mode.

[0217] 9, for clarity of illustration, the pressure of the refrigerant decompressed by the cooling expansion valve 14c (point d9 in FIG. 9) is set to a value higher than the pressure of the refrigerant decompressed by the cooling expansion valve 14b (point f9 in FIG. 9), but this is not limited thereto. The pressure of the refrigerant decompressed by the cooling expansion valve 14c may be lower than or equal to the pressure of the refrigerant decompressed by the cooling expansion valve 14b.

[0218] The other refrigerant branched at first three-way joint 12a is flow-regulated and decompressed by bypass-side flow control valve 14d arranged in bypass passage 21a (from point a9 to point d9 in FIG. 9). The refrigerant decompressed by bypass-side flow control valve 14d flows into one inlet of sixth three-way joint 12f, as in the hot gas heating mode.

[0219] The refrigerant flowing out from bypass-side flow control valve 14d and the refrigerant flowing out from cooling expansion valve 14c are mixed at sixth three-way joint 12f, as in the hot gas heating mode. Furthermore, the refrigerant flowing into chiller 20 from sixth three-way joint 12f is mixed homogeneously in chiller 20. The refrigerant flowing out from chiller 20 flows into fifth three-way joint 12e.

[0220] At the fifth three-way joint 12e, the flow of refrigerant flowing out from the indoor evaporator 18 and the flow of refrigerant flowing out from the chiller 20 join together. The refrigerant flowing out from the fifth three-way joint 12e flows into the accumulator 23. The gas phase refrigerant separated in the accumulator 23 is sucked into the compressor 11 and compressed again.

[0221] In the interior air conditioning unit 50 in the hot gas dehumidifying heating mode, the blown air that has been cooled and dehumidified in the interior evaporator 18 is reheated in the interior condenser 13 and blown into the vehicle cabin. This achieves dehumidifying heating of the vehicle cabin.

[0222] Therefore, in the hot gas dehumidifying heating mode, as in the hot gas heating mode, the heat generated by the work of the compressor 11 can be effectively used to heat the blown air. Furthermore, the heat absorbed by the refrigerant from the blown air in the indoor evaporator 18 can be used to heat the blown air. As a result, in the hot gas dehumidifying heating mode, a decrease in the heating capacity of the blown air can be suppressed even when the outside air temperature Tam is low.

[0223] (g) Single cooling mode The single cooling mode is an operation mode in which the battery 70 is cooled without air conditioning the interior of the vehicle.

[0224] In the heat pump cycle 10 in the single cooling mode, the control device 60 fully opens the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, fully closes the bypass flow control valve 14d, and fully closes the defrosting flow control valve 14e. The control device 60 also closes the dehumidification on-off valve 22a.

[0225] Therefore, in the heat pump cycle 10 in the single cooling mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a fully open state, the outdoor heat exchanger 15, the cooling expansion valve 14c which is in a throttled state, the chiller 20, the accumulator 23, and the intake port of the compressor 11.

[0226] In the low-temperature side heat medium circuit 30 in the single cooling mode, the control device 60 operates the low-temperature side pump 31 in the same manner as in the air-conditioning cooling mode. Therefore, in the low-temperature side heat medium circuit 30, the low-temperature side heat medium pumped from the low-temperature side pump 31 circulates in the same manner as in the air-conditioning cooling mode.

[0227] Furthermore, in the indoor air conditioning unit 50 in the single cooling mode, the control device 60 stops the indoor blower 52.

[0228] Therefore, in the heat pump cycle 10 in the single cooling mode, a vapor compression refrigeration cycle is configured in which the outdoor heat exchanger 15 functions as a condenser and the chiller 20 functions as an evaporator.

[0229] In the low-temperature side heat medium circuit 30 in the single cooling mode, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70, thereby cooling the battery 70, as in the cooling air-conditioning mode.

[0230] (h) Standalone warm-up mode The single warm-up mode is an operation mode for warming up the battery 70. In the control program of this embodiment, the single warm-up mode is selected when the IG switch is turned on while the battery temperature TB is equal to or lower than a predetermined reference warm-up temperature KTBL1.

[0231] In the single warm-up mode, the high-low pressure difference control described with reference to Fig. 5 is executed, as in the hot gas heating mode. In step S11 in the single warm-up mode, the target high-low pressure difference ΔP0 is determined based on the outside air temperature Tam by referring to a control map stored in advance in the control device 60. The control map for the single warm-up mode determines the target high-low pressure difference ΔP0 to increase as the outside air temperature Tam decreases.

[0232] In the heat pump cycle 10 in the single warm-up mode, the control device 60 fully closes the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, fully closes the bypass flow control valve 14d, and fully closes the defrosting flow control valve 14e. The control device 60 also opens the dehumidification on-off valve 22a.

[0233] Therefore, in the heat pump cycle 10 in the single warm-up mode, as shown by the solid arrows in Figure 10, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: the indoor condenser 13, the dehumidification passage 21b, the cooling expansion valve 14c in a throttling state, the chiller 20, the accumulator 23, and the intake port of the compressor 11.

[0234] Furthermore, the control device 60 appropriately controls the operation of other controlled devices. Specifically, for the compressor 11, the control device 60 controls the refrigerant discharge capacity (i.e., rotation speed) of the compressor 11, in the same way as in the hot gas heating mode, so that the discharge refrigerant pressure Pd approaches the target discharge refrigerant pressure PDO1 for the single warm-up mode.

