Heat pump cycle device

Abstract

The heat pump cycle device includes a compressor (11), a branch section (12a), a heating section (15), a low-temperature side pressure reducing section (19, 26, 27), a bypass passage (13), a bypass side pressure reducing section (14), a confluence section (12b, 25), a heat absorption section (20), and a control section (70). The control section controls the switching between a first heating mode and a second heating mode. In the first heating mode, all refrigerant discharged from the compressor flows into the heating section through the branch section, absorbing heat from the heat absorption object in the heat absorption section to heat the object. In the second heating mode, a portion of the refrigerant discharged from the compressor flows into the bypass passage through the branch section, guiding the refrigerant flowing out of the bypass side pressure reducing section to the confluence section. When switching from the first heating mode to the second heating mode, the control section performs a limiting action to reduce the heat dissipation in the heating section of the first heating mode. After performing the limiting action, the switching to the second heating mode is completed.

Description

[0001] Cross-reference of related applications

[0002] This application is based on Japanese Patent Application No. 2023-109418, filed on July 3, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a heat pump cycle device. Background Technology

[0004] Previously, technology that applied heat pump circulation devices to vehicle air conditioning systems achieved a heat pump heating mode that uses heat absorbed from an external heat source to heat the object to be heated. Specifically, a vehicle air conditioning system is known to have a heat pump heating mode that uses the supply air to the vehicle cabin as the object to be heated.

[0005] The heating capacity of this heat pump heating mode is affected by the amount of heat absorbed from the heat source. Therefore, it is conceivable that if the amount of heat absorbed from the heat source is relatively low compared to the required heating capacity, the object to be heated may not be sufficiently heated. For example, when using outside air as the heat source, the heating capacity (i.e., heating capacity) cannot be fully utilized in environments with low outside temperatures.

[0006] In heat pump cycle devices, for such situations, the following operating mode is employed: by utilizing a portion of the heat possessed by the high-pressure refrigerant discharged from the compressor to increase the compressor's workload, thereby maximizing the heating capacity of the object being heated. As a technology related to heat pump cycle devices having these two operating modes, the technology described in Patent Document 1 is known.

[0007] The vehicle air conditioning unit of Patent Document 1 is configured to switch between a heat pump heating mode and a hot air heating mode, which is equivalent to a heat pump heating mode. The hot air heating mode is an operating mode in which a portion of the refrigerant discharged from the compressor is bypassed to the low-pressure side, thereby increasing the workload of the compressor itself and utilizing the heating capacity of the object to be heated (i.e., the air supplied).

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent document 1: Japanese Patent Application Publication No. 2021-156567.

[0011] Here, imagine that if we simply switch from a heat pump heating mode to an operating mode that increases the workload of the compressor by utilizing a portion of the heat from the refrigerant discharged from the compressor, thereby increasing the heating capacity, the heating capacity of the object being heated will decrease.

[0012] Taking the heat pump heating mode and hot gas heating mode of Patent Document 1 as examples, in the hot gas heating mode, the heating capacity of the object being heated is determined by the workload of the compressor. The compressor workload is proportional to the refrigerant flow rate in the compressor, and the refrigerant flow rate in the compressor is proportional to the refrigerant's suction density relative to the compressor. Therefore, in order to increase the heating capacity in the hot gas heating mode, it is important to increase the refrigerant's suction density relative to the compressor; in other words, it is necessary to increase the refrigerant's suction pressure in the compressor.

[0013] On the other hand, in heat pump heating mode, the heating capacity of the object being heated corresponds to the amount of heat absorbed in the absorber, and the amount of heat absorbed in the absorber corresponds to the temperature difference between the temperature of the low-pressure refrigerant flowing through the absorber and the temperature of the object being heated. Therefore, in order to increase the heating capacity in heat pump heating mode, the pressure of the low-pressure refrigerant in the absorber needs to be as low as possible relative to a reference temperature established based on the temperature of the object being heated.

[0014] Thus, in hot gas heating mode, the higher the low-pressure in the circulation, the better the heating capacity can be ensured; conversely, in heat pump heating mode, the lower the low-pressure in the circulation, the better the heating capacity can be ensured.

[0015] When switching between heat pump heating mode and gas heating mode, which have opposite characteristics, the heating capacity may vary due to differences in required conditions. For example, when switching from heat pump heating mode to gas heating mode, if the low-pressure state of the circulation is low, the heating capacity may be insufficient relative to the heating capacity required for gas heating, and this will vary with the mode switch. Furthermore, in gas heating mode, which is transitioned to this state, the low-pressure portion needs to be increased, potentially resulting in a period of insufficient heating capacity in order to achieve the same heating capacity as before the switch. Summary of the Invention

[0016] In view of the above problems, the object of this disclosure is to provide a heat pump cycle device that can suppress the variation in heating capacity when switching from a heat pump heating mode to an operating mode that utilizes a portion of the heat of the high-pressure refrigerant discharged from the compressor to exert the heating capacity.

[0017] The heat pump cycle device according to the first aspect of this disclosure includes a compressor, a branch section, a heating section, a low-temperature side pressure reducing section, a bypass passage, a bypass side pressure reducing section, a confluence section, a heat absorption section, and a control section.

[0018] The compressor compresses and discharges the refrigerant. A branch section branches the flow of refrigerant discharged from the compressor. A heating section uses the refrigerant flowing from one outlet of the branch section as a heat source to heat the object being heated. A low-temperature side pressure reducing section depressurizes the refrigerant flowing from the heating section. A bypass passage allows refrigerant flowing from the other branch section to pass through. A bypass side pressure reducing section depressurizes the refrigerant flowing through the bypass passage. A merging section merges the flow of refrigerant flowing from the bypass side pressure reducing section with the flow of refrigerant flowing from the low-temperature side pressure reducing section, and they flow out towards the compressor's suction port. A heat absorption section ensures that the heat possessed by the object being heated is absorbed at least by the refrigerant flowing from the low-temperature side pressure reducing section.

[0019] The control unit controls the switching between a first heating mode and a second heating mode. In the first heating mode, all refrigerant discharged from the compressor flows into the heating section via a branch, absorbing heat from the object being heated in the heat-absorbing section to heat the object. In the second heating mode, a portion of the refrigerant discharged from the compressor flows into a bypass passage via a branch, guiding the refrigerant flowing from the bypass-side pressure reducing section to the confluence section. Simultaneously, in the second heating mode, the remaining portion of the refrigerant discharged from the compressor flows into the heating section via a branch, causing the refrigerant flowing from the heating section to merge with the flow of refrigerant from the bypass-side pressure reducing section at the confluence section and be drawn into the compressor.

[0020] Then, when switching from the first heating mode to the second heating mode, the control unit performs a limiting action, which limits the heat dissipation in the heating unit of the first heating mode to a low level. After the limiting action is performed, the switching to the second heating mode is completed.

[0021] Therefore, according to the heat pump cycle device of the first embodiment, by performing a limiting action when switching from the first heating mode to the second heating mode, the heat dissipation from the refrigerant in the heating unit is suppressed, thereby increasing the heat possessed by the refrigerant before switching to the second heating mode. Thus, the heat pump cycle device of the first embodiment can minimize the difference between the heating capacity in the first heating mode and the heating capacity in the second heating mode, and can suppress fluctuations in heating capacity.

[0022] In addition, the heat pump cycle device involved in the second aspect of this disclosure includes a compressor, a branch section, a heating section, a low-temperature side pressure reducing section, a bypass passage, a bypass side pressure reducing section, a confluence section, a heat absorption section, and a control section.

[0023] The compressor compresses and discharges the refrigerant. A branch section branches the flow of refrigerant discharged from the compressor. A heating section uses the refrigerant flowing from one outlet of the branch section as a heat source to heat the object being heated. A low-temperature side pressure reducing section depressurizes the refrigerant flowing from the heating section. A bypass passage allows refrigerant flowing from the other branch section to pass through. A bypass side pressure reducing section depressurizes the refrigerant flowing through the bypass passage. A merging section merges the flow of refrigerant flowing from the bypass side pressure reducing section with the flow of refrigerant flowing from the low-temperature side pressure reducing section, and they flow out towards the compressor's suction port. A heat absorption section ensures that the heat possessed by the object being heated is absorbed at least by the refrigerant flowing from the low-temperature side pressure reducing section.

[0024] The control unit controls the switching between a first heating mode and a second heating mode. In the first heating mode, all refrigerant discharged from the compressor flows into the heating section via a branch, absorbing heat from the object being heated in the heat-absorbing section to heat the object. In the second heating mode, a portion of the refrigerant discharged from the compressor flows into the bypass passage via a branch, guiding the refrigerant flowing from the bypass-side pressure-reducing section towards the confluence section. Simultaneously, in the second heating mode, the remaining portion of the refrigerant discharged from the compressor flows into the heating section via a branch, causing the refrigerant flowing from the heating section to merge with the flow of refrigerant from the bypass-side pressure-reducing section at the confluence section and be drawn into the compressor.

[0025] Then, when switching from the first heating mode to the second heating mode, the control unit performs a heat absorption assurance operation. This operation utilizes the heat possessed by the refrigerant discharged from the compressor and the heat absorbed by the heat-absorbing part from the heat-absorbing object to ensure the heat absorption in the heat-absorbing part. After performing the heat absorption assurance operation, the control unit completes the switch to the second heating mode.

[0026] Therefore, according to the heat pump cycle device of the second method, by performing a heat absorption assurance operation when switching from the first heating mode to the second heating mode, the heat absorption of the refrigerant is ensured, thereby increasing the heat present in the refrigerant before switching to the second heating mode. Thus, the heat pump cycle device of the second method can minimize the difference between the heating capacity in the first heating mode and the heating capacity in the second heating mode, and can suppress fluctuations in heating capacity.

[0027] Furthermore, the heat pump cycle device according to the third aspect of this disclosure includes a heat pump cycle, a heat medium circuit, and a control unit. The heat pump cycle includes a compressor, a heat medium refrigerant heat exchanger, a pressure reducing unit, and a cooler. The compressor compresses and discharges the refrigerant. The heat medium refrigerant heat exchanger dissipates heat from the high-pressure refrigerant discharged from the compressor to the heat medium. The pressure reducing unit reduces the pressure of the refrigerant flowing out of the heat medium refrigerant heat exchanger. The cooler allows the refrigerant, after being pressure reduced by the pressure reducing unit, to exchange heat with the heat medium, thereby absorbing heat from the refrigerant.

[0028] The heat transfer medium circuit includes a first circuit, a second circuit, a heat transfer medium connecting flow path, and a flow rate regulating unit. The first circuit is configured to allow heat transfer medium flowing from a heat transfer medium refrigerant heat exchanger to circulate, and includes a heat transfer medium radiator that dissipates heat from the heat transfer medium to the object being heated. The second circuit is configured to allow heat transfer medium to circulate in a cooler, and includes a heat transfer medium absorber that absorbs heat from the object being heated through heat exchange with the heat transfer medium. The heat transfer medium connecting flow path connects the first circuit and the second circuit in a manner that allows heat transfer medium to flow in and out. The flow rate regulating unit regulates the flow rate of the heat transfer medium flowing in and out between the first and second circuits via the heat transfer medium connecting flow path.

[0029] The control unit controls the switching between independent circulation heating mode and loop cooperative heating mode. In independent circulation heating mode, heat is absorbed and drawn from the object being heated by a heat transfer medium that circulates independently in the second loop, and then heated via the heat transfer medium that circulates independently in the first loop through a heat transfer medium radiator. In loop cooperative heating mode, a portion of the heat transfer medium flowing in the heat transfer medium refrigerant heat exchanger flows through the heat transfer medium connection path into the cooler, while the remaining portion of the heat transfer medium flowing in the heat transfer medium refrigerant heat exchanger circulates through the heat transfer medium radiator in the first loop and heats the object being heated via the heat transfer medium radiator.

[0030] Then, when switching from independent circulation heating mode to loop cooperative heating mode, the control unit performs a limiting action, which limits the heat dissipation in the heat transfer medium radiator of independent circulation heating mode to a lower level. After the limiting action is performed, the switch to loop cooperative heating mode is completed.

[0031] Therefore, according to the heat pump cycle device of the third embodiment, by performing a limiting action when switching from an independent cycle heating mode to a loop cooperative heating mode, the heat dissipation in the heat transfer medium radiator is suppressed, thereby increasing the heat of the refrigerant just before switching to the loop cooperative heating mode. Thus, the heat pump cycle device of the third embodiment can minimize the difference between the heating capacity in the independent cycle heating mode and the heating capacity in the loop cooperative heating mode, and can suppress fluctuations in heating capacity. Attached Figure Description

[0032] The above-mentioned and other objects, features, and advantages of this disclosure will become more apparent from the accompanying drawings and the following detailed description.

[0033] Figure 1 This is a structural diagram of the heat pump cycle device according to the first embodiment.

[0034] Figure 2 This is a structural diagram of the indoor air conditioning unit involved in the first embodiment.

[0035] Figure 3 This is a block diagram illustrating the control system of the heat pump cycle device according to the first embodiment.

[0036] Figure 4 It is a Morrill diagram of the heat pump heating operation in the heat pump cycle device according to the first embodiment.

[0037] Figure 5 It is a Morrill diagram of the heat pump circulation device according to the first embodiment during hot gas heating operation.

[0038] Figure 6 This is an explanatory diagram illustrating an example of switching control in a heat pump cycle device according to the first embodiment.

[0039] Figure 7 This is a structural diagram of the heat pump cycle device according to the second embodiment.

[0040] Figure 8 This is an explanatory diagram showing the first state in the switching control of the heat pump cycle device according to the second embodiment.

[0041] Figure 9 This is an explanatory diagram showing the second state in the switching control of the heat pump cycle device according to the second embodiment.

[0042] Figure 10 This is a structural diagram of the heat pump cycle device involved in the third embodiment.

[0043] Figure 11 This is an explanatory diagram showing the first state in the switching control of the heat pump cycle device according to the third embodiment.

[0044] Figure 12 This is an explanatory diagram showing the second state in the switching control of the heat pump cycle according to the third embodiment.

[0045] Figure 13 This is a structural diagram of the heat pump cycle device according to the fourth embodiment.

[0046] Figure 14 This is an explanatory diagram of the operation of the heat pump circulation device according to the fourth embodiment during independent circulation heating.

[0047] Figure 15 This is an explanatory diagram of the operation of the heat pump cycle device according to the fourth embodiment during loop cooperative heating operation.

[0048] Figure 16 This is an explanatory diagram illustrating an example of the switching control of the heat pump cycle device according to the fourth embodiment. Detailed Implementation

[0049] Hereinafter, various methods for implementing this disclosure are described with reference to the accompanying drawings. In each embodiment, the same reference numerals are sometimes used to denote parts corresponding to matters described in previous embodiments, and repeated descriptions are omitted. Where only a part of the structure is described in each embodiment, other previously described embodiments can be applied to the other parts of the structure. Not only combinations of specific combinations that are explicitly shown as feasible in each embodiment, but also embodiments can be partially combined with each other, even if not explicitly shown, as long as there are no particular obstacles to the combination.

[0050] (First Implementation)

[0051] Reference Figures 1-6 A first embodiment of the heat pump cycle device of this disclosure will be described. In the first embodiment, the heat pump cycle device of this disclosure is applied to a vehicle air conditioning system 1 installed in an electric vehicle. The electric vehicle is a vehicle that obtains driving force for driving from an electric motor.

[0052] The vehicle air conditioning unit 1 according to the first embodiment includes a heat pump cycle 10, a heat medium circuit 30, an indoor air conditioning unit 60, a control device 70, etc., and performs air conditioning on the vehicle interior, which is the space to be air-conditioned.

[0053] Next, the general structure of the vehicle air conditioning unit 1 according to the first embodiment will be described. First, referring to... Figure 1 The structure of the heat pump cycle 10 in the vehicle air conditioning unit 1 according to the first embodiment will be described.

[0054] The heat pump cycle 10 of the vehicle air conditioning unit 1 according to the first embodiment is a vapor compression refrigeration cycle that adjusts the temperature of the heat medium circulating in the heat medium circuit 30 for the air blown into the vehicle interior.

[0055] The heat pump cycle 10 is configured to switch refrigerant circuits according to various operating modes for vehicle interior air conditioning. In the heat pump cycle 10, an HFO-based refrigerant (specifically R1234yf) is used. The heat pump cycle 10 constitutes a subcritical refrigeration cycle where the pressure of the refrigerant on the high-pressure side does not exceed the critical pressure of the refrigerant.

[0056] The refrigerant contains refrigeration oil used to lubricate the compressor 11. The refrigeration oil is either PAG oil (polyalkylene glycol oil) or POE (polyol ester), which is miscible with the liquid refrigerant. A portion of the refrigeration oil circulates with the refrigerant in the heat pump cycle 10.

[0057] like Figure 1As shown, the heat pump cycle 10 according to the first embodiment includes a compressor 11, a bypass passage 13, a bypass-side expansion valve 14, an indoor condenser 16, a receiver 18, a low-temperature-side expansion valve 19, and a cooler 21.

[0058] In the heat pump cycle 10, the compressor 11 draws in, compresses, and discharges refrigerant. The compressor 11 is an electric compressor with a fixed capacity type, driven by an electric motor to rotate a compressor mechanism with a fixed discharge capacity. The refrigerant discharge capacity (i.e., rotational speed) of the compressor 11 is controlled according to a control signal output from the control device 70.

[0059] The compressor 11 is disposed in a drive unit compartment formed on the front side of the vehicle compartment. The drive unit compartment forms a space for at least a portion of equipment used to generate and adjust the driving force for vehicle travel (such as an electric generator that serves as a motor for travel).

[0060] The discharge port of compressor 11 is connected to the inlet side of branch 12a, which is formed as a three-way connector. Branch 12a has three interconnected inlet and outlet ports. Branch 12a can be a connector formed by joining multiple pipes or a connector formed by providing multiple refrigerant passages in a metal block or resin block.

[0061] Furthermore, the heat pump cycle 10 according to the first embodiment has a confluence section 12b formed in the shape of a three-way connector. The basic structure of the confluence section 12b is the same as that of the branch section 12a, and it has three inflow and outflow outlets that are interconnected.

[0062] That is, when one of the three inlet and outlet ports in the three-way connector is used as an inlet and the remaining two are used as outlets, it functions as a branch section for branching the refrigerant flow. Alternatively, when two of the three inlet and outlet ports are used as inlets and the remaining one is used as an outlet, it functions as a confluence section for merging the refrigerant flow. Branch 12a is a branch section for branching the flow of the discharged refrigerant from the compressor 11.

[0063] One outlet of branch 12a is connected to the inlet side of the indoor condenser 16 that constitutes the heating section 15. The other outlet of branch 12a is connected via bypass passage 13 to the inlet side of one of the inlet sections of confluence 12b, which is formed as a tee joint.

[0064] The bypass passage 13 is a refrigerant passage that directs the flow of refrigerant from the high-pressure refrigerant discharged from the compressor 11, which exits from another outlet in branch 12a, to an inlet in the confluence section 12b. For example... Figure 1 As shown, a bypass-side expansion valve 14 is provided in the bypass passage 13.

[0065] The bypass-side expansion valve 14 is a pressure-reducing section on the bypass passage 13 side. In various operating modes, such as hot gas heating mode, this bypass-side expansion valve 14 reduces the pressure of the high-pressure refrigerant flowing out from the other outlet of the branch 12a (i.e., the discharged refrigerant branching off from the other side of the branch 12a). Alternatively, the bypass-side expansion valve 14 can also be referred to as a bypass-side flow regulating section, adjusting the flow rate (mass flow rate) of the refrigerant flowing through the bypass passage 13.

[0066] The bypass-side expansion valve 14 is an electrically operated variable throttling mechanism having a valve core that changes the throttling opening and an electric actuator (specifically a stepper motor) that drives the valve core to move. The bypass-side expansion valve 14 is controlled by control pulses output from the control device 70.

[0067] The bypass-side expansion valve 14 has a fully open function, which allows it to function as a simple refrigerant passage with almost no refrigerant pressure reduction or flow regulation by making the throttling opening fully open. Additionally, the bypass-side expansion valve 14 has a fully closed function, which blocks the refrigerant passage by making the throttling opening fully closed.

[0068] As described above, one outlet of branch 12a is connected to the interior condenser 16. The interior condenser 16 is a heat exchange section for dissipating heat by exchanging heat between the high-pressure refrigerant discharged from the compressor 11 and the supply air supplied to the vehicle interior. The interior condenser 16 also constitutes a heating section 15, which uses the refrigerant discharged from the compressor 11 as a heat source to heat the supply air.

[0069] The outlet side of the indoor condenser 16 is connected to the receiver 18. The receiver 18 is a gas-liquid separator that separates the refrigerant gas from the condenser (i.e., the indoor condenser 16) in the heat pump cycle 10 and allows the liquid refrigerant to flow downstream, and stores the remaining refrigerant in the cycle.

