Ejector-type refrigeration cycle device

Abstract

This ejector-type refrigeration cycle device comprises a compression part (11), a heating part (12), a branching part (13a), an outdoor-side decompression part (14a), an outdoor heat exchange part (15), a suction-side evaporation part (20), and an ejector (17). The ejector-type refrigeration cycle device has a series reheating mode and a parallel reheating mode as operation modes in which a temperature adjustment object which has been cooled by the suction-side evaporation part (20) is re-heated by the heating part (12). In the series reheating mode, a switch is made to a refrigerant circuit that causes refrigerant which has flowed out from the outdoor heat exchange part (15) to flow into a nozzle part (17a) of the ejector (17). In the parallel reheating mode, a switch is made to a refrigerant circuit that causes the refrigerant of one side resulting from being branched by the branch part (13a) to flow into the outdoor-side decompression part (14a), and causes the refrigerant of the other side resulting from being branched by the branch part (13a) to flow into the nozzle part (17a). During implementation of the series reheating mode, when the refrigerant suction capacity of the ejector (17) becomes less than or equal to a predetermined reference suction capacity, the mode is switched to the parallel reheating mode.

Description

Ejector type refrigeration cycle device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-109564, filed on July 8, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an ejector-type refrigeration cycle apparatus that includes an ejector and is configured to be able to switch refrigerant circuits.

[0003] A conventional ejector-type refrigeration cycle device applied to a vehicle air conditioner is disclosed in Patent Document 1. The ejector-type refrigeration cycle device of Patent Document 1 includes an ejector and is configured to be able to switch refrigerant circuits.

[0004] In this type of ejector-type refrigeration cycle system, the ejector draws in the refrigerant flowing out of the suction-side evaporator. This suction action of the ejector allows the refrigerant to flow into the suction-side evaporator. Furthermore, in this ejector-type refrigeration cycle system, the ejector's refrigerant pressure increase action increases the pressure of the refrigerant drawn into the compressor above the refrigerant evaporation pressure in the suction-side evaporator. This reduces the compressor's power consumption and improves the cycle's coefficient of performance (COP).

[0005] Furthermore, the ejector-type refrigeration cycle device of Patent Document 1 is configured to be able to switch between various operating modes by switching the refrigerant circuit. More specifically, when dehumidifying and heating the vehicle cabin, the operating mode is switched between an operating mode in which refrigerant flows into the nozzle of the ejector and an operating mode in which refrigerant does not flow into the nozzle. In each operating mode, the refrigerant pressure in the exterior heat exchanger is adjusted to continuously adjust the heating capacity of the blown air over a wide range.

[0006] JP 2018-63071 A

[0007] However, as in the ejector-type refrigeration cycle device of Patent Document 1, when dehumidifying and heating the vehicle cabin, if the refrigerant circuit is switched to one that does not allow refrigerant to flow into the nozzle portion of the ejector, it will not be possible to obtain the COP improvement effect due to the refrigerant pressure-boosting action of the ejector.

[0008] On the other hand, when the refrigerant circuit is switched to one that directs refrigerant to the nozzle and the refrigerant pressure in the outdoor heat exchanger is changed, if the pressure of the refrigerant flowing into the nozzle drops, the ejector may not be able to perform its refrigerant suction function, which results in an inability to supply refrigerant to the suction-side evaporator and the cycle not operating stably.

[0009] In view of the above, the present disclosure aims to provide an ejector-type refrigeration cycle device that can achieve both a high COP and stable operation when reheating a cooled temperature-adjusted object.

[0010] The ejector-type refrigeration cycle device of the first aspect of the present disclosure includes a compression unit, a heating unit, a branching unit, an outdoor pressure reduction unit, an outdoor heat exchange unit, a suction-side evaporation unit, an ejector, and a refrigerant circuit switching unit.

[0011] The compression unit compresses and discharges the refrigerant. The heating unit heats the object to be temperature-adjusted using the refrigerant discharged from the compression unit as a heat source. The branching unit branches the flow of refrigerant flowing out from the heating unit. The outdoor pressure reduction unit reduces the pressure of the refrigerant. The outdoor heat exchange unit exchanges heat between the refrigerant flowing out from the outdoor pressure reduction unit and outside air. The suction-side evaporation unit evaporates the refrigerant to cool the object to be temperature-adjusted.

[0012] The ejector has a nozzle portion and a body portion. The nozzle portion reduces the pressure of the refrigerant and sprays it. The body portion is formed with a suction port and a pressure-boosting portion. The suction port is a portion that sucks in the refrigerant that has flowed out from the suction-side evaporation portion. The pressure-boosting portion is a portion that mixes the refrigerant sprayed from the nozzle portion with the suction refrigerant sucked from the suction port to increase the pressure. The refrigerant circuit switching portion switches the refrigerant circuit.

[0013] Furthermore, the apparatus has a series reheating mode and a parallel reheating mode as operation modes in which the object to be temperature-adjusted that has been cooled in the suction-side evaporation section is reheated in the heating section.

[0014] In the series reheating mode, the refrigerant circuit switching unit switches to a refrigerant circuit that causes the refrigerant flowing out of the heating unit to flow into the outdoor pressure reduction unit and the refrigerant flowing out of the outdoor heat exchange unit to flow into the nozzle unit.In the parallel reheating mode, the refrigerant circuit switching unit switches to a refrigerant circuit that causes one refrigerant branched at the branch unit to flow into the outdoor pressure reduction unit and the other refrigerant branched at the branch unit to flow into the nozzle unit.

[0015] When the refrigerant suction capacity of the ejector becomes equal to or less than a predetermined reference suction capacity during execution of the series reheating mode, the mode is switched to the parallel reheating mode.

[0016] In the refrigerant circuit in the series reheating mode, the pressure of the refrigerant in the outdoor heat exchanger can be adjusted to a range higher than the saturation pressure of the refrigerant at the outdoor temperature by adjusting the amount of pressure reduction in the outdoor heat exchanger. Therefore, in the series reheating mode, the heating capacity of the heating unit can be continuously reduced as the amount of heat dissipated from the refrigerant in the outdoor heat exchanger to the outdoor air increases.

[0017] In the refrigerant circuit in the parallel reheating mode, the pressure of the refrigerant in the outdoor heat exchanger can be adjusted to a range lower than the saturation pressure of the refrigerant at the outdoor temperature by adjusting the amount of pressure reduction in the outdoor pressure reduction unit. Therefore, in the parallel reheating mode, the heating capacity of the heating unit can be continuously improved as the amount of heat absorbed by the refrigerant from the outdoor air in the outdoor heat exchanger increases.

[0018] Furthermore, when the refrigerant suction capacity of the ejector falls below a predetermined reference suction capacity during the serial reheating mode, the system switches to the parallel reheating mode. This allows the ejector to exhibit appropriate refrigerant suction capacity and refrigerant pressure increase capacity in either operating mode.

[0019] As a result, the ejector-type refrigeration cycle device of the first aspect can continuously adjust the heating capacity of the object to be temperature-adjusted over a wide range when reheating the cooled object to be temperature-adjusted, and can achieve both a high COP and stable operation.

[0020] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 1. A schematic overall configuration diagram of an ejector refrigeration cycle device of a first embodiment. 2. A schematic overall configuration diagram of an interior air conditioning unit of the first embodiment. 3. A block diagram showing an electrical control unit of a vehicle air conditioning device of the first embodiment. 4. A control characteristics diagram for determining an operation mode of the first embodiment. 5. A flowchart showing a control flow for determining an operation mode of the first embodiment. 6. A table showing the operating states of each component device of the first embodiment. 7. A schematic overall configuration diagram showing refrigerant flow in a cooling mode and a first dehumidifying heating mode of the ejector refrigeration cycle device of the first embodiment. 8. A control characteristics diagram for opening pattern control. 9. A Mollier diagram showing changes in refrigerant state in a first dehumidifying heating mode of the ejector refrigeration cycle device of the first embodiment. 10. A schematic overall configuration diagram showing refrigerant flow in a second dehumidifying heating mode and a third dehumidifying heating mode of the ejector refrigeration cycle device of the first embodiment. 11. A Mollier diagram showing changes in refrigerant state in a second dehumidifying heating mode of the ejector refrigeration cycle device of the first embodiment. Fig. 1 is a Mollier diagram showing a change in the state of refrigerant in a third dehumidifying heating mode of the ejector-type refrigeration cycle of the first embodiment. Fig. 2 is a schematic overall configuration diagram showing a flow of refrigerant in a heating mode of the ejector-type refrigeration cycle device of the first embodiment. Fig. 3 is a flowchart showing a control flow for determining an operation mode of the second embodiment. Fig. 4 is a schematic overall configuration diagram of an ejector-type refrigeration cycle device of a third embodiment. Fig. 5 is a schematic overall configuration diagram of an ejector-type refrigeration cycle device of a fourth embodiment.

[0021] Hereinafter, multiple embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicate descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0022] 1 to 13, a first embodiment of an ejector-type refrigeration cycle device according to the present disclosure will be described. In this embodiment, the ejector-type refrigeration cycle device according to the present disclosure is applied to a vehicle air conditioner 1. The vehicle air conditioner 1 conditions the air inside a vehicle cabin, which is a space to be air-conditioned. The vehicle air conditioner 1 includes an ejector-type refrigeration cycle 10, an interior air conditioning unit 30, a control device 50, and the like.

[0023] First, an ejector-type refrigeration cycle device 10 will be described with reference to the overall configuration diagram of Fig. 1. The ejector-type refrigeration cycle device 10 is a vapor compression refrigeration cycle device that includes an ejector 17 (described later) and adjusts the temperature of the air blown into the vehicle cabin. Therefore, the object to be temperature-adjusted in the ejector-type refrigeration cycle device of this embodiment is the blown air.

[0024] The ejector refrigeration cycle 10 is configured to be able to switch a refrigerant circuit according to various operating modes (described later) to provide air conditioning for the vehicle cabin. The ejector refrigeration cycle 10 uses carbon dioxide, a natural refrigerant, as the refrigerant. The ejector refrigeration cycle 10 constitutes a supercritical refrigeration cycle in which the refrigerant pressure on the high-pressure side is equal to or higher than the critical pressure of the refrigerant.

[0025] The refrigerant is mixed with refrigerating machine oil to lubricate the compressor 11. The refrigerating machine oil is PAG oil (i.e., polyalkylene glycol oil) or POE (i.e., polyol ester) that is compatible with the liquid-phase refrigerant. A portion of the refrigerating machine oil circulates through the ejector-type refrigeration cycle 10 together with the refrigerant.

[0026] The compressor 11 is a compression unit in the ejector-type refrigeration cycle 10 that draws in, compresses, and discharges refrigerant. The compressor 11 is an electric compressor that uses an electric motor to rotate a fixed-displacement compression mechanism with a fixed discharge capacity. The rotation speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from a control device 50, which will be described later.

[0027] The compressor 11 is disposed in a drive unit compartment formed in the front side of the vehicle compartment. The drive unit compartment forms a space in which at least some of the devices used to generate and adjust the drive force for vehicle operation are disposed. The space formed by the drive unit compartment is outside the vehicle compartment (i.e., outside the space to be air-conditioned).

[0028] The discharge port of the compressor 11 is connected to the refrigerant inlet side of an indoor radiator 12. The indoor radiator 12 is a heating heat exchanger that exchanges heat between the refrigerant discharged from the compressor and the blown air that has passed through a suction-side evaporator 20 (described later). The indoor radiator 12 heats the blown air by radiating heat from the discharged refrigerant to the blown air. The indoor radiator 12 is disposed in an air passage formed in an air conditioning case 31 of an indoor air-conditioning unit 30 (described later).

[0029] Therefore, the indoor radiator 12 is a heating section that heats the blown air using the refrigerant discharged from the compressor 11 as a heat source.

