Ejector-type refrigeration cycle

Abstract

This ejector-type refrigeration cycle comprises a compression unit (11), a heat dissipation unit (12, 12b, 30), an evaporation unit (17b, 17c), and an ejector (16). The compression unit (11) raises the pressure of refrigerant to a critical pressure or higher. The heat dissipation unit (12, 12b, 30) causes heat to be dissipated from the refrigerant discharged from the compression unit (11). The ejector (16) has: a nozzle part (61) for decompressing the refrigerant that has flowed out from the heat dissipation unit (12, 12b, 30); and a body part (62) in which is formed a suction port (621) for sucking in the refrigerant that has flowed out from the evaporation unit (17b, 17c). In a Mollier diagram of the refrigerant, a drawn line of the refrigerant that arrives at an ejection port (615) of the nozzle part (61) of the ejector (16) from the outlet of the heat dissipation unit (12, 12b, 30) passes through either the critical point or the saturated gas line.

Description

Ejector type refrigeration cycle CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-029888 filed on February 29, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an ejector-type refrigeration cycle device including an ejector.

[0003] Patent Document 1 discloses an ejector-type refrigeration cycle including an ejector. In this type of ejector, a nozzle converts pressure energy of a fluid into velocity energy. The high-speed ejected fluid from the nozzle increases the pressure of a mixed fluid obtained by mixing the ejected fluid with a suction fluid sucked through a suction port.

[0004] Therefore, in a typical ejector refrigeration cycle, the pressure of the refrigerant drawn into the compressor is increased to a level higher than the refrigerant evaporation pressure in the evaporator by utilizing the fluid pressure increasing function of the ejector, thereby reducing the power consumption of the compressor and improving the coefficient of performance (COP) of the cycle.

[0005] Furthermore, the ejector-type refrigeration cycle of Patent Document 1 uses carbon dioxide as a refrigerant and constitutes a supercritical refrigeration cycle in which the pressure of the refrigerant discharged from the compressor is equal to or higher than the critical pressure of the refrigerant. In the ejector-type refrigeration cycle constituting the supercritical refrigeration cycle, the amount of pressure reduction of the fluid in the nozzle portion is more likely to increase than in the ejector-type refrigeration cycle constituting a subcritical refrigeration cycle in which the pressure of the refrigerant discharged does not exceed the critical pressure of the refrigerant.

[0006] Therefore, in the ejector refrigeration cycle of Patent Document 1, the amount of recovered energy increases with an increase in the amount of pressure reduction of the fluid in the nozzle, thereby improving the COP compared to the ejector refrigeration cycle constituting a subcritical refrigeration cycle. Here, the amount of recovered energy can be defined as the amount of pressure energy of the fluid that is effectively converted into velocity energy in the nozzle.

[0007] Patent No. 3322263

[0008] However, according to the study by the present inventors, when the operating conditions change, the ejector-type refrigeration cycle of Patent Document 1 may not be able to sufficiently achieve the COP improvement effect achieved by configuring a supercritical refrigeration cycle.The present inventors investigated the cause and found that the ejector-type refrigeration cycle of Patent Document 1 causes a supercooled liquid-phase refrigerant to flow into the nozzle of the ejector.

[0009] More specifically, in an ejector that introduces supercooled liquid-phase refrigerant into a nozzle, in order to increase the amount of energy recovered in the nozzle, it is necessary to phase-change the flow of the supercooled liquid-phase refrigerant into a mist flow in the refrigerant passage of the nozzle. Furthermore, it is necessary to refine the particles of the liquid-phase refrigerant (hereinafter referred to as droplets) contained in the mist flow in the refrigerant passage of the nozzle, so that the gas-phase fluid and the liquid droplets approach an equilibrium state.

[0010] Therefore, in an ejector that introduces a supercooled liquid-phase refrigerant into a nozzle, it is necessary to ensure that the axial length of the refrigerant passage in the nozzle is sufficient to bring the gas-phase fluid and liquid droplets close to an equilibrium state in the refrigerant passage in the nozzle.Furthermore, sufficient time is required for the refrigerant to change its flow pattern in the refrigerant passage in the nozzle.