[0070] The outlet side of receiver 18 is connected to low-temperature side expansion valve 19. Low-temperature side expansion valve 19 is a pressure-reducing section that reduces the pressure of the refrigerant flowing into the refrigerant passage 21a of the cooler 21 constituting the heat-absorbing section 20 when the refrigerant absorbs heat in the heat-absorbing section 20. Alternatively, low-temperature side expansion valve 19 can also be referred to as a flow regulating section on the cooler side that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the cooler 21.

[0071] The cryogenic side expansion valve 19, like the bypass side expansion valve 14, is an electrically operated variable throttling mechanism with a valve core and an electric actuator. The cryogenic side expansion valve 19 is controlled by control pulses output from the control device 70. Furthermore, the cryogenic side expansion valve 19, like the bypass side expansion valve 14, has both fully open and fully closed functions.

[0072] Furthermore, the outlet side of the low-temperature expansion valve 19 is connected to the cooler 21 that constitutes the heat absorption section 20. The heat absorption section 20 is the part that absorbs heat from the low-pressure refrigerant after it has been depressurized by the low-temperature expansion valve 19. In the first embodiment, the heat absorption section 20 is composed of a heat medium circuit 30 and a cooler 21.

[0073] Cooler 21 has a refrigerant passage 21a and a heat medium passage 21b. The refrigerant passage 21a allows low-pressure refrigerant, after being depressurized by the low-temperature side expansion valve 19, to flow through it. The heat medium passage 21b allows heat medium circulating in the heat medium circuit 30 to flow through it. Cooler 21 is a low-temperature side heat medium heat exchange section that allows heat exchange between the low-pressure refrigerant flowing in the refrigerant passage 21a and the heat medium flowing in the heat medium passage 21b. In cooler 21, the heat medium is cooled by absorbing heat through the evaporation of the low-pressure refrigerant.

[0074] like Figure 1 As shown, the outlet side of the refrigerant passage 21a in the cooler 21 is connected to a three-way connector-shaped confluence section 12b. As described above, one inlet of the confluence section 12b is connected to the bypass passage 13 and the bypass-side expansion valve 14. Additionally, the other inlet of the confluence section 12b is connected to the outlet side of the refrigerant passage 21a in the cooler 21.

[0075] Furthermore, the outlet side of the confluence section 12b is connected to the suction side of the compressor 11. Therefore, the confluence section 12b can cause the flow of refrigerant flowing out of the refrigerant passage 21a of the cooler 21 to merge with the flow of refrigerant flowing in the bypass passage 13 and be directed to the suction side of the compressor 11.

[0076] Next, the heat medium circuit 30 of the vehicle air conditioning unit 1 according to the first embodiment will be described with reference to the accompanying drawings. The heat medium circuit 30 is a circuit for circulating the heat supply medium. In this embodiment, an aqueous solution of ethylene glycol is used as the heat medium.

[0077] like Figure 1 As shown, the heat medium circuit 30 in the first embodiment is configured to exchange heat with the low-pressure refrigerant in the cooler 21 and the heat pump cycle 10, and can therefore be called the low-temperature side circuit 31. In the low-temperature side circuit 31, in addition to the heat medium passage 21b of the cooler 21, a low-temperature side pump 32, an outside air heat exchanger 33, a heat medium three-way valve 34, and a bypass connection 35 are also provided.

[0078] The cryogenic side pump 32 is a heat medium pressurization unit that draws in the heat medium flowing out of the heat medium three-way valve 34 and pressurizes it to the external air heat exchanger 33. The cryogenic side pump 32 is an electric water pump whose rotational speed (i.e., pressurization capacity) is controlled by a control voltage output from the control device 70. Therefore, in the first embodiment, the circulation of the heat medium in the cryogenic side circuit 31 can be achieved by driving the cryogenic side pump 32.

[0079] The outlet side of the cryogenic side pump 32 is connected to the outside air heat exchanger 33. The outside air heat exchanger 33 is located outside the vehicle compartment, allowing the heat medium cooled by the cooler 21 and circulating in the cryogenic side circuit 31 to exchange heat with the outdoor air outside the vehicle compartment. The outside air heat exchanger 33 is configured as part of a heat absorption section for allowing the low-pressure refrigerant to absorb heat from the outdoor air via the heat medium.

[0080] The hot medium outlet side of the external air heat exchanger 33 is connected to the hot medium three-way valve 34. The hot medium three-way valve 34 is an electrically operated three-way flow regulating valve with three inlet and outlet ports, and is configured to continuously adjust the passage area ratio of each outlet port. The hot medium three-way valve 34 is controlled by a control signal output from the control device 70.

[0081] As described above, one inlet / outlet of the hot medium three-way valve 34 is connected to the hot medium outlet side of the external air heat exchanger 33, and the other inlet / outlet of the hot medium three-way valve 34 is connected to one side of the inlet / outlet in the hot medium passage 21b of the cooler 21. Furthermore, another inlet / outlet of the hot medium three-way valve 34 is connected to the hot medium bypass passage 36.

[0082] like Figure 1 As shown, the other side of the inflow outlet in the heat medium passage 21b of the cooler 21 is connected to the bypass connection 35. The bypass connection 35 is formed as a three-way connector with three inflow outlets. As described above, one of the inflow outlets of the bypass connection 35 is connected to the other side of the inflow outlet in the heat medium passage 21b of the cooler 21.

[0083] Furthermore, another inlet / outlet in the bypass connection 35 is connected to the hot medium bypass flow path 36, and yet another inlet / outlet in the hot medium bypass flow path 36 is connected to the suction port side of the cryogenic side pump 32.

[0084] Therefore, according to the cryogenic side circuit 31 of the first embodiment, the circulation path of the heat medium via the cooler 21 and the outside air heat exchanger 33 can be switched by controlling the operation of the cryogenic side pump 32 and the heat medium three-way valve 34.

[0085] Next, refer to Figure 2The structure of the interior air conditioning unit 60 constituting the vehicle air conditioning system 1 will be described. The interior air conditioning unit 60 is a unit in the vehicle air conditioning system 1 used to blow the supplied air, after the temperature has been adjusted by the heat pump cycle 10, to appropriate parts of the vehicle interior. The interior air conditioning unit 60 is located inside the instrument panel (instrument panel) at the front of the vehicle interior.

[0086] The indoor air conditioning unit 60 according to the first embodiment is configured such that an indoor air supply fan 62, a cooling core 33a, an indoor condenser 16, etc., are housed in an air passage formed inside an air conditioning housing 61 that forms the outer shell of the indoor air conditioning unit 60. The air conditioning housing 61 forms an air passage for supply air blown into the vehicle interior. The air conditioning housing 61 is molded from a resin (specifically polypropylene) that has a constant degree of elasticity and excellent strength.

[0087] like Figure 2 As shown, an indoor / outdoor air switching device 63 is provided on the upstream side of the air supply airflow of the air conditioning housing 61. The indoor / outdoor air switching device 63 switches the introduction of indoor air (indoor air) and outdoor air (outdoor air) into the air conditioning housing 61.

[0088] The indoor / outdoor air switching device 63 continuously adjusts the opening areas of the indoor air inlet (for introducing indoor air) and the outdoor air inlet (for introducing outdoor air) into the air conditioning housing 61 via an indoor / outdoor air switching door, thereby changing the ratio of indoor air intake to outdoor air intake. The indoor / outdoor air switching door is driven by an electric actuator. This electric actuator is controlled by a control signal output from the control device 70.

[0089] An indoor air supply fan 62 is disposed downstream of the airflow from the indoor / outdoor air switching device 63. The indoor air supply fan 62 is an electric air supply mechanism consisting of a centrifugal multi-bladed fan driven by an electric motor. The indoor air supply fan 62 blows air drawn in via the indoor / outdoor air switching device 63 into the vehicle interior. The indoor air supply fan 62's rotational speed (i.e., airflow capacity) is controlled by a control voltage output from the control device 70. The indoor air supply fan 62 can adjust the airflow volume for temperature regulation purposes, thus functioning as an example of a temperature regulation unit.

[0090] In the first embodiment, on the downstream side of the airflow from the indoor fan 62, the cooling core 33a and the indoor condenser 16 are arranged sequentially relative to the flow of the airflow. The cooling core 33a is a heat exchanger for cooling the airflow by exchanging heat between a medium (e.g., a heat medium, refrigerant, etc.) cooled by a heat source (not shown) and the airflow flowing in the air conditioning housing 61.

[0091] like Figure 2As shown, within the air conditioning housing 61 of the indoor air conditioning unit 60, the cooling core 33a is positioned upstream of the supply airflow compared to the indoor condenser 16. Therefore, in the indoor air conditioning unit 60 of the vehicle air conditioning system 1, at least a portion of the supply air that has passed through the cooling core 33a can be heated by the indoor condenser 16.

[0092] In addition, a cold air bypass passage 65 is formed inside the air conditioner housing 61. The cold air bypass passage 65 is an air passage that allows the supply air that has passed through the cooling core 33a to bypass the indoor condenser 16 and flow downstream.

[0093] An air mixing door 64 is provided downstream of the supply airflow of the cooling core 33a and upstream of the supply airflow of the indoor condenser 16. The air mixing door 64 adjusts the ratio of the airflow through the indoor condenser 16 to the airflow through the cold air bypass passage 65 in the supply air after passing through the cooling core 33a.

[0094] The air mixing door 64 is driven by an electric actuator for driving the air mixing door. The electric actuator is controlled by a control signal output from the control device 70. The air mixing door 64 controls and adjusts the supply amount of air to the indoor condenser 16 and the like, which is the object of temperature adjustment, by its operation, and thus is equivalent to an example of a supply adjustment unit.

[0095] Furthermore, a mixing space is provided downstream of the supply air flow of the indoor condenser 16. In the mixing space, the supply air heated by the indoor condenser 16 is mixed with the supply air that has passed through the cold air bypass passage 65 and has not been heated by the indoor condenser 16.

[0096] Furthermore, at the lowest point of the airflow in the air conditioning housing 61, an opening is provided to blow the mixed airflow (air conditioning air) into the vehicle interior. This opening includes a face opening, a foot opening, and a defrost opening (none shown).

[0097] The face opening is for blowing air conditioning air towards the upper body of the occupants inside the vehicle. The foot opening is for blowing air conditioning air towards the feet of the occupants. The defrost opening is for blowing air conditioning air towards the inside of the window glass on the front surface of the vehicle.

[0098] These face openings, foot openings, and defrost openings are connected to face air vents, foot air vents, and defrost air vents (not shown) located inside the vehicle interior via ducts that form air passages.

[0099] Therefore, the air mixing door 64 adjusts the temperature of the air conditioning air mixed in the mixing space by adjusting the ratio of the air volume passing through the indoor condenser 16 to the air volume passing through the cold air bypass passage 65. As a result, the temperature of the supply air (air conditioning air) blown into the vehicle interior from each outlet is also adjusted.

[0100] Furthermore, a face panel, a foot panel, and a defrost door (not shown) are respectively located upstream of the airflow from the face opening, foot opening, and defrost opening. The face panel adjusts the opening area of ​​the face opening. The foot panel adjusts the opening area of ​​the foot opening. The defrost door adjusts the opening area of ​​the defrost opening.

[0101] These face panels, foot panels, and defrost doors constitute a blowing mode switching device that switches the airflow outlet from which the air is blown out. The face panels, foot panels, and defrost doors are rotated in conjunction with an electric actuator that drives the airflow outlet mode door via a linkage mechanism. The electric actuator is controlled by a control signal output from the control device 70.

[0102] Next, use Figure 3 The general outline of the control system of the vehicle air conditioning unit 1 will be described. The control unit 70 consists of a well-known microcomputer including a CPU, ROM, and RAM, and its peripheral circuitry. The control unit 70 performs various calculations and processes based on the air conditioning control program stored in the ROM, and controls the operation of various controllable devices connected to the output side. The control unit 70 is an example of a control section.

[0103] In the first embodiment, the various controlled devices include a compressor 11, a bypass-side expansion valve 14, a cryogenic-side expansion valve 19, a cryogenic-side pump 32, a heat medium three-way valve 34, an indoor air supply fan 62, an indoor / outdoor air switching device 63, an air mixing door 64, etc.

[0104] Moreover, such as Figure 3 As shown, the input side of the control device 70 is connected to various control sensors. These control sensors include an interior air temperature sensor 72a, an exterior air temperature sensor 72b, and a solar radiation sensor 72c. Additionally, control sensors include a high-pressure sensor 72d, a low-pressure sensor 72e, a first refrigerant temperature sensor 72f, and a second refrigerant temperature sensor 72g. Furthermore, control sensors include a low-temperature side heat transfer medium temperature sensor 73a and an air conditioning fan temperature sensor 73b.

[0105] Furthermore, the interior air temperature sensor 72a is an interior air temperature detection unit that detects the temperature inside the vehicle, i.e., the interior air temperature Tr. The exterior air temperature sensor 72b is an exterior air temperature detection unit that detects the temperature outside the vehicle, i.e., the exterior air temperature Tam. The solar radiation sensor 72c is a solar radiation detection unit that detects the amount of solar radiation As that shines into the vehicle interior.

[0106] High-pressure sensor 72d is a high-pressure detection unit that detects the pressure of the high-pressure refrigerant discharged from compressor 11, i.e., high-pressure pressure Pd. Low-pressure sensor 72e is a low-pressure detection unit that detects the suction pressure (low-pressure pressure Ps) of the suction refrigerant drawn into compressor 11. First refrigerant temperature sensor 72f is a high-pressure side temperature detection unit that detects the temperature of the high-pressure refrigerant in heat pump cycle 10. First refrigerant temperature sensor 72f is, for example, disposed on the outlet side of indoor condenser 16. Second refrigerant temperature sensor 72g is a low-pressure side temperature detection unit that detects the temperature of the low-pressure refrigerant in heat pump cycle 10. Second refrigerant temperature sensor 72g is, for example, disposed on the outlet side of refrigerant passage 21a in cooler 21.

[0107] The low-temperature side heat medium temperature sensor 73a is a temperature detection unit that detects the temperature of the heat medium circulating in the low-temperature side circuit 31 of the heat medium circuit 30. The low-temperature side heat medium temperature sensor 73a is, for example, disposed on the outlet side of the heat medium passage 21b in the cooler 21. Furthermore, the air conditioning air temperature sensor 73b is an air conditioning air temperature detection unit that detects the temperature of the air blown from the mixing space into the vehicle interior (TAV).

[0108] Furthermore, the input side of the control device 70 is connected to the operation panel 71 located near the instrument panel at the front of the vehicle interior. Operation signals from various operation switches provided on the operation panel 71 are input to the control device 70.

[0109] The various operating switches located on the control panel 71 include automatic switches, air conditioning switches, fan speed setting switches, temperature setting switches, etc. The automatic switches are used to set or deactivate the automatic control operation of the heat pump cycle 10.

[0110] The air conditioning switch is an operating switch that requires cooling of the supplied air through the cooling core 33a. The fan speed setting switch is an operating switch operated when manually setting the fan speed of the indoor air supply fan 62. The temperature setting switch is an operating switch for setting the target temperature Tset inside the vehicle.

[0111] Furthermore, the control device 70 of this embodiment is integrally configured as a control unit for controlling various controllable devices connected to its output side. Therefore, the structure (i.e., hardware and software) for controlling the operation of each controllable device constitutes the control unit for controlling the operation of each controllable device.

[0112] For example, the structure in the control device 70 that performs switching control to reduce the difference in heating capacity of the object to be heated (i.e., the supply air) when switching from the heat pump heating mode to the hot gas heating mode (described later) is equivalent to the switching control execution unit 70a.

[0113] Furthermore, the structure in the control device 70 that performs control related to limiting the heat dissipation of the heating unit 15 during the switching control when switching from heat pump heating mode to hot gas heating mode is equivalent to the limiting control unit 70b.

[0114] Furthermore, the structure in the control device 70 that performs a heat absorption assurance operation to ensure the heat absorption in the heat absorption section 20 during the switching control when switching from heat pump heating mode to hot gas heating mode is equivalent to the heat absorption assurance control section 70c.

[0115] Here, the operating modes of the vehicle air conditioning unit 1, which heats the supply air that is the object to be heated, include heat pump heating mode and hot air heating mode. First, refer to Figure 4 The heat pump heating mode of the vehicle air conditioning unit 1 is explained.

[0116] In the heat pump heating mode of the first embodiment, the air supply is heated by drawing heat from the heat source (air outside the vehicle) via the low-temperature side circuit 31 and dissipating it to the air supply air through the indoor condenser 16 constituting the heating unit 15. Therefore, the heat pump heating mode corresponds to heating the air supply air by drawing heat from the heat source, and thus is equivalent to an example of the first heating mode.

[0117] In the heat pump heating mode of the first embodiment, the control device 70 makes the bypass-side expansion valve 14 fully closed and the low-temperature-side expansion valve 19 throttled. Therefore, in the heat pump cycle 10 of the heat pump heating mode, the refrigerant is switched to circulate in the order of compressor 11, branch section 12a, indoor condenser 16, receiver 18, low-temperature-side expansion valve 19, cooler 21, confluence section 12b, and compressor 11.

[0118] Control device 70 controls the refrigerant discharge capacity of compressor 11 so that the high pressure Pd detected by high pressure sensor 72d is close to the target high pressure PDO. Based on the target discharge temperature TAO, the target high pressure PDO is determined with reference to a control mapping pre-stored in control device 70. In the control mapping, it is determined that the target high pressure PDO increases as the target discharge temperature TAO increases.

[0119] In addition, the control device 70 controls the throttling opening of the low-temperature side expansion valve 19 so that the superheat SHC of the refrigerant at the outlet side of the refrigerant passage 21a in the cooler 21 is close to the reference superheat KSH when the refrigerant evaporation temperature in the cooler 21 is lower than the outside temperature Tam.

[0120] For the heat medium circuit 30, the control device 70 determines the pressure delivery capacity of the cryogenic side pump 32 and the ratio of the opening areas of the three inflow and outflow outlets in the heat medium three-way valve 34 to ensure the heat absorption required to achieve the target blow-out temperature.

[0121] Furthermore, for the indoor air conditioning unit 60, the control device 70 determines and controls the air supply capacity of the indoor fan 62, the ratio of indoor and outdoor air in the indoor and outdoor air switching device 63, and the ratio of the air mixing door 64 according to the operating conditions set for the heat pump heating mode.

[0122] Therefore, as Figure 4 As shown in the Morrill diagram, the refrigerant state changes in heat pump cycle 10 during heat pump heating mode. Specifically, the discharged refrigerant from compressor 11... Figure 4 The refrigerant flowing into the indoor condenser 16 via branch 12a (point A1) condenses inside the indoor air conditioning unit 60 by dissipating heat to the supply air, which is the object to be heated. Figure 4 (From point A1 to point A2). Thus, the supply air, which is the object to be heated, is heated, thereby achieving heating inside the vehicle.

[0123] The refrigerant flowing from the indoor condenser 16 flows into the receiver 18 where it undergoes gas-liquid separation. The liquid refrigerant flowing from the receiver 18 flows into the low-temperature side expansion valve 19 where it is depressurized (from...). Figure 4 (Points A2 to A3). The refrigerant, after being depressurized by the low-temperature side expansion valve 19, flows into the cooler 21, which constitutes the heat absorption section 20. The refrigerant flowing into the cooler 21 through the refrigerant passage 21a absorbs heat from the heat medium flowing through the heat medium passage 21b and evaporates (from...). Figure 4 (Points A3 to A4). The refrigerant flowing out of the refrigerant passage 21a of the cooler 21 is drawn into the compressor 11 and compressed again (from... Figure 4 (From point A4 to point A1).

[0124] That is, in the heat pump cycle 10 of the heat pump heating mode, a vapor compression refrigeration cycle is formed in which the indoor condenser 16 functions as a condenser and the cooler 21 functions as an evaporator.

[0125] Next, refer to Figure 5 The hot air heating mode of the vehicle air conditioning unit 1 will be described. In the hot air heating mode according to the first embodiment, a portion of the high-pressure refrigerant discharged from the compressor 11 is introduced to the low-pressure side via the bypass passage 13, thereby increasing the heating capacity of the object to be heated by utilizing the workload of the compressor 11. The hot air heating mode is an example of the second heating mode.

[0126] Then, in the hot gas heating mode, the heating object is heated by the workload of the compressor 11 without using the heat source (i.e., the low temperature side circuit 31 and the outdoor air). Therefore, even if the heat absorption from the heat source cannot be guaranteed, the heating capacity can be improved.

[0127] In the heat pump cycle 10 of the hot gas heating mode according to the first embodiment, the control device 70 throttles the bypass-side expansion valve 14 and the low-temperature-side expansion valve 19. Therefore, in the hot gas heating mode, a portion of the refrigerant discharged from the compressor 11 circulates in the following sequence: compressor 11, branch section 12a, indoor condenser 16, receiver 18, low-temperature-side expansion valve 19, cooler 21, confluence section 12b, and compressor 11. Simultaneously, the remaining portion of the refrigerant discharged from the compressor 11 circulates in the following sequence: compressor 11, branch section 12a, bypass passage 13, bypass-side expansion valve 14, confluence section 12b, and compressor 11. That is, in the hot gas heating mode, a refrigerant circuit is switched to a path where the refrigerant circulates via the indoor condenser 16 and a path where the refrigerant circulates via the bypass passage 13 coexist.