[0030] The inlet side of a first three-way joint 13a is connected to the refrigerant outlet of the indoor radiator 12. The first three-way joint 13a has three inlet and outlet ports that communicate with each other. The first three-way joint 13a can be a joint formed by joining multiple pipes or a joint formed by providing multiple refrigerant passages in a metal block or a resin block.

[0031] Furthermore, the ejector-type refrigeration cycle 10 includes a second three-way joint 13b to a fourth three-way joint 13d, as will be described later. The second three-way joint 13b to the fourth three-way joint 13d have the same basic configuration as the first three-way joint 13a. The basic configuration of each three-way joint described in the embodiments below is also the same as the first three-way joint 13a.

[0032] The three-way joint branches the refrigerant flow when one of the three inlet / outlet ports is used as an inlet and the remaining two are used as outlet ports. The three-way joint merges the refrigerant flows when two of the three inlet / outlet ports are used as inlet ports and the remaining one is used as an outlet port. The first three-way joint 13a is a branching section that branches the refrigerant flow that flows out of the indoor radiator 12.

[0033] One outlet of the first three-way joint 13a is connected to the inlet side of the heating expansion valve 14a, and the other outlet of the first three-way joint 13a is connected to the inlet of the first passage 22a.

[0034] The heating expansion valve 14a is an outdoor-side pressure reducing unit that reduces the pressure of the refrigerant flowing out from one outlet of the first three-way joint 13a during a dehumidifying heating mode, etc., which will be described later. The heating expansion valve 14a also serves as an outdoor-side flow rate adjusting unit that adjusts the flow rate (in this embodiment, the mass flow rate) of the refrigerant flowing into the outdoor heat exchanger 15.

[0035] The heating expansion valve 14a is an electric variable throttle mechanism having a valve body that changes the opening of the throttle passage and an electric actuator (specifically, a stepping motor or a brushless DC motor) that acts as a drive unit that displaces the valve body. The operation of the heating expansion valve 14a is controlled by a control signal output from the control device 50.

[0036] The heating expansion valve 14a has a fully open function, in which it functions simply as a refrigerant passage by fully opening the valve and exerting almost no refrigerant decompression or flow rate adjustment functions, and also has a fully closed function, in which the valve body fully closes the throttle passage and blocks the refrigerant passage.

[0037] Furthermore, the ejector refrigeration cycle 10 includes a cooling expansion valve 14b and an evaporative pressure control valve 14c, as will be described later. The cooling expansion valve 14b and the evaporative pressure control valve 14c have the same basic configuration as the heating expansion valve 14a. The basic configurations of various expansion valves described in the following embodiments are also the same as the heating expansion valve 14a.

[0038] Therefore, the cooling expansion valve 14b and the evaporation pressure regulating valve 14c have a fully open function and a fully closed function. The heating expansion valve 14a, the cooling expansion valve 14b, and the evaporation pressure regulating valve 14c can switch the circuit configuration of the refrigerant circuit by performing the fully closed function. Therefore, the heating expansion valve 14a, the cooling expansion valve 14b, and the evaporation pressure regulating valve 14c also function as a refrigerant circuit switching unit.

[0039] Of course, the heating expansion valve 14a, the cooling expansion valve 14b, and the evaporation pressure regulating valve 14c may be formed by combining a variable throttle mechanism that does not have a full-closing function with an on-off valve that opens and closes the throttle passage. In this case, the on-off valve serves as the refrigerant circuit switching unit.

[0040] The outlet of the heating expansion valve 14a is connected to the refrigerant inlet side of an exterior heat exchanger 15. The exterior heat exchanger 15 is an exterior heat exchanger that exchanges heat between the refrigerant flowing out of the heating expansion valve 14a and outside air blown in by an outside air fan (not shown). The exterior heat exchanger 15 is located on the front side of the drive unit compartment. Therefore, when the vehicle is traveling, traveling air that flows into the drive unit compartment through the grille can be directed against the exterior heat exchanger 15.

[0041] The inlet side of the second three-way joint 13b is connected to the refrigerant outlet of the outdoor heat exchanger 15. One outlet side of the second three-way joint 13b is connected to one inlet side of the third three-way joint 13c via a first check valve 16a. The other outlet side of the second three-way joint 13b is connected to the inlet of the second passage 22b.

[0042] The other inlet of the third three-way joint 13c is connected to the outlet of the first passage 22a. The outlet of the third three-way joint 13c is connected to the inlet of the cooling expansion valve 14b. The first check valve 16a allows the refrigerant to flow from the second three-way joint 13b to the third three-way joint 13c, but prevents the refrigerant from flowing from the third three-way joint 13c to the second three-way joint 13b.

[0043] The cooling expansion valve 14b is a nozzle-side pressure reducing part that reduces the pressure of the refrigerant flowing out from the third three-way joint 13c in the dehumidifying heating mode, etc. The cooling expansion valve 14b is also a nozzle-side flow rate adjusting part that adjusts the flow rate of the refrigerant flowing into the nozzle 17a of the ejector 17.

[0044] The outlet of the cooling expansion valve 14b is connected to the inlet side of a nozzle 17a of an ejector 17. The ejector 17 reduces the pressure of the refrigerant flowing out of the cooling expansion valve 14b during a dehumidifying heating mode or the like. The ejector 17 is a refrigerant transport unit that sucks in and transports the refrigerant flowing out of the suction-side evaporator 20. The ejector 17 also functions as a refrigerant pressurizing unit that pressurizes the refrigerant that flows into the ejector 17.

[0045] The ejector 17 has a nozzle portion 17a and a body portion 17b. The nozzle portion 17a is formed of a generally cylindrical metal (stainless steel alloy in this embodiment) member that tapers in the direction of refrigerant flow. The nozzle portion 17a isentropically decompresses the refrigerant in a refrigerant passage formed therein, accelerates the refrigerant to supersonic speed, and then sprays the refrigerant. A so-called Laval nozzle or a tapered nozzle may be used as the nozzle portion 17a.

[0046] The body portion 17b is formed of a substantially cylindrical member made of metal (aluminum alloy in this embodiment). The body portion 17b is a fixing member that supports and fixes the nozzle portion 17a, and also forms the outer shell of the ejector 17. Specifically, the nozzle portion 17a is fixed by press-fitting so as to be housed inside one longitudinal end of the body portion 17b. The body portion 17b may be formed of resin.

[0047] When viewed from the outer periphery of the body portion 17b, a suction port 17c is formed at a portion corresponding to the outer periphery of the nozzle portion 17a. The suction port 17c penetrates the body portion 17b from inside to outside and communicates with the refrigerant injection port of the nozzle portion 17a. The suction port 17c is a through-hole that draws the refrigerant flowing out from the suction-side evaporator 20 into the inside of the ejector 17 by the suction action of the refrigerant injected from the nozzle portion 17a.

[0048] The body 17b includes a suction passage and a diffuser 17d. The suction passage guides the refrigerant drawn through the suction port 17c toward the refrigerant jet nozzle of the nozzle 17a. The diffuser 17d mixes the drawn refrigerant with the jetted refrigerant to increase the pressure.

[0049] More specifically, the diffuser 17d is a refrigerant passage that is connected to the outlet of the suction passage. The diffuser 17d is shaped like a truncated cone, with the cross-sectional area expanding downstream in the refrigerant flow. The diffuser 17d converts the kinetic energy of the mixed refrigerant into pressure energy by the action of shock waves generated by the injected refrigerant and the expansion of the cross-sectional area of ​​the passage.

[0050] Furthermore, the ejector 17 of this embodiment has dimensional specifications set so as to exhibit a reference suction capacity when the pressure Pnoz of the refrigerant flowing into the nozzle portion 17a is equal to or greater than a predetermined reference pressure KPnoz.

[0051] More specifically, the reference pressure KPnoz in this embodiment is the saturation pressure of the refrigerant at the lowest outdoor temperature (e.g., 10°C) expected when the first dehumidifying heating mode described below is executed. The reference suction capacity is a suction capacity that allows the ejector-type refrigeration cycle 10 to operate stably.

[0052] The outlet of the diffuser section 17d is connected to the inlet side of a gas-liquid separator 18. The gas-liquid separator 18 is an ejector-side gas-liquid separator that separates the refrigerant flowing out from the ejector 17 into gas and liquid. The inlet side of a fixed throttle 19 is connected to a liquid-phase refrigerant outlet from which mainly liquid-phase refrigerant flows out of the gas-liquid separator 18. The inlet side of the evaporation pressure control valve 14c is connected to a gas-phase refrigerant outlet from which mainly gas-phase refrigerant flows out of the gas-liquid separator 18.

[0053] The fixed throttle 19 is a separator-side pressure reducing section that reduces the pressure of the refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18. The fixed throttle 19 also serves as a flow rate adjusting section that adjusts the flow rate of the refrigerant flowing into the suction-side evaporator 20. The fixed throttle 19 may be an orifice, a capillary tube, or the like.

[0054] The outlet of the fixed throttle 19 is connected to the refrigerant inlet side of the suction-side evaporator 20. The suction-side evaporator 20 is a cooling heat exchanger that exchanges heat between the low-pressure refrigerant flowing out from the fixed throttle 19 and the air blown into the vehicle cabin by the interior blower 32.

[0055] The suction-side evaporator 20 is a suction-side evaporator that cools the blown air by evaporating low-pressure refrigerant and absorbing heat. The suction-side evaporator 20 is disposed in an air passage in the air conditioning case 31 of the indoor air conditioning unit 30. The suction port 17c side of the ejector 17 is connected to the refrigerant outlet of the suction-side evaporator 20.

[0056] The evaporation pressure regulating valve 14c maintains the refrigerant evaporation pressure in the suction side evaporator 20 at or above a predetermined set pressure to suppress frost formation on the suction side evaporator 20. An outlet of the evaporation pressure regulating valve 14c is connected to one inlet of a fourth three-way joint 13d via a second check valve 16b. An outlet of the second passage 22b is connected to the other inlet of the fourth three-way joint 13d.

[0057] The second check valve 16b allows the refrigerant to flow from the evaporation pressure adjustment valve 14c side to the fourth three-way joint 13d side, but prevents the refrigerant from flowing from the fourth three-way joint 13d side to the evaporation pressure adjustment valve 14c side. The outlet of the fourth three-way joint 13d is connected to the inlet side of the accumulator 21.

[0058] The accumulator 21 is a low-pressure side gas-liquid separator that separates the refrigerant flowing out from the fourth three-way joint 13d into gas and liquid phases and stores the separated liquid phase refrigerant as surplus refrigerant for the cycle. The gas phase refrigerant outlet of the accumulator 21 is connected to the refrigerant suction port side of the compressor 11.

[0059] As described above, the first passage 22a is a refrigerant passage that connects the other outlet of the first three-way joint 13a and the other inlet of the third three-way joint 13c. The first passage 22a is provided with a first on-off valve 23a that opens and closes the first passage 22a. The first on-off valve 23a is an electromagnetic valve whose opening and closing operation is controlled by a control voltage output from the control device 50.

[0060] The second passage 22b is a refrigerant passage that connects the other outlet of the second three-way joint 13b and the other inlet of the fourth three-way joint 13d. A second on-off valve 23b and a third check valve 16c that open and close the second passage 22b are arranged in the second passage 22b. The basic configuration of the second on-off valve 23b is the same as that of the first on-off valve 23a.

[0061] The third check valve 16c allows the refrigerant to flow from the second three-way joint 13b to the fourth three-way joint 13d and prohibits the refrigerant from flowing from the fourth three-way joint 13d to the second three-way joint 13b. More specifically, the third check valve 16c in this embodiment is arranged to allow the refrigerant that has flowed out from the second on-off valve 23b to flow to the fourth three-way joint 13d.

[0062] The first on-off valve 23a and the second on-off valve 23b open and close the first passage 22a and the second passage 22b, respectively, to switch the refrigerant circuit of the ejector refrigeration cycle 10. Therefore, the first on-off valve 23a and the second on-off valve 23b are refrigerant circuit switching units.