[0011] However, in the ejector of Patent Document 1, when the operating conditions change, the axial length of the refrigerant passage in the nozzle or the time the refrigerant flows through the refrigerant passage in the nozzle may become insufficient, making it impossible to increase the amount of recovered energy. As a result, the ejector-type refrigeration cycle of Patent Document 1 may not be able to fully achieve the COP improvement effect achieved by configuring a supercritical refrigeration cycle.

[0012] In view of the above, an object of the present disclosure is to provide an ejector-type refrigeration cycle that raises the pressure of a refrigerant to or above its critical pressure and that can sufficiently improve the COP.

[0013] To achieve the above object, an ejector refrigeration cycle according to a first aspect of the present disclosure includes a compression section, a heat dissipation section, an evaporation section, and an ejector.

[0014] The compressor increases the pressure of the refrigerant above its critical pressure, the heat dissipation section dissipates heat from the refrigerant discharged from the compressor, and the evaporation section evaporates the refrigerant.

[0015] The ejector has a nozzle section and a body section. The nozzle section reduces the pressure of the refrigerant flowing out from the heat dissipation section and sprays it from an injection port. The body section is formed with a suction port, a mixing section, and a refrigerant outlet. The suction port is a section that sucks in the refrigerant flowing out from the evaporation section. The mixing section is a section that mixes the injected refrigerant sprayed from the injection port with the suction refrigerant sucked in from the suction port. The refrigerant outlet is a section that allows the mixed refrigerant mixed in the mixing section to flow out toward the suction port of the compression section.

[0016] In the Mollier diagram of the refrigerant, the line drawn by the refrigerant from the outlet of the heat dissipation section to the injection port passes through either the critical point or the saturated gas line.

[0017] This allows the refrigerant flowing from the outlet of the heat dissipation section to the nozzle outlet to change from a supercritical state to a two-phase gas-liquid state without becoming a liquid. In other words, the flow of the supercritical refrigerant flowing out of the heat dissipation section can be phase-changed to a mist flow within the refrigerant passage of the nozzle without changing to a liquid flow or a bubble flow.

[0018] Furthermore, the decompression process of the refrigerant in the refrigerant passage of the nozzle section after passing either the critical point or the saturated gas line is a condensation process in which the quality of the refrigerant decreases. The droplets generated by the decrease in quality of the refrigerant are smaller in size than the droplets contained in the mist flow that has undergone a phase change from the liquid phase flow or the bubbly flow. Therefore, the droplets generated by the decrease in quality of the refrigerant are rapidly broken down into smaller droplets by the shear force of the surrounding gas phase refrigerant flow immediately after their generation.

[0019] Therefore, even if the operating conditions change, the gas-phase refrigerant and the liquid droplets can be brought closer to an equilibrium state in the refrigerant passage of the nozzle, and both the gas-phase refrigerant and the liquid droplets can be accelerated equally in the refrigerant passage of the nozzle.

[0020] As a result, according to the ejector refrigeration cycle of the first aspect of the present disclosure, the decompression process in the nozzle of the ejector can be made closer to isentropic decompression, thereby increasing the amount of energy recovered in the nozzle and sufficiently improving the COP. In other words, the COP improvement effect achieved by configuring a supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0021] Here, the liquid-phase flow refers to a flow state of a liquid-phase fluid that does not contain bubbles. The bubbly flow refers to a flow state of a fluid in which bubbles exist in a liquid-phase fluid. The mist flow refers to a flow state of a fluid in which droplets exist in a saturated gas-phase fluid. Furthermore, bringing the gas-phase fluid and droplets closer to an equilibrium state in the nozzle section means bringing the temperature of the gas-phase refrigerant and the temperature of the droplets closer to equilibrium, and further bringing the axial velocity of the gas-phase refrigerant and the axial velocity of the droplets closer to equilibrium.

[0022] 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.

[0016] Fig. 1 is a schematic overall configuration diagram of a vehicle air conditioner of a first embodiment.

[0017] Fig. 2 is an axial cross-sectional view of an ejector of the first embodiment.

[0018] Fig. 3 is a Mollier diagram showing changes in refrigerant state in the ejector refrigeration cycle of the first embodiment.

[0019] Fig. 4 is a schematic overall configuration diagram of a vehicle air conditioner of a second embodiment.