[0235] As in the hot gas heating mode, the control device 60 also uses a feedforward control method to adjust the throttle opening of the cooling expansion valve 14c so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO.

[0236] In the low-temperature side heat medium circuit 30 in the single warm-up mode, the control device 60 controls the operation of the low-temperature side pump 31 in the same way as in the cooling and cooling mode. Therefore, in the low-temperature side heat medium circuit 30 in the cooling series dehumidifying and heating mode, the low-temperature side heat medium circulates in the same way as in the cooling and cooling mode.

[0237] Furthermore, in the indoor air conditioning unit 50 in the single warm-up mode, the control device 60 stops the indoor blower 52.

[0238] Therefore, in the heat pump cycle 10 in the single warm-up mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0239] That is, the refrigerant discharged from the compressor 11 (point a11 in FIG. 11) flows into the cooling expansion valve 14c via the indoor condenser 13 and the dehumidification passage 21b, and is decompressed (from point a11 to point b11 in FIG. 11). Here, in the single warm-up mode, the indoor blower 52 is stopped, so the refrigerant does not dissipate heat to the blown air in the indoor condenser 13.

[0240] The refrigerant that flows out from cooling expansion valve 14c flows into the refrigerant passage of chiller 20. The refrigerant that flows into the refrigerant passage of chiller 20 dissipates heat to the low-temperature side heat medium flowing through the heat medium passage of chiller 20 (from point b11 to point c11 in FIG. 11). This heats the low-temperature side heat medium. The refrigerant that flows out from chiller 20 flows into accumulator 23. The gas-phase refrigerant separated in accumulator 23 is drawn into compressor 11 and compressed again.

[0241] In the low-temperature side heat medium circuit 30 in the single warm-up mode, the low-temperature side heat medium pumped from the low-temperature side pump 31 flows into the chiller 20 and is heated. Then, the low-temperature side heat medium heated in the chiller 20 flows through the coolant passage 70a of the battery 70, thereby warming up the battery 70.

[0242] As is clear from the above description, in the single warm-up mode, the cooling expansion valve 14c is an upstream pressure reducing section. In the single warm-up mode, the battery 70 is a low-pressure side heating object. In the single warm-up mode, the chiller 20 and each component of the low-temperature side heat medium circuit 30 are low-pressure side heating sections. In addition, the single warm-up mode may be terminated when the battery temperature TB becomes equal to or higher than a predetermined warm-up termination point KTBL2.

[0243] (i) Defrost mode The defrosting mode is an operation mode executed to remove frost formed on the outdoor heat exchanger 15. In the control program of this embodiment, the defrosting mode is selected when it is determined that the frosting condition is met during execution of the parallel dehumidifying heating mode and the heating mode.

[0244] Here, the frosting condition in this embodiment is met when the time during which the outdoor unit side refrigerant temperature T2 detected by the outdoor unit side refrigerant temperature pressure sensor 62c remains below the reference frosting temperature KTDF (-5°C in this embodiment) becomes equal to or longer than the reference frosting time KTmDF (5 minutes in this embodiment) while the parallel dehumidifying heating mode and the heating mode are being executed.

[0245] In the defrost mode, similarly to the hot gas heating mode, the high-low pressure difference control described with reference to Fig. 5 is executed. In step S11 of the defrost mode, the target high-low pressure difference ΔP0 is determined based on the outside air temperature Tam by referring to a control map stored in advance in the control device 60. The control map for the defrost mode determines the target high-low pressure difference ΔP0 to increase as the outside air temperature Tam decreases.

[0246] In the defrosting mode of the heat pump cycle 10, the control device 60 fully opens the heating expansion valve 14a, fully closes the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, fully closes the bypass flow control valve 14d, and throttles the defrosting flow control valve 14e. The control device 60 also closes the dehumidifying on-off valve 22a.

[0247] Therefore, in the heat pump cycle 10 in the defrosting mode, as shown by the solid arrows in Figure 12, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a fully open state, the outdoor heat exchanger 15, the defrosting flow control valve 14e arranged in the heating passage 21c which is in a throttled state, the accumulator 23, and the intake port of the compressor 11.

[0248] Furthermore, the control device 60 appropriately controls the operation of other controlled devices. Specifically, with regard to the compressor 11, the control device 60 controls the refrigerant discharge capacity (i.e., rotation speed) of the compressor 11, in the same way as in the hot gas heating mode, so that the suction refrigerant pressure Ps approaches the third target suction refrigerant pressure PSO3 for the defrost mode.

[0249] As in the hot gas heating mode, the control device 60 also uses a feedforward control method to adjust the throttle opening of the defrosting flow control valve 14e so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO.

[0250] Furthermore, in the indoor air conditioning unit 50 in the defrosting mode, the control device 60 stops the indoor blower 52.

[0251] Therefore, in the heat pump cycle 10 in the defrosting mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0252] That is, the refrigerant discharged from the compressor 11 (point a13 in FIG. 13) flows into the outdoor heat exchanger 15 via the indoor condenser 13. Here, in the defrosting mode, the indoor blower 52 is stopped, so the refrigerant does not dissipate heat to the blown air in the indoor condenser 13.