[0063] Next, the interior air conditioning unit 30 will be described with reference to Figure 2. The interior air conditioning unit 30 is a unit that integrates multiple components to blow out air adjusted to an appropriate temperature for air conditioning the vehicle cabin to an appropriate location within the vehicle cabin. The interior air conditioning unit 30 is located within the vehicle cabin. More specifically, the interior air conditioning unit 30 is located inside the instrument panel at the front of the vehicle cabin.

[0064] 2, the indoor air conditioning unit 30 has an air conditioning case 31 that forms an air passage for blown air. The air passage formed in the air conditioning case 31 accommodates an indoor blower 32, a suction-side evaporator 20, an indoor radiator 12, etc. The air conditioning case 31 is made of a resin (specifically, polypropylene) that has a certain degree of elasticity and excellent strength.

[0065] An inside / outside air switching device 33 is disposed at the most upstream side of the blown air flow of the air conditioning case 31. The inside / outside air switching device 33 is an inside / outside air switching unit that switches between introducing inside air (i.e., air inside the vehicle cabin) and outside air (i.e., air outside the vehicle cabin) into the air conditioning case 31. The operation of the inside / outside air switching device 33 is controlled by a control signal output from the control device 50.

[0066] An interior blower 32 is disposed downstream of the inside / outside air switching device 33 in the flow of blown air. The interior blower 32 is a blower that blows air drawn in through the inside / outside air switching device 33 toward the vehicle interior. The rotation speed (i.e., blowing capacity) of the interior blower 32 is controlled by a control voltage output from the control device 50.

[0067] The suction-side evaporator 20 and the indoor radiator 12 are disposed downstream in the flow of air blown by the indoor blower 32. The suction-side evaporator 20 is disposed upstream in the flow of air blown from the indoor radiator 12. A cool air bypass passage 35 is formed in the air conditioning case 31, allowing the blown air that has passed through the suction-side evaporator 20 to bypass the indoor radiator 12.

[0068] An air mix door 34 is disposed downstream of the suction-side evaporator 20 in the air conditioning case 31 in the direction of the blown air flow, and upstream of the indoor radiator 12 and the cool air bypass passage 35 in the direction of the blown air flow.

[0069] The air mix door 34 adjusts the ratio of the volume of the blown air that passes through the heating air passage in which the indoor radiator 12 is disposed to the volume of the blown air that passes through the cold air bypass passage 35 after passing through the suction side evaporator 20. The operation of the actuator for driving the air mix door 34 is controlled by a control signal output from the control device 50.

[0070] A mixing space 36 is disposed downstream of the indoor radiator 12 and the cold air bypass passage 35 in the flow direction of the blown air. The mixing space 36 is a space where the blown air heated by the indoor radiator 12 is mixed with the blown air that has passed through the cold air bypass passage 35 and has not been heated.

[0071] In the interior air conditioning unit 30, the temperature of the blown air (i.e., conditioned air) that is mixed in the mixing space 36 and blown into the vehicle cabin can be adjusted by adjusting the opening degree of the air mix door 34. Therefore, the air mix door 34 is a heat exchange air volume adjustment unit that adjusts the volume of the blown air that is heat exchanged in the interior radiator 12.

[0072] A plurality of openings (not shown) for blowing conditioned air toward various locations in the vehicle cabin are formed at the most downstream portion of the airflow of the air-conditioning case 31. Blowing mode doors (not shown) for opening and closing the respective openings are disposed in the plurality of openings. The operation of the actuators for driving the blowing mode doors is controlled by a control signal output from the control device 50.

[0073] Therefore, in the interior air conditioning unit 30, by switching the opening holes that the blow-out mode door opens and closes, conditioned air that has been adjusted to an appropriate temperature can be blown out to an appropriate location in the vehicle interior.

[0074] Next, the electrical control unit of the vehicle air conditioner 1 will be described with reference to Figure 3. The control device 50 has a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 50 performs various calculations and processes based on control programs stored in the ROM. The control device 50 controls the operation of various controlled devices connected to the output side based on the results of the calculations and processes.

[0075] 3, a group of control sensors is connected to the input side of the control device 50. The group of control sensors includes an inside air temperature sensor 51a, an outside air temperature sensor 51b, a solar radiation amount sensor 51c, a discharge refrigerant temperature sensor 52a, a radiator refrigerant sensor 52b, an outdoor unit refrigerant sensor 52c, an evaporator refrigerant sensor 52d, an evaporator temperature sensor 52f, an air conditioning air temperature sensor 53, and the like.

[0076] The inside air temperature sensor 51a is an inside air temperature detector that detects the inside air temperature (i.e., the temperature inside the vehicle cabin) Tr. The outside air temperature sensor 51b is an outside air temperature detector that detects the outside air temperature (i.e., the temperature outside the vehicle cabin) Tam. The solar radiation sensor 51c is an solar radiation amount detector that detects the amount of solar radiation As irradiating into the vehicle cabin.

[0077] The discharge refrigerant temperature sensor 52a is a radiator refrigerant temperature detector that detects a discharge refrigerant temperature Td, which is the temperature of the refrigerant discharged from the compressor 11. The radiator refrigerant sensor 52b is a radiator refrigerant temperature and pressure detector that detects a first refrigerant temperature T1 and a first refrigerant pressure P1, which are the temperature and pressure of the refrigerant flowing out from the indoor radiator 12. The outdoor unit refrigerant sensor 52c is an outdoor unit refrigerant temperature and pressure detector that detects a second refrigerant temperature T2 and a second refrigerant pressure P2, which are the temperature and pressure of the refrigerant flowing out from the outdoor heat exchanger 15.

[0078] The evaporator refrigerant sensor 52d is an evaporator refrigerant temperature and pressure detection unit that detects the suction refrigerant temperature Tes and suction refrigerant pressure Pes, which are the temperature and pressure of the refrigerant flowing out from the suction side evaporator 20. The evaporator temperature sensor 52f is an evaporator temperature detection unit that detects the evaporator temperature Tefin, which is the temperature of the suction side evaporator 20. Specifically, the evaporator temperature sensor 52f in this embodiment detects the heat exchange fin temperature of the suction side evaporator 20.

[0079] The conditioned air temperature sensor 53 is an conditioned air temperature detection unit that detects the temperature TAV of the air blown from the interior air conditioning unit 30 into the vehicle interior.

[0080] 3, an operation panel 59 located near the instrument panel at the front of the vehicle interior is connected to the input side of the control device 50 via wired or wireless connection. Operation signals are input to the control device 50 from various operation switches provided on the operation panel 59. Specific examples of the various operation switches provided on the operation panel 59 include an auto switch, an air conditioning switch, an air volume setting switch, a temperature setting switch, etc.

[0081] The auto switch is an automatic control setting unit that sets or cancels automatic control operation of the vehicle air conditioner 1. The air conditioner switch is a cooling request unit that requests cooling of the blown air by the suction side evaporator 20. The air volume setting switch is an air volume setting unit that manually sets the volume of the blown air to be blown into the vehicle cabin. The temperature setting switch is a temperature setting unit that sets the set temperature Tset inside the vehicle cabin.

[0082] The control device 50 of this embodiment is a device in which a control unit for controlling various control target devices connected to the output side is integrated, and therefore the configuration (hardware and software) for controlling the operation of each control target device constitutes a control unit for controlling the operation of each control target device.

[0083] For example, in the control device 50, the component that controls the refrigerant discharge capacity of the compressor 11 constitutes a discharge capacity control unit, and the component that controls the operation of the refrigerant circuit switching unit constitutes a refrigerant circuit control unit.

[0084] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. The vehicle air conditioner 1 switches between various operating modes to provide appropriate air conditioning for the vehicle cabin. The switching of operating modes is performed by executing a control program stored in advance in the control device 50.

[0085] The control program is executed when the auto switch is turned on while the air conditioning switch on the operation panel 59 is turned on. The control program reads detection signals from the control sensors described above and operation signals from the operation switches on the operation panel 59. The control program also calculates a required blowout temperature TAO. The required blowout temperature TAO is the target temperature of the air blown into the vehicle cabin from the mixing space 36 of the interior air conditioning unit 30.

[0086] The required air temperature TAO is calculated using the following formula F1: TAO=Kset×Tset−Kr×Tr−Kam×Tam−Ks×As+C (F1) Tset is the vehicle interior temperature set by the temperature setting switch on the operation panel 59. Tr is the inside air temperature detected by the inside air temperature sensor 51a. Tam is the outside air temperature detected by the outside air temperature sensor 51b. As is the amount of solar radiation detected by the solar radiation amount sensor 51c. Kset, Kr, Kam, and Ks are control gains, and C is a correction constant.

[0087] Furthermore, the control program determines the operation mode based on the outside air temperature Tam and the required blow-out temperature TAO, a control map stored in advance in the control device 50, and the determination result of the suction capacity determination program.

[0088] More specifically, in the control program of this embodiment, the operation mode is determined based on the position of a point determined by the outside air temperature Tam and the required blow-out temperature TAO, as shown in the control characteristics diagram of Fig. 4. Furthermore, if the operation mode determined by the control characteristics diagram of Fig. 4 is the first dehumidifying and heating mode, indicated by dotted hatching, the control device 50 executes a suction capacity determination program shown in the flowchart of Fig. 5.

[0089] The suction capacity determination program shown in the flowchart of Fig. 5 is a subroutine called by the main routine of the control program when the operation mode determined by the control characteristics diagram of Fig. 4 is the first dehumidifying and heating mode. Each control step shown in the flowchart of Fig. 5 is a function realization part of the control device 50.

[0090] 5, it is determined whether the superheat degree SH of the refrigerant on the outlet side of the suction side evaporator 20 is equal to or greater than a predetermined reference superheat degree KSH1. Here, an increase in the superheat degree SH beyond what is necessary means that the flow rate of the refrigerant flowing into the suction side evaporator 20 is decreasing. Therefore, an increase in the superheat degree SH beyond what is necessary means that the refrigerant suction capacity of the ejector 17 is decreasing.

[0091] Therefore, in the suction capacity determination program of this embodiment, when the superheat degree SH is equal to or greater than the reference superheat degree KSH1 in step S51a, it is determined that the refrigerant suction capacity of the ejector 17 is equal to or less than the reference suction capacity, and the program proceeds to step S52, where the operation mode is changed to the second dehumidifying and heating mode, and the program returns to the main routine.

[0092] If it is determined in step S51a that the superheat degree SH is lower than the reference superheat degree KSH1, it is determined that the refrigerant suction capacity of the ejector 17 is higher than the reference suction capacity, and the process returns to the main routine. That is, the operation mode is maintained in the first dehumidifying and heating mode, and the process returns to the main routine. Therefore, step S51a of the suction capacity determination program is a suction capacity determination section.

[0093] Furthermore, the control program controls the operation of various control target devices according to the determined operation mode. The control program repeats control routines such as reading the detection signal and operation signal, calculating the required blow-out temperature TAO, determining the operation mode, and controlling the operation of various control target devices according to the determined operation mode at each predetermined control cycle until a predetermined termination condition is met. Detailed operations in each operation mode are described below.

[0094] (a) Cooling Mode The cooling mode is an operating mode in which cooled air is blown into the vehicle cabin to cool the interior of the vehicle. The cooling mode is likely to be selected when the auto switch and the air conditioner switch are on, the outside air temperature Tam is relatively high (in this embodiment, 25°C or higher), or the required air outlet temperature TAO is relatively low.

[0095] 6, in the cooling mode, the control device 50 fully opens the heating expansion valve 14a, fully opens the cooling expansion valve 14b, and fully opens the evaporation pressure control valve 14c. The control device 50 also closes the first on-off valve 23a and the second on-off valve 23b.