[0128] Here, the control device 70 controls the refrigerant discharge capacity of the compressor 11 so that the refrigerant pressure Pc on the cooler side is close to a preset target low pressure. Controlling the cooler-side refrigerant pressure Pc, which corresponds to the suction refrigerant pressure (low pressure Ps), to be close to a constant pressure is effective in stabilizing the discharge flow rate Gr (mass flow rate) of the compressor 11.

[0129] More specifically, by setting the low-pressure Ps of the saturated gaseous refrigerant to a constant pressure, the density of the drawn-in refrigerant becomes constant. Therefore, if the low-pressure Ps is controlled to a near-constant pressure, it is easy to stabilize the discharge flow rate Gr of the compressor 11 at the same rotational speed.

[0130] Additionally, the control device 70 controls the throttling opening of the bypass-side expansion valve 14 so that the discharge refrigerant pressure (high pressure Pd) is close to the target high pressure PDO. Moreover, the control device 70 controls the throttling opening of the low-temperature-side expansion valve 19 so that the superheat SH of the intake refrigerant is close to the reference superheat KSH.

[0131] Furthermore, in the heat medium circuit 30 of the hot gas heating mode, the control device 70 stops the low-temperature side pump 32. Additionally, in the indoor air conditioning unit 60 of the hot gas heating mode, the control device 70 controls the operation of the indoor fan 62, the indoor / outdoor air switching device 63, and the air mixing door 64. In the hot gas heating mode, the opening of the air mixing door 64 is mostly controlled so that almost all the airflow from the indoor fan 62 passes through the indoor condenser 16.

[0132] Therefore, under the heat pump cycle 10 of the hot gas heating mode according to the first embodiment, the state of the refrigerant is as follows: Figure 5 The changes are as shown in the Moriarty diagram.

[0133] First, the refrigerant discharged from compressor 11 ( Figure 5 The refrigerant flow at point B1 branches at branch 12a. The refrigerant branching off at branch 12a flows into the indoor condenser 16, which constitutes the heating section 15, and dissipates heat to the supply air within the indoor air conditioning unit 60 (from...). Figure 5 (From point B1 to point B2). Thus, the supply air, which is the object to be heated, is heated, enabling heating inside the vehicle.

[0134] The refrigerant flowing from the indoor condenser 16 flows through the receiver 18 into the low-temperature side expansion valve 19 and is depressurized (from... Figure 5 (From point B2 to point B3). The refrigerant, after being depressurized by the low-temperature side expansion valve 19, flows into the cooler 21, which constitutes the heat absorption section 20. In the hot gas heating mode, the low-temperature side pump 32 stops, so there is no heat exchange between the refrigerant and the heat medium of the low-temperature side circuit 31 in the cooler 21. The refrigerant flowing out of the cooler 21 flows into another inlet in the confluence section 12b.

[0135] Additionally, the refrigerant branching off from branch 12a flows into bypass passage 13. The refrigerant flowing into bypass passage 13 is depressurized by bypass-side expansion valve 14 (from...). Figure 5 Points B1 to B5). The refrigerant, after being depressurized by the bypass-side expansion valve 14, flows into one inlet of the confluence section 12b. The refrigerant flowing out of the cooler 21 mixes with the refrigerant flowing out of the bypass-side expansion valve 14 at the three-way connector-shaped confluence section 12b. Figure 5 (Point B5), and is sucked into compressor 11.

[0136] In the heat pump cycle 10 of the hot gas heating mode, the refrigerant with lower enthalpy flowing out from the cooler 21 ( Figure 5 Point B3), and the refrigerant with higher enthalpy flowing out from bypass passage 13 ( Figure 5 At point B4, refrigerants are mixed at the confluence section 12b. That is, in the heat pump cycle 10 of the hot gas heating mode, refrigerants with different enthalpies are mixed together and drawn into the compressor 11.

[0137] Here, the hot air heating mode is an operating mode performed when the heat absorption in the heat absorption section 20 is low, such as when the outside temperature Tam is extremely low. Therefore, when the refrigerant flowing from the indoor condenser 16 circulates on the heat absorption section 20 side, the heat possessed by the refrigerant may be dissipated to the outside. Moreover, if the heat possessed by the refrigerant is dissipated to the outside, the amount of heat dissipated by the refrigerant to the supply air in the indoor condenser 16 is reduced, and the heating capacity of the supply air is reduced.

[0138] In contrast, in the hot gas heating mode of this embodiment, the circulation of the heat medium that will be the object of heat exchange for the refrigerant flowing out from the bypass passage 13 stops, so that the heat of the refrigerant discharged from the compressor 11 can be maintained as much as possible.

[0139] Furthermore, in hot gas heating mode, the throttling opening of the low-temperature side expansion valve 19 is controlled so that the superheat SH of the drawn refrigerant is close to the reference superheat KSH. Therefore, by increasing the refrigerant discharge capacity of the compressor 11, even if the heat dissipation from the discharged refrigerant to the supply air in the indoor condenser 16 is increased, the drawn refrigerant ( Figure 5 The state of point B5) becomes a superheated gaseous refrigerant.

[0140] Therefore, in hot air heating mode, even if the heat absorbed from the heat source is small, the heat generated by the operation of the compressor 11 can be effectively used to heat the air supply, thus achieving heating in the vehicle interior.

[0141] Here, in the heat pump heating mode of the vehicle air conditioning unit 1, as described above, heat absorbed in the heat absorption section 20 is used to heat the object to be heated (the supply air) in the heating section 15. Therefore, the heating capacity in the heat pump heating mode is strongly correlated with the amount of heat absorbed in the heat absorption section 20; the more heat absorbed, the greater the heating capacity.

[0142] The amount of heat absorbed in the heat-absorbing section 20 is affected by the temperature of the object to be absorbed and the temperature or pressure of the low-pressure refrigerant in the heat pump cycle 10. That is, in order to fully ensure the amount of heat absorbed in the heat-absorbing section 20, the temperature of the low-pressure refrigerant in the heat pump cycle 10 needs to be adjusted to a lower temperature than the object to be absorbed in the heat-absorbing section 20 (e.g., heat medium, air).

[0143] Furthermore, the heating capacity in heat pump heating mode is strongly affected by the amount of heat absorbed in the heat absorption section 20. Therefore, depending on the state of the heat absorption section 20, it is possible to anticipate situations where the required heating capacity cannot be achieved for the object being heated. For example, in the heat absorption section 20, when the air temperature is too low in the case of a structure that absorbs heat from the air, sufficient heat absorption may not be ensured, resulting in insufficient heating capacity in heat pump heating mode.

[0144] In this regard, in hot gas heating mode, the heating capacity is determined by the workload of the compressor 11. Therefore, the heating capacity of the object being heated can be increased without being affected by the amount of heat absorbed in the heat absorption section 20. Here, the workload of the compressor 11 is proportional to the flow rate of the refrigerant flowing through the compressor 11, and the flow rate of the refrigerant flowing through the compressor 11 is proportional to the density of the refrigerant drawn into the compressor 11 (drawing density).

[0145] Therefore, in order to increase the heating capacity of the object being heated in the hot gas heating mode, it is necessary to increase the intake density of the refrigerant in the compressor 11; in other words, it is necessary to increase the intake pressure of the refrigerant in the compressor 11.

[0146] Thus, for the heating capacity of the object being heated in heat pump heating mode, the lower the low-pressure refrigerant in heat pump cycle 10, the greater the heating capacity can be ensured. On the other hand, for the heating capacity of the object being heated in hot gas heating mode, the higher the low-pressure refrigerant in heat pump cycle 10, the greater the heating capacity can be ensured.

[0147] That is, the relationship between the heating capacity of the object being heated and the low-pressure refrigerant in the heat pump cycle 10 has opposite characteristics between the heat pump heating mode and the hot gas heating mode.

[0148] Therefore, when switching from heat pump heating mode to hot gas heating mode, the change in heating capacity is considered due to the opposite relationship between the heating capacity of the object being heated and the low-pressure of the refrigerant in the heat pump cycle 10.

[0149] To elaborate further, when switching from heat pump heating mode to hot gas heating mode, in order to further enhance the heating capacity in heat pump heating mode, it is advisable to reduce the low-pressure refrigerant in heat pump cycle 10.

[0150] When switching from the low-pressure state of the refrigerant in the heat pump cycle 10 to the hot-gas heating mode, the workload of the compressor 11 decreases because the refrigerant suction density in the compressor 11 is low. That is, when switching to the hot-gas heating mode under low pressure, the required heating capacity in the hot-gas heating mode cannot be guaranteed, and the same heating capacity as the heat pump heating mode before the switch cannot be guaranteed. Therefore, because the heating capacity of the supplied air is reduced, the temperature of the air conditioning air supplied to the vehicle interior is expected to decrease, resulting in a decline in the comfort of the occupants inside the vehicle.

[0151] Subsequently, when switching to hot gas heating mode, the low-pressure refrigerant in heat pump cycle 10 is increased to ensure the required heating capacity. By increasing the low-pressure refrigerant in heat pump cycle 10, the heating capacity of the object being heated can be increased, and the temperature of the air blown out by the air conditioner can be raised to the state before the switch.

[0152] However, during the period from the moment of switching from heat pump heating mode to hot gas heating mode until the heating capacity rises to the state before switching to hot gas heating mode, time is required for the low-pressure in heat pump cycle 10 to rise. As a result, with the switching of operating modes, the temperature of the air conditioning air supplied to the vehicle interior changes, creating a period that reduces the comfort of the occupants.

[0153] The vehicle air conditioning unit 1 according to the first embodiment performs switching control to suppress changes in the heating capacity of the object to be heated due to the difference in operating mode when switching from heat pump heating mode to hot gas heating mode.

[0154] As mentioned above, the heating capacity in both heat pump heating mode and hot gas heating mode is affected by the low pressure of the refrigerant in heat pump cycle 10. In order to suppress the fluctuation of heating capacity during mode switching and make it a shorter-term fluctuation, it is desirable to quickly move from the low pressure state required by heat pump heating mode to the high pressure state required by hot gas heating mode.

[0155] In order to increase the low-pressure of the refrigerant in the heat pump cycle 10, it is necessary to increase the heat possessed by the refrigerant. Therefore, as an action in the switching control for increasing the low-pressure of the heat pump cycle 10 to suppress fluctuations in heating capacity, an action to suppress the heat dissipation on the high-pressure side of the heat pump cycle 10 is considered.

[0156] Therefore, by suppressing the heat dissipation on the high-pressure side of the heat pump cycle 10, it achieves a state with the heat characteristic of the refrigerant discharged from the compressor 11, thus enabling the low-pressure side of the heat pump cycle 10 to rise. This allows the low-pressure side of the heat pump cycle 10 to rise rapidly to the desired state, quickly eliminating fluctuations in heating capacity associated with operating mode switching. Hereinafter, the action of suppressing the heat dissipation on the high-pressure side of the heat pump cycle 10 during operating mode switching control will be referred to as the limiting action.

[0157] In addition, as an action in the switching control used to suppress the variation in heating capacity by increasing the low-pressure side of the heat pump cycle 10, an action that can maintain the heat absorption on the low-pressure side of the heat pump cycle 10 as much as possible is considered.

[0158] As described above, in the heat pump heating mode before switching, heat absorption occurs in the heat absorption section 20 on the low-pressure side of the heat pump cycle 10 via the heat medium circuit 30. The heat absorbed in the heat absorption section 20 then constitutes the heat of the refrigerant flowing on the low-pressure side. In this state, for example, if the low-temperature side pump 32 is stopped and heat absorption in the heat absorption section 20 stops, the heat supplied from the heat absorption section 20 to the refrigerant on the low-pressure side immediately disappears, thus assuming a temporary drop in the low-pressure area of ​​the heat pump cycle 10.

[0159] With this in mind, when switching from heat pump heating mode to hot gas heating mode, heat absorption in the heat absorption section 20 continues from the heat pump heating mode. However, during the switching control when changing operating modes, the decrease in low-pressure of the heat pump cycle 10 is suppressed within a range that can maintain the amount of heat absorbed in the heat absorption section 20. Hereinafter, the operation used to maintain the amount of heat absorbed on the low-pressure side of the heat pump cycle 10 as much as possible during the switching control of operating modes will be referred to as the heat absorption assurance operation.

[0160] Next, refer to Figure 6 The switching control when switching from heat pump heating mode to hot gas heating mode in the vehicle air conditioning unit 1 according to the first embodiment is described in detail, including the operation of each structure.

[0161] exist Figure 6 In the example shown, the vehicle air conditioning unit 1 operates in heat pump heating mode from time ta. As described above, in the vehicle air conditioning unit 1 operating in heat pump heating mode, the operation control of the compressor 11, bypass side expansion valve 14, low temperature side expansion valve 19, low temperature side pump 32, indoor fan 62, air mixing door 64, etc. is performed by the control device 70.

[0162] As described above, in heat pump heating mode, the throttling opening of the bypass-side expansion valve 14 is controlled to be fully closed. Furthermore, the compressor speed 11, the throttling opening of the low-temperature side expansion valve 19, the pressure delivery capacity of the low-temperature side pump 32, the air delivery capacity of the indoor fan 62, and the opening of the air mixing door 64 are controlled as conditions set for the aforementioned heat pump heating mode.

[0163] Here, at time tb, the switching of the operating mode from heat pump heating mode to hot air heating mode is determined, and the switching control in the vehicle air conditioning unit 1 begins. For example, a starting condition for the switching control could be that the heat absorbed from the heat absorption unit 20 is insufficient relative to the required heating capacity, making it impossible to meet the required heating capacity in heat pump heating mode. The relationship between the required heating capacity and the heat absorbed is determined based on the relationship between the target blowing temperature of the air conditioning air and the temperature of the object (air) in the heat absorption unit 20.

[0164] Furthermore, the start conditions for switching control are not limited to the examples described above. For instance, the switch from heat pump heating mode to hot gas heating mode can also be determined based on the operation of the occupants using the control panel 71.

[0165] When the switching control from heat pump heating mode to hot gas heating mode begins at time tb, the operating mode of the compressor 11 speed, the throttling opening of the low-temperature side expansion valve 19, the pressure delivery capacity of the low-temperature side pump 32, the air delivery capacity of the indoor fan 62, and the opening mode of the air mixing door 64 are controlled.

[0166] The speed of compressor 11 is adjusted from the speed in heat pump heating mode to the speed set in the switching control. The throttling opening of low-temperature side expansion valve 19 is switched from the throttling opening variation method in heat pump heating mode to the method of maintaining the throttling opening set in the switching control.

[0167] Furthermore, the throttling opening of the bypass side expansion valve 14 is controlled from the fully closed state of the heat pump heating mode (i.e., throttling opening = 0) to maintain the specified throttling opening set in the switching control.

[0168] Thus, in the heat pump cycle 10 during control switching, a portion of the refrigerant circulates in the order of compressor 11, branch section 12a, indoor condenser 16, receiver 18, low-temperature side expansion valve 19, cooler 21, and confluence section 12b. Simultaneously, the remaining portion of the refrigerant discharged from compressor 11 circulates in the order of compressor 11, branch section 12a, bypass passage 13, bypass side expansion valve 14, confluence section 12b, and compressor 11.

[0169] That is, in the switching control, the refrigerant circuit is switched to a coexistence of the refrigerant circulation path via the indoor condenser 16 and the refrigerant circulation path via the bypass passage 13. At this time, in the heat pump cycle 10 in the switching control, the indoor condenser 16 functions as a radiator and the cooler 21 functions as a heat absorber.

[0170] The pressure delivery rate (i.e., the discharge rate of the heat medium) of the low-temperature side pump 32 is controlled during switching control to maintain the pressure delivery rate required for heat pump heating mode. Therefore, during switching control, the heat absorption of the low-pressure refrigerant by the heat pump cycle 10 is maintained at the same level as in heat pump heating mode. Maintaining the pressure delivery rate of the low-temperature side pump 32 during switching control is equivalent to an example of ensuring heat absorption during switching control.

[0171] Furthermore, the air volume of the indoor fan 62 is controlled to a preset air volume for the switching control, and operates to maintain the air volume at a specified value during the switching control. The air volume of the indoor fan 62 during the switching control is set lower than the air volume in the heat pump heating mode; therefore, after time tb, the air volume of the indoor fan 62 is controlled to gradually decrease towards the specified value at the time of the switching control.

[0172] That is, in the switching control, the amount of heated object (supply air) supplied to the indoor condenser 16 constituting the heating unit 15 is limited by the operation control of the indoor fan 62. Therefore, in the switching control, the limiting action of restricting the air supply capacity of the indoor fan 62 to a level lower than the air supply capacity in the heat pump heating mode is equivalent to an example of the limiting action in the switching control.

[0173] Furthermore, the opening degree of the air mixing door 64 is controlled to a predetermined value, which is set to make the opening degree of the cold air bypass passage 65 larger than that in the heat pump heating mode. That is, during the switching operation, the air mixing door 64 is controlled to allow most of the supply air that has passed through the cooling core 33a to bypass the indoor condenser 16.

[0174] Here, when the supply of heated object (supply air) to the indoor condenser 16 is limited to a level lower than that in heat pump heating mode, the heat dissipation from the high-pressure refrigerant of the heat pump cycle 10 in the heating section 15 is also reduced compared to heat pump heating mode. Therefore, in the switching control, adjusting the opening of the air mixing door 64 is equivalent to an example of a limiting action in the switching control.

[0175] In this way, when the switching control of various structures is performed after time tb, the high-pressure refrigerant in heat pump cycle 10 decreases. Figure 6 In this context, the completion time of various actions in the switching control is represented as time tc.

[0176] During the switching control period after time tc, the aforementioned limiting action and heat absorption assurance action also continue. The state in which the limiting action and heat absorption assurance action are performed simultaneously during the switching control is called the first state of the switching control.

[0177] Then, since the heat dissipation from the high-pressure side of the refrigerant in the heat pump cycle 10 is limited by the limiting action, the value of the high-pressure refrigerant increases as time passes from the start of the limiting action. That is, the heating capacity of the heat pump cycle 10 can be improved by utilizing the limiting action in the switching control.

[0178] Furthermore, because the heat absorption in the heat absorption section 20 is ensured to be at the same level as the heat pump heating operation on the low-pressure side of the heat pump cycle 10 through the heat absorption assurance operation, the low-pressure of the refrigerant gradually increases as time passes from the start of the heat absorption assurance operation. Similarly, the temperature of the low-pressure refrigerant flowing in the heat absorption section 20 (i.e., the temperature of the low-pressure refrigerant flowing out of the refrigerant passage 21a of the cooler 21) also increases as time passes from time tc. That is, by switching the heat absorption assurance operation in the control, the density of the refrigerant drawn into the compressor 11 gradually increases, thereby increasing the workload of the compressor 11.

[0179] Furthermore, the speed of compressor 11, the throttling opening of cryogenic side expansion valve 19, the throttling opening of bypass side expansion valve 14, and the pressure delivery of cryogenic side pump 32 are controlled to maintain the specified values ​​set for the switching control.

[0180] As a switching control, when the limiting action and heat absorption assurance action continue from time tc, the refrigerant temperature in the refrigerant passage 21a of the cooler 21 reaches a preset reference cooler-side temperature KTc. The reference cooler-side temperature KTc is set based on the temperature of the heat medium flowing in the heat medium passage 21b of the cooler 21, indicating that the heat absorbed in the cooler 21 is less than a preset amount. The refrigerant temperature in the refrigerant passage 21a of the cooler 21 exceeding the preset reference cooler-side temperature KTc is an example of a heat absorption stop condition.

[0181] The moment when the temperature of the low-pressure refrigerant in the refrigerant passage 21a of the cooler 21 becomes the reference cooler-side temperature KTc and the heat absorption cessation condition is met is called time td. Since the moment when time td is the moment when the heat absorption in the heat absorption section 20 can no longer be sufficiently guaranteed, it can be said to be a state in which even if the heat absorption guarantee operation is performed, it is difficult to use heat absorption to make the low-pressure refrigerant rise.

[0182] Therefore, after time td has elapsed, the operation of the cryogenic side pump 32 is stopped, and the pressure delivery of the heat medium in the cryogenic side pump 32 is reduced to 0. As a result, the heat absorbed in the cooler 21 constituting the heat absorption section 20 becomes sufficiently small, thus ensuring the completion of the operation by switching the heat absorption in the control.

[0183] In addition, Figure 6 In the example shown, the heat absorption assurance operation is terminated by stopping the operation of the cryogenic side pump 32, but this method is not limited to it. For example, as an example of stopping the heat absorption assurance operation by reducing the supply of heat medium to the cooler 21, the circulation path of the heat medium in the cryogenic side circuit 31 can also be switched to a path that does not pass through the heat medium passage 21b of the cooler 21. By using the operation control of the heat medium three-way valve 34 to switch the circulation path of the heat medium as described above, the same effect as stopping the operation of the cryogenic side pump 32 can be achieved.