[0253] The refrigerant that flows into the outdoor heat exchanger 15 dissipates heat to the frost that has formed on the outdoor heat exchanger 15 (from point a13 to point b13 in FIG. 13). This melts the frost that has formed on the outdoor heat exchanger 15, thereby defrosting the outdoor heat exchanger 15. The refrigerant that flows out of the outdoor heat exchanger 15 flows into the defrosting flow control valve 14e that is arranged in the heating passage 21c, and is reduced in pressure (from point b13 to point c13 in FIG. 13).

[0254] The refrigerant flowing out from the defrosting flow rate adjustment valve 14e flows into the accumulator 23. The gas phase refrigerant separated in the accumulator 23 is sucked into the compressor 11 and compressed again.

[0255] As is clear from the above description, in the defrost mode, the outdoor heat exchanger 15 is a high-pressure side heating section. The frost formed on the outdoor heat exchanger 15 is a high-pressure side heating object. In the defrost mode, the defrost flow control valve 14e is a downstream pressure reducing section. Furthermore, the defrost mode may be terminated after a predetermined time has elapsed, and the system may transition to the parallel dehumidifying heating mode and the heating mode.

[0256] As described above, the vehicle air conditioner 1 of this embodiment can provide comfortable air conditioning for the vehicle interior and appropriately adjust the temperature of the battery 70, which is an on-board device, by switching the operation mode.

[0257] In the hot gas heating mode and hot gas dehumidifying heating mode of the vehicle air conditioner 1 of this embodiment, the blown air, which is the object to be heated, is heated mainly using heat generated by the work of the compressor 11. For this reason, in the hot gas heating mode and hot gas dehumidifying heating mode, it is necessary to appropriately control the operation of the controlled devices so that the amount of work done by the compressor 11 is an appropriate amount of heat for heating the blown air.

[0258] For example, in a cycle in which the suction refrigerant pressure Ps is controlled to approach the target suction refrigerant pressure PSO, suppose that the refrigerant discharge capacity of the compressor 11 is increased to increase the heating capacity of the blown air in the indoor condenser 13. In this case, there is a possibility that the cycle cannot be operated stably.

[0259] More specifically, when the refrigerant discharge capacity of the compressor 11 is increased, the amount of heat supplied to the suction refrigerant through the bypass passage 21a increases, causing the suction refrigerant pressure Ps to rise. Therefore, in order to bring the suction refrigerant pressure Ps closer to the target suction refrigerant pressure PSO, it is conceivable to reduce the opening of the bypass-side flow control valve 14d to reduce the amount of heat supplied to the suction refrigerant.

[0260] However, even if the bypass-side flow control valve 14d reduces the throttle opening and makes the suction refrigerant pressure Ps approach the target suction refrigerant pressure PSO, if the heat quantity of the discharge refrigerant flowing into the indoor condenser 13 is excessively supplied, the discharge refrigerant pressure Pd continues to rise, making it impossible to operate the cycle stably.

[0261] Similarly, for example, in a cycle in which the discharge refrigerant pressure Pd is controlled to approach a predetermined target discharge refrigerant pressure PDO, if the refrigerant discharge capacity of the compressor 11 is increased to increase the heating capacity of the blown air in the indoor condenser 13, there is a possibility that the cycle will not operate stably.

[0262] More specifically, when the refrigerant discharge capacity of the compressor 11 is increased, the heat quantity of the discharge refrigerant flowing into the indoor condenser 13 increases, and therefore the discharge refrigerant pressure Pd rises. Therefore, in order to bring the discharge refrigerant pressure Pd closer to the target discharge refrigerant pressure PDO, it is conceivable that the bypass-side flow control valve 14d increases its throttle opening to reduce the heat quantity of the discharge refrigerant flowing into the indoor condenser 13.

[0263] However, even if the bypass-side flow control valve 14d increases its throttle opening and the discharge refrigerant pressure Pd approaches the target discharge refrigerant pressure PDO, if the amount of heat supplied to the suction refrigerant is excessive, the suction refrigerant pressure Ps continues to rise, making it impossible to operate the cycle stably.

[0264] In contrast, in the hot gas heating mode and hot gas dehumidifying heating mode of the vehicle air conditioner 1 of this embodiment, the operation of the bypass-side flow rate control valve 14d is controlled so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. Therefore, by appropriately determining the target high-low pressure difference ΔP, the workload of the compressor 11 can be adjusted to a heat quantity that can appropriately heat the blown air.

[0265] As a result, the cycle can be operated stably even in operation modes that mainly use heat generated by the compressor to heat the air, such as the hot gas heating mode and the hot gas dehumidifying heating mode, thereby improving the stability of operation when heating the air.

[0266] Furthermore, in the hot gas heating mode and the hot gas dehumidifying heating mode, the target high-low pressure difference determiner of this embodiment determines the target high-low pressure difference ΔP0 to increase as the target blown air temperature TAO increases. This allows the workload of the compressor 11 to increase as the heating temperature of the blown air increases. Therefore, the target high-low pressure difference ΔP0 can be appropriately determined.