[0096] 7, in the cooling mode, the ejector refrigeration cycle 10 switches to a refrigerant circuit in which the refrigerant discharged from the compressor 11 flows in the following order: the indoor radiator 12, the heating expansion valve 14a, the outdoor heat exchanger 15, the cooling expansion valve 14b, the ejector 17, and the gas-liquid separator 18. Furthermore, the refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18 flows in the following order: the fixed throttle 19, the suction-side evaporator 20, and the suction port 17c of the ejector 17, and the refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 flows in the following order: the evaporation pressure control valve 14c, the accumulator 21, and the suction port of the compressor 11.

[0097] The control device 50 also performs evaporator temperature control on the compressor 11. In the evaporator temperature control, the refrigerant discharge capacity of the compressor 11 is controlled so that the evaporator temperature Tefin detected by the evaporator temperature sensor 52f approaches the target evaporator temperature TEO.

[0098] The target evaporator temperature TEO is determined based on the required air outlet temperature TAO by referring to a control map stored in advance in the control device 50. The control map increases the target evaporator temperature TEO as the required air outlet temperature TAO increases. The control map also determines the target evaporator temperature TEO within a range that can suppress frost formation on the suction side evaporator 20.

[0099] The control device 50 also performs outdoor unit outlet pressure control on the cooling expansion valve 14b. In the outdoor unit outlet pressure control, the throttle opening of the cooling expansion valve 14b is controlled so that the second refrigerant pressure P2 detected by the outdoor unit refrigerant sensor 52c approaches a target second refrigerant pressure P02.

[0100] The target second refrigerant pressure PO2 is determined based on the discharge refrigerant temperature Td detected by the discharge refrigerant temperature sensor 52a and by referring to a control map pre-stored in the control device 50. The control map determines the target second refrigerant pressure PO2 so that the COP of the ejector refrigeration cycle 10 approaches its maximum value.

[0101] In the indoor air conditioning unit 30 in the cooling mode, the control device 50 controls the air blowing capacity of the indoor blower 32 so as to achieve the target air blowing capacity. The target air blowing capacity of the indoor blower 32 is determined based on the required blowing temperature TAO by referring to a control map stored in advance in the control device 50.

[0102] In the control map, when the required blowing temperature TAO is in the extremely low temperature range (i.e., during maximum cooling), the blowing capacity is determined to approach the maximum air volume. Furthermore, as the required blowing temperature TAO moves from the extremely low temperature range to the intermediate temperature range, the blowing capacity is determined to decrease. And when the required blowing temperature TAO is in the intermediate temperature range, the blowing capacity is determined to approach the minimum air volume.

[0103] The control device 50 also controls the operation of the electric actuator for the air mix door 34 so that the blown air temperature TAV detected by the air conditioning air temperature sensor 53 approaches the required blown air temperature TAO.

[0104] The control device 50 also controls the operation of the inside / outside air switching device 33 based on the operation signal and the required blowing temperature TAO. The control device 50 also controls the operation of the electric actuator for the blowing mode door based on the required blowing temperature TAO by referring to a control map pre-stored in the control device 50. The control device 50 also controls the operation of other control target devices as appropriate.

[0105] Therefore, in the cooling mode of the ejector refrigeration cycle 10, the refrigerant discharged from the compressor 11 flows into the indoor radiator 12. The refrigerant flowing into the indoor radiator 12 dissipates heat to the blown air cooled by the suction-side evaporator 20, depending on the opening degree of the air mix door 34. In the cooling mode, the operation of the air mix door 34 is often controlled so that the volume of the blown air flowing into the cool air bypass passage 35 is greater than the volume of the blown air flowing toward the indoor radiator 12.

[0106] The refrigerant flowing out from the indoor radiator 12 flows into the outdoor heat exchanger 15 via the heating expansion valve 14a. The refrigerant flowing into the outdoor heat exchanger 15 dissipates heat to the outside air. The refrigerant flowing out from the outdoor heat exchanger 15 flows into the cooling expansion valve 14b and is depressurized. The refrigerant depressurized by the cooling expansion valve 14b flows into the nozzle 17a of the ejector 17. The refrigerant flowing into the nozzle 17a is isentropically depressurized and injected toward the diffuser 17d.

[0107] In the ejector 17, the refrigerant ejected from the nozzle 17a is sucked from the suction port 17c, which sucks the refrigerant flowing out from the suction-side evaporator 20. The suctioned refrigerant is guided through the suction passage to the diffuser 17d. Furthermore, the suction of the refrigerant causes the refrigerant decompressed by the fixed throttle 19 to flow into the suction-side evaporator 20.

[0108] In the diffuser 17d, the velocity energy of the refrigerant mixture of the injected refrigerant and the suctioned refrigerant is converted into pressure energy due to the action of shock waves generated by the injected refrigerant and the expansion of the cross-sectional area of ​​the passage. This increases the pressure of the refrigerant mixture of the injected refrigerant and the suctioned refrigerant. The refrigerant flowing out of the diffuser 17d flows into the gas-liquid separator 18 and is separated into gas and liquid.

[0109] The refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18 is depressurized by the fixed throttle 19 and flows into the suction-side evaporator 20. The refrigerant flowing into the suction-side evaporator 20 absorbs heat from the blown air blown by the indoor blower 32 and evaporates. This cools the blown air.

[0110] The refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 flows into the accumulator 21 via the evaporation pressure control valve 14c. The accumulator 21 separates the refrigerant into gas and liquid phases and stores the separated liquid-phase refrigerant as surplus refrigerant for the cycle. Therefore, the refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 may contain liquid-phase refrigerant. The refrigerant flowing out from the gas-phase refrigerant outlet of the accumulator 21 is drawn into the compressor 11 and compressed again.

[0111] In addition, in the interior air conditioning unit 30 in cooling mode, the air blown from the interior blower 32 toward the vehicle interior is cooled as it passes through the suction-side evaporator 20. The air cooled by the suction-side evaporator 20 is reheated depending on the opening degree of the air mix door 34. The temperature-adjusted air is then blown out to an appropriate location in the vehicle interior, thereby cooling the vehicle interior.

[0112] (b) Dehumidifying and Heating Mode The dehumidifying and heating mode is an operating mode in which cooled and dehumidified ventilation air is reheated and blown into the passenger compartment to dehumidify and heat the passenger compartment. The dehumidifying and heating mode is likely to be selected when the auto switch and air conditioner switch are on, the outside air temperature Tam is in the intermediate range (in this embodiment, 10°C or higher and lower than 25°C), or when the required outlet temperature TAO is in the intermediate range.

[0113] The dehumidifying and heating modes include a first dehumidifying and heating mode, a second dehumidifying and heating mode, and a third dehumidifying and heating mode. In the second dehumidifying and heating mode, the air can be reheated with a higher heating capacity than in the first dehumidifying and heating mode. In the third dehumidifying and heating mode, the air can be reheated with a higher heating capacity than in the second dehumidifying and heating mode. The operation of each dehumidifying and heating mode will be described in detail below.

[0114] (b-1) First Dehumidifying and Heating Mode In the ejector refrigeration cycle 10 in the first dehumidifying and heating mode, the control device 50 controls the heating expansion valve 14a, controls the cooling expansion valve 14b, and fully opens the evaporation pressure control valve 14c, as shown in the diagram of Fig. 6. The control device 50 also closes the first on-off valve 23a and the second on-off valve 23b.

[0115] Therefore, in the ejector refrigeration cycle 10 in the first dehumidifying and heating mode, the refrigerant is switched to a refrigerant circuit in which the refrigerant flows in the same manner as in the cooling mode, as shown in Fig. 7. Therefore, the first dehumidifying and heating mode is a serial reheating mode in which the refrigerant flowing out of the indoor radiator 12 flows into the heating expansion valve 14a, and the refrigerant flowing out of the outdoor heat exchanger 15 flows into the nozzle 17a of the ejector 17.

[0116] The controller 50 also controls the evaporator temperature of the compressor 11 in the same manner as in the cooling mode. The controller 50 also controls the opening pattern of the heating expansion valve 14 a and the cooling expansion valve 14 b. In the opening pattern control, the controller 50 adjusts the opening pattern KPN based on the required air temperature TAO by referring to a control map stored in advance in the controller 50.

[0117] The opening pattern KPN is a parameter for determining the combination of the throttle opening of the heating expansion valve 14 a and the throttle opening of the cooling expansion valve 14 b. As shown in the control characteristics diagram of Fig. 8, the opening pattern KPN corresponds to the ratio of the throttle opening of the cooling expansion valve 14 b to the throttle opening of the heating expansion valve 14 a.

[0118] In the control map, the opening pattern KPN is increased as the required air temperature TAO increases. As shown in the control characteristics diagram of Figure 8, as the opening pattern KPN increases, the opening of the heating expansion valve 14a, indicated by the thick dashed line, decreases, and the opening of the cooling expansion valve 14b, indicated by the thick solid line, increases. The operation of the other components is the same as in the cooling mode.

[0119] Therefore, in the ejector refrigeration cycle 10 in the first dehumidifying heating mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 9. That is, the refrigerant discharged from the compressor 11 (point a in Fig. 9) flows into the indoor radiator 12. The refrigerant that has flowed into the indoor radiator 12 dissipates heat to the blown air cooled by the suction-side evaporator 20 according to the opening degree of the air mix door 34 (from point a9 to point b9 in Fig. 9).

[0120] The refrigerant flowing out of the indoor radiator 12 flows into the heating expansion valve 14a and is decompressed (from point b9 to point c9 in FIG. 9 ). The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor heat exchanger 15.

[0121] Here, the dimensions of the ejector 17 of this embodiment are set so that the ejector 17 exerts a reference suction capacity when the pressure Pnoz of the refrigerant flowing into the nozzle portion 17a is equal to or greater than the reference pressure KPnoz.

[0122] Therefore, when the first dehumidifying and heating mode is selected, the pressure of the refrigerant flowing into the outdoor heat exchanger 15, which is located upstream of the ejector 17, is reliably higher than the reference pressure KPnoz. That is, the temperature of the refrigerant flowing into the outdoor heat exchanger 15 is reliably higher than the outside air temperature Tam.

[0123] Therefore, the refrigerant that flows into the outdoor heat exchanger 15 dissipates heat to the outside air (from point c9 to point d9 in FIG. 9 ). The refrigerant that flows out of the outdoor heat exchanger 15 flows into the cooling expansion valve 14b and is decompressed (from point d9 to point e9 in FIG. 9 ). The refrigerant that has been decompressed by the cooling expansion valve 14b flows into the nozzle 17a of the ejector 17.

[0124] The refrigerant flowing into the nozzle 17a is isentropically decompressed and sprayed (from point e9 to point f9 in FIG. 9). The refrigerant flowing out of the suction-side evaporator 20 is sucked through the suction port 17c by the suction action of the sprayed refrigerant. The sprayed refrigerant and the suctioned refrigerant flow into the diffuser 17d of the ejector 17 and are mixed (from point f9 to point g9 and from point k9 to point g9 in FIG. 9).

[0125] In the diffuser 17d, the pressure of the mixed refrigerant of the injected refrigerant and the suctioned refrigerant increases (from point g9 to point h9 in FIG. 9). The refrigerant flowing out of the diffuser 17d flows into the gas-liquid separator 18 and is separated into gas and liquid (from point h9 to point m9 and from point h9 to point i9 in FIG. 9).

[0126] The refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18 is decompressed by the fixed throttle 19 and flows into the suction-side evaporator 20 (from point i9 to point j9 in FIG. 9). The refrigerant flowing into the suction-side evaporator 20 absorbs heat from the air blown by the indoor blower 32 and evaporates (from point j9 to point k9 in FIG. 9). This cools the air.

[0127] The refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 flows through the evaporation pressure control valve 14c into the accumulator 21. The gas-phase refrigerant separated in the accumulator 21 is drawn into the compressor 11 and compressed again (from point m9 to point a9 in FIG. 9 ).