[0184] By stopping the heat absorption protection action at the moment when the heat absorption stop condition is met, the waste of energy required for the heat absorption protection action can be suppressed, thus achieving highly energy-efficient switching control.

[0185] Even after the heat absorption assurance operation has ended, the refrigerant circulation and limiting operations in the heat pump cycle 10 under switching control continue. This state is referred to as the second state of switching control. Because the limiting operations continue to be performed in the second state of switching control, the high-pressure, low-pressure, and low-pressure side refrigerant temperatures in the heat pump cycle 10 also increase over time, including time td and after the heat absorption assurance operation has ended.

[0186] As described above, the switching control is executed to suppress changes in heating capacity when switching from heat pump heating mode to hot gas heating mode. As one way to suppress changes in heating capacity, in the second state of the switching control, it is determined whether the high pressure of the refrigerant in the heat pump cycle 10 has risen to the same level as the heating capacity in the hot gas heating mode.

[0187] Specifically, it determines whether the high-pressure refrigerant in the switching-controlled heat pump cycle 10 is higher than the preset reference high-pressure pressure KPd. When the high-pressure refrigerant in the switching-controlled heat pump cycle 10 is higher than the reference high-pressure pressure KPd, it can exert the same heating capacity as the heat pump heating in hot gas heating mode, thus suppressing fluctuations in heating capacity.

[0188] As another method to suppress changes in heating capacity when switching to hot gas heating mode, consider increasing the workload of compressor 11 to a state equivalent to the heating capacity in hot gas heating mode during the second state of switching control. That is, during the second state of switching control, determine whether the low-pressure refrigerant of heat pump cycle 10 is higher than the reference low-pressure KPs.

[0189] The reference low-pressure KPs represents the low-pressure refrigerant in the heat pump cycle 10 and is set to ensure that the workload of the compressor 11 in the hot gas heating mode is equal to the heating capacity in the heat pump heating mode. Even when the low-pressure in the heat pump cycle 10 under switching control is higher than the reference low-pressure KPs, the heating capacity in the hot gas heating mode is equal to that in the heat pump heating mode, thus suppressing fluctuations in heating capacity.

[0190] like Figure 6 As shown, when the system transitions to the second state of switching control after time td, the high-pressure and low-pressure in heat pump cycle 10 gradually increase. The moment when either the high-pressure of heat pump cycle 10 reaches or exceeds the reference high-pressure KPd, or the moment when the low-pressure of heat pump cycle 10 reaches or exceeds the reference low-pressure KPs, is taken as time te.

[0191] In addition, Figure 6 The example shown illustrates a scenario where the high-pressure of heat pump cycle 10 reaches or exceeds the reference high-pressure pressure KPd and the low-pressure of heat pump cycle 10 reaches or exceeds the reference low-pressure pressure KPs simultaneously. However... Figure 6 The example is just one instance; the moment when the first of the two conditions is met can also be taken as time te. Furthermore, considering the reliable suppression of variations in heating capacity, the moment when both the high-pressure side condition and the low-pressure side condition are met can also be taken as time te.

[0192] When the time *te* required to satisfy either the high-pressure side or low-pressure side condition of the refrigerant in heat pump cycle 10 is elapsed, the switching control ends and the system switches to hot gas heating mode. By using the satisfaction of the high-pressure side condition of the refrigerant as a condition, the limiting action ends and the system switches to hot gas heating mode. Thus, the hot gas heating mode begins when the heating capacity of heat pump cycle 10 reaches a preset level (i.e., the level before switching control). Therefore, the execution of hot gas heating mode can begin while suppressing fluctuations in the heating capacity of the supply air, the object to be heated.

[0193] Furthermore, by satisfying the low-pressure side condition of the refrigerant, the limiting operation ends and the system switches to hot gas heating mode. Thus, the hot gas heating mode begins when the workload of compressor 11 reaches a preset level (i.e., the level before the control switch). In this case, the execution of the hot gas heating mode can also begin when the variation in the heating capacity of the supply air to be heated is suppressed.

[0194] Furthermore, in the hot gas heating mode, as described above, the operation control of the compressor 11, bypass side expansion valve 14, low temperature side expansion valve 19, low temperature side pump 32, indoor fan 62, air mixing door 64, etc. is performed by the control device 70.

[0195] Specifically, in hot gas heating mode, the throttling openings of the bypass-side expansion valve 14 and the low-temperature-side expansion valve 19 are controlled to the throttling openings set for the hot gas heating mode. Furthermore, the compressor speed 11, the air delivery capacity of the indoor fan 62, and the opening of the air mixing door 64 are controlled to meet the conditions set for the aforementioned hot gas heating mode. Moreover, when the switching control subsequently switches to hot gas heating mode, the pressure delivery rate of the low-temperature-side pump 32 remains at the state it stopped when transitioning from the second state of the switching control, and is therefore represented as 0.

[0196] In this way, when switching from heat pump heating mode to hot gas heating mode in the vehicle air conditioning unit 1, a limiting action is performed by switching control, enabling the hot gas heating mode to be started while sufficiently improving the heating capacity of the heat pump cycle 10. Thus, the switching of operating modes can be achieved while suppressing the difference in heating capacity caused by the structure of the refrigerant circuit between the heat pump heating mode and the hot gas heating mode.

[0197] like Figure 6 As shown, as a limiting action of the switching control, the operation of the indoor fan 62 is controlled to limit the supply of air to the indoor condenser 16 constituting the heating unit 15. By limiting the supply air volume generated by the indoor fan 62, the heat dissipation on the high-pressure side of the heat pump cycle 10 can be limited, thereby improving the heating capacity of the high-pressure side of the heat pump cycle 10.

[0198] Furthermore, as a limiting action for switching control, the opening degree of the air mixing door 64 is controlled to limit the supply of air to the indoor condenser 16 constituting the heating unit 15. Based on the operation of the air mixing door 64, the supply of air to the indoor condenser 16 can be limited from the perspective of the airflow path of the air to be heated. Therefore, the limiting action involved in the operation of the air mixing door 64 ensures sufficient heating capacity of the heat pump cycle 10 before switching to the hot gas heating mode.

[0199] like Figure 6 As shown, in the switching control, both the limiting action and the heat absorption assurance action are performed simultaneously. That is, by simultaneously performing the limiting action and the heat absorption assurance action, both the viewpoint of utilizing the heating capacity of the high-pressure side of the heat pump cycle 10 and the viewpoint of utilizing the workload of the compressor 11 on the low-pressure side of the heat pump cycle 10 can be considered. As a result, when switching from heat pump heating mode to hot gas heating mode, the period of change in the heating capacity of the object being heated can be further shortened, and the change can be suppressed to a smaller extent.

[0200] Furthermore, in the switching control of the first embodiment, similar to heat pump heating, the heat absorption assurance operation is performed simultaneously with the operation of the cooler 21 absorbing heat from the heat medium relative to the low-pressure refrigerant, so that a portion of the discharged refrigerant from the compressor 11 circulates through the bypass passage 13. This allows for an increase in the low-pressure of the heat pump cycle 10, an increase in the workload of the compressor 11, and a loop structure that facilitates easy transition to hot gas heating mode.

[0201] like Figure 6 As shown in time td, the heat absorption assurance action in the switching control ends when the heat absorption stop condition is met and the heat absorption becomes less than a preset reference hour. That is, in the switching control, the heat absorption assurance action can be executed efficiently to suppress fluctuations in heating capacity.

[0202] In addition, such as Figure 6 As shown, when performing the heat absorption assurance operation, the operation of the cryogenic side pump 32 is stopped when the heat absorption stop condition is met, reducing the supply of heat medium to the cooler 21 of the heat absorption section 20 to 0. This allows for a reduction in the amount of heat absorbed via the heat medium in the heat absorption section 20 through simple operation control.

[0203] As explained above, in the vehicle air conditioning unit 1 according to the first embodiment, during the switching control when switching from heat pump heating mode to hot gas heating mode, a limiting action is performed to restrict the heat dissipation of the indoor condenser 16 constituting the heating unit 15. By performing the limiting action in the switching control, the heating capacity of the high-pressure side of the heat pump cycle 10 can be sufficiently improved, and the variation in heating capacity between the heat pump heating mode and the hot gas heating mode can be minimized.

[0204] like Figure 6 As shown, as a limiting action of the switching control, the operation of the indoor fan 62 is controlled to limit the supply of air to the indoor condenser 16 constituting the heating unit 15. By limiting the supply air volume generated by the indoor fan 62, the heat dissipation on the high-pressure side of the heat pump cycle 10 can be limited, thereby improving the heating capacity of the high-pressure side of the heat pump cycle 10.

[0205] Furthermore, as a limiting action in the switching control, the opening degree of the air mixing door 64 is controlled to limit the supply of air to the indoor condenser 16 constituting the heating unit 15. Based on the operation of the air mixing door 64, the supply of air to the indoor condenser 16 can be limited from the perspective of the airflow path of the air to be heated. Therefore, the limiting action involved in controlling the operation of the air mixing door 64 ensures sufficient heating capacity of the heat pump cycle 10 before switching to the hot gas heating mode.

[0206] like Figure 6 As shown in the time interval tc to te, the limiting action in the switching control releases the heat dissipation limitation when the high pressure of heat pump cycle 10 is above the reference high pressure KPd. The state where the high pressure is above the reference high pressure indicates that the heating capacity of heat pump cycle 10 has increased to a preset reference state. Therefore, from the viewpoint of the heating capacity of heat pump cycle 10, the limiting action can end and the system can transition to hot gas heating mode while suppressing fluctuations in heating capacity.

[0207] Furthermore, the limiting action in the switching control releases the heat dissipation limitation when the low-pressure pressure of the heat pump cycle 10 is above the reference low-pressure pressure KPs. The state where the low-pressure pressure is above the reference high-pressure pressure indicates that the workload of the compressor 11 has increased to a preset reference level. Therefore, from the viewpoint of the workload of the compressor 11, the limiting action can be terminated and the system can transition to hot gas heating mode while suppressing fluctuations in heating capacity.

[0208] like Figure 6 As shown, in the switching control involved in switching from heat pump heating mode to hot gas heating mode, the transition to hot gas heating mode is performed after simultaneously executing a limiting action and a heat absorption assurance action. This allows for increasing the heating capacity of the heat pump cycle 10 through the limiting action while simultaneously increasing the workload of the compressor 11 through the heat absorption assurance action. Therefore, by simultaneously executing the limiting action and the heat absorption assurance action, the required switching control period can be shortened, and fluctuations in heating capacity can be suppressed in a short time.

[0209] Furthermore, during the switching control when switching from heat pump heating mode to hot gas heating mode, an action is performed to ensure that the heat absorbed in the heat absorption section 20 is at the same level as the switching process. By performing the heat absorption assurance action during the switching control, the density of the refrigerant drawn into the compressor 11 can be increased, the workload of the compressor 11 can be sufficiently increased, and the variation in heating capacity between heat pump heating mode and hot gas heating mode can be minimized.

[0210] Furthermore, as described above, in the heat pump cycle 10 with the heat absorption assurance operation performed, a portion of the refrigerant discharged from the compressor 11 circulates via the cooler 21. Simultaneously, the remaining portion of the refrigerant discharged from the compressor 11 circulates via the bypass passage 13. In the heat absorption assurance operation during switching control, the operation is performed with two refrigerant circulation paths existing concurrently, similar to the hot gas heating mode. Therefore, a simple operation can be performed in a short time to switch from switching control to hot gas heating mode.

[0211] like Figure 6 As shown at time td, the heat absorption assurance operation in the switching control ends heat absorption in the heat absorption section 20 when the heat absorption stop condition is met. The heat absorption stop condition indicates a situation where the heat absorption of the heat absorption section 20 decreases, and there is no need to continue the heat absorption assurance operation. That is, by ending the heat absorption assurance operation when the heat absorption stop condition is met, the vehicle air conditioning unit 1 can efficiently perform switching control to switch to the hot air heating mode in a way that suppresses fluctuations in heating capacity.

[0212] Furthermore, when the heat absorption is stopped and the heat absorption in the heat absorption section 20 is suppressed, the pressure delivery rate of the cryogenic side pump 32 is reduced to 0. That is, heat absorption is suppressed by reducing the supply of the heat medium constituting the heat absorption object to the cooler 21 constituting the heat absorption section 20. By adopting this structure, heat absorption in the heat absorption section 20 can be suppressed by simple control.

[0213] (Second Implementation)

[0214] Next, refer to Figures 7-9 The second embodiment, which differs from the embodiment described above, will now be described. The heat pump circulation device in the second embodiment is applied to a vehicle air conditioning unit 1 mounted on an electric vehicle, just as in the first embodiment. However, in the vehicle air conditioning unit 1 according to the second embodiment, the structure of the heat-absorbing part 20 is changed from that in the first embodiment, and the heat-absorbing part 20 is configured as a heating device for a vehicle.

[0215] The other structures (heat pump cycle 10, indoor air conditioning unit 60, etc.) in the vehicle air conditioning device 1 involved in the second embodiment are the same as those in the above embodiment, so they will not be described again.

[0216] like Figure 7 As shown, unlike the first embodiment, the heat absorption section 20 of the vehicle air conditioning unit 1 in the second embodiment is composed of an outside air heat absorber 22. Furthermore, unlike the first embodiment, the components related to the heat medium circuit 30 and the heat medium circuit 30 are omitted in the second embodiment. Specifically, a low-temperature side pump 32, an outside air heat exchanger 33, and a heat medium three-way valve 34, etc., are provided in the low-temperature side circuit 31 of the heat medium circuit 30.

[0217] Furthermore, apart from the different structure of the heat absorption section 20, the heat pump cycle 10 involved in the second embodiment has the same structure as that in the first embodiment described above. The outside air heat absorber 22 is similarly disposed between the outlet side of the low-temperature side expansion valve 19 and the confluence section 12b, just like the cooler 21 in the first embodiment. The outside air heat absorber 22 is a heat absorber that exchanges heat between the refrigerant flowing out of the low-temperature side expansion valve 19 and the outside air present outside the vehicle body, thereby absorbing the heat of the outside air. That is, the heat absorption target in the heat absorption section 20 of the second embodiment is the outside air.

[0218] Furthermore, there is no particular limitation on the method of supplying external air to the external air absorber 22. For example, it can be supplied by the operation of an external air fan (not shown), or a structure that utilizes the driving air of an electric vehicle can be adopted.

[0219] Furthermore, a gate device 23 is disposed upstream of the outside air flow relative to the outside air absorber 22. The gate device 23 is configured such that multiple blades are rotatably disposed at the opening of the frame-shaped frame. The multiple blades rotate in conjunction with the operation of an electric actuator (not shown), adjusting the opening area at the opening of the frame.

[0220] Therefore, the gate device 23 can adjust the flow rate of the outside air supplied to the outside air absorber 22, and can adjust the amount of heat absorbed in the outside air absorber 22. Thus, the gate device 23 is equivalent to an example of a heat absorption adjustment unit.

[0221] In the vehicle air conditioning unit 1 according to the second embodiment with this configuration, both heat pump heating mode and hot air heating mode can be realized. In the heat pump heating mode according to the second embodiment, the bypass side expansion valve 14 is fully closed, and the low temperature side expansion valve 19 is adjusted to a throttling state. At this time, the opening area of ​​the gate device 23 is ensured to ensure that outside air is supplied to the outside air absorber 22.

[0222] By controlling the operation in this way, the heat pump cycle 10 can absorb heat from the outside air through the outside air absorber 22 constituting the heat absorption section 20, and dissipate the absorbed heat to the supply air through the indoor condenser 16 constituting the heating section 15. The heat pump heating mode according to the second embodiment is also the same as that of the first embodiment, and is equivalent to an example of the first heating mode.

[0223] Furthermore, in the hot gas heating mode of the second embodiment, the bypass-side expansion valve 14 and the low-temperature-side expansion valve 19 are respectively set to a set throttling state to circulate the refrigerant in the heat pump cycle 10. At this time, the gate device 23 is controlled to have the opening area minimized, thereby achieving a state where the supply of outside gas to the outside gas absorber 22 is minimized.

[0224] Therefore, in the heat pump cycle 10 of the hot gas heating mode according to the second embodiment, a refrigerant circuit is formed in which the refrigerant circulates through the indoor condenser 16 and the refrigerant circulates through the bypass passage 13. That is, a portion of the refrigerant discharged from the compressor 11 flows and circulates in the order of compressor 11, branch section 12a, indoor condenser 16, receiver 18, low-temperature side expansion valve 19, outdoor air absorber 22, confluence section 12b, and compressor 11. At the same time, the other portion of the refrigerant discharged from the compressor 11 flows and circulates in the order of compressor 11, branch section 12a, bypass passage 13, bypass side expansion valve 14, confluence section 12b, and compressor 11.

[0225] As described above, in the hot gas heating mode, refrigerants with different enthalpies, such as the refrigerant with a lower enthalpy flowing from the outside air heat absorber 22 and the refrigerant with a higher enthalpy flowing from the bypass passage 13, are mixed and drawn into the compressor 11. Therefore, similar to the first embodiment, in the hot gas heating mode, even if the heat absorbed from the heat source (outside air) is small, the heat generated by the operation of the compressor 11 can be effectively utilized to heat the supply air, thereby achieving heating inside the vehicle. That is, the hot gas heating mode according to the second embodiment is also an example of the second heating mode.

[0226] In the vehicle air conditioning unit 1 according to the second embodiment, it is also envisioned that the heating capacity may be insufficient during the execution of the heat pump heating mode. For example, if the outside temperature is too low compared to the required heating capacity, the heat pump heating mode may not be able to cope, and there may be a need to switch to the hot air heating mode.

[0227] Therefore, in the second embodiment, switching control is performed to suppress changes in heating capacity when switching from heat pump heating mode to hot gas heating mode.

[0228] In the vehicle air conditioning unit 1 according to the second embodiment, when the switching control is started, the speed of the compressor 11 is controlled to a preset speed, just like in the first embodiment, and the throttling opening of the bypass side expansion valve 14 and the low temperature side expansion valve 19 is controlled to a specified value.

[0229] Then, with the start of the switching control, the operation control of the indoor air supply fan 62 and the air mixing door 64 is performed, executing the same limiting actions as in the first embodiment. In the switching control of the second embodiment, as a heat absorption assurance action, the gate device 23 is operated in a manner that maximizes the opening area to ensure the supply of outside air to the outside air absorber 22.

[0230] Therefore, the vehicle air conditioning unit 1 of the second embodiment is as follows: Figure 8 The refrigerant circulation in the heat pump cycle 10 is achieved in the manner shown. In this first state, the heat dissipation in the heating unit 15 is limited by a limiting action, and the heat absorption in the outside air receiver 22 is ensured by a heat absorption ensuring action. As a result, from the viewpoints of the high-pressure side and the low-pressure side of the heat pump cycle 10, the heating capacity after the switch can be increased to the same level as before the switch, and fluctuations in heating capacity can be suppressed.

[0231] Then, during the transition to the second state in the switching control of the second embodiment, the heat absorption assurance operation performed in the first state is stopped, and the system enters a state where only the limiting operation is performed. Similar to the first embodiment described above, the transition from the first state to the second state in the switching control occurs when the heat absorption in the heat absorption section 20 decreases. Therefore, the transition period is determined by the relationship between the temperature of the low-pressure refrigerant in the outside air absorber 22 and the outside air temperature.

[0232] Starting from the first state of the switching control involved in the second embodiment, the supply of outside air to the outside air absorber 22 is set to a minimum through the operation control of the gate device 23, thus ending the heat absorption assurance operation. The result is that, Figure 9 As shown, the second state of the switching control according to the second embodiment is implemented. Furthermore, in the second state of the switching control, the refrigerant circulation and limiting operations continue to be performed.

[0233] Therefore, it is possible to suppress the energy consumption of the operation by suppressing the heat absorption in a state of reduced heat absorption, and at the same time, increase the heating capacity to the same level as before the switch by limiting the heat dissipation.

[0234] That is, in the vehicle air conditioning device 1 according to the second embodiment, when switching from heat pump heating mode to hot gas heating mode, the change in heating capacity that accompanies the switch of operating mode can be suppressed by performing switching control.

[0235] As explained above, the vehicle air conditioning unit 1 according to the second embodiment can achieve the same effect as the above embodiment in terms of structure and operation, even if the structure of the heat absorption section 20 is changed.

[0236] (Third Implementation)

[0237] Next, refer to Figures 10-12 A third embodiment, different from the embodiments described above, will now be described. In the vehicle air conditioning unit 1 according to the third embodiment, the structure of the heat pump cycle 10 is changed from that in the embodiments described above. The other structures in the vehicle air conditioning unit 1 according to the third embodiment (heat medium circuit 30, indoor air conditioning unit 60, etc.) are the same as in the embodiments described above, so they will not be described again.

[0238] like Figure 10 As shown, the vehicle air conditioning unit 1 according to the third embodiment is configured to include a heat pump cycle 10, a heat medium circuit 30, an indoor air conditioning unit 60, and a control device 70. The structures of the heat medium circuit 30, the indoor air conditioning unit 60, and the control device 70 are the same as those in the first embodiment described above, so further explanation is omitted.