[0267] In addition, the discharge capacity control unit 60a of this embodiment controls the operation of the compressor 11 so that the suction refrigerant pressure Ps approaches the first target suction refrigerant pressure PSO1 and the second target suction refrigerant pressure PSO2, respectively, during the hot gas heating mode and the hot gas dehumidification heating mode.

[0268] This makes it possible to stabilize the discharge flow rate Gr of the compressor 11 in each operation mode. Therefore, by changing the target high-low pressure difference ΔPO, the workload of the compressor 11 can be adjusted with higher precision.

[0269] Furthermore, the bypass-side control section 60c of this embodiment controls the operation of the bypass-side flow rate adjustment valve 14d by feedforward control, which allows the workload of the compressor 11 to be quickly changed and the heating capacity of the indoor condenser 13 for heating the blown air to be quickly adjusted to an appropriate value.

[0270] Furthermore, in the single warm-up mode of the vehicle air conditioner 1 of this embodiment, the battery 70, which is the low-pressure side heating object, is warmed up using heat generated by the work of the compressor 11, without using heat absorbed from the outside air, etc. Therefore, in the single warm-up mode, it is necessary to appropriately control the operation of the controlled devices so that the amount of work done by the compressor 11 becomes an appropriate amount of heat for warming up the battery 70.

[0271] For example, in a cycle in which the discharge refrigerant pressure Pd is controlled to approach a predetermined target discharge refrigerant pressure PDO, the refrigerant discharge capacity of the compressor 11 may be increased to increase the heating capacity of the battery 70 in the low-pressure side heating section formed by the chiller 20 and the low-temperature side heat medium circuit 30. In this case, it may become impossible to operate the cycle stably.

[0272] More specifically, increasing the refrigerant discharge capacity of the compressor 11 increases the discharge refrigerant pressure Pd. Therefore, in order to bring the discharge refrigerant pressure Pd closer to the target discharge refrigerant pressure PDO, it is conceivable to increase the throttle opening of the cooling expansion valve 14c, which is the upstream pressure reducing section.

[0273] However, increasing the throttle opening of the cooling expansion valve 14c increases the pressure of the refrigerant flowing into the chiller 20, reducing the high-low pressure difference ΔP. This makes it impossible to increase the heating capacity of the battery 70 in the low-pressure side heating section. As a result, it becomes necessary to further increase the refrigerant discharge capacity of the compressor 11, making it impossible to operate the cycle stably.

[0274] In contrast, in the single warm-up mode of the vehicle air conditioner 1 of this embodiment, the operation of the cooling expansion valve 14c is controlled so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. Therefore, by appropriately determining the target high-low pressure difference ΔP, the workload of the compressor 11 can be adjusted to a heat quantity that allows the battery 70 to be appropriately warmed up.

[0275] As a result, even in an operation mode such as the sole warm-up mode in which the battery 70 is warmed up using only the heat generated by the work of the compressor, the cycle can be operated stably. In other words, the stability of operation when warming up the battery 70 can be improved.

[0276] Furthermore, in the single warm-up mode of this embodiment, refrigerant decompressed by the cooling expansion valve 14c is flowed into the chiller 20. This allows refrigerant at a lower pressure than the discharged refrigerant to flow into the chiller 20. Therefore, there is no need to improve the pressure resistance of the chiller 20 in order to execute the single warm-up mode.

[0277] Furthermore, in the defrosting mode of the vehicle air conditioner 1 of this embodiment, the frost on the outdoor heat exchanger 15, which is the high-pressure side heating object, is heated using only the heat generated by the work of the compressor 11, without using heat absorbed from the outside air, etc. Therefore, in the defrosting mode, it is necessary to appropriately control the operation of the controlled devices so that the amount of work done by the compressor 11 becomes an appropriate amount of heat for heating the frost that has formed on the outdoor heat exchanger 15.

[0278] For example, in a cycle in which the suction refrigerant pressure Ps is controlled to approach a predetermined target suction refrigerant pressure PSO, suppose that the refrigerant discharge capacity of the compressor 11 is increased to increase the frost heating capacity in the high-pressure side heating section formed by the outdoor heat exchanger 15. In this case, there is a possibility that the cycle cannot be operated stably.

[0279] More specifically, increasing the refrigerant discharge capacity of the compressor 11 reduces the suction refrigerant pressure Ps. Therefore, in order to bring the suction refrigerant pressure Ps closer to the target suction refrigerant pressure PSO, it is conceivable to increase the throttle opening of the defrosting flow control valve 14e, which is the downstream pressure reducing section.

[0280] However, increasing the throttle opening of the defrost flow control valve 14e reduces the pressure of the refrigerant flowing into the outdoor heat exchanger 15, reducing the high-low pressure difference ΔP. This makes it impossible to increase the heating capacity for removing frost from the high-pressure side heating section. As a result, it becomes necessary to further increase the refrigerant discharge capacity of the compressor 11, making it impossible to operate the cycle stably.

[0281] In contrast, in the defrost mode of the vehicle air conditioner 1 of this embodiment, the operation of the defrosting flow control valve 14e is controlled so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. Therefore, by appropriately determining the target high-low pressure difference ΔP, the workload of the compressor 11 can be adjusted to a heat quantity that allows appropriate defrosting of the exterior heat exchanger 15.