[0128] In the interior air conditioning unit 30 in the first dehumidifying and heating mode, the air blown from the interior blower 32 is cooled as it passes through the suction-side evaporator 20. The air cooled by the suction-side evaporator 20 is reheated by the interior radiator 12. The temperature- and humidity-adjusted air is then blown out to an appropriate location in the vehicle cabin, thereby achieving dehumidifying and heating the vehicle cabin.

[0129] Furthermore, in the first dehumidifying and heating mode, the opening pattern control is performed, so that the throttle opening of the heating expansion valve 14a can be reduced as the required blowing temperature TAO increases. This reduces the amount of heat radiated from the refrigerant in the outdoor heat exchanger 15 to the outside air, and increases the amount of heat radiated from the refrigerant in the indoor radiator 12 to the blown air.

[0130] Therefore, in the first dehumidifying heating mode, the cooling capacity of the suction side evaporator 20 is kept constant, and the heating capacity of the blown air in the indoor radiator 12 can be improved as the required blowing temperature TAO increases.

[0131] (b-2) Second Dehumidifying and Heating Mode In the ejector refrigeration cycle 10 in the second dehumidifying and heating mode, the control device 50 controls the heating expansion valve 14a, controls the cooling expansion valve 14b, and fully opens the evaporation pressure control valve 14c, as shown in the diagram of Fig. 6. The control device 50 also opens the first on-off valve 23a and the second on-off valve 23b.

[0132] 10 , in the ejector refrigeration cycle 10 in the second dehumidifying and heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant flows, in order, through the indoor radiator 12, the heating expansion valve 14a, the outdoor heat exchanger 15, the accumulator 21, and the suction port of the compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant flows, in order, through the indoor radiator 12, the cooling expansion valve 14b, the ejector 17, and the gas-liquid separator 18. Furthermore, the refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18 flows, in order, through the fixed throttle 19, the suction-side evaporator 20, and the suction port 17c of the ejector 17, and the refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 flows, in order, through the evaporation pressure control valve 14c, the accumulator 21, and the suction port of the compressor 11.

[0133] Therefore, the second dehumidifying heating mode is a parallel reheating mode in which one of the refrigerants branched at the first three-way joint 13a flows into the heating expansion valve 14a, and the other refrigerant branched at the first three-way joint 13a flows from the cooling expansion valve 14b into the nozzle portion 17a of the ejector 17.

[0134] The controller 50 also controls the evaporator temperature of the compressor 11 in the same manner as in the cooling mode. The controller 50 also controls the opening pattern of the heating expansion valve 14a and the cooling expansion valve 14b in the same manner as in the first dehumidifying heating mode. The operation of the other components is the same as in the first dehumidifying heating mode.

[0135] Therefore, in the ejector refrigeration cycle 10 in the second dehumidifying and heating mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 11. In Fig. 11, the states of the refrigerant at the same parts in the cycle configuration as those in Fig. 9, which were explained in the first dehumidifying and heating mode, are indicated by the same reference characters (alphabet), and only the subscripts (numbers) are changed to match the diagram numbers. This also applies to the following Mollier diagrams.

[0136] That is, the refrigerant discharged from the compressor 11 (point a11 in FIG. 11 ) flows into the indoor radiator 12. The refrigerant that has flowed into the indoor radiator 12 dissipates heat to the blown air cooled by the suction-side evaporator 20 (from point a11 to point b11 in FIG. 11 ). The flow of the refrigerant that has flowed out of the indoor radiator 12 is branched at the first three-way joint 13 a.

[0137] The refrigerant flowing out from one outlet of the first three-way joint 13a (i.e., one of the refrigerant branches at the first three-way joint 13a) flows into the heating expansion valve 14a and is decompressed (from point b11 to point c11 in FIG. 11 ). The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor heat exchanger 15.

[0138] In the control map for the second dehumidifying and heating mode, the opening pattern KPN is determined so that the flow rate of refrigerant flowing into the outdoor heat exchanger 15 becomes an appropriate value. In other words, the opening pattern KPN is determined so that the amount of heat absorbed by the refrigerant in the outdoor heat exchanger 15 becomes an appropriate value. Therefore, the refrigerant flowing into the outdoor heat exchanger 15 absorbs heat from the outside air (from point c11 to point m11 in FIG. 11 ). The refrigerant flowing out of the outdoor heat exchanger 15 flows into the accumulator 21 via the second passage 22b.

[0139] The refrigerant flowing out from the other outlet of the first three-way joint 13a (i.e., the other refrigerant branched by the first three-way joint 13a) flows into the cooling expansion valve 14b and is decompressed (from point b11 to point e11 in FIG. 11 ). The refrigerant decompressed by the cooling expansion valve 14b flows into the nozzle 17a of the ejector 17. In the ejector 17, the injected refrigerant and the suctioned refrigerant are mixed and pressurized in the diffuser 17d (from point g11 to point h11 in FIG. 11 ), as in the first dehumidifying and heating mode.

[0140] As in the first dehumidifying and heating mode, the refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18 is decompressed by the fixed throttle 19 and flows into the suction-side evaporator 20. The refrigerant flowing into the suction-side evaporator 20 absorbs heat from the air blown by the indoor blower 32 and evaporates (from point j11 to point k11 in FIG. 11 ). This cools the air.

[0141] As in the first dehumidifying and heating mode, the refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 flows into the accumulator 21 via the evaporation pressure control valve 14c. The refrigerant flowing out from the accumulator 21 is drawn into the compressor 11 and compressed again (from point m11 to point a11 in FIG. 11 ).

[0142] In the interior air conditioning unit 30 in the second dehumidifying and heating mode, the air blown from the interior blower 32 is cooled as it passes through the suction-side evaporator 20. The air cooled by the suction-side evaporator 20 is reheated by the interior radiator 12. The temperature- and humidity-adjusted air is then blown out to an appropriate location in the vehicle cabin, thereby achieving dehumidifying and heating the vehicle cabin.

[0143] Furthermore, in the second dehumidifying and heating mode, the refrigerant evaporation temperature in the outdoor heat exchanger 15 is lowered below the outdoor air temperature Tam, so that the heat of the outdoor air can be absorbed by the refrigerant in the outdoor heat exchanger 15. This allows the amount of heat radiated from the indoor radiator 12 to be increased more than in the first dehumidifying and heating mode, and therefore the blown air can be heated with a heating capacity higher than in the first dehumidifying and heating mode.

[0144] In the second dehumidifying and heating mode, the opening pattern control is performed, so that the throttle opening of the heating expansion valve 14a can be increased as the required blowing temperature TAO rises. This increases the refrigerant flow rate through the outdoor heat exchanger 15, increasing the amount of heat absorbed by the refrigerant from the outdoor air in the outdoor heat exchanger 15, and increasing the amount of heat radiated from the refrigerant to the blown air in the indoor radiator 12.

[0145] Therefore, in the second dehumidifying and heating mode, the cooling capacity of the suction side evaporator 20 is kept constant, and the heating capacity of the blown air in the indoor radiator 12 can be improved as the required blowing temperature TAO increases.

[0146] (b-3) Third Dehumidifying and Heating Mode In the ejector refrigeration cycle 10 in the third dehumidifying and heating mode, the control device 50 controls the heating expansion valve 14a, the cooling expansion valve 14b, and the evaporation pressure control valve 14c, as shown in the diagram of Fig. 6. The control device 50 also opens the first on-off valve 23a and the second on-off valve 23b.

[0147] Therefore, in the ejector refrigeration cycle 10 in the third dehumidifying and heating mode, as shown in FIG. 10, the refrigerant circuit is switched to one in which the same refrigerant flows as in the second dehumidifying and heating mode.

[0148] The control device 50 also performs blowout temperature control on the compressor 11. In the blowout temperature control, the refrigerant discharge capacity of the compressor 11 is controlled so that the blowout air temperature TAV detected by the air conditioning air temperature sensor 53 approaches the required blowout temperature TAO.

[0149] Furthermore, the control device 50 controls the opening pattern of the heating expansion valve 14a and the cooling expansion valve 14b in the same manner as in the first dehumidifying heating mode.

[0150] The control device 50 also performs frost suppression control on the evaporation pressure control valve 14c. In the frost suppression control, the throttle opening of the evaporation pressure control valve 14c is controlled so that the evaporator temperature Tefin is equal to or higher than a frost reference temperature (0°C in this embodiment) that can suppress frost formation on the suction side evaporator. The operation of the other components is the same as in the cooling mode.

[0151] Therefore, in the ejector refrigeration cycle 10 in the third dehumidifying heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0152] That is, the refrigerant discharged from the compressor 11 (point a12 in FIG. 12 ) dissipates heat in the indoor radiator 12 (from point a12 to point b12 in FIG. 12 ) as in the second dehumidifying and heating mode, and is branched at the first three-way joint 13a. One of the refrigerants branched at the first three-way joint 13a flows into the heating expansion valve 14a and is decompressed (from point b12 to point c12 in FIG. 12 ). The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor heat exchanger 15.

[0153] In the control map for the third dehumidifying and heating mode, the opening pattern KPN is determined so that the temperature of the refrigerant flowing into the outdoor heat exchanger 15 is lower than the outdoor air temperature Tam. Furthermore, the opening pattern KPN is determined so that the pressure of the refrigerant flowing out of the outdoor heat exchanger 15 is lower than the pressure of the refrigerant flowing out of the diffuser portion 17d of the ejector 17.

[0154] Therefore, the refrigerant that has flowed into the outdoor heat exchanger 15 absorbs heat from the outside air (from point c12 to point n12 in FIG. 12). The refrigerant that has flowed out of the outdoor heat exchanger 15 flows into the other inlet of the fourth three-way joint 13d.

[0155] The other refrigerant branched at the first three-way joint 13a flows into the cooling expansion valve 14b and is decompressed (from point b12 to point e12 in FIG. 12 ). The refrigerant decompressed by the cooling expansion valve 14b flows into the nozzle 17a of the ejector 17. In the ejector 17, the injected refrigerant and the suctioned refrigerant are mixed and pressurized in the diffuser 17d, as in the first dehumidifying heating mode (from point g12 to point h12 in FIG. 12 ).

[0156] The refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 18 (point i12 in FIG. 12) is decompressed by the fixed throttle 19, as in the first dehumidifying and heating mode, and flows into the suction-side evaporator 20. The refrigerant flowing into the suction-side evaporator 20 absorbs heat from the blown air sent from the indoor blower 32 and evaporates (from point j12 to point k12 in FIG. 12). This cools the blown air.

[0157] The refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 18 (point m12 in FIG. 12) flows into the evaporation pressure control valve 14c and is reduced in pressure. The evaporation pressure control valve 14c reduces the pressure of the refrigerant flowing out from the gas-liquid separator 18 to the same pressure as the refrigerant flowing out from the outdoor heat exchanger 15 (from point m12 to point n12 in FIG. 12). The refrigerant flowing out from the evaporation pressure control valve 14c flows into one inlet of the fourth three-way joint 13d.

[0158] The refrigerant that flows out from the fourth three-way joint 13d flows into the accumulator 21. The refrigerant that flows out from the accumulator 21 is drawn into the compressor 11 and compressed again (from point n12 to point a12 in FIG. 12).

[0159] In the interior air conditioning unit 30 in the third dehumidifying and heating mode, the air blown from the interior blower 32 is cooled as it passes through the suction-side evaporator 20. The air cooled by the suction-side evaporator 20 is reheated by the interior radiator 12. The temperature- and humidity-adjusted air is then blown out to an appropriate location in the vehicle cabin, thereby achieving dehumidifying and heating the vehicle cabin.

[0160] Furthermore, in the third dehumidifying and heating mode, the refrigerant evaporation temperature in the outdoor heat exchanger 15 is lowered below the pressure of the refrigerant flowing out from the diffuser portion 17d, so that heat from the outside air can be absorbed by the refrigerant in the outdoor heat exchanger 15. This allows the amount of heat radiated from the indoor radiator 12 to be increased more than in the second dehumidifying and heating mode, and therefore the blown air can be heated with a heating capacity higher than in the second dehumidifying and heating mode.