[0239] The heat pump cycle 10 according to the third embodiment includes a compressor 11, a bypass passage 13, a bypass-side expansion valve 14, an indoor condenser 16, a cooler 21, an outdoor air absorber 22, a first expansion valve 26, a second expansion valve 27, and a liquid receiver 28. That is, the heat pump cycle 10 according to the third embodiment differs from the embodiments described above in that it is configured as a parallel circuit on the low-pressure side, with the cooler 21 and the outdoor air absorber 22 connected in parallel, and is configured as a liquid receiver cycle.

[0240] In the heat pump cycle 10 according to the third embodiment, the outlet of the compressor 11 is connected to the branch 12a. The structure of the compressor 11 and the branch 12a is the same as that of the first embodiment, so it will not be described again.

[0241] One outlet of branch 12a is connected to the inlet side of the indoor condenser 16 constituting the heating section 15. The other outlet of branch 12a is connected to the bypass passage 13 and the bypass-side expansion valve 14. The structure and configuration of the indoor condenser 16, and the structure of the bypass passage 13 and the bypass-side expansion valve 14 are the same as those in the first embodiment described above.

[0242] A first connection portion 24 in the shape of a three-way connector is disposed on the outlet side of the indoor condenser 16. The first connection portion 24 has one inlet and two outlets. One outlet of the first connection portion 24 is connected to the first expansion valve 26 and the refrigerant passage 21a of the cooler 21. The other outlet of the first connection portion 24 is connected to the second expansion valve 27 and the outside air absorber 22.

[0243] Here, the first expansion valve 26 and the second expansion valve 27 are electrically operated expansion valves with the same configuration as the cryogenic side expansion valve 19 described above. Therefore, the first expansion valve 26 and the second expansion valve 27 have valve cores and electric actuators, and their operation is controlled by control pulses output from the control device 70. Furthermore, the first expansion valve 26 and the second expansion valve 27 have both fully open and fully closed functions.

[0244] The outlet side of the first expansion valve 26 is connected to the cooler 21 that constitutes the heat absorption section 20. Similar to the first embodiment, the cooler 21 has a refrigerant passage 21a and a heat medium passage 21b, through which heat exchange occurs between the refrigerant flowing in the refrigerant passage 21a and the heat medium flowing in the heat medium passage 21b. The outlet side of the refrigerant passage 21a of the cooler 21 is connected to a second connection portion 25 in the form of a four-way connector.

[0245] Furthermore, similar to the first embodiment, the heat medium flowing through the heat medium passage 21b is the same heat medium circulating in the low-temperature side circuit 31. The low-temperature side circuit 31 has a low-temperature side pump 32, an external air heat exchanger 33, a heat medium three-way valve 34, and a bypass connection 35, and has the same structure as the first embodiment.

[0246] Therefore, according to the heat pump cycle 10 of the third embodiment, by using the cooler 21 as the heat absorption unit 20, the heat of the outdoor air, which is the heat source, can be absorbed by the low-pressure refrigerant via the heat medium of the low-temperature side circuit 31.

[0247] Furthermore, the outlet side of the second expansion valve 27 is connected to the outside air heat absorber 22, which constitutes the heat absorption section 20. Similar to the second embodiment, the outside air heat absorber 22 facilitates heat exchange between the heat medium flowing through it and the outside air outside the vehicle. The outlet side of the outside air heat absorber 22 is connected to a second connecting portion 25 in the form of a four-way connector.

[0248] Therefore, according to the heat pump cycle 10 of the third embodiment, by using the outside air heat absorber 22 as the heat absorption part 20, the heat of the outside air, which is the heat source, can be absorbed by the low-pressure refrigerant.

[0249] The second connection portion 25 is formed as a four-way connector, having three inlets and one outlet. One inlet of the second connection portion 25 is connected to the other end of the bypass passage 13 and the bypass-side expansion valve 14. Another inlet of the second connection portion 25 is connected to the outlet side of the refrigerant passage 21a of the cooler 21. In addition, yet another inlet of the second connection portion 25 is connected to the outlet side of the outside air absorber 22.

[0250] Furthermore, the outlet side of the second connection 25 is connected to the inlet side of the reservoir 28. That is, the second connection 25 constitutes a merging section 12b, which merges and directs the flow of refrigerant via the bypass passage 13 side, the flow of refrigerant via the cooler 21, and the flow of refrigerant via the outside air absorber 22 to the reservoir 28 side.

[0251] The outlet side of the second connecting portion 25, which constitutes the confluence section 12b, is connected to the inlet side of the liquid receiver 28. The liquid receiver 28 is a low-pressure gas-liquid separator that separates the low-pressure refrigerant gas from the second connecting portion 25 and stores the separated liquid refrigerant as residual refrigerant in the cycle. The gaseous refrigerant outlet of the liquid receiver 28 is connected to the suction port side of the compressor 11.

[0252] In the vehicle air conditioning unit 1 according to the third embodiment configured as described above, as an operating mode for heating the supply air that is the object to be heated, it is possible to execute a heat pump heating mode and a hot air heating mode.

[0253] An example of the heat pump heating mode in the third embodiment will be described. In the heat pump heating mode of the third embodiment, the bypass-side expansion valve 14 and the first expansion valve 26 are fully closed, and the second expansion valve 27 is set to a pre-defined throttling state. At this time, the circulation of the heat medium in the heat medium circuit 30 can continue or stop by controlling the operation of the low-temperature side pump 32.

[0254] Thus, in the heat pump cycle 10 of the heat pump heating mode according to the third embodiment, the refrigerant flows and circulates in the order of compressor 11, branch 12a, indoor condenser 16, first connection 24, second expansion valve 27, outdoor air absorber 22, second connection 25, and liquid receiver 28.

[0255] That is, in the heat pump heating mode of the third embodiment, a refrigerant circuit is configured with the outdoor air absorber 22 as the absorber and the indoor condenser 16 as the radiator, so as to realize the heating operation of heating the supply air by using the outdoor air as a heat source. The heat pump heating mode of the third embodiment is equivalent to an example of the first heating mode.

[0256] Furthermore, as another example of the heat pump heating mode involved in the third embodiment, a structure can be adopted in which the bypass-side expansion valve 14 and the second expansion valve 27 are fully closed, and the first expansion valve 26 is in a preset throttling state. In this case, the heat medium circuit 30 is controlled such that the heat medium circulates through the cooler 21 and the outdoor air heat exchanger 33. According to this structure, a heat pump heating mode that uses outdoor air as a heat absorption source can be realized.

[0257] Next, the hot gas heating mode in the third embodiment will be described. In the hot gas heating mode of the third embodiment, control is performed so that the bypass-side expansion valve 14 and the first expansion valve 26 are respectively in a set throttling state, and the second expansion valve 27 is in a fully closed state. At this time, the heat medium circuit 30 is controlled to stop the circulation of the heat medium.

[0258] According to this structure, in the hot gas heating mode involved in the third embodiment, a refrigerant circuit is switched to a path in which the refrigerant circulates through the indoor condenser 16 and a path in which the refrigerant circulates through the bypass passage 13 coexist.

[0259] That is, a portion of the refrigerant discharged from the compressor 11 circulates in the following order: compressor 11, branch section 12a, indoor condenser 16, first connection 24, first expansion valve 26, cooler 21, second connection 25, receiver 28, and compressor 11. Simultaneously, the remaining portion of the refrigerant discharged from the compressor 11 circulates in the following order: compressor 11, branch section 12a, bypass passage 13, bypass-side expansion valve 14, second connection 25, receiver 28, and compressor 11.

[0260] That is, in the hot gas heating mode according to the third embodiment, the refrigerant with lower enthalpy flowing out of the cooler 21 and the refrigerant with higher enthalpy flowing out of the bypass passage 13 are mixed in the confluence section 12b. By mixing refrigerants with different enthalpies and drawing them into the compressor 11, the workload of the compressor 11 can be increased, thereby improving the heating capacity for the object to be heated. The hot gas heating mode according to the third embodiment is an example of the second heating mode.

[0261] In the vehicle air conditioning unit 1 according to the third embodiment, it is also envisioned that the heating capacity may be insufficient during the execution of the heat pump heating mode. For example, if the outside temperature is too low compared to the required heating capacity, the heat pump heating mode may not be able to cope, and there may be a need to switch to the hot air heating mode.

[0262] Therefore, in the third embodiment, switching control to suppress changes in heating capacity is also performed when switching from heat pump heating mode to hot gas heating mode.

[0263] In the vehicle air conditioning unit 1 according to the third embodiment, when switching control from the heat pump heating mode, the speed of the compressor 11 is controlled to a preset speed, similar to the first embodiment. At this time, the throttling openings of the bypass-side expansion valve 14, the first expansion valve 26, and the second expansion valve 27 are each controlled to a predetermined value. Furthermore, in the heat medium circuit 30, the circulation of the heat medium via the cooler 21 is stopped by stopping the operation of the low-temperature side pump 32.

[0264] Then, with the start of the switching control, the operation control of the indoor air supply fan 62 and the air mixing door 64 is performed, executing the same limiting actions as in the above-described embodiment. In the switching control of the third embodiment, as a heat absorption guarantee action, heat absorption from the outside air in the outside air absorber 22 is performed.

[0265] Furthermore, when a gate device 23 is provided for the external air receiver 22, the gate device 23 is operated in a manner similar to the second embodiment to maximize the opening area, so as to ensure the supply of external air to the external air receiver 22.

[0266] Therefore, the vehicle air conditioning unit 1 of the third embodiment is as follows: Figure 11 The refrigerant circulation in the heat pump cycle 10 is achieved in the manner shown. In this first state, the heat dissipation in the heating unit 15 is limited by a limiting action, and the heat absorption in the outside air receiver 22 is ensured by a heat absorption ensuring action. As a result, from the viewpoints of the high-pressure side and the low-pressure side of the heat pump cycle 10, the heating capacity after the switch can be increased to the same level as before the switch, and the variation in heating capacity before and after the switch can be suppressed.

[0267] Then, during the transition to the second state in the switching control of the third embodiment, the heat absorption assurance operation performed in the first state is stopped, and the system becomes a state where only the limiting operation is performed. Similar to the embodiment described above, the transition from the first state to the second state in the switching control occurs when the heat absorption in the heat absorption section 20 decreases. Therefore, the transition period is determined by the relationship between the temperature of the low-pressure refrigerant in the outside air absorber 22 and the outside air temperature.

[0268] The transition from the first state to the second state in the switching control involved in the third embodiment (i.e., heat absorption to ensure the end of the operation) is achieved by changing the refrigerant flow path in the heat pump cycle 10. For example... Figure 11 As shown, during the heat absorption assurance operation, a portion of the refrigerant that has passed through the first connection 24 flows through the second expansion valve 27 and the outside air heat absorber 22, thereby absorbing heat from the outside air. When the heat absorption assurance operation ends, the refrigerant path is switched so that all the refrigerant that has passed through the first connection 24 passes through the first expansion valve 26 and the cooler 21.

[0269] Specifically, the state of the second expansion valve 27 is switched from the throttling state in the first state to the fully closed state. As a result, since the supply of low-pressure refrigerant to the outside air heat absorber 22 stops, the heat absorption assurance operation ends. Furthermore, in the second state of control switching, the refrigerant circulation and limiting operations continue to be performed.

[0270] The result is, as Figure 12 As shown, the second state of switching control involved in the third application mode is realized. Moreover, it is possible to suppress energy consumption such as ensuring operation by reducing heat absorption in a state of reduced heat absorption, while increasing the heating capacity to a state where the heating capacity can be exerted to the same level as before the switching by limiting the heat dissipation.

[0271] That is, in the vehicle air conditioning device 1 according to the third embodiment, when switching from heat pump heating mode to hot gas heating mode, the change in heating capacity that accompanies the switch of operating mode can also be suppressed by performing switching control.

[0272] As explained above, the vehicle air conditioning unit 1 according to the third embodiment can achieve the same effect as the above embodiment in terms of structure and operation, even when a heat pump cycle 10 in which multiple heat absorbers constituting the heat absorption section 20 are arranged in parallel.

[0273] In addition, such as Figure 11 , Figure 12 As shown, in the vehicle air conditioning unit 1 according to the third embodiment, the heat absorption assurance operation is terminated by switching the flow of refrigerant through the outside air heat absorber 2 used in the heat absorption assurance operation. With the termination of the heat absorption assurance operation, the flow of refrigerant that has absorbed heat through the outside air heat absorber 22 in the heat absorption assurance operation is switched to the flow of refrigerant via the parallel-connected cooler 21, bypassing the outside air heat absorber 22, thereby stopping the supply of low-pressure refrigerant to the outside air heat absorber 22.

[0274] In the vehicle air conditioning unit 1 according to the third embodiment, multiple heat absorbers (cooler 21, outside air heat absorber 22) constituting the heat absorption section 20 are arranged in parallel to perform a heat absorption assurance operation using any one of the heat absorbers. When the heat absorption assurance operation ends, the refrigerant flow path on the low-pressure side is switched from a structure passing through any one of the heat absorbers (outside air heat absorber 22) to a structure passing through another heat absorber (cooler 21). Therefore, the heat absorption assurance operation can be ended by switching the refrigerant flow path, and the heat absorption involved in the heat absorption assurance operation can be suppressed by simple control.

[0275] (Fourth Implementation)

[0276] Next, refer to Figures 13-16 A fourth embodiment, different from the embodiments described above, will now be described. This fourth embodiment applies the heat pump cycle device of this disclosure to an air conditioning system 1 for an electric vehicle in the same way as the first embodiment. Similar to the embodiments described above, the fourth embodiment is characterized by suppressing variations in heating capacity when switching between multiple operating modes for heating the object being heated.

[0277] In the fourth embodiment, an operating mode is performed that extracts heat absorbed on the low-pressure side of the heat pump cycle 10 and uses it to heat the object being heated, and an operating mode is performed that uses a portion of the refrigerant discharged from the compressor 11 to increase the workload of the compressor 11, thereby maximizing its heating capacity. That is, although the operating modes in the fourth embodiment differ in detail, they are based on the same ideas as the embodiments described above.

[0278] The vehicle air conditioning unit 1 according to the fourth embodiment consists of a heat pump cycle 10, a heat medium circuit 30, an indoor air conditioning unit 60, and a control device 70. In the fourth embodiment, the structures of the heat pump cycle 10 and the heat medium circuit 30 are different from those in the embodiments described above. In other words, the other structures in the vehicle air conditioning unit 1 according to the fourth embodiment (indoor air conditioning unit 60, control device 70, etc.) are basically the same as those in the embodiments described above, and therefore, further explanation is omitted.

[0279] like Figure 13 As shown, the heat pump cycle 10 of the vehicle air conditioning unit 1 according to the fourth embodiment includes a compressor 11, a heat medium refrigerant heat exchanger 17, a low-temperature side expansion valve 19, and a cooler 21. The compressor 11 has the same structure as in the embodiment described above. Therefore, a detailed description of the compressor 11 is omitted.

[0280] The outlet side of the compressor 11 is connected to the refrigerant inlet side of the heat medium refrigerant heat exchanger 17. The heat medium refrigerant heat exchanger 17 has a refrigerant passage 17a for the high-pressure refrigerant discharged from the compressor 11 to flow through and a heat medium passage 17b for the heat medium circulating in the high-temperature side circuit 41 that constitutes the heat medium circuit 30 to flow through.

[0281] The heat exchanger 17 is a condenser that condenses the high-pressure refrigerant flowing in the refrigerant passage 17a by exchanging heat with the heat medium flowing in the heat medium passage 17b. In other words, the heat exchanger 17 heats the heat from the high-pressure refrigerant discharged from the compressor 11 by transferring heat to the heat medium circulating in the heat medium circuit 30. Therefore, the heat exchanger 17 constitutes part of the heating section 15.

[0282] The outlet side of the refrigerant passage 17a in the heat exchanger 17 is connected to the cryogenic expansion valve 19. The cryogenic expansion valve 19 has the same structure as in the embodiment described above, including a valve core and an electric actuator. The cryogenic expansion valve 19 is controlled by a control pulse output from the control device 70. Furthermore, the cryogenic expansion valve 19 has both fully open and fully closed functions.

[0283] The outlet side of the low-temperature expansion valve 19 is connected to the inlet side of the refrigerant passage 21a of the cooler 21. Similar to the embodiment described above, the cooler 21 has a refrigerant passage 21a and a heat medium passage 21b, allowing heat exchange between the refrigerant flowing in the refrigerant passage 21a and the heat medium flowing in the heat medium passage 21b. Therefore, the cooler 21 constitutes a part of a heat-absorbing section 20 where the heat of the heat medium flowing in the heat medium passage 21b is absorbed by the low-pressure refrigerant flowing in the refrigerant passage 21a. The outlet side of the refrigerant passage 21a of the cooler 21 is connected to the suction side of the compressor 11.

[0284] The heat pump cycle 10 of the fourth embodiment thus configured can be used to extract heat absorbed by the heat-absorbing part 20 on the low-pressure side and dissipate heat to the heating part 15 on the high-pressure side, thereby heating the object to be heated.

[0285] Next, the heat transfer medium circuit 30 of the vehicle air conditioning unit 1 according to the fourth embodiment will be described. For example... Figure 13 As shown, the heat medium circuit 30 according to the fourth embodiment includes a low-temperature side circuit 31, a high-temperature side circuit 41, a heat medium connection flow path 50, and a heat medium flow rate adjustment unit 55.

[0286] Similar to the first embodiment described above, the cryogenic side circuit 31 in the fourth embodiment includes a heat medium passage 21b of the cooler 21, a cryogenic side pump 32, an external air heat exchanger 33, a heat medium three-way valve 34, a bypass connection 35, and a heat medium bypass flow path 36. In the cryogenic side circuit 31, the positional relationship between the cooler 21 and the cryogenic side pump 32 to the heat medium bypass flow path 36 is the same as in the embodiment described above.

[0287] Therefore, in the low-temperature side circuit 31 of the fourth embodiment, by passing the heat medium after it has been heated by the cooler 21 through the outside air heat exchanger 33, the heat of the outside air can be absorbed by the low-pressure refrigerant through the heat medium.

[0288] Here, as Figure 13 As shown, in the low-temperature side circuit 31 of the fourth embodiment, in addition to the cooler 21 and the low-temperature side pump 32 to the heat medium bypass flow path 36 described above, a low-temperature side flow adjustment unit 37 and a low-temperature side connection unit 38 are provided.

[0289] The cryogenic side flow adjustment unit 37 is an electrically operated three-way flow adjustment valve with three inlet and outlet ports, configured to continuously adjust the passage area ratio of each outlet port. The cryogenic side flow adjustment unit 37 is controlled by a control signal output from the control device 70.

[0290] A low-temperature flow adjustment section 37 is disposed between the outlet side of the heat medium passage 21b of the cooler 21 and the bypass connection section 35. Specifically, one inflow outlet of the low-temperature flow adjustment section 37 is connected to the outlet side of the heat medium passage 21b of the cooler 21, and another inflow outlet of the low-temperature flow adjustment section 37 is connected to one inflow outlet of the bypass connection section 35. Furthermore, yet another inflow outlet of the low-temperature flow adjustment section 37 is connected to the second connecting flow path 52. The second connecting flow path 52 will be described later.

[0291] The low-temperature side connection 38 is formed as a three-way connector with three inflow and outflow outlets, and is disposed between the inlet side of the heat medium passage 21b of the cooler 21 and the heat medium three-way valve 34. Therefore, one inflow and outflow outlet of the low-temperature side connection 38 is connected to the inlet side of the heat medium passage 21b of the cooler 21, and another inflow and outflow outlet of the low-temperature side connection 38 is connected to one inflow and outflow outlet of the heat medium three-way valve 34. Yet another inflow and outflow outlet of the low-temperature side connection 38 is connected to the first connecting flow path 51. The first connecting flow path 51 will be described later.

[0292] According to the fourth embodiment with such a configuration, the low-temperature side circuit 31 can achieve multiple circulation modes of the heat medium by controlling the operation of the heat medium three-way valve 34, etc. As one circulation mode of the heat medium in the low-temperature side circuit 31, the heat medium is made to flow and circulate in the following order: low-temperature side pump 32, outside air heat exchanger 33, heat medium three-way valve 34, low-temperature side connection 38, cooler 21, low-temperature side flow adjustment unit 37, bypass connection 35, and low-temperature side pump 32.

[0293] Furthermore, as another circulation method for the heat medium in the low-temperature side circuit 31, it is possible to achieve a sequential flow circulation of the low-temperature side pump 32, the outside air heat exchanger 33, the heat medium three-way valve 34, the heat medium bypass flow path 36, the bypass connection 35, and the low-temperature side pump 32. Therefore, the low-temperature side circuit 31 in the fourth embodiment is equivalent to an example of the second circuit, and the outside air heat exchanger 33 in the fourth embodiment is equivalent to an example of the heat medium absorber. The low-temperature side circuit 31, together with the cooler 21, constitutes the heat absorption section 20.