[0282] As a result, even in an operation mode such as the defrosting mode in which the outdoor heat exchanger 15 is defrosted using only the heat generated by the work of the compressor, the cycle can be operated stably. In other words, the stability of operation when defrosting the outdoor heat exchanger 15 can be improved.

[0283] Furthermore, when the vehicle air conditioner 1 of this embodiment is in the defrost mode, the air blown from the interior blower 52 may be heated by the interior condenser 13 and blown into the vehicle compartment. This allows the vehicle compartment to continue to be heated even in the defrost mode.

[0284] (Second embodiment) In this embodiment, an example will be described in which a heat pump cycle device according to the present invention is applied to a stationary heating device 2. The heating device 2 of this embodiment has a heat pump cycle 10a and a control device 601.

[0285] As shown in FIG. 14, the heat pump cycle 10a includes a compressor 11, an upstream expansion valve 14f, and an indoor condenser 13.

[0286] The upstream expansion valve 14f is an upstream pressure reducing unit that reduces the pressure of the discharged refrigerant. The basic configuration of the upstream expansion valve 14f is similar to that of the bypass flow rate adjustment valve 14d and the like.

[0287] The indoor condenser 13 of this embodiment is a heating heat exchanger that exchanges heat between the refrigerant flowing out from the upstream expansion valve 14f and the blown air sent from the indoor blower 52 toward the space to be air-conditioned. The indoor condenser 13 heats the blown air by dissipating the heat of the refrigerant flowing out from the upstream expansion valve 14f to the blown air.

[0288] Therefore, in this embodiment, the blown air is a low-pressure-side heating object. The indoor condenser 13 is a low-pressure-side heating part that heats the blown air using the refrigerant flowing out from the bypass-side flow control valve 14d as a heat source and causes the refrigerant to flow out to the suction port side of the compressor 11.

[0289] The basic configuration of the control device 601 is the same as that of the control device 60 described in the first embodiment. The control device 601 of this embodiment has a target temperature determination unit S31 corresponding to step S3 of the control program described in the first embodiment, a target high / low pressure difference determination unit S111 corresponding to step S11 of the control program, and the like.

[0290] Next, the operation of the heating device 2 of this embodiment with the above configuration will be described. The basic operation of the heating device 2 of this embodiment is the same as the operation of the vehicle air conditioner 1 in the single warm-up mode described in the first embodiment.

[0291] In the heating device 2, when an operation switch of an operation panel 691 connected to the control device 601 is turned on, the control device 601 executes a control program. As in the first embodiment, the control program for the heating device 2 reads detection signals from the group of control sensors and operation signals from the operation panel at predetermined intervals to determine a target blow-out temperature TAO and a target high-low pressure difference ΔP0.

[0292] Furthermore, the control device 601 appropriately controls the operation of other control target devices so that the temperature of the air blown into the air-conditioned space becomes the target blowout temperature TAO.

[0293] Specifically, with regard to the compressor 11, the control device 601 controls the refrigerant discharge capacity (i.e., rotation speed) of the compressor 11 so that the suction refrigerant pressure Ps approaches the target suction refrigerant pressure PSO, similar to the single warm-up mode of the first embodiment.

[0294] Furthermore, similar to the single warm-up mode of the first embodiment, the control device 601 adjusts the throttle opening of the upstream expansion valve 14f using a feedforward control method so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO.

[0295] Therefore, in the heat pump cycle 10a of the heating device 2, the state of the refrigerant changes in the same manner as in the Mollier diagram of Fig. 11 described in the single warm-up mode of the first embodiment. Therefore, the air blown from the indoor blower 52 is heated in the indoor condenser 13 by heat exchange with the refrigerant flowing out from the upstream expansion valve 14f. The heated air is then blown into the space to be air-conditioned, thereby realizing heating of the space to be air-conditioned.

[0296] The heating device 2 of this embodiment can achieve the same effect as the single warm-up mode of the first embodiment. That is, the heating device 2 of this embodiment can stably operate the cycle even in an operation mode in which the blown air is heated using only the heat generated by the work of the compressor. That is, the stability of operation when heating the blown air, which is the low-pressure side heating object, can be improved.

[0297] (Third embodiment) In this embodiment, an example will be described in which a heat pump cycle device according to the present invention is applied to a stationary heating device 3. The heating device 3 of this embodiment has a heat pump cycle 10b and a control device 601.

[0298] As shown in FIG. 15, the heat pump cycle 10b includes a compressor 11, an indoor condenser 13, and a downstream expansion valve 14g.

[0299] The indoor condenser 13 of this embodiment is a heating heat exchanger that exchanges heat between the discharged refrigerant discharged from the compressor 11 and the blown air sent from the indoor blower 52 toward the space to be air-conditioned. The indoor condenser 13 heats the blown air by radiating heat from the discharged refrigerant to the blown air.

[0300] The downstream expansion valve 14g is a downstream pressure reducing section that reduces the pressure of the refrigerant that has flowed out from the indoor condenser 13 and causes the refrigerant to flow toward the suction port side of the compressor 11. The basic configuration of the downstream expansion valve 14g is similar to that of the bypass flow control valve 14d and the like.

[0301] Therefore, in this embodiment, the blown air is the high-pressure side heating object. The indoor condenser 13 is the high-pressure side heating part that heats the blown air using the discharged refrigerant as a heat source. A configuration similar to that of the second embodiment can be adopted.