[0161] In the third dehumidifying and heating mode, the opening pattern control is performed, so that the throttle opening of the heating expansion valve 14a can be reduced even if the rotation speed of the compressor 11 increases and the refrigerant flow rate increases as the required blowing temperature TAO increases. This makes it possible to increase the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 15 and the amount of heat radiated from the refrigerant to the blown air in the indoor radiator 12 while maintaining a constant refrigerant flow rate.

[0162] Therefore, in the third dehumidifying and heating mode, the cooling capacity of the suction side evaporator 20 is kept constant, and the heating capacity of the blown air in the indoor radiator 12 can be improved as the required blowing temperature TAO increases.

[0163] (c) Heating Mode The heating mode is an operating mode in which the vehicle interior is heated by heating the ventilation air and blowing it into the vehicle interior. The heating mode is likely to be selected when the auto switch and the air conditioner switch are on, the outside air temperature Tam is relatively low (less than 10°C in this embodiment), or the required air outlet temperature TAO is relatively high.

[0164] In the heating mode, as shown in the diagram of Fig. 6, the control device 50 controls the heating expansion valve 14a, fully closes the cooling expansion valve 14b, and fully opens the evaporation pressure control valve 14c. The control device 50 also closes the first on-off valve 23a and opens the second on-off valve 23b.

[0165] Therefore, in the ejector-type refrigeration cycle 10 in the heating mode, as shown in FIG. 13, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant flows in the following order: the indoor radiator 12, the heating expansion valve 14a, the outdoor heat exchanger 15, the accumulator 21, and the suction port of the compressor 11.

[0166] The controller 50 also controls the compressor 11 to control the outlet temperature in the same manner as in the third dehumidifying and heating mode. The controller 50 also controls the radiator outlet pressure of the heating expansion valve 14a. In the radiator outlet pressure control, the throttle opening of the heating expansion valve 14a is controlled so that the first refrigerant pressure P1 detected by the radiator refrigerant sensor 52b approaches the target first refrigerant pressure PO1.

[0167] The target first refrigerant pressure PO1 is determined based on the outdoor unit outlet refrigerant temperature T1 by referring to a control map stored in advance in the control device 50. The control map determines the target first refrigerant pressure PO1 so that the COP of the ejector refrigeration cycle 10 approaches its maximum value. The operation of the other components is the same as in the cooling mode.

[0168] Therefore, in the ejector refrigeration cycle 10 in the heating mode, the refrigerant discharged from the compressor 11 flows into the indoor radiator 12. The refrigerant that has flowed into the indoor radiator 12 dissipates heat to the blown air that has passed through the suction-side evaporator 20. This heats the blown air.

[0169] The refrigerant that flows into the indoor radiator 12 flows into the heating expansion valve 14a and is decompressed. The refrigerant that has been decompressed by the heating expansion valve 14a flows into the outdoor heat exchanger 15. The refrigerant that flows into the outdoor heat exchanger 15 absorbs heat from the outside air and evaporates. The refrigerant that flows out of the outdoor heat exchanger 15 flows into the accumulator 21 via the second passage 22b. The refrigerant that flows out from the gas-phase refrigerant outlet of the accumulator 21 is drawn into the compressor 11 and compressed again.

[0170] In the interior air conditioning unit 30 in the heating mode, the air blown from the interior blower 32 toward the vehicle interior passes through the suction-side evaporator 20. The air that has passed through the suction-side evaporator 20 is heated by the interior radiator 12. The temperature-adjusted air is then blown out to an appropriate location in the vehicle interior, thereby heating the vehicle interior.

[0171] As described above, the vehicle air conditioner 1 of this embodiment can provide comfortable air conditioning for the vehicle interior by switching the operation mode.

[0172] Furthermore, the vehicle air conditioner 1 of this embodiment can switch between the first dehumidifying and heating mode and the second dehumidifying and heating mode, so that the heating capacity of the blown air can be adjusted over a wide range when dehumidifying and heating the vehicle cabin. In addition, when dehumidifying and heating the vehicle cabin, it is possible to achieve both a high COP and stable operation.

[0173] More specifically, in the refrigerant circuit in the first dehumidifying heating mode, the pressure of the refrigerant in the outdoor heat exchanger 15 can be adjusted to a range higher than the saturation pressure of the refrigerant at the outdoor air temperature Tam by adjusting the pressure reduction amount of the heating expansion valve 14a.

[0174] Therefore, in the first dehumidifying and heating mode, the amount of pressure reduction in the heating expansion valve 14a is reduced to increase the amount of heat radiated from the refrigerant to the outside air in the outdoor heat exchanger 15, thereby continuously reducing the heating capacity of the indoor radiator 12 for the blown air. In other words, in the first dehumidifying and heating mode, the temperature of the blown air reheated in the indoor radiator 12 can be continuously adjusted within a relatively low temperature range.

[0175] In addition, in the refrigerant circuit in the second dehumidifying heating mode, the pressure of the refrigerant in the outdoor heat exchanger 15 can be adjusted to a range lower than the saturation pressure of the refrigerant at the outdoor air temperature Tam by adjusting the amount of pressure reduction of the heating expansion valve 14a.

[0176] Therefore, in the second dehumidifying and heating mode, the amount of pressure reduction in the heating expansion valve 14a is increased to increase the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 15, thereby continuously improving the heating capacity of the indoor radiator 12 for the blown air. In other words, in the second dehumidifying and heating mode, the temperature of the blown air reheated in the indoor radiator 12 can be continuously adjusted within a relatively high temperature range.

[0177] Furthermore, when the refrigerant suction capacity of the ejector 17 falls below a reference suction capacity during execution of the first dehumidifying and heating mode, the mode is switched to the second dehumidifying and heating mode. In other words, even if the ejector 17 is exerting a sufficient refrigerant pressure increasing effect, when the refrigerant suction capacity of the ejector 17 falls below the reference suction capacity, the mode can be switched to the second dehumidifying and heating mode.

[0178] Therefore, in both the first dehumidifying and heating mode and the second dehumidifying and heating mode, the ejector 17 can be made to exhibit appropriate refrigerant suction and pressure increasing capabilities. As a result, the vehicle air conditioning system 1 of this embodiment can continuously adjust the heating capacity of the blown air over a wide range when dehumidifying and heating the vehicle cabin, and can also achieve both a high COP and stable operation.

[0179] In the vehicle air conditioner 1 of this embodiment, in the first dehumidifying heating mode, the refrigerant circuit is switched to one in which the liquid-phase refrigerant flowing out of the gas-liquid separator 18 flows into the suction-side evaporator 20 via the fixed throttle 19. Therefore, in the refrigerant circuit in the first dehumidifying heating mode, the discharge pressure of the compressor 11 cannot be directly applied to the inlet side of the suction-side evaporator 20.

[0180] Therefore, in the refrigerant circuit in the first dehumidifying and heating mode, the refrigerant suction action of the ejector 17 is utilized to cause the refrigerant to flow from the gas-liquid separator 18 side into the suction-side evaporator 20. Therefore, switching to the second dehumidifying and heating mode when the refrigerant suction capacity of the ejector 17 falls below the reference suction capacity, i.e., switching the operation mode based on the refrigerant suction capacity of the ejector 17, is extremely effective for stable operation of the cycle.

[0181] Furthermore, the vehicle air conditioner 1 of this embodiment can execute a third dehumidifying and heating mode in addition to the first and second dehumidifying and heating modes. In the third dehumidifying and heating mode, the ventilation air can be reheated with a higher heating capacity than in the second dehumidifying and heating mode. Therefore, the heating capacity of the ventilation air can be adjusted over an even wider range.

[0182] Second Embodiment In the vehicle air conditioner 1 of this embodiment, an example in which the suction capacity determination program is modified will be described as shown in Fig. 14. In control step S51b, which is the suction capacity determination unit of this embodiment, it is determined whether the second refrigerant pressure P2 is equal to or lower than the saturation pressure Pams of the refrigerant at the outside air temperature Tam.

[0183] As described in the first embodiment, the ejector 17 exerts the reference suction capacity when the pressure Pnoz of the refrigerant flowing into the nozzle portion 17a is equal to or higher than the reference pressure KPnoz. Therefore, as long as the second refrigerant pressure P2 is higher than the saturation pressure Pams during execution of the first dehumidifying and heating mode, the ejector 17 reliably exerts the reference suction capacity.

[0184] Therefore, in the suction capacity determination program of this embodiment, when the second refrigerant pressure P2 is equal to or lower than the saturation pressure Pams in step S51b, it is determined that the refrigerant suction capacity of the ejector 17 is equal to or lower than the reference suction capacity, and the program proceeds to step S52, where the operation mode is changed to the second dehumidifying and heating mode, and the program returns to the main routine.

[0185] On the other hand, if it is determined in step S51a that the degree of superheat SH is lower than the reference degree of superheat KSH1, it is determined that the refrigerant suction capacity of the ejector 17 is higher than the reference suction capacity, and the process returns to the main routine. That is, the operation mode is maintained in the first dehumidifying and heating mode, and the process returns to the main routine.

[0186] Other configurations and operations of the vehicle air conditioner 1 are the same as those of the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can also achieve the same effects as those of the first embodiment. That is, when performing dehumidifying and heating of the vehicle cabin, not only can the heating capacity of the blown air be continuously adjusted over a wide range, but also a high COP can be achieved and stable operation can be achieved.

[0187] Third Embodiment In this embodiment, an example will be described in which an ejector-type refrigeration cycle device according to the present disclosure is applied to a vehicle air conditioner 1a. The vehicle air conditioner 1a includes an ejector-type refrigeration cycle 10a.

[0188] 15, the ejector refrigeration cycle 10a is configured by adding a fifth three-way joint 13e, a suction-side expansion valve 14d, and an outlet-side evaporator 24 to the ejector refrigeration cycle 10 described in the first embodiment. Also, the ejector refrigeration cycle 10a does not include the gas-liquid separator 18 and the fixed throttle 19 of the ejector refrigeration cycle 10.

[0189] In the ejector-type refrigeration cycle 10a, the inlet side of a fifth three-way joint 13e is connected to the outlet side of the cooling expansion valve 14b. One outlet of the fifth three-way joint 13e is connected to the inlet side of the nozzle 17a of the ejector 17. One outlet of the fifth three-way joint 13e is connected to the inlet side of the suction expansion valve 14d.

[0190] Therefore, the fifth three-way joint 13e is a nozzle-side branching portion that further branches the other refrigerant flow branched at the first three-way joint 13a in the dehumidifying heating mode, etc.

[0191] The suction-side expansion valve 14d is a suction-side pressure reducing unit that reduces the pressure of the refrigerant flowing out from the other outlet of the fifth three-way joint 13e (i.e., the other refrigerant branched at the fifth three-way joint 13e). The suction-side expansion valve 14d also serves as a flow rate adjusting unit that adjusts the flow rate of the refrigerant flowing into the suction-side evaporator 20.

[0192] In the ejector-type refrigeration cycle 10a, the refrigerant inlet side of the outlet-side evaporator 24 is connected to the outlet of the diffuser portion 17d of the ejector 17. The outlet-side evaporator 24 is a cooling heat exchanger that exchanges heat between the refrigerant flowing out from the diffuser portion 17d and the air blown into the vehicle cabin by the interior blower 32.

[0193] The outlet-side evaporator 24 is an outlet-side evaporator that cools the blown air by evaporating the refrigerant and exerting a heat absorption effect. The outlet-side evaporator 24, together with the suction-side evaporator 20, is disposed in the air passage in the air conditioning case 31 of the indoor air conditioning unit 30.