[0294] Next, refer to Figure 13The structure of the high-temperature side circuit 41 of the heat medium circuit 30 according to the fourth embodiment will be described. The high-temperature side circuit 41 according to the fourth embodiment is the circuit in the heat medium circuit 30 in which the heat medium circulates through the heat medium refrigerant heat exchanger 17 constituting the heating unit 15. In the high-temperature side circuit 41 according to the fourth embodiment, in addition to the heat medium passage 17b of the heat medium refrigerant heat exchanger 17, a high-temperature side pump 42, a heater core 43, a high-temperature side flow adjustment unit 44, and a high-temperature side connection unit 45 are arranged.

[0295] In the high-temperature side circuit 41 according to the fourth embodiment, the inlet side of the heat medium passage 17b of the heat medium refrigerant heat exchanger 17 is connected to the high-temperature side pump 42. The high-temperature side pump 42 is a heat medium pressure delivery unit constructed in the same way as the low-temperature side pump 32 described above. The high-temperature side pump 42 controls its pressure delivery capacity using a control voltage output from the control device 70.

[0296] Furthermore, the heater core 43 is connected to the inlet side of the heat medium passage 17b in the heat medium refrigerant heat exchanger 17. Similar to the indoor condenser 16 in the above embodiment, it is disposed within the air conditioning housing 61 of the indoor air conditioning unit 60. The heater core 43 is an air heat exchange section that allows the heat medium flowing out of the heat medium refrigerant heat exchanger 17 to exchange heat with the supply air that has passed through the cooling core 33a. In the heater core 43, the heat of the heat medium flowing out of the heat medium refrigerant heat exchanger 17 is dissipated to the supply air, thereby heating the supply air. Therefore, the heater core 43 is equivalent to an example of a heat medium radiator.

[0297] The heat medium outlet side of the heater core 43 is connected to the high-temperature side flow regulating unit 44. The high-temperature side flow regulating unit 44, like the low-temperature side flow regulating unit 37, is composed of an electrically operated three-way flow regulating valve with three inflow and outflow ports. The high-temperature side flow regulating unit 44 is controlled by a control signal output from the control device 70.

[0298] One inflow outlet of the high-temperature side flow adjustment section 44 is connected to the outlet side of the heat medium passage 17b of the heat medium refrigerant heat exchanger 17, and the other inflow outlet of the high-temperature side flow adjustment section 44 is connected to one inflow outlet of the three-way connector-shaped high-temperature side connection section 45. Furthermore, the remaining inflow outlet of the high-temperature side flow adjustment section 44 is connected to the first connection flow path 51 that constitutes the heat medium connection flow path 50.

[0299] like Figure 13As shown, the suction port of the high-temperature side pump 42 is connected to a three-way connector-shaped high-temperature side connection 45. The structure of the high-temperature side connection 45 is the same as that of the branch 12a and the low-temperature side connection 38 described above. As described above, one inflow outlet of the high-temperature side connection 45 is connected to the suction port of the high-temperature side pump 42, and the other inflow outlet of the high-temperature side connection 45 is connected to the other inflow outlet of the high-temperature side flow adjustment unit 44. Furthermore, the remaining inflow outlet of the high-temperature side connection 45 is connected to the second connecting flow path 52.

[0300] The high-temperature side circuit 41 in the fourth embodiment, configured in this way, enables the heat medium to circulate in the order of high-temperature side pump 42, heat medium refrigerant heat exchanger 17, heater core 43, high-temperature side flow adjustment unit 44, high-temperature side connection unit 45, and high-temperature side pump 42.

[0301] That is, according to the high-temperature side circuit 41 of the fourth embodiment, the heat medium, after being heated by the heat of the high-pressure refrigerant in the heat medium refrigerant heat exchanger 17, flows into the heater core 43, and the heat of the heat medium in the heater core 43 heats the supply air. Therefore, the high-temperature side circuit 41 of the fourth embodiment is equivalent to an example of the first circuit.

[0302] Furthermore, the heat medium circuit 30 according to the fourth embodiment includes a heat medium connection flow path 50 that connects the high-temperature side circuit 41 and the low-temperature side circuit 31 in a manner that allows the inflow and outflow of heat medium. For example... Figure 13 As shown, the heat medium connection flow path 50 is composed of a first connection flow path 51 and a second connection flow path 52.

[0303] As described above, the first connecting flow path 51 connects an inflow outlet of the high-temperature side flow adjustment section 44 disposed on the high-temperature side circuit 41 side to an inflow outlet of the low-temperature side connecting section 38 disposed on the low-temperature side circuit 31 side. Therefore, by controlling the operation of the high-temperature side flow adjustment section 44, the inflow outlet on the high-temperature side flow adjustment section 44 side is opened, so that the heat medium can flow in and out between the high-temperature side circuit 41 and the low-temperature side circuit 31.

[0304] Furthermore, the second connecting flow path 52 connects an inflow outlet of the low-temperature side flow adjustment section 37 disposed on the low-temperature side circuit 31 side to an inflow outlet of the high-temperature side connecting section 45 disposed on the high-temperature side circuit 41 side. Therefore, by controlling the operation of the low-temperature side flow adjustment section 37, the inflow outlet on the low-temperature side flow adjustment section 37 side is opened, so that the heat medium can flow in and out between the high-temperature side circuit 41 and the low-temperature side circuit 31.

[0305] Furthermore, the low-temperature side flow adjustment unit 37 and the high-temperature side flow adjustment unit 44 are controlled when the hot medium flows in and out through the hot medium connection flow path 50, thus they are equivalent to an example of a flow adjustment unit.

[0306] In the fourth embodiment, the vehicle air conditioning unit 1, which heats the supply air that is the object to be heated, has two heating modes. In the vehicle air conditioning unit 1 according to the fourth embodiment, heating of the vehicle interior can be achieved using an independent circulation heating mode and a loop cooperative heating mode.

[0307] First, refer to Figure 14 The independent circulation heating mode of the vehicle air conditioning unit 1 according to the fourth embodiment will be described. In the independent circulation heating mode of the fourth embodiment, the heat absorbed from the heat source (air inside the vehicle) is drawn by the heat medium in the low-temperature side circuit 31, and the heat is dissipated to the supply air by the heater core 43 via the heat medium in the high-temperature side circuit 41, thereby heating the supply air. Therefore, the independent circulation heating mode of the fourth embodiment can be considered a type of heat pump heating mode.

[0308] The control device 70 compresses and discharges the refrigerant via the compressor 11 and puts the low-temperature side expansion valve 19 into a throttling state. Therefore, in the heat pump cycle 10 of the independent cycle heating mode, the refrigerant is switched to a refrigerant circuit in which the refrigerant flows and circulates in the order of compressor 11, heat medium refrigerant heat exchanger 17, low-temperature side expansion valve 19, cooler 21, and compressor 11.

[0309] Control device 70 controls the refrigerant discharge capacity of compressor 11 so that the high pressure Pd detected by high pressure sensor 72d is close to the target high pressure PDO. Based on the target discharge temperature TAO, the target high pressure PDO is determined with reference to the control mapping pre-stored in control device 70.

[0310] In addition, the control device 70 controls the throttling opening of the low-temperature side expansion valve 19 so that the superheat SHC of the refrigerant at the outlet side of the refrigerant passage 21a in the cooler 21 is close to the reference superheat KSH when the refrigerant evaporation temperature in the cooler 21 is lower than the outside temperature Tam.

[0311] For the low-temperature side circuit 31 of the heat medium circuit 30, the control device 70 determines the pressure delivery capacity of the low-temperature side pump 32 and the opening area ratio of the three inflow and outflow ports in the heat medium three-way valve 34 to ensure the heat absorption required to achieve the target blowing temperature. At this time, the control device 70 controls the operation of the low-temperature side flow adjustment unit 37 to connect the inflow and outflow ports on the cooler 21 side and the bypass connection unit 35 side while keeping the inflow and outflow ports on the second connecting flow path 52 side fully closed.

[0312] Therefore, in the low-temperature side loop 31 of the independent circulation heating mode, the heat medium flows and circulates in the following order: low-temperature side pump 32, outside air heat exchanger 33, heat medium three-way valve 34, low-temperature side connection 38, cooler 21, low-temperature side flow adjustment unit 37, bypass connection 35, and low-temperature side pump 32. That is, in the low-temperature side loop 31 of the independent circulation heating mode, the inflow and outflow of heat medium via the heat medium connection flow path 50 do not occur, and the heat medium circulates independently within the low-temperature side loop 31.

[0313] On the other hand, for the high-temperature side circuit 41 of the heat medium circuit 30, the control device 70 determines the pressure delivery capacity of the high-temperature side pump 42 to ensure the heating capacity required to achieve the target blowing temperature. At this time, the control device 70 controls the operation of the high-temperature side flow adjustment unit 44 to connect the inflow and outflow of the heat medium refrigerant heat exchanger 17 side and the high-temperature side connection unit 45 side while keeping the inflow and outflow of the first connecting flow path 51 side fully closed.

[0314] Therefore, in the high-temperature side circuit 41 of the independent circulation heating mode, the heat medium flows and circulates in the following order: high-temperature side pump 42, heat medium refrigerant heat exchanger 17, heater core 43, high-temperature side flow adjustment unit 44, high-temperature side connection unit 45, and high-temperature side pump 42. That is, in the high-temperature side circuit 41 of the independent circulation heating mode, the inflow and outflow of heat medium via the heat medium connection flow path 50 do not occur, and the heat medium circulates independently within the high-temperature side circuit 41.

[0315] Then, for the indoor air conditioning unit 60, the control device 70 determines and controls the air supply capacity of the indoor fan 62, the ratio of indoor and outdoor air in the indoor and outdoor air switching device 63, and the ratio of the air mixing door 64 according to the operating conditions set for the independent circulation heating mode.

[0316] Therefore, in the independent circulation heating mode according to the fourth embodiment, the vehicle air conditioning unit 1 can extract heat from the heat medium absorbed in the cooler 21 through the heat pump cycle 10, and use this heat in the heater core 43 to heat the supply air via the heat medium in the high-temperature side circuit 41. Moreover, in the low-temperature side circuit 31, the heat medium can absorb heat from the heat source (outdoor air) via the outside air heat exchanger 33, and the refrigerant flowing in the cooler 21 can absorb heat from the heat medium.

[0317] That is, compared with the heat pump heating mode described above, the independent circulation heating mode according to the fourth embodiment can extract heat absorbed by the heat absorption section 20 on the low-pressure side and use that heat in the heating section 15 on the high-pressure side to heat the object to be heated (the supply air). The independent circulation heating mode in the fourth embodiment is an example of the independent circulation heating mode in this disclosure.

[0318] Next, refer to Figure 15 The loop cooperative heating mode of the vehicle air conditioning unit 1 according to the fourth embodiment will be described. In the loop cooperative heating mode according to the fourth embodiment, the operation mode is to increase the workload of the compressor 11 by guiding a portion of the heat medium flowing in the high-temperature side loop 41 to the heat absorption section 20 disposed on the low-temperature side, thereby heating the supply air.

[0319] The control device 70 compresses and discharges the refrigerant via the compressor 11 and puts the low-temperature side expansion valve 19 into a throttling state. Therefore, in the heat pump cycle 10 of the loop cooperative heating mode, the refrigerant is switched to a refrigerant loop in which the refrigerant flows and circulates in the order of compressor 11, heat medium refrigerant heat exchanger 17, low-temperature side expansion valve 19, cooler 21, and compressor 11.

[0320] The control device 70 controls the refrigerant discharge capacity of the compressor 11 and the throttling opening of the low-temperature side expansion valve 19 to their respective target values. The target values ​​for the refrigerant discharge capacity of the compressor 11 and the throttling opening of the low-temperature side expansion valve 19 can, for example, be set in the same way as in the independent cycle heating mode.

[0321] Then, for the low-temperature side circuit 31 of the heat medium circuit 30, the control device 70 controls the operation of the heat medium three-way valve 34 to connect the inflow and outflow of the outside air heat exchanger 33 and the heat medium bypass flow path 36 while making the inflow and outflow of the low-temperature side connection 38 side fully closed.

[0322] Furthermore, the control device 70 controls the operation of the low-temperature side flow adjustment unit 37 to connect the inflow and outflow of the cooler 21 side and the second connecting flow path 52 side while keeping the inflow and outflow of the bypass connection unit 35 side fully closed. Moreover, the control device 70 determines the pressure delivery capacity of the low-temperature side pump 32 to a state preset for the loop cooperative heating mode.

[0323] Therefore, in the low-temperature side loop 31 of the loop-cooperative heating mode, the heat medium circulates in the following sequence: low-temperature side pump 32, outside air heat exchanger 33, heat medium three-way valve 34, heat medium bypass flow path 36, bypass connection 35, and low-temperature side pump 32. That is, in the loop-cooperative heating mode, the low-temperature side loop 31 is switched to a loop structure in which a portion of the heat medium circulates through the outside air heat exchanger 33 and the heat medium bypass flow path 36 in the low-temperature side loop 31.

[0324] On the other hand, for the high-temperature side circuit 41 of the heat medium circuit 30, the control device 70 determines the pressure delivery capacity of the high-temperature side pump 42 to ensure the heating capacity required to achieve the target blowing temperature. At this time, the control device 70 controls the operation of the high-temperature side flow adjustment unit 44 to connect all inflow and outflow outlets of the first connecting flow path 51 side, the heat medium refrigerant heat exchanger 17 side, and the high-temperature side connecting part 45 side.

[0325] Therefore, in the high-temperature side circuit 41 of the loop-cooperative heating mode, when the heat medium circulates in the high-temperature side circuit 41, it branches into a flow that cooperates with the low-temperature side circuit 31 via the heat medium connection flow path 50. In the flow circulating in the high-temperature side circuit 41, the heat medium circulates in the following order: high-temperature side pump 42, heat medium refrigerant heat exchanger 17, heater core 43, high-temperature side flow adjustment unit 44, high-temperature side connection unit 45, and high-temperature side pump 42.

[0326] Furthermore, in the process of cooperating with the low-temperature side circuit 31 via the heat medium connecting flow path 50, the circulation path of the heat medium passage 21b through the cooler 21 is formed by the control of the aforementioned low-temperature side flow adjustment unit 37 and high-temperature side flow adjustment unit 44 through the heat medium connecting flow path 50. That is, the heat medium flows and circulates in the following order: high-temperature side pump 42, heat medium refrigerant heat exchanger 17, heater core 43, high-temperature side flow adjustment unit 44, first connecting flow path 51, low-temperature side connection unit 38, cooler 21, low-temperature side flow adjustment unit 37, second connecting flow path 52, and high-temperature side connection unit 45.

[0327] For the indoor air conditioning unit 60 in the loop cooperative heating mode, the control device 70 determines and controls the air supply capacity of the indoor fan 62, the ratio of indoor and outdoor air in the indoor and outdoor air switching device 63, and the ratio of the air mixing door 64 according to the operating conditions set for the loop cooperative heating mode.

[0328] Therefore, in the loop cooperative heating mode according to the fourth embodiment, the vehicle air conditioning unit 1 can use the heat medium connecting flow path 50 and heat medium flow adjustment unit 55 to make a portion of the heat medium flowing in the high temperature side loop 41 flow into the cooler 21 that constitutes the heat absorption unit 20.

[0329] In the cooler 21, due to the heat exchange between the hot medium flowing in from the high-temperature side circuit 41 and the low-pressure refrigerant, the temperature of the low-pressure refrigerant in the heat pump cycle 10 can be increased. As the refrigerant temperature of the low-pressure refrigerant increases, the density of the refrigerant drawn into the compressor 11 also increases, thereby increasing the workload of the compressor 11 and increasing the heating capacity of the object to be heated in the loop cooperative heating mode. The loop cooperative heating mode in the fourth embodiment is an example of the loop cooperative heating mode in this disclosure.

[0330] As described above, in the independent circulation heating mode, heat is absorbed from the heat source (outdoor air) via the heat medium in the low-temperature side loop 31, and the absorbed heat is extracted by the heat pump cycle 10. The extracted heat is dissipated from the heater core 43 to the supply air that is the object to be heated via the heat medium in the high-temperature side loop 41, thereby heating the object. Therefore, the heating capacity of the independent circulation heating mode according to the fourth embodiment is affected by the amount of heat absorbed in the low-temperature side loop 31 in the same way as the heat pump heating mode of the above-described embodiment.

[0331] On the other hand, in the loop cooperative heating mode involved in the fourth embodiment, although the loop structure of the heat pump cycle 10 is the same as that of the independent loop heating mode, the structure of the circulation path of the heat medium in the heat medium loop 30 is different.

[0332] like Figure 15 As shown, in the loop-cooperative heating mode, a portion of the heat medium flowing out of the heat medium refrigerant heat exchanger 17 circulates through the heater core 43 in the high-temperature side loop 41, while the remaining portion of the heat medium flows through the cooler 21 via the heat medium connection flow path 50. That is, a portion of the heating capacity of the heat medium in the heat medium refrigerant heat exchanger 17 is used to heat the object being heated (supply air), while the remaining portion of the heating capacity is used for the temperature rise of the low-pressure refrigerant via the cooler 21.

[0333] Here, it is assumed that before and after switching from independent cycle heating mode to loop cooperative heating mode, the heating capacity of the heat medium in the heat medium refrigerant heat exchanger 17 will not increase instantaneously and will remain in essentially the same state.

[0334] When switching to the loop-cooperative heating mode, a portion of the heat medium flowing out of the heat medium refrigerant heat exchanger 17 is used to heat the supply air via the heater core 43, but the remaining portion of the heat medium is guided to the cooler 21 side via the heat medium connection flow path 50 and the heat medium flow adjustment section 55. That is, in the heater core 43, the supply air is heated by a portion of the heat medium heated by the heat of the high-pressure refrigerant, so it is considered that the heating capacity of the supply air is temporarily reduced immediately after switching from the independent circulation heating mode to the loop-cooperative heating mode.

[0335] Here, in the vehicle air conditioning device 1 according to the fourth embodiment, when switching from independent circulation heating mode to loop cooperative heating mode, switching control is performed to suppress the change in heating capacity of the object to be heated caused by the difference in operating mode.

[0336] As described above, the heating capacity in the independent cycle heating mode and the loop cooperative heating mode corresponds to the amount of heat absorbed in the heat absorption section 20 and the workload of the compressor 11, respectively, and is therefore affected by the low pressure of the refrigerant in the heat pump cycle 10. In order to suppress the fluctuation of heating capacity during mode switching and make it a shorter-term fluctuation, it is preferable to quickly move from a low-pressure state required by the independent cycle heating mode to a high-pressure state, so as to increase the workload of the compressor 11 in the loop cooperative heating mode.

[0337] In order to increase the low-pressure of the refrigerant in the heat pump cycle 10, it is necessary to increase the heat possessed by the refrigerant. Therefore, as one of the actions in the switching control for increasing the low-pressure of the heat pump cycle 10 to suppress fluctuations in heating capacity, an action to suppress the heat dissipation on the high-pressure side of the heat pump cycle 10 is considered.

[0338] Therefore, by suppressing the heat dissipation on the high-pressure side of the heat pump cycle 10, it achieves a state of heat characteristic of the refrigerant discharged from the compressor 11, thereby increasing the low-pressure side of the heat pump cycle 10. This allows the low-pressure side of the heat pump cycle 10 to rise rapidly to the desired state, quickly eliminating fluctuations in heating capacity associated with operating mode switching. Hereinafter, the action of suppressing the heat dissipation on the high-pressure side of the heat pump cycle 10 during operating mode switching control will be referred to as a limiting action.

[0339] In addition, as one of the actions in the switching control used to increase the low-pressure side of the heat pump cycle 10 and suppress fluctuations in heating capacity, the action of maintaining the heat absorption on the low-pressure side of the heat pump cycle 10 as much as possible is considered.

[0340] As described above, in the independent heating mode before switching, heat absorption via the heat medium circuit 30 occurs in the heat absorption section 20 on the low-pressure side of the heat pump cycle 10. Furthermore, the heat absorbed by the heat absorption section 20 constitutes the heat of the refrigerant flowing on the low-pressure side.

[0341] Considering this, when switching from independent cycle heating mode to loop cooperative heating mode, heat absorption in the heat absorption unit 20 continues from independent cycle heating mode. However, during the switching control when changing operating modes, the operation is performed within a range that can maintain the amount of heat absorbed in the heat absorption unit 20, suppressing the decrease in the low-pressure side of the heat pump cycle 10. Hereinafter, the action taken to maintain the amount of heat absorbed on the low-pressure side of the heat pump cycle 10 as much as possible during the switching control of operating modes will be referred to as the heat absorption assurance action.

[0342] Next, in the vehicle air conditioning unit 1 according to the fourth embodiment, the switching control when switching from independent circulation heating mode to loop cooperative heating mode includes the operation of each structure, as referred to Figure 16Please provide a detailed explanation.