[0302] Next, the operation of the heating device 3 of this embodiment with the above configuration will be described. The basic operation of the heating device 3 of this embodiment is the same as the operation of the defrosting mode of the vehicle air conditioner 1 described in the first embodiment.

[0303] In the heating device 3, when an operation switch of an operation panel 691 connected to the control device 601 is turned on, the control device 601 executes a control program. As in the first embodiment, the control program for the heating device 3 reads detection signals from the group of control sensors and operation signals from the operation panel at predetermined intervals to determine a target blow-out temperature TAO and a target high-low pressure difference ΔP0.

[0304] Furthermore, the control device 601 appropriately controls the operation of other control target devices so that the temperature of the air blown into the air-conditioned space becomes the target blowout temperature TAO.

[0305] Specifically, with regard to the compressor 11, the control device 601 controls the refrigerant discharge capacity (i.e., rotation speed) of the compressor 11 so that the suction refrigerant pressure Ps approaches the target suction refrigerant pressure PSO, similar to the defrosting mode of the first embodiment.

[0306] Furthermore, similarly to the defrosting mode of the first embodiment, the control device 601 adjusts the throttle opening of the downstream expansion valve 14g using a feedforward control method so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO.

[0307] Therefore, in the heat pump cycle 10b of the heating device 3, the state of the refrigerant changes in the same manner as in the Mollier diagram of Fig. 13 described in the defrosting mode of the first embodiment. Therefore, the air blown from the indoor blower 52 is heated by heat exchange with the discharged refrigerant in the indoor condenser 13. Then, the heated air is blown into the space to be air-conditioned, thereby realizing heating of the space to be air-conditioned.

[0308] The heating device 3 of this embodiment can achieve the same effect as the defrosting mode of the first embodiment. That is, the heating device 3 of this embodiment can stably operate the cycle even in an operation mode in which the blown air is heated using only the heat generated by the work of the compressor. That is, the stability of operation when heating the blown air, which is the high-pressure side heating object, can be improved.

[0309] (Other embodiments) The present invention is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the spirit of the present invention.

[0310] (1) In the above embodiment, an example in which the heat pump cycle apparatus according to the present invention is applied to an air conditioner has been described, but the application of the heat pump cycle apparatus is not limited to air conditioners. For example, the heat pump cycle apparatus may be applied to a hot water supply apparatus that heats domestic water or the like as the object to be heated, the low-pressure side object to be heated, and the high-pressure side object to be heated.

[0311] (2) The configuration of the heat pump cycle device according to the present invention is not limited to the configuration disclosed in the above-described embodiment.

[0312] In the above-described first embodiment, an example in which the indoor condenser 13 is used as the heating unit has been described, but the heating unit is not limited to the indoor condenser 13. For example, the heating unit may be one in which a high-temperature side pump, a water-refrigerant heat exchanger, a heater core, etc. are arranged in a high-temperature side heat medium circulation circuit that circulates the high-temperature side heat medium.

[0313] The high-temperature side pump is a pump that pumps the high-temperature side heat medium into the water passage of the water-refrigerant heat exchanger. The same type of fluid as the low-temperature side heat medium can be used as the high-temperature side heat medium. The water-refrigerant heat exchanger is a heat exchanger that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the high-temperature side heat medium pumped from the high-temperature side pump. The heater core is a heating heat exchanger that exchanges heat between the high-temperature side heat medium heated in the water-refrigerant heat exchanger and the blown air.

[0314] The heater core is disposed in the air passage of the indoor air conditioning unit 50 in the same manner as the indoor condenser 13. With this, in a hot gas heating mode or the like, the discharged refrigerant can be used as a heat source to indirectly heat the blown air, which is the object to be heated, via the high-temperature heat medium.

[0315] Of course, a low-temperature side heating part using a high-temperature side heat medium circulation circuit may be employed instead of the indoor condenser 13 which is the low-temperature side heating part in the second embodiment. A high-temperature side heating part using a high-temperature side heat medium circulation circuit may be employed instead of the indoor condenser 13 which is the high-temperature side heating part in the third embodiment.

[0316] In the above-described first embodiment, an example has been described in which the accumulator 23 is used as a gas-liquid separator that stores excess liquid-phase refrigerant in the heat pump cycle 10. However, a receiver may be used instead of the accumulator 23. The receiver is a high-pressure side gas-liquid separator that separates the refrigerant flowing out from the indoor condenser 13 into gas and liquid and stores excess liquid-phase refrigerant in the cycle.

[0317] Furthermore, if a receiver is used instead of the accumulator 23, the control device 60 controls the operation of the heating unit side pressure reducing section so that the superheat SH of the intake refrigerant becomes a predetermined reference superheat KSH during the hot gas heating mode and the hot gas dehumidifying heating mode.

[0318] The degree of superheat SH of the suctioned refrigerant can be calculated using the evaporator side refrigerant temperature Te and evaporator side refrigerant pressure Pe detected by the evaporator side refrigerant temperature and pressure sensor 62d, or the chiller side refrigerant temperature Tc and chiller side refrigerant pressure Pc detected by the chiller side refrigerant temperature and pressure sensor 62e.