[0194] More specifically, the outlet-side evaporator 24 and the suction-side evaporator 20 in this embodiment are integrally formed. Specifically, both the outlet-side evaporator 24 and the suction-side evaporator 20 are formed as so-called tank-and-tube heat exchangers. The tank-and-tube heat exchanger has multiple tubes through which the refrigerant flows and a pair of collection-distribution tanks disposed on both ends of the multiple tubes to collect or distribute the refrigerant flowing through the tubes.

[0195] The collection and distribution tanks for the outlet-side evaporator 24 and the suction-side evaporator 20 are formed from the same material, thereby integrating the outlet-side evaporator 24 and the suction-side evaporator 20. The outlet-side evaporator 24 and the suction-side evaporator 20 are arranged such that the outlet-side evaporator 24 is located upstream of the suction-side evaporator 20 in the flow of blown air. The rest of the configuration of the vehicle air conditioner 1a is the same as that of the vehicle air conditioner 1 described in the first embodiment.

[0196] Next, the operation of the vehicle air conditioner 1a of this embodiment having the above-described configuration will be described. The vehicle air conditioner 1a of this embodiment switches between operation modes in the same manner as in the first embodiment. The basic operation in each operation mode is the same as in the first embodiment.

[0197] Therefore, in the ejector refrigeration cycle 10 a in (a) the cooling mode and (b) the dehumidifying heating mode, the refrigerant flowing out from the cooling expansion valve 14 b flows into the nozzle portion 17 a of the ejector 17 .

[0198] More specifically, in the ejector-type refrigeration cycle 10a, the refrigerant flowing out from the cooling expansion valve 14b is branched at the fifth three-way joint 13e. The refrigerant flowing out from one outlet of the fifth three-way joint 13e (i.e., one of the refrigerant branches at the fifth three-way joint 13e) flows into the nozzle 17a of the ejector 17.

[0199] The refrigerant flowing into the nozzle 17a is isentropically depressurized and sprayed, as in the first embodiment. The refrigerant flowing out of the suction-side evaporator 20 is then sucked through the suction port 17c by the suction action of the sprayed refrigerant. The sprayed refrigerant and the suctioned refrigerant are mixed in the diffuser 17d and pressurized.

[0200] The refrigerant flowing out from the diffuser portion 17d flows into the outlet-side evaporator 24. The refrigerant flowing into the outlet-side evaporator 24 absorbs heat from the air blown by the indoor blower 32 and evaporates. This cools the air. The refrigerant flowing out from the outlet-side evaporator 24 flows into the accumulator 21 via the evaporation pressure control valve 14c.

[0201] The other refrigerant branched at the fifth three-way joint 13e flows into the suction-side expansion valve 14d and is decompressed. At this time, the control device 50 determines the throttle opening of the suction-side expansion valve 14d based on the degree of superheat SH of the refrigerant on the outlet side of the suction-side evaporator 20, with reference to a control map stored in advance in the control device 50.

[0202] In the control map, the throttle opening of the suction side expansion valve 14d is determined so that the flow rate ratio η of the refrigerant flow rate into the suction side expansion valve 14d to the refrigerant flow rate into the nozzle portion 17a becomes an appropriate value.

[0203] The refrigerant flowing out from the suction-side expansion valve 14d flows into the suction-side evaporator 20. The refrigerant flowing into the suction-side evaporator 20 absorbs heat from the blown air cooled by the outlet-side evaporator 24 and evaporates. This further cools the blown air cooled by the outlet-side evaporator 24. The refrigerant flowing out from the suction-side evaporator 20 is drawn into the suction port 17c of the ejector 17.

[0204] In the interior air conditioning unit 30 in (a) cooling mode and (b) dehumidifying and heating mode, the blown air is cooled as it passes through the outlet-side evaporator 24 and the suction-side evaporator 20. The cooled blown air is heated by the interior radiator 12 as needed. The temperature-adjusted blown air is then blown out to an appropriate location in the vehicle cabin, thereby cooling the vehicle cabin in (a) cooling mode and heating the vehicle cabin in (b) dehumidifying and heating mode.

[0205] Other aspects of the operation of the vehicle air conditioner 1a are the same as those of the first embodiment. Therefore, the vehicle air conditioner 1a of this embodiment can also achieve the same effects as those of the first embodiment. That is, when performing dehumidifying and heating of the vehicle cabin, not only can the heating capacity of the blown air be continuously adjusted over a wide range, but also a high COP can be achieved and stable operation can be achieved.

[0206] Fourth Embodiment In this embodiment, an example will be described in which an ejector-type refrigeration cycle device according to the present disclosure is applied to a vehicle air conditioner 1b. The vehicle air conditioner 1b includes an ejector-type refrigeration cycle 10b.

[0207] 16, the ejector-type refrigeration cycle 10b is configured by adding an internal heat exchanger 25 to the ejector-type refrigeration cycle 10a described in the third embodiment. Furthermore, the ejector-type refrigeration cycle 10b does not include the outlet-side evaporator 24, which is different from the ejector-type refrigeration cycle 10a.

[0208] The internal heat exchanger 25 has a high-pressure side passage and a low-pressure side passage, and exchanges heat between the high-pressure side refrigerant flowing through the high-pressure side passage and the low-pressure side refrigerant flowing through the low-pressure side passage.

[0209] The inlet of the high-pressure side passage is connected to one outlet side of the second three-way joint 13b. The outlet of the high-pressure side passage is connected to one inlet side of the third three-way joint 13c via a first check valve 16a. The inlet of the low-pressure side passage is connected to the outlet side of the diffuser portion 17d of the ejector 17. The outlet of the low-pressure side passage is connected to the inlet side of the evaporation pressure control valve 14c.

[0210] Therefore, the refrigerant flowing out from the exterior heat exchanger 15 via the second three-way joint 13b flows into the high-temperature side passage of the internal heat exchanger 25. The refrigerant flowing out from the ejector 17 flows into the low-temperature side passage of the internal heat exchanger 25.

[0211] Therefore, the internal heat exchanger 25 is an internal heat exchanger that exchanges heat between the refrigerant flowing out from the exterior heat exchanger 15 and the refrigerant flowing out from the ejector 17. The rest of the configuration of the vehicle air conditioner 1b is the same as that of the vehicle air conditioner 1a described in the third embodiment.

[0212] Next, the operation of the vehicle air conditioner 1b of this embodiment having the above-described configuration will be described. The vehicle air conditioner 1a of this embodiment switches between operation modes in the same manner as in the first embodiment. The basic operation in each operation mode is the same as in the first embodiment.

[0213] Therefore, in the ejector refrigeration cycle 10 b in (a) the cooling mode and (b) the dehumidifying and heating mode, the refrigerant flowing out from the cooling expansion valve 14 b flows into the nozzle portion 17 a of the ejector 17 .

[0214] More specifically, in the ejector refrigeration cycle 10b, as in the second embodiment, one of the refrigerant paths branched at the fifth three-way joint 13e flows into the nozzle 17a of the ejector 17. Then, the refrigerant flowing out of the diffuser 17d flows into the low-pressure side passage of the internal heat exchanger 25.

[0215] The refrigerant flowing out from the low-pressure side passage of the internal heat exchanger 25 flows into the accumulator 21 via the evaporation pressure control valve 14c. Furthermore, similar to the second embodiment, the other refrigerant branched at the fifth three-way joint 13e absorbs heat from the blown air and evaporates in the suction-side evaporator 20. This cools the blown air.

[0216] Furthermore, in the ejector refrigeration cycle 10b in the (a) cooling mode and the (b-1) dehumidifying and heating mode, the refrigerant flowing out of the outdoor heat exchanger 15 flows into the high-temperature side passage of the internal heat exchanger 25. In the internal heat exchanger 25, the refrigerant flowing through the high-temperature side passage exchanges heat with the refrigerant flowing through the high-temperature side passage, and the enthalpy of the refrigerant flowing out of the high-temperature side passage decreases.

[0217] The refrigerant flowing out from the high-temperature side passage of the internal heat exchanger 25 flows through the cooling expansion valve 14b and the suction expansion valve 14d into the suction-side evaporator 20. Therefore, in the (a) cooling mode and the (b-1) dehumidifying and heating mode, the refrigeration capacity exerted by the suction-side evaporator 20 can be increased, and the COP can be further improved.

[0218] Other aspects of the operation of the vehicle air conditioner 1b are the same as those of the first embodiment. Therefore, the vehicle air conditioner 1b of this embodiment can also achieve the same effects as those of the first embodiment. That is, when performing dehumidifying and heating of the vehicle cabin, not only can the heating capacity of the blown air be continuously adjusted over a wide range, but also a high COP can be achieved and stable operation can be achieved.

[0219] The present disclosure is not limited to the above-described embodiments, and various modifications can be made as follows within the scope of the present disclosure.

[0220] In the above embodiment, an example has been described in which the ejector-type refrigeration cycle device according to the present disclosure is applied to a vehicle air conditioner, but the application of the ejector-type refrigeration cycle device is not limited to vehicle air conditioners.

[0221] For example, the present invention may be applied to a stationary air conditioner or a cold storage cabinet. A cold storage cabinet is a storage cabinet that keeps an object to be temperature-adjusted at a desired temperature. For example, the present invention may be applied to an adsorption device that adsorbs a specific object to be adsorbed. An adsorption device is a device that reheats a fluid to be adsorbed (e.g., a gas containing carbon dioxide) from which moisture has been removed to a predetermined temperature, adsorbs the fluid onto an adsorbent, and recovers the fluid.

[0222] In the third embodiment, the outlet-side evaporator 24 and the suction-side evaporator 20 are integrally formed and used to cool the blown air. However, the present invention is not limited to this. For example, the outlet-side evaporator 24 and the suction-side evaporator 20 may be formed as separate members, and each may cool the blown air to be blown to a different space. Alternatively, one evaporator may cool the blown air for air conditioning, and the other evaporator may cool the coolant.

[0223] The configuration of the ejector refrigeration cycle apparatus according to the present disclosure is not limited to the configuration disclosed in the above-described embodiment.

[0224] For example, in the above embodiment, an example in which the indoor radiator 12 is used as the heating unit has been described, but the heating unit is not limited to the indoor radiator. For example, the heating unit may be configured such that a high-temperature side pump, a water-refrigerant heat exchanger, a heater core, etc. are arranged in a high-temperature side heat medium circulation circuit that circulates the heat medium.

[0225] The water-refrigerant heat exchanger is a heat exchanger that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the high-temperature side heat medium pumped from the high-temperature side pump. The heater core is a heating heat exchanger that exchanges heat between the high-temperature side heat medium heated in the water-refrigerant heat exchanger and the blown air. The heater core may be disposed in the air passage of the indoor air conditioning unit 30 in the same manner as the indoor radiator 12.

[0226] In the above embodiment, an example in which an electric variable throttle mechanism is used as the evaporation pressure regulating valve 14c has been described, but a variable throttle mechanism constituted by a mechanical mechanism may also be used as the evaporation pressure regulating valve. Specifically, a variable throttle mechanism constituted by a mechanical mechanism that increases the valve opening degree in response to an increase in the pressure of the refrigerant on the outlet side of the suction side evaporator 20 or an increase in the pressure of the refrigerant flowing out of the ejector 17 may be used.

[0227] Furthermore, multiple cycle components may be integrated as long as the effects described in the above-described embodiment can be obtained. For example, although the example in which the cooling expansion valve 14b and the ejector 17 are configured as separate components has been described, the cooling expansion valve 14b and the ejector 17 may be integrated. Specifically, a needle-shaped valve element may be disposed in the refrigerant passage of the nozzle portion 17a, and by displacing the valve element, the same function as the cooling expansion valve 14b may be achieved.

[0228] Furthermore, an auxiliary evaporator may be added which is connected in parallel to the ejector 17 or the suction side evaporator 20. The auxiliary evaporator may be used to cool heat-generating equipment that generates heat during operation.