[0343] exist Figure 16 In the example shown, the vehicle air conditioning unit 1 operates in independent circulation heating mode from time ta. In the vehicle air conditioning unit 1 operating in independent circulation heating mode, the operation of the compressor 11, the low-temperature side expansion valve 19, the low-temperature side pump 32, the heat medium three-way valve 34, and the low-temperature side flow adjustment unit 37 are controlled by the control device 70. Furthermore, the operation of the high-temperature side pump 42, the high-temperature side flow adjustment unit 44, the indoor fan 62, and the air mixing door 64 are also controlled by the control device 70.

[0344] In the fourth embodiment, the switching of the operating mode from independent circulation heating mode to loop cooperative heating mode is determined at time tb, and the switching control in the vehicle air conditioning unit 1 is initiated. For example, a starting condition for the switching control could be that the heat absorbed from the heat absorption unit 20 is insufficient relative to the required heating capacity, making it impossible to meet the required heating capacity in independent circulation heating mode. The relationship between the required heating capacity and the heat absorbed is determined based on the relationship between the target blowing temperature of the air conditioning air and the temperature of the heat-absorbing object (air) in the heat absorption unit 20.

[0345] When the switching control from independent cycle heating mode to loop cooperative heating mode begins at time tb, the operating mode of the compressor 11 speed, the throttling opening of the low-temperature side expansion valve 19, the pressure delivery capacity of the low-temperature side pump 32, the air delivery capacity of the indoor fan 62, and the opening mode of the air mixing door 64 are controlled.

[0346] The speed of compressor 11 is adjusted from the speed in independent cycle heating mode to the speed set in the switching control. The throttling opening of low-temperature side expansion valve 19 is switched from the throttling opening variation method in independent cycle heating mode to the method of maintaining the throttling opening set in the switching control.

[0347] Furthermore, the control device 70 controls the operation of the low-temperature side flow adjustment unit 37 and the high-temperature side flow adjustment unit 44 that constitute the heat medium flow adjustment unit 55, allowing the heat medium to flow in and out between the low-temperature side circuit 31 and the high-temperature side circuit 41.

[0348] Therefore, although the refrigerant discharge capacity of the compressor 11 and the pressure reduction in the low-temperature side expansion valve 19 are different when switching control, the heat pump cycle 10 is switched to the same refrigerant circuit as the independent cycle heating mode.

[0349] Furthermore, in the heat medium circuit 30 during switching control, while the heat medium on the low-temperature side circuit 31 and the heat medium in the high-temperature side circuit 41 continue to circulate in the independent circulation heating mode, the inflow and outflow of heat medium via the heat medium connection flow path 50 are allowed.

[0350] Therefore, in the high-temperature side circuit 41, a portion of the heat medium heated by the high-pressure refrigerant flows into the low-temperature side circuit 31 via the second connecting flow path 52, where it is absorbed by the low-pressure refrigerant in the cooler 21. Thus, in the switching control, while continuing to absorb heat in the heat-absorbing section 20 from the independent cycle heating mode, the flow of heat medium between the low-temperature side circuit 31 and the high-temperature side circuit 41 via the heat medium connecting flow path 50 is permitted, which is equivalent to an example of ensuring heat absorption operation.

[0351] That is, the heat absorption assurance operation involved in the fourth embodiment can be said to ensure the heat absorption operation for the heat pump cycle 10 by utilizing the heat absorption from the heat source (outdoor air) and the heat absorption from the heat medium originating from the high-pressure refrigerant (discharged refrigerant). Moreover, a portion of the heat medium flowing out from the cooler 21 flows into the high-temperature side circuit 41 via the first connection flow path 51, and dissipates the heat of the high-pressure refrigerant in the heat medium refrigerant heat exchanger 17.

[0352] In addition, the air volume of the indoor fan 62 is controlled to a preset air volume for the switching control, and operates by maintaining the specified air volume during the switching control. The air volume of the indoor fan 62 in the switching control is set to be lower than the air volume in the independent circulation heating mode. Therefore, as time tb elapses, the air volume of the indoor fan 62 is controlled to gradually decrease towards the specified value during the switching control.

[0353] That is, in the switching control, the amount of heated object (supply air) supplied to the heater core 43 constituting the heating unit 15 is limited by the operation control of the indoor fan 62. As a result, in the switching control, the air supply capacity of the indoor fan 62 is limited to a lower operating limit than in the independent circulation heating mode, which limits the heat dissipation destination of the high-pressure refrigerant. Therefore, this is equivalent to an example of the limiting operation in the switching control.

[0354] Furthermore, the opening degree of the air mixing door 64 is controlled to a predetermined value, which is set to make the opening degree of the cold air bypass passage 65 larger than that in the independent circulation heating mode. That is, during the switching operation, the air mixing door 64 is controlled to allow most of the supply air that has passed through the cooling core 33a to bypass the heater core 43.

[0355] Here, when the supply of air to the heater core 43 is limited to a level lower than that in the independent cycle heating mode, the heat dissipation from the high-pressure refrigerant of the heat pump cycle 10 in the heating section 15 is also reduced compared to the independent cycle heating mode. Therefore, in the switching control, adjusting the opening of the air mixing door 64 is equivalent to an example of a limiting action in the switching control.

[0356] In this way, when the switching control of various structures is performed after time tb, the high-pressure refrigerant in heat pump cycle 10 decreases. Figure 16 In this context, the completion time of various actions in the switching control is represented as time tc.

[0357] During the period after time tc when the switching control continues, the aforementioned limiting action and heat absorption assurance action also continue. In the fourth embodiment, the state in which the limiting action and heat absorption assurance action are performed simultaneously during the switching control is also referred to as the first state of the switching control.

[0358] Then, since the heat dissipation from the high-pressure side of the refrigerant in the heat pump cycle 10 is limited by the limiting action, the value of the high-pressure refrigerant increases as time passes from the start of the limiting action. That is, the heating capacity of the heat pump cycle 10 can be improved by utilizing the limiting action in the switching control.

[0359] Furthermore, it is shown that, by absorbing heat to ensure operation, the heat absorbed in the heat absorption section 20 on the low-pressure side of the heat pump cycle 10 is greater than that in the independent cycle heating mode. This is because the heat medium heated by the high-pressure refrigerant is directly introduced into the heat medium passage 21b of the cooler 21 via the heat medium connection flow path 50.

[0360] As a result, the low-pressure refrigerant pressure rises rapidly from the start of the heat absorption assurance operation. Similarly, the temperature of the low-pressure refrigerant flowing through the heat absorption section 20 (i.e., the temperature of the low-pressure refrigerant flowing out of the refrigerant passage 21a of the cooler 21) also rises rapidly from time tc. That is, by switching the heat absorption assurance operation in the control, the density of the refrigerant drawn into the compressor 11 can be rapidly increased, thereby increasing the workload of the compressor 11.

[0361] As a switching control, when the limiting action and heat absorption assurance action continue from time tc, the refrigerant temperature in the refrigerant passage 21a of the cooler 21 reaches the preset reference cooler-side temperature KTc. The refrigerant temperature in the refrigerant passage 21a of the cooler 21 reaching the preset reference cooler-side temperature KTc is an example of a heat absorption stop condition.

[0362] In the fourth embodiment, the time when the temperature of the low-pressure refrigerant in the refrigerant passage 21a of the cooler 21 is taken as the reference cooler-side temperature KTc and the heat absorption stop condition is met is called time tdx. Since the time tdx refers to the moment when the heat absorption in the heat absorption section 20 can no longer be sufficiently ensured, it can be said to be a state in which even if the heat absorption assurance operation is performed, it is difficult to use the heat absorption to make the low-pressure refrigerant rise.

[0363] In the heat absorption assurance operation of the fourth embodiment, in addition to heat absorption using outdoor air as the heat source, as in the embodiments described above, heat absorption also occurs from the heat medium flowing in from the high-temperature side circuit 41. By utilizing the heat medium from the high-temperature side circuit 41, the temperature of the low-pressure refrigerant can rise more easily. That is, in the fourth embodiment, the time required from time tc to time tdx is shorter than the time required from time tc to time td in the embodiments described above.

[0364] After time tdx, the heat absorption is ensured to end. Specifically, for heat absorption in the heat absorption section 20 during switching control, heat absorption from the outdoor air is stopped. For example, the operation of the heat medium three-way valve 34 is controlled to connect the inlet and outlet of the outdoor air heat exchanger 33 and the heat medium bypass flow path 36 while keeping the inlet and outlet of the low-temperature side connection section 38 fully closed. Moreover, the operation of the low-temperature side flow adjustment section 37 is controlled to connect the inlet and outlet of the cooler 21 and the second connection flow path 52 while keeping the inlet and outlet of the bypass connection section 35 fully closed.

[0365] Therefore, the circulation path of the heat medium in the low-temperature side loop 31 is switched to a circulation path through the outside air heat exchanger 33 and the heat medium bypass flow path 36, thus bypassing the cooler 21 and stopping heat absorption from the outside air as a heat source. Alternatively, the low-temperature side pump 32 can be stopped to stop heat absorption from the heat source.

[0366] By stopping the heat absorption protection action at the moment when the heat absorption stop condition is met, the waste of energy required for the heat absorption protection action can be suppressed, thus achieving highly energy-efficient switching control.

[0367] Even after the heat absorption assurance operation has ended, the refrigerant circulation and limiting operations in the heat pump cycle 10 under switching control continue. This state is referred to as the second state of switching control. Because the limiting operations continue to be performed in the second state of switching control, the high-pressure, low-pressure, and low-pressure side refrigerant temperatures in the heat pump cycle 10 also increase over time, after time tdx and the end of the heat absorption assurance operation.

[0368] As described above, the switching control is executed to suppress changes in heating capacity when switching from independent cycle heating mode to loop cooperative heating mode. As one way to suppress changes in heating capacity, in the second state of the switching control, it is determined whether the high pressure of the refrigerant in the heat pump cycle 10 has risen to the same level as the heating capacity in the loop cooperative heating mode and the independent cycle heating mode.

[0369] Specifically, it determines whether the high-pressure refrigerant in the switching-controlled heat pump cycle 10 is higher than the preset reference high-pressure pressure KPd. When the high-pressure refrigerant in the switching-controlled heat pump cycle 10 is higher than the reference high-pressure pressure KPd, it can exert the same heating capacity as the independent cycle heating mode in the loop cooperative heating mode, thus suppressing fluctuations in heating capacity.

[0370] As another method to suppress changes in heating capacity when switching to the loop cooperative heating mode, consider increasing the workload of compressor 11 to a state equivalent to the heating capacity in independent cycle heating mode during the second state of switching control. That is, during the second state of switching control, determine whether the low-pressure refrigerant of heat pump cycle 10 is higher than the reference low-pressure KPs.

[0371] The reference low-pressure KPs represents the low-pressure refrigerant in the heat pump cycle 10 and is set to make the workload of the compressor 11 in the loop-cooperative heating mode equal to the heating capacity in the independent cycle heating mode. When the low-pressure in the heat pump cycle 10 under switching control is higher than the reference low-pressure KPs, the heating capacity in the loop-cooperative heating mode is equal to that in the independent cycle heating mode, thus suppressing fluctuations in heating capacity.

[0372] like Figure 16 As shown, when the system transitions to the second state of switching control after time tdx, the high-pressure and low-pressure in heat pump cycle 10 gradually increase. The moment when either the high-pressure of heat pump cycle 10 reaches or exceeds the reference high-pressure KPd, or the moment when the low-pressure of heat pump cycle 10 reaches or exceeds the reference low-pressure KPs, is taken as time te.

[0373] In addition, Figure 16 The example shown illustrates a scenario where both the high-pressure side of heat pump cycle 10 and the low-pressure side of heat pump cycle 10 simultaneously meet the reference high-pressure KPd and the reference low-pressure KPs. However, this is only one example. The moment when the first of the two conditions meets can also be taken as time te. Furthermore, considering the reliable suppression of variations in heating capacity, the moment when both the high-pressure side condition and the low-pressure side condition meet can also be taken as time te.

[0374] When the time *te* required to satisfy either the high-pressure side or low-pressure side condition of the refrigerant in heat pump cycle 10 is elapsed, the switching control ends and the system transitions to loop cooperative heating mode. By using the satisfaction of the high-pressure side condition of the refrigerant as a condition, the limiting action ends and the system transitions to loop cooperative heating mode. Thus, the loop cooperative heating mode begins when the heating capacity of heat pump cycle 10 reaches a preset level (i.e., the level before switching control). Therefore, the execution of loop cooperative heating mode can begin while suppressing fluctuations in the heating capacity of the supply air, which is the object to be heated.

[0375] Furthermore, by satisfying the low-pressure side condition of the refrigerant, the limiting action ends and the system switches to loop cooperative heating mode. Thus, the loop cooperative heating mode begins when the workload of compressor 11 reaches a preset level (i.e., the level before switching control). In this case, the loop cooperative heating mode can also be started while suppressing changes in the heating capacity of the supply air to be heated.

[0376] In this way, according to the fourth embodiment, when switching from independent cycle heating mode to loop cooperative heating mode, a limiting action is performed by switching control, which enables the loop cooperative heating mode to be started while the heating capacity of the heat pump cycle 10 is sufficiently improved. Thus, the switching of operating modes can be achieved while suppressing the difference in heating capacity caused by the structure of the refrigerant circuit in independent cycle heating mode and loop cooperative heating mode.

[0377] like Figure 16 As shown, as a limiting action of the switching control, the operation of the indoor fan 62 is controlled to limit the supply of air to the heater core 43 constituting the heating unit 15. By limiting the supply air volume generated by the indoor fan 62, the heat dissipation on the high-pressure side of the heat pump cycle 10 can be limited, thereby improving the heating capacity of the high-pressure side of the heat pump cycle 10.

[0378] Furthermore, as a limiting action for switching control, the opening degree of the air mixing gate 64 is controlled to limit the supply of air to the heater core 43 constituting the heating unit 15. Based on the operation of the air mixing gate 64, the supply of air to the heater core 43 can be limited from the perspective of the airflow path of the airflow to the object being heated. Therefore, the limiting action involved in the operation of the air mixing gate 64 ensures sufficient heating capacity of the heat pump cycle 10 before switching to the loop-cooperative heating mode.

[0379] like Figure 16As shown, in the switching control, both the limiting action and the heat absorption assurance action are performed simultaneously. That is, by simultaneously performing the limiting action and the heat absorption assurance action, both the heating capacity of the high-pressure side of the heat pump cycle 10 and the workload of the compressor 11 on the low-pressure side of the heat pump cycle 10 can be utilized. As a result, when switching from independent cycle heating mode to loop cooperative heating mode, the period of change in the heating capacity of the object being heated can be further shortened, and the change can be suppressed to a smaller extent.

[0380] Furthermore, similar to independent cycle heating, the heat absorption assurance operation in the fourth embodiment is performed simultaneously with the operation of the cooler 21 absorbing heat from the heat medium relative to the low-pressure refrigerant. This is achieved by absorbing heat from the heat medium flowing in from the high-temperature side circuit 41 via the heat medium connection flow path 50. Therefore, in addition to the heat source (outdoor air), a portion of the heat from the discharged refrigerant from the compressor 11 can be utilized, thus increasing the low-pressure of the heat pump cycle 10 in a shorter time and increasing the workload of the compressor 11.

[0381] like Figure 16 As shown in the time tdx, the heat absorption assurance action in the switching control ends when the heat absorption stop condition is met and the heat absorption becomes less than a preset reference hour. That is, in the switching control, the heat absorption assurance action can be executed efficiently to suppress fluctuations in heating capacity.

[0382] In addition, such as Figure 16 As shown, when performing the heat absorption assurance operation, if the heat absorption stop condition is met, the supply of the heat medium circulating in the low-temperature side circuit 31 to the cooler becomes 0. Specifically, the circulation path of the heat medium in the low-temperature side circuit 31 is switched to a circulation path that bypasses the cooler 21's heat medium passage 21b and passes through the external air heat exchanger 33 and the heat medium bypass flow path 36. Thus, the heat absorption assurance operation can be terminated with simple operation control.

[0383] As explained above, in the vehicle air conditioning unit 1 according to the fourth embodiment, during the switching control when switching from independent circulation heating mode to loop cooperative heating mode, a limiting action is performed to restrict the heat dissipation of the heater core 43 constituting the heating unit 15. By performing the limiting action in the switching control, the heating capacity of the high-pressure side of the heat pump cycle 10 can be sufficiently improved, and the variation in heating capacity between the independent circulation heating mode and the loop cooperative heating mode can be minimized.

[0384] like Figure 16As shown, as a limiting action of the switching control, the operation of the indoor fan 62 is controlled to limit the supply of air to the heater core 43 constituting the heating unit 15. By limiting the supply air volume generated by the indoor fan 62, the heat dissipation on the high-pressure side of the heat pump cycle 10 can be limited, thereby improving the heating capacity of the high-pressure side of the heat pump cycle 10.

[0385] Furthermore, as a limiting action in the switching control, the opening degree of the air mixing gate 64 is controlled to limit the supply of air to the heater core 43 constituting the heating unit 15. Based on the operation of the air mixing gate 64, the supply of air to the heater core 43 can be limited from the perspective of the airflow path of the airflow to the object being heated. Therefore, the limiting action involved in controlling the operation of the air mixing gate 64 ensures sufficient heating capacity of the heat pump cycle 10 before switching to the loop cooperative heating mode.

[0386] like Figure 16 As shown in the time interval tc to te, the limiting action in the switching control is lifted when the high pressure of heat pump cycle 10 is above the reference high pressure KPd. The state where the high pressure is above the reference high pressure indicates that the heating capacity of heat pump cycle 10 has risen to a preset reference state. Therefore, from the viewpoint of the heating capacity of heat pump cycle 10, the limiting action can be terminated and the system can transition to loop cooperative heating mode while suppressing fluctuations in heating capacity.

[0387] Furthermore, the limiting action in the switching control releases the heat dissipation limitation when the low-pressure pressure of the heat pump cycle 10 is above the reference low-pressure pressure KPs. The state where the low-pressure pressure is above the reference low-pressure pressure indicates that the workload of the compressor 11 has increased to a preset reference level. Therefore, from the viewpoint of the workload of the compressor 11, the limiting action can be terminated and the system can transition to the loop cooperative heating mode while suppressing fluctuations in heating capacity.

[0388] like Figure 16 As shown, in the switching control involved in switching from independent cycle heating mode to loop cooperative heating mode, the transition to loop cooperative heating mode is achieved after simultaneously executing a limiting action and a heat absorption assurance action. While increasing the heating capacity of heat pump cycle 10 through the limiting action, the workload of compressor 11 is increased through the heat absorption assurance action. Therefore, by simultaneously executing the limiting action and the heat absorption assurance action, the required switching control period can be shortened, and fluctuations in heating capacity can be suppressed in a short time.

[0389] This disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of this disclosure.

[0390] In the above embodiments, the heat pump circulation device of this disclosure is applied to a vehicle air conditioning system 1 installed in an electric vehicle, but it is not limited to this method. For example, the object to be heated in the heat pump circulation device of this disclosure is not limited to the supply air that is the object of air conditioning. That is, the heat pump circulation device of this disclosure can also be applied, for example, to a water heater that uses water as the object to be heated.

[0391] Furthermore, in the above embodiments, outdoor air, heat transfer medium, etc., are listed as the heat-absorbing object and heat source in the heat pump cycle device, but this method is not limited to this. For example, the heat exhaust of equipment installed in electric vehicles can also be used as the heat source, or the heat exhaust generated by batteries, inverters, PCUs, drive axles, control devices for ADAS, etc., can also be used as the heat source.

[0392] Inverters supply power to electric generators and other devices. The PCU (Power Control Unit) is an electrical control unit responsible for power conversion and distribution. The drive axle is a power transmission mechanism that integrates the transmission, differential gears, and other components. The control devices used in ADAS (Advanced Driver Assistance Systems) are the control devices used in advanced driver assistance systems.

[0393] In the structure of the heating unit 15 in the above-described embodiment, a structure is adopted that directly dissipates the heat of the high-pressure refrigerant to the object being heated, such as the indoor condenser 16, and a structure that indirectly dissipates the heat of the high-pressure refrigerant to the object being heated, such as the heat medium refrigerant heat exchanger 17 and the high-temperature side circuit 41. That is, the heating unit 15 only needs to ultimately use the heat of the high-pressure refrigerant to heat the object being heated, and is not limited to the state along the way to the object being heated.

[0394] Furthermore, as examples of the structure of the heat-absorbing section 20 in the above embodiments, structures including one with a cooler 21, one with an external air heat absorber 22, and one with both a cooler 21 and an external air heat absorber 22 are listed, but the structure is not limited to this. The heat-absorbing section 20 can be configured to absorb heat from the heat source as long as it can absorb heat from the heat source. It may also be composed of more heat absorbers.

[0395] In the above embodiments, the termination conditions for the limiting action are listed as the case where the high pressure is above the reference high pressure KPd and the low pressure is above the reference low pressure KPs. The reference high pressure KPd and the reference low pressure KPs are set with consideration for the purpose of the vehicle air conditioning unit 1. That is, the reference high pressure KPd and the reference low pressure KPs are set to a change in heating capacity that does not cause significant discomfort to the occupants due to the change in heating capacity before and after the switch.