[0319] Furthermore, the accumulator 23 may be eliminated, and a subcooling type heat exchanger may be used as the indoor condenser 13. The subcooling type heat exchanger has a condensing section that condenses the refrigerant, a liquid receiving section that separates the refrigerant condensed in the condensing section into gas and liquid and stores the liquid-phase refrigerant, and a supercooling section that supercools the liquid-phase refrigerant that flows out from the liquid receiving section.

[0320] In the first embodiment described above, an example in which the evaporating pressure control valve 19 configured as a mechanical mechanism is used has been described, but of course an evaporating pressure control valve configured as an electrical mechanism may also be used. As an evaporating pressure control valve with an electrical mechanism, a variable throttle mechanism configured similarly to the heating expansion valve 14a or the like may be used.

[0321] In the above-described embodiment, the refrigerant used in the heat pump cycles 10, 10a, and 10b is R1234yf, but this is not limiting. For example, R134a, R600a, R410A, R404A, R32, R407C, etc. may be used. Alternatively, a mixed refrigerant containing a combination of these refrigerants may be used. Furthermore, carbon dioxide may be used as the refrigerant to configure a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure is equal to or higher than the critical pressure of the refrigerant.

[0322] Although the above-described embodiment has been described with reference to an example in which an ethylene glycol aqueous solution is used as the low-temperature heat medium and the high-temperature heat medium, the present invention is not limited to this. For example, the high-temperature heat medium and the low-temperature heat medium may be a solution containing dimethylpolysiloxane or nanofluid, an antifreeze, an aqueous liquid refrigerant containing alcohol, or a liquid medium containing oil.

[0323] (3) The control aspects of the heat pump cycle device according to the present invention are not limited to the control aspects disclosed in the above-described embodiments.

[0324] In the first embodiment described above, the vehicle air conditioner 1 is capable of executing various operation modes, but it is not necessary that all of the above operation modes be executable. As long as at least one of the hot gas heating mode, hot gas defrost heating mode, single warm-up mode, and defrost mode can be executed, the stability of the cycle can be improved and the object to be heated can be appropriately heated.

[0325] In the above-described embodiment, the high-low pressure difference ΔP is calculated using the discharge refrigerant pressure Pd detected by the discharge refrigerant temperature / pressure sensor 62a and the suction refrigerant pressure Ps detected by the suction refrigerant temperature / pressure sensor 62f when performing the high-low pressure difference control. However, the present invention is not limited to this. For example, the high-low pressure difference ΔP may be calculated by subtracting the saturation pressure at the suction refrigerant temperature Ts from the saturation pressure at the discharge refrigerant temperature Td.

[0326] Furthermore, the hot gas heating mode of the first embodiment described above is an operating mode that is executed when the outside air temperature is extremely low, and therefore there is no need to cool the battery 70. However, when the outside air temperature is low, it may be necessary to warm up the battery 70. Therefore, when the battery temperature TB falls below the reference lower limit temperature KTBL during the hot gas heating mode, the low-temperature side pump 31 may be operated to execute a hot gas heating warm-up mode that warms up the battery 70.

[0327] Furthermore, in the hot gas heating mode of the first embodiment described above, an example was described in which the operation of the bypass side flow control valve 14d was controlled so that the high-low pressure difference ΔP approached the target high-low pressure difference ΔPO, but this is not limited to this.

[0328] For example, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. In this case, the control device 60 may control the operation of the bypass-side flow control valve 14d so that the suction refrigerant pressure Ps approaches the first target suction refrigerant pressure PSO1. Furthermore, the control device 60 may control the operation of the cooling expansion valve 14c so that the subcooling degree SC1 approaches the first target subcooling degree SCO1.

[0329] For example, the control device 60 may control the operation of the cooling expansion valve 14c so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. In this case, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches the first target suction refrigerant pressure PSO1. Furthermore, the control device 60 may control the operation of the bypass-side flow control valve 14d so that the subcooling degree SC1 approaches the first target subcooling degree SCO1.

[0330] In this case, if a receiver is used instead of the accumulator 23, the controlled device that adjusted the subcooling degree SC1 can adjust the superheat degree SH of the suction refrigerant to a predetermined reference superheat degree KSH.

[0331] Similar control can be adopted in the hot gas dehumidifying heating mode. That is, for example, in the hot gas dehumidifying heating mode, the refrigerant discharge capacity of the compressor 11 may be controlled so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. Alternatively, in the hot gas dehumidifying heating mode, the throttle opening of the cooling expansion valve 14c may be adjusted so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP.

[0332] Furthermore, in the single warm-up mode of the vehicle air conditioning system 1 of the first embodiment described above and the heating system 2 of the second embodiment, examples have been described in which the operation of the upstream pressure reducing section is controlled so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO, but this is not limited to this.

[0333] For example, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. In this case, the control device 60 may control the operation of the upstream pressure reducing section so that the discharge refrigerant pressure Pd approaches the target discharge refrigerant pressure PDO1 for the single warm-up mode.

[0334] Furthermore, in the defrosting mode of the vehicle air conditioning system 1 of the first embodiment described above and the heating system 3 of the third embodiment, examples have been described in which the operation of the downstream pressure reducing section is controlled so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔPO, but this is not limited to this.