[0020] Fig. 5 is a Mollier diagram showing changes in refrigerant state in the ejector refrigeration cycle of the second embodiment.

[0021] Fig. 6 is a schematic overall configuration diagram of a vehicle air conditioner of a third embodiment.

[0022] Fig. 7 is a Mollier diagram showing changes in refrigerant state in the ejector refrigeration cycle of the third embodiment.

[0023] Fig. 8 is a schematic overall configuration diagram of a vehicle air conditioner of a fourth embodiment.

[0024] Fig. 9 is a schematic overall configuration diagram of a vehicle air conditioner of a fifth embodiment.

[0025] Fig. 10 is a schematic overall configuration diagram of a vehicle cooling device of a sixth embodiment.

[0026] Fig. 11 is a Mollier diagram showing changes in refrigerant state in the ejector refrigeration cycle of the sixth embodiment.

[0027] Fig. 12 is a schematic overall configuration diagram of a vehicle air conditioner of a seventh embodiment. FIG. 13 is a Mollier diagram showing changes in the state of a refrigerant in an ejector refrigeration cycle of the seventh embodiment.

[0023] 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.

[0024] 1 to 3, a first embodiment of an ejector-type refrigeration cycle according to the present disclosure will be described. In this embodiment, an ejector-type refrigeration cycle 10 shown in the overall configuration diagram of Fig. 1 is applied to a vehicle air conditioner 1. The vehicle air conditioner 1 includes the ejector-type refrigeration cycle 10, a control device 20, an interior air conditioning unit (not shown), and the like.

[0025] The ejector-type refrigeration cycle 10 is a vapor compression refrigeration cycle that cools the air to be blown into the vehicle cabin in the vehicle air conditioner 1. The ejector-type refrigeration cycle 10 uses carbon dioxide (i.e., R744) as a refrigerant. The ejector-type refrigeration cycle 10 constitutes a supercritical refrigeration cycle in which the pressure of the refrigerant discharged from the compressor 11 is equal to or higher than the critical pressure of the refrigerant.

[0026] The refrigerant is mixed with refrigeration oil to lubricate the compressor 11. The refrigeration oil may be oil containing PAG (i.e., polyalkylene glycol) that is compatible with the liquid refrigerant. A portion of the refrigeration oil circulates through the ejector-type refrigeration cycle 10 together with the refrigerant.

[0027] The compressor 11 is a compression unit in the ejector-type refrigeration cycle 10 that draws in refrigerant, compresses it to a critical pressure or higher, and then discharges the refrigerant. The compressor 11 is an electric compressor that rotates a fixed-displacement compression mechanism with a fixed discharge capacity using an electric motor. The rotation speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from a control device 20, which will be described later.

[0028] The discharge port of the compressor 11 is connected to the refrigerant inlet side of an outdoor heat exchanger 12. The outdoor heat exchanger 12 is a heat dissipation unit that exchanges heat between the refrigerant discharged from the compressor 11 and outside air blown by an outside air fan (not shown), thereby dissipating heat contained in the refrigerant to the outside air.

[0029] The inlet side of a branching section 13 is connected to the refrigerant outlet of the outdoor heat exchanger 12. The branching section 13 branches the flow of refrigerant flowing out from the outdoor heat exchanger 12. The branching section 13 is a three-way joint having three inlet and outlet ports that communicate with each other. The branching section 13 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.

[0030] An inlet side of the nozzle-side expansion valve 14 a is connected to one outlet of the branching portion 13. Further, an inlet side of a high-pressure passage of the internal heat exchanger 15 is connected to the other outlet of the branching portion 13.

[0031] The nozzle-side expansion valve 14a is a variable throttle mechanism that reduces the pressure of one of the refrigerant branches at the branch section 13. The nozzle-side expansion valve 14a is a nozzle-side flow rate adjustment section that adjusts the flow rate of the refrigerant flowing into the nozzle section 61 of the ejector 16. Therefore, the nozzle-side expansion valve 14a is a pressure reduction section that reduces the pressure of the refrigerant that flows out of the outdoor heat exchanger 12 and into the nozzle section 61 of the ejector 16.