[0396] In the first and second embodiments described above, the heat pump cycle 10 is configured as a receiver cycle, and in the third embodiment, the heat pump cycle 10 is configured as a liquid reservoir cycle, but it is not limited to this configuration. As for the heat pump cycle involved in this disclosure, the configuration of the gas-liquid separation section is not limited, and heat pump cycles with various structures can be applied.

[0397] The features of the heat pump cycle device disclosed in this specification are shown below.

[0398] (Project 1)

[0399] A heat pump circulation device, comprising:

[0400] The compressor compresses and discharges the refrigerant;

[0401] A branch section that branches the flow of the refrigerant discharged from the compressor;

[0402] A heating section that uses the refrigerant flowing out from one outlet of the branch as a heat source to heat the object to be heated;

[0403] A low-temperature side pressure reduction section, which reduces the pressure of the refrigerant flowing out of the heating section;

[0404] A bypass passage for the refrigerant to flow to the other side of the branch;

[0405] A bypass-side pressure reducing unit that adjusts the flow rate of the refrigerant flowing in the bypass passage;

[0406] A confluence section that allows the flow of refrigerant from the bypass-side pressure reducing section to merge with the flow of refrigerant from the low-temperature-side pressure reducing section and flow out toward the suction port side of the compressor;

[0407] A heat-absorbing section, wherein the heat possessed by the object to be heated is absorbed at least by the refrigerant flowing out from the low-temperature side depressurization section; and

[0408] The control unit performs control for switching between the first heating mode and the second heating mode.

[0409] In the first heating mode, all the refrigerant discharged from the compressor flows into the heating section via the branch, and heats the object being heated by drawing heat absorbed from the object in the heat-absorbing section.

[0410] In the second heating mode, a portion of the refrigerant discharged from the compressor flows into the bypass passage via the branch, guides the refrigerant flowing from the bypass-side pressure reducing section towards the confluence section, and allows the remaining portion of the refrigerant discharged from the compressor to flow into the heating section via the branch. The refrigerant flowing from the heating section then merges with the flow of refrigerant from the bypass-side pressure reducing section at the confluence section and is drawn into the compressor.

[0411] When switching from the first heating mode to the second heating mode, the control unit performs a limiting action to reduce the heat dissipation of the heating unit in the first heating mode. After performing the limiting action, the switching to the second heating mode is completed.

[0412] (Project 2)

[0413] The heat pump circulation device described in Project 1, wherein,

[0414] The heating unit includes a radiator and a supply adjustment unit. The radiator dissipates heat from the refrigerant flowing into the heating unit, and the supply adjustment unit adjusts the amount of refrigerant supplied to the radiator for the object to be heated.

[0415] The limiting action controls the operation of the supply adjustment unit, limiting the supply amount to the object to be heated by the radiator to be lower than a preset reference amount.

[0416] (Project 3)

[0417] The heat pump circulation device described in Project 1 or 2, wherein,

[0418] When the limiting action is performed, if the heating capacity of the heating unit exceeds a preset reference heating capacity, the control unit ends the limiting action and releases the limitation on the heat dissipation of the heating unit.

[0419] (Project 4)

[0420] The heat pump circulation device described in Project 1 or 2, wherein,

[0421] When the limiting action is performed, the control unit terminates the limiting action and releases the limitation on the heat dissipation in the heating unit when the pressure of the refrigerant in the heat absorption section exceeds a preset reference low pressure.

[0422] (Project 5)

[0423] The heat pump circulation device described in any one of items 1 to 4, wherein,

[0424] When switching from the first heating mode to the second heating mode, the control unit simultaneously performs a heat absorption assurance action and a limiting action. The heat absorption assurance action ensures the heat absorption in the heat absorption section by using the heat possessed by the refrigerant discharged from the compressor and the heat absorbed by the heat absorption section from the heat absorption object.

[0425] After performing the heat absorption assurance action and the limiting action, the switch to the second heating mode is completed.

[0426] (Project 6)

[0427] A heat pump circulation device, comprising:

[0428] The compressor compresses and discharges the refrigerant;

[0429] A branch section that branches the flow of the refrigerant discharged from the compressor;

[0430] A heating section that uses the refrigerant flowing out from one outlet of the branch as a heat source to heat the object to be heated;

[0431] A low-temperature side pressure reduction section, which reduces the pressure of the refrigerant flowing out of the heating section;

[0432] A bypass passage for the refrigerant to flow to the other side of the branch;

[0433] A bypass-side pressure reducing unit that adjusts the flow rate of the refrigerant flowing in the bypass passage;

[0434] A confluence section that allows the flow of refrigerant from the bypass-side pressure reducing section to merge with the flow of refrigerant from the low-temperature-side pressure reducing section and flow out toward the suction port side of the compressor;

[0435] A heat-absorbing section, wherein the heat possessed by the object to be heated is absorbed at least by the refrigerant flowing out from the low-temperature side depressurization section; and

[0436] The control unit performs control for switching between the first heating mode and the second heating mode.

[0437] In the first heating mode, all the refrigerant discharged from the compressor flows into the heating section via the branch, and heats the object being heated by drawing heat absorbed from the object in the heat-absorbing section.

[0438] In the second heating mode, a portion of the refrigerant discharged from the compressor flows into the bypass passage via the branch, guides the refrigerant flowing from the bypass-side pressure reducing section towards the confluence section, and allows the remaining portion of the refrigerant discharged from the compressor to flow into the heating section via the branch. The refrigerant flowing from the heating section then merges with the flow of refrigerant from the bypass-side pressure reducing section at the confluence section and is drawn into the compressor.

[0439] When switching from the first heating mode to the second heating mode, the control unit performs a heat absorption assurance operation. This heat absorption assurance operation ensures the heat absorption in the heat absorption section by using the heat of the refrigerant discharged from the compressor and the heat absorbed by the heat absorption section from the heat absorption object. After performing the heat absorption assurance operation, the switch to the second heating mode is completed.

[0440] (Project 7)

[0441] The heat pump circulation device described in Project 6, wherein,

[0442] The heat pump circulation device is configured such that, while operating in the first heating mode, the heat absorption ensures that the heat absorption section continues to absorb heat from the heat-absorbing object.

[0443] A portion of the refrigerant discharged from the compressor flows into the bypass passage via the branch, and the refrigerant flowing out of the bypass-side pressure reducing section is guided to the confluence section.

[0444] (Project 8)

[0445] The heat pump circulation device described in item 6 or 7, wherein,

[0446] When performing the heat absorption assurance operation, the control unit suppresses heat absorption in the heat absorption section when the heat absorption stop condition is met. The heat absorption stop condition means that the amount of heat absorbed by the refrigerant from the heat absorption object in the heat absorption section is lower than a preset reference heat absorption.

[0447] (Project 9)

[0448] The heat pump circulation device described in Project 8, wherein,

[0449] When the heat absorption ensuring operation is performed, and the heat absorption stopping condition is met, the control unit reduces the supply of the heat-absorbing object to the heat-absorbing section, thereby suppressing heat absorption in the heat-absorbing section.

[0450] (Project 10)

[0451] The heat pump circulation device described in Project 8, wherein,

[0452] It has a refrigerant bypass flow path, which is connected such that the flow of refrigerant flowing out of the heating section bypasses the heat absorption section and is guided to the confluence section.

[0453] When the heat absorption is ensured, and the heat absorption stop condition is met, the control unit stops the supply of refrigerant to the heat absorption section by utilizing the refrigerant bypass flow path, thereby suppressing heat absorption in the heat absorption section.

[0454] (Project 11)

[0455] A heat pump circulation device, comprising:

[0456] A heat pump cycle includes a compressor, a refrigerant heat exchanger, a pressure reducing unit, and a cooler. The compressor compresses and discharges the refrigerant. The refrigerant heat exchanger dissipates heat from the high-pressure refrigerant discharged from the compressor to the heat medium. The pressure reducing unit reduces the pressure of the refrigerant flowing from the refrigerant heat exchanger. The cooler allows the pressure-reduced refrigerant to exchange heat with the heat medium, thereby absorbing heat from the refrigerant.

[0457] A heat medium circuit includes a first circuit, a second circuit, a heat medium connecting flow path, and a flow rate adjustment unit. The first circuit is configured to allow the heat medium flowing out from the heat medium refrigerant heat exchanger to circulate, and includes a heat medium radiator that dissipates heat from the heat medium to a heated object. The second circuit is configured to allow the heat medium to circulate in the cooler, and includes a heat medium absorber that absorbs heat from a heat-absorbing object through heat exchange with the heat medium. The heat medium connecting flow path is connected between the first circuit and the second circuit in a manner that allows the heat medium to flow in and out. The flow rate adjustment unit adjusts the flow rate of the heat medium flowing in and out between the first circuit and the second circuit via the heat medium connecting flow path.

[0458] The control unit controls the switching between independent cycle heating mode and loop cooperative heating mode.

[0459] The independent circulation heating mode utilizes the heat medium circulating independently in the second circuit to absorb and extract heat from the heat-absorbing object, and then heats the object via the heat medium radiator through the heat medium circulating independently in the first circuit.

[0460] The loop-cooperative heating mode causes a portion of the heat medium flowing through the heat medium refrigerant heat exchanger to flow through the heat medium connection path into the cooler, and causes the remaining portion of the heat medium flowing through the heat medium refrigerant heat exchanger to circulate in the first loop through the heat medium radiator, whereby the object to be heated is heated.

[0461] When switching from the independent circulation heating mode to the loop cooperative heating mode, the control unit performs a limiting action that restricts the heat dissipation in the heat transfer medium radiator of the independent circulation heating mode to a lower level. After performing the limiting action, the switching to the loop cooperative heating mode is completed.

[0462] (Project 12)

[0463] The heat pump circulation device described in Project 11, wherein,

[0464] It includes a supply adjustment unit that adjusts the supply amount of the heated object to the heat medium radiator.

[0465] The limiting action controls the operation of the supply adjustment unit, limiting the supply amount to the object to be heated by the heat medium radiator to a lower amount than a preset reference amount.

[0466] (Project 13)

[0467] The heat pump circulation device described in item 11 or 12, wherein,

[0468] When the limiting action is performed, the control unit ends the limiting action and releases the limitation on the heat dissipation in the heat medium radiator when the heating capacity of the heat medium circulating in the first loop exceeds a preset reference heating capacity.

[0469] (Project 14)

[0470] When the limiting action is performed, the control unit terminates the limiting action and releases the limitation on the heat dissipation of the heat transfer medium radiator when the pressure of the refrigerant in the cooler exceeds a preset low pressure.

[0471] (Project 15)

[0472] A heat pump circulation device described in any one of items 11 to 14, wherein,

[0473] When switching from the independent circulation heating mode to the loop cooperative heating mode, the control unit simultaneously performs a heat absorption assurance action and a limiting action. The heat absorption assurance action ensures the heat absorption in the cooler by combining the heat absorbed by the heat medium absorber from the heat-absorbing object and the heat possessed by the heat medium guided from the first loop to the cooler via the heat medium connection flow path.

[0474] After performing the heat absorption assurance action and the limiting action, the switch to the loop cooperative heating mode is completed.

[0475] Although this disclosure is based on embodiments, it is not to be construed as being limited to those embodiments or structures. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and methods, even those containing only one element, or more than one or fewer other combinations and methods, also fall within the scope and spirit of this disclosure.

Claims

1. A heat pump circulation device, characterized in that, have: The compressor compresses and discharges the refrigerant; A branch section that branches the flow of the refrigerant discharged from the compressor; A heating section that uses the refrigerant flowing out from one outlet of the branch as a heat source to heat the object to be heated; A low-temperature side pressure reduction section, which reduces the pressure of the refrigerant flowing out of the heating section; A bypass passage for the refrigerant to flow to the other side of the branch; A bypass-side pressure reducing unit that adjusts the flow rate of the refrigerant flowing through the bypass passage; A confluence section that allows the flow of refrigerant from the bypass-side pressure reducing section to merge with the flow of refrigerant from the low-temperature-side pressure reducing section and flow out toward the suction port side of the compressor; The heat-absorbing section allows the heat possessed by the heat-absorbing object to be absorbed at least by the refrigerant flowing out from the low-temperature side pressure-reducing section; as well as The control unit performs control for switching between the first heating mode and the second heating mode. In the first heating mode, all the refrigerant discharged from the compressor flows into the heating section via the branch, and heats the object being heated by drawing heat absorbed from the object in the heat-absorbing section. In the second heating mode, a portion of the refrigerant discharged from the compressor flows into the bypass passage via the branch, guides the refrigerant flowing from the bypass-side pressure reducing section towards the confluence section, and allows the remaining portion of the refrigerant discharged from the compressor to flow into the heating section via the branch. The refrigerant flowing from the heating section then merges with the flow of refrigerant from the bypass-side pressure reducing section at the confluence section and is drawn into the compressor. When switching from the first heating mode to the second heating mode, the control unit performs a limiting action to reduce the heat dissipation of the heating unit in the first heating mode. After performing the limiting action, the switching to the second heating mode is completed.

2. The heat pump circulation device according to claim 1, characterized in that, The heating unit includes a radiator and a supply adjustment unit. The radiator dissipates heat from the refrigerant flowing into the heating unit, and the supply adjustment unit adjusts the amount of refrigerant supplied to the radiator for the object to be heated. The limiting action controls the operation of the supply adjustment unit, limiting the supply amount to the object to be heated by the radiator to be lower than a preset reference amount.

3. The heat pump circulation device according to claim 1, characterized in that, When the limiting action is performed, if the heating capacity of the heating unit exceeds a preset reference heating capacity, the control unit ends the limiting action and releases the limitation on the heat dissipation of the heating unit.

4. The heat pump circulation device according to claim 1, characterized in that, When the limiting action is performed, the control unit terminates the limiting action and releases the limitation on the heat dissipation in the heating unit when the pressure of the refrigerant in the heat absorption section exceeds a preset reference low pressure.

5. The heat pump circulation device according to any one of claims 1 to 4, characterized in that, When switching from the first heating mode to the second heating mode, the control unit simultaneously performs a heat absorption assurance action and a limiting action. The heat absorption assurance action ensures the heat absorption in the heat absorption section by using the heat possessed by the refrigerant discharged from the compressor and the heat absorbed by the heat absorption section from the heat absorption object. After performing the heat absorption assurance action and the limiting action, the switch to the second heating mode is completed.

6. A heat pump circulation device, characterized in that, have: The compressor compresses and discharges the refrigerant; A branch section that branches the flow of the refrigerant discharged from the compressor; A heating section that uses the refrigerant flowing out from one outlet of the branch as a heat source to heat the object to be heated; A low-temperature side pressure reduction section, which reduces the pressure of the refrigerant flowing out of the heating section; A bypass passage for the refrigerant to flow to the other side of the branch; A bypass-side pressure reducing unit that adjusts the flow rate of the refrigerant flowing through the bypass passage; A confluence section that allows the flow of refrigerant from the bypass-side pressure reducing section to merge with the flow of refrigerant from the low-temperature-side pressure reducing section and flow out toward the suction port side of the compressor; The heat-absorbing section allows the heat possessed by the heat-absorbing object to be absorbed at least by the refrigerant flowing out from the low-temperature side pressure-reducing section; as well as The control unit performs control for switching between the first heating mode and the second heating mode. In the first heating mode, all the refrigerant discharged from the compressor flows into the heating section via the branch, and heats the object being heated by drawing heat absorbed from the object in the heat-absorbing section. In the second heating mode, a portion of the refrigerant discharged from the compressor flows into the bypass passage via the branch, guides the refrigerant flowing from the bypass-side pressure reducing section towards the confluence section, and allows the remaining portion of the refrigerant discharged from the compressor to flow into the heating section via the branch. The refrigerant flowing from the heating section then merges with the flow of refrigerant from the bypass-side pressure reducing section at the confluence section and is drawn into the compressor. When switching from the first heating mode to the second heating mode, the control unit performs a heat absorption assurance operation. This heat absorption assurance operation ensures the heat absorption in the heat absorption section by using the heat of the refrigerant discharged from the compressor and the heat absorbed by the heat absorption section from the heat absorption object. After performing the heat absorption assurance operation, the switch to the second heating mode is completed.

7. The heat pump circulation device according to claim 6, characterized in that, The heat pump circulation device is configured such that, while operating in the first heating mode, the heat absorption ensures that the heat absorption section continues to absorb heat from the heat-absorbing object. A portion of the refrigerant discharged from the compressor flows into the bypass passage via the branch, and the refrigerant flowing out of the bypass-side pressure reducing section is guided to the confluence section.

8. The heat pump circulation device according to claim 6, characterized in that, When performing the heat absorption assurance operation, the control unit suppresses heat absorption in the heat absorption section when the heat absorption stop condition is met. The heat absorption stop condition means that the amount of heat absorbed by the refrigerant from the heat absorption object in the heat absorption section is lower than a preset reference heat absorption.

9. The heat pump circulation device according to claim 8, characterized in that, When the heat absorption ensuring operation is performed, and the heat absorption stopping condition is met, the control unit reduces the supply of the heat-absorbing object to the heat-absorbing section, thereby suppressing heat absorption in the heat-absorbing section.

10. The heat pump circulation device according to claim 8, characterized in that, It has a refrigerant bypass flow path, which is connected such that the flow of refrigerant flowing out of the heating section bypasses the heat absorption section and is guided to the confluence section. When the heat absorption is ensured, and the heat absorption stop condition is met, the control unit stops the supply of refrigerant to the heat absorption section by utilizing the refrigerant bypass flow path, thereby suppressing heat absorption in the heat absorption section.

11. A heat pump cycle apparatus characterized by comprising: have: A heat pump cycle includes a compressor, a refrigerant heat exchanger, a pressure reducing unit, and a cooler. The compressor compresses and discharges the refrigerant. The refrigerant heat exchanger dissipates heat from the high-pressure refrigerant discharged from the compressor to the heat medium. The pressure reducing unit reduces the pressure of the refrigerant flowing from the refrigerant heat exchanger. The cooler allows the pressure-reduced refrigerant to exchange heat with the heat medium, thereby absorbing heat from the refrigerant. A heat medium circuit includes a first circuit, a second circuit, a heat medium connecting flow path, and a flow rate adjustment unit. The first circuit is configured to allow the heat medium flowing out from the heat medium refrigerant heat exchanger to circulate, and includes a heat medium radiator that dissipates heat from the heat medium to a heated object. The second circuit is configured to allow the heat medium to circulate in the cooler, and includes a heat medium absorber that absorbs heat from a heat-absorbing object through heat exchange with the heat medium. The heat medium connecting flow path is connected between the first circuit and the second circuit in a manner that allows the heat medium to flow in and out. The flow rate adjustment unit adjusts the flow rate of the heat medium flowing in and out between the first circuit and the second circuit via the heat medium connecting flow path. as well as The control unit controls the switching between independent cycle heating mode and loop cooperative heating mode. The independent circulation heating mode utilizes the heat medium circulating independently in the second circuit to absorb and extract heat from the heat-absorbing object, and then heats the object via the heat medium radiator through the heat medium circulating independently in the first circuit. The loop-cooperative heating mode causes a portion of the heat medium flowing through the heat medium refrigerant heat exchanger to flow through the heat medium connection path into the cooler, and causes the remaining portion of the heat medium flowing through the heat medium refrigerant heat exchanger to circulate in the first loop through the heat medium radiator, whereby the object to be heated is heated. When switching from the independent circulation heating mode to the loop cooperative heating mode, the control unit performs a limiting action that restricts the heat dissipation in the heat transfer medium radiator of the independent circulation heating mode to a lower level. After performing the limiting action, the switching to the loop cooperative heating mode is completed.

12. The heat pump circulation device according to claim 11, characterized in that, It includes a supply adjustment unit that adjusts the supply amount of the heated object to the heat medium radiator. The limiting action controls the operation of the supply adjustment unit, limiting the supply amount to the object to be heated by the heat medium radiator to a lower amount than a preset reference amount.

13. The heat pump circulation device according to claim 11, characterized in that, When the limiting action is performed, the control unit ends the limiting action and releases the limitation on the heat dissipation in the heat medium radiator when the heating capacity of the heat medium circulating in the first loop exceeds a preset reference heating capacity.

14. The heat pump circulation device according to claim 11, characterized in that, When the limiting action is performed, the control unit terminates the limiting action and releases the limitation on the heat dissipation of the heat transfer medium radiator when the pressure of the refrigerant in the cooler exceeds a preset low pressure.

15. The heat pump cycle device according to any one of claims 11 to 14, characterized in that, When switching from the independent circulation heating mode to the loop cooperative heating mode, the control unit simultaneously performs a heat absorption assurance action and a limiting action. The heat absorption assurance action ensures the heat absorption in the cooler by combining the heat absorbed by the heat medium absorber from the heat-absorbing object and the heat possessed by the heat medium guided from the first loop to the cooler via the heat medium connection flow path. After performing the heat absorption assurance action and the limiting action, the switch to the loop cooperative heating mode is completed.

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