[0229] Specifically, a parallel passage is added that connects the inlet side of the nozzle portion 17a or the cooling expansion valve 14b with the outlet side of the evaporation pressure control valve 14c. Furthermore, a parallel passage expansion valve and a chiller serving as an auxiliary evaporation section are arranged in the parallel circuit. The chiller is a heat exchanger that exchanges heat between the low-pressure refrigerant decompressed by the parallel passage expansion valve and the coolant. The coolant cooled by the chiller may be used to cool heat-generating devices such as a battery, a motor generator, and an inverter.

[0230] Furthermore, the group of control sensors connected to the input side of the control device 50 is not limited to the detection units disclosed in the above embodiment, and various detection units may be added as necessary.

[0231] Although the above embodiment describes an example in which carbon dioxide is used as the refrigerant in the ejector-type refrigeration cycle device, the refrigerant is not limited to this. For example, R134a, R600a, R410A, R404A, R32, R407C, R290, or a mixture thereof may be used to configure a subcritical refrigeration cycle in which the refrigerant pressure on the high-pressure side does not exceed the critical pressure of the refrigerant.

[0232] The operation of the ejector refrigeration cycle apparatus according to the present disclosure is not limited to the configurations disclosed in the above-described embodiments.

[0233] In the above-described embodiment, the vehicle air conditioners 1 to 1b are described as being capable of implementing various operating modes, but it is not necessary for the air conditioner according to the present disclosure to be capable of implementing all of the operating modes described above. The air conditioner according to the present disclosure can achieve the effects described in the above-described embodiment as long as it is capable of implementing at least (b-1) the first dehumidifying heating mode and (b-2) the second dehumidifying heating mode.

[0234] In other words, when dehumidifying and heating the vehicle interior, not only can the heating capacity of the blown air be continuously adjusted over a wide range, but it is also possible to achieve both a high COP and stable operation.

[0235] The suction capacity determination unit is not limited to the determination unit described in the first and second embodiments. For example, a suction capacity determination unit may be employed that determines that the refrigerant suction capacity of the ejector 17 is equal to or less than a reference suction capacity when a pressure difference ΔP2 obtained by subtracting the saturation pressure Pams of the refrigerant at the outside air temperature Tam from the pressure Pnoz of the refrigerant flowing into the nozzle portion 17a is equal to or less than a predetermined reference pressure difference KΔP2.

[0236] For example, a suction capacity determination unit may be employed that determines that the refrigerant suction capacity of the ejector 17 is equal to or less than a predetermined reference pressure increase amount KΔP1 when the pressure increase amount ΔP1 of the ejector 17 is equal to or less than a predetermined reference pressure increase amount KΔP1. The pressure increase amount ΔP1 may be defined as a value obtained by subtracting the refrigerant pressure on the suction port 17c side from the refrigerant pressure on the outlet side of the diffuser 17d of the ejector 17. Alternatively, the pressure increase amount ΔP1 may be defined as a value obtained by subtracting the refrigerant pressure on the outlet side of the suction-side evaporator 20 from the refrigerant pressure on the outlet side of the diffuser 17d of the ejector 17.

[0237] Furthermore, a suction capacity determination unit may be employed that determines whether the refrigerant suction capacity of the ejector is equal to or less than a predetermined reference suction capacity by combining two or more determination criteria.

[0238] The means disclosed in each of the above embodiments may be combined as appropriate within a practicable range. For example, the suction capacity determination unit described in the second embodiment may be applied to the ejector-type refrigeration cycle apparatus described in the third and fourth embodiments.

[0239] The ejector-type refrigeration cycle device disclosed in this specification has the following features. an outdoor heat exchange section (15) that exchanges heat between the refrigerant flowing out from the outdoor pressure reduction section and outside air; an ejector (17) having a nozzle section (17a) that reduces the pressure of the refrigerant and sprays it, a suction port (17c) that sucks the refrigerant flowing out from the suction side evaporation section, and a body section (17b) formed with a pressure increasing section (17d) that mixes and increases the pressure of the sprayed refrigerant sprayed from the nozzle section and the suction refrigerant sucked from the suction port; and a refrigerant circuit switching section (23a, 23b) that switches a refrigerant circuit, The ejector-type refrigeration cycle device has a series reheating mode and a parallel reheating mode as operating modes in which the temperature-adjusted object cooled in the suction-side evaporation section is reheated in the heating section, wherein in the series reheating mode, the refrigerant circuit switching section switches to a refrigerant circuit in which the refrigerant flowing out of the heating section flows into the outdoor-side pressure reduction section and the refrigerant flowing out of the outdoor heat exchange section flows into the nozzle section, and in the parallel reheating mode, the refrigerant circuit switching section switches to a refrigerant circuit in which one of the refrigerants branched at the branch section flows into the outdoor-side pressure reduction section and the other of the refrigerant branched at the branch section flows into the nozzle section, and when the refrigerant suction capacity of the ejector is equal to or less than a predetermined reference suction capacity during execution of the series reheating mode, the ejector-type refrigeration cycle device switches to the parallel reheating mode. (Item 2) The ejector type refrigeration cycle device according to item 1, further comprising a suction capacity determination unit (S51a) that determines whether the refrigerant suction capacity is equal to or less than the reference suction capacity, wherein the suction capacity determination unit determines that the refrigerant suction capacity is equal to or less than the reference suction capacity when a superheat (SH) of the outlet side refrigerant of the suction side evaporation unit is equal to or greater than a predetermined reference superheat (KSH1).a suction capacity determination unit (S51b) that determines whether the refrigerant suction capacity is equal to or less than the reference suction capacity when a pressure (P2) of the refrigerant on an outlet side of the outdoor heat exchange unit is equal to or less than a saturation pressure (Pams) of the refrigerant at an outdoor temperature. (Item 4) The ejector refrigeration cycle apparatus according to any one of items 1 to 3, further comprising: a gas-liquid separation unit (18) that separates the refrigerant into gas and liquid phases, and a separator-side decompression unit (19) that decompresses the liquid-phase refrigerant separated by the gas-liquid separation unit and causes the liquid-phase refrigerant to flow to an inlet side of the suction-side evaporation unit. (Item 5) An ejector-type refrigeration cycle device according to any one of items 1 to 3, comprising: a nozzle-side branch section (13e) that branches the other flow of the refrigerant branched at the branch section; a suction-side pressure reduction section (14d) that reduces the pressure of the refrigerant and causes it to flow out to an inlet side of the suction-side evaporation section; and an outlet-side evaporation section (24) that evaporates the refrigerant flowing out of the ejector to cool the object to be temperature-controlled, wherein one outlet of the nozzle-side branch section (13e) is connected to an inlet side of the nozzle section (17a), the other outlet of the nozzle-side branch section (13e) is connected to an inlet side of the suction-side pressure reduction section, and the refrigerant outlet of the outlet-side evaporation section is connected to a suction port side of the compression section. (Item 6) The ejector-type refrigeration cycle apparatus according to any one of Items 1 to 3, comprising: a nozzle-side branch section (13e) that branches the other flow of the refrigerant branched at the branch section; a suction-side pressure reduction section (14d) that reduces the pressure of the refrigerant and causes it to flow out to an inlet side of the suction-side evaporation section; and an internal heat exchange section (25) that exchanges heat between the refrigerant flowing out of the outdoor heat exchange section and the refrigerant flowing out of the ejector, wherein one outlet of the nozzle-side branch section (13e) is connected to an inlet side of the nozzle section (17a), and the other outlet of the nozzle-side branch section (13e) is connected to an inlet side of the suction-side pressure reduction section.

[0240] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. An ejector (17) comprising: a compression section (11) that compresses and discharges a refrigerant; a heating section (12) that heats an object to be temperature-controlled using the refrigerant discharged from the compression section as a heat source; a branching section (13a) that branches the flow of the refrigerant flowing out from the heating section; an outdoor side decompression section (14a) that decompresses the refrigerant; an outdoor heat exchange section (15) that exchanges heat between the refrigerant flowing out from the outdoor side decompression section and outside air; a suction side evaporation section (20) that evaporates the refrigerant to cool the object to be temperature-controlled; a nozzle section (17a) that decompresses and sprays the refrigerant; a suction port (17c) that sucks the refrigerant flowing out from the suction side evaporation section; and a body section (17b) formed with a pressure-boosting section (17d) that mixes and pressurizes the sprayed refrigerant sprayed from the nozzle section and the suction refrigerant sucked from the suction port; and a refrigerant circuit switching section (23a, 23b) that switches a refrigerant circuit. The ejector-type refrigeration cycle device has a series reheating mode and a parallel reheating mode as operating modes in which the temperature-adjusted object cooled in the suction-side evaporation section is reheated in the heating section, wherein in the series reheating mode, the refrigerant circuit switching section switches to a refrigerant circuit in which the refrigerant flowing out of the heating section flows into the outdoor-side pressure reduction section and the refrigerant flowing out of the outdoor heat exchange section flows into the nozzle section, and in the parallel reheating mode, the refrigerant circuit switching section switches to a refrigerant circuit in which one of the refrigerants branched at the branch section flows into the outdoor-side pressure reduction section and the other of the refrigerant branched at the branch section flows into the nozzle section, and when the refrigerant suction capacity of the ejector is equal to or less than a predetermined reference suction capacity during execution of the series reheating mode, the ejector-type refrigeration cycle device switches to the parallel reheating mode.

2. An ejector-type refrigeration cycle device as described in claim 1, comprising a suction capacity determination unit (S51a) that determines whether the refrigerant suction capacity is equal to or less than the standard suction capacity, wherein the suction capacity determination unit determines that the refrigerant suction capacity is equal to or less than the standard suction capacity when the superheat (SH) of the outlet side refrigerant of the suction side evaporation unit is equal to or greater than a predetermined standard superheat (KSH1).

3. An ejector-type refrigeration cycle device as described in claim 1, comprising a suction capacity determination unit (S51b) that determines whether the refrigerant suction capacity is equal to or less than the standard suction capacity, wherein the suction capacity determination unit determines that the refrigerant suction capacity is equal to or less than the standard suction capacity when the pressure (P2) of the refrigerant on the outlet side of the outdoor heat exchange unit is equal to or less than the saturation pressure (Pams) of the refrigerant at the outdoor air temperature.

4. An ejector-type refrigeration cycle device as described in any one of claims 1 to 3, comprising: a gas-liquid separation section (18) that separates the refrigerant flowing out from the ejector into gas and liquid; and a separator-side pressure reduction section (19) that reduces the pressure of the liquid-phase refrigerant separated in the gas-liquid separation section and causes it to flow out to the inlet side of the suction-side evaporation section.

5. An ejector-type refrigeration cycle device according to any one of claims 1 to 3, comprising: a nozzle-side branching section (13e) that branches the other flow of the refrigerant branched at the branching section; a suction-side pressure reduction section (14d) that reduces the pressure of the refrigerant and causes it to flow out to the inlet side of the suction-side evaporation section; and an outlet-side evaporation section (24) that evaporates the refrigerant flowing out of the ejector to cool the object to be temperature-controlled, wherein one outlet of the nozzle-side branching section (13e) is connected to the inlet side of the nozzle section (17a), the other outlet of the nozzle-side branching section (13e) is connected to the inlet side of the suction-side pressure reduction section, and the refrigerant outlet of the outlet-side evaporation section is connected to the suction port side of the compression section.

6. An ejector-type refrigeration cycle device according to any one of claims 1 to 3, comprising: a nozzle-side branching section (13e) that branches the other flow of the refrigerant branched at the branching section; a suction-side pressure reduction section (14d) that reduces the pressure of the refrigerant and causes it to flow out to the inlet side of the suction-side evaporation section; and an internal heat exchange section (25) that exchanges heat between the refrigerant flowing out of the outdoor heat exchange section and the refrigerant flowing out of the ejector, wherein one outlet of the nozzle-side branching section (13e) is connected to the inlet side of the nozzle section (17a), and the other outlet of the nozzle-side branching section (13e) is connected to the inlet side of the suction-side pressure reduction section.

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