[0335] For example, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the high-low pressure difference ΔP approaches the target high-low pressure difference ΔP. In this case, the control device 60 may control the operation of the downstream pressure reducing section so that the suction refrigerant pressure Ps approaches the third target suction refrigerant pressure PSO3 for the defrost mode. [Explanation of symbols]

[0336] 1, 2, 3 Vehicle air conditioning and heating systems (heat pump cycle systems) 11 Compressor 12a First three-way joint (branch) 12f 6th three-way joint (confluence) 13 Indoor condenser (heating section) 14c Cooling expansion valve (heating section side pressure reducing section) 14d Bypass side flow rate adjustment valve (bypass side flow rate adjustment part) 14f Upstream expansion valve (upstream pressure reducing section) 14g Downstream expansion valve (downstream pressure reducing section) 21a Bypass Passage

Claims

1. a compressor (11) that compresses and discharges a refrigerant; a branching portion (12a) for branching a flow of the refrigerant discharged from the compressor; a heating section (13) that heats an object to be heated using one of the refrigerants branched at the branch section as a heat source; a heating unit side decompression unit (14c) for decompressing the refrigerant flowing out from the heating unit; a bypass passage (21a) for guiding the other of the discharged refrigerants branched at the branching portion to a suction port side of the compressor; a bypass-side flow rate adjusting section (14d) for adjusting the flow rate of the refrigerant flowing through the bypass passage; a mixing section (12f) that mixes the refrigerant flowing out from the bypass-side flow rate adjustment section and the refrigerant flowing out from the heating section-side pressure reduction section and causes the refrigerant to flow out to a suction port side of the compressor; a target high-low pressure difference determination unit (S11) that determines a target high-low pressure difference (ΔP) that is a target value of the high-low pressure difference (ΔP) obtained by subtracting a suction refrigerant pressure (Ps) of the suction refrigerant sucked into the compressor from a discharge refrigerant pressure (Pd) of the discharge refrigerant, a heat pump cycle device that controls the operation of at least one of the compressor, the heating unit-side pressure reduction unit, and the bypass-side flow rate adjustment unit, excluding the one used for adjusting the high-low pressure difference (ΔP), so that the suction refrigerant pressure (Ps) approaches a target suction refrigerant pressure (PSO1), during an operation mode in which the refrigerant flowing out of the bypass-side flow rate adjustment unit and the refrigerant flowing out of the heating unit-side pressure reduction unit are directly mixed in the mixing unit;

2. a bypass-side control unit (60c) for controlling operation of the bypass-side flow rate adjustment unit; The heat pump cycle apparatus according to claim 1 , wherein the bypass-side control unit controls the operation of the bypass-side flow rate adjustment unit so that the high-low pressure difference (ΔP) approaches the target high-low pressure difference (ΔPO).

3. 3. The heat pump cycle apparatus according to claim 2, wherein the bypass side control unit estimates a throttle passage area (Ab) of the bypass side flow rate adjustment unit using the target high-low pressure difference (ΔP) and controls the operation of the bypass side flow rate adjustment unit by feedforward control.

4. A discharge capacity control unit (60a) for controlling the refrigerant discharge capacity of the compressor, 4. The heat pump cycle apparatus according to claim 1, wherein the discharge capacity control unit controls the operation of the compressor so that the suction refrigerant pressure (Ps) approaches a target suction refrigerant pressure (PSO1).

5. a compressor (11) that compresses and discharges a refrigerant; a branching portion (12a) for branching a flow of the refrigerant discharged from the compressor; a heating section (13) that heats an object to be heated using one of the refrigerants branched at the branch section as a heat source; a heating unit side decompression unit (14c) for decompressing the refrigerant flowing out from the heating unit; a bypass passage (21a) for guiding the other of the discharged refrigerants branched at the branching portion to a suction port side of the compressor; a bypass-side flow rate adjusting section (14d) for adjusting the flow rate of the refrigerant flowing through the bypass passage; a mixing section (12f) that mixes the refrigerant flowing out from the bypass-side flow rate adjustment section and the refrigerant flowing out from the heating section-side pressure reduction section and causes the refrigerant to flow out to a suction port side of the compressor; a target high-low pressure difference determination unit (S11) for determining a target high-low pressure difference (ΔP) which is a target value of the high-low pressure difference (ΔP) obtained by subtracting a suction refrigerant pressure (Ps) of the suction refrigerant sucked into the compressor from a discharge refrigerant pressure (Pd) of the discharge refrigerant; a bypass-side control unit (60c) that controls the operation of the bypass-side flow rate adjustment unit, the bypass-side control unit controls the operation of the bypass-side flow rate adjustment unit so that the high-low pressure difference (ΔP) approaches the target high-low pressure difference (ΔPO); The bypass side control unit estimates a throttle passage area (Ab) of the bypass side flow rate adjustment unit using the target high-low pressure difference (ΔPO) and controls the operation of the bypass side flow rate adjustment unit by feedforward control.

6. A target temperature determination unit (S3) that determines a target temperature (TAO) of the object to be heated, 6. The heat pump cycle apparatus according to claim 1, wherein the target high-low pressure difference determining unit determines the target high-low pressure difference (ΔPO) so as to increase as the target temperature (TAO) increases.

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