[0032] Furthermore, by adjusting the throttle opening, the nozzle-side expansion valve 14a can adjust the pressure of the refrigerant in the outdoor heat exchanger 12. In this way, the nozzle-side expansion valve 14a can adjust the state (i.e., pressure and enthalpy) of the refrigerant at the refrigerant outlet of the outdoor heat exchanger 12.

[0033] The nozzle-side expansion valve 14a has a valve body and a drive unit. The valve body changes the throttle opening of the nozzle-side expansion valve 14a. The drive unit displaces the valve body. An electric actuator such as a stepping motor or a brushless DC motor can be used as the drive unit. The operation of the nozzle-side expansion valve 14a is controlled by a control signal output from the control device 20.

[0034] The outlet of the nozzle-side expansion valve 14a is connected to the refrigerant inlet 611 side of the nozzle portion 61 of the ejector 16. The ejector 16 is a fluid transport portion that, by the action of the refrigerant sprayed from the nozzle portion 61, draws refrigerant from a suction port 621 formed in the body portion 62 and transports it to the refrigerant outlet 624 side. The ejector 16 is a fluid pressurizing portion that, by the action of the sprayed refrigerant, pressurizes a mixed refrigerant obtained by mixing the suction refrigerant drawn from the suction port 621 with the sprayed refrigerant. The detailed configuration of the ejector 16 will be described later.

[0035] The refrigerant inlet side of the outlet-side evaporator 17a is connected to the refrigerant outlet 624 of the ejector 16. The outlet-side evaporator 17a is a heat exchanger that exchanges heat between the refrigerant flowing out from the ejector 16 and the air being blown into the vehicle cabin. The outlet-side evaporator 17a causes the refrigerant flowing out from the ejector 16 to absorb heat from the air, thereby evaporating the refrigerant.

[0036] The outlet-side evaporator 17a, together with the suction-side evaporator 17b (described later), is disposed in an air passage formed in the interior air-conditioning unit. The interior air-conditioning unit is an air-flow path switching device that blows temperature-adjusted air to appropriate locations within the vehicle cabin for air conditioning. The interior air-conditioning unit is disposed inside the instrument panel at the front of the vehicle cabin.

[0037] The refrigerant outlet of the outlet-side evaporator 17a is connected to the inlet side of the accumulator 18. The accumulator 18 is a low-pressure gas-liquid separator that separates the refrigerant flowing out from the outlet-side evaporator 17a into gas and liquid phases and stores the separated liquid-phase refrigerant as excess refrigerant for the cycle. The gas-phase refrigerant outlet of the accumulator 18 is connected to the inlet side of the low-pressure passage of the internal heat exchanger 15. The outlet of the low-pressure passage of the internal heat exchanger 15 is connected to the suction port side of the compressor 11.

[0038] The internal heat exchanger 15 is a heat exchanger that exchanges heat between a high-pressure refrigerant flowing through a high-pressure passage and a low-pressure refrigerant flowing through a low-pressure passage. The other refrigerant branched at the branching portion 13 flows through the high-pressure passage of the internal heat exchanger 15. The gas-phase refrigerant that flows out of the accumulator 18 and is drawn into the compressor 11 flows through the low-pressure passage.

[0039] The internal heat exchanger 15 is an internal heat exchange unit that exchanges heat between the other refrigerant branched at the branching section 13 and the intake refrigerant drawn into the compressor 11, and dissipates heat contained in the other refrigerant branched at the branching section 13 to the intake refrigerant. Therefore, the internal heat exchanger 15 is an auxiliary heat dissipation unit that dissipates heat from the other refrigerant branched at the branching section 13.

[0040] The inlet side of the suction side expansion valve 14b is connected to the outlet of the high-pressure passage of the internal heat exchanger 15. The suction side expansion valve 14b is a variable throttle mechanism that reduces the pressure of the refrigerant flowing out from the high-pressure passage of the internal heat exchanger 15. The suction side expansion valve 14b is a suction side flow rate adjustment unit that adjusts the flow rate of refrigerant flowing into the suction side evaporator 17b. The basic configuration of the suction side expansion valve 14b is similar to that of the nozzle side expansion valve 14a.

[0041] The outlet of the suction-side expansion valve 14b is connected to the refrigerant inlet side of the suction-side evaporator 17b. The suction-side evaporator 17b is a heat exchanger that exchanges heat between the refrigerant flowing out of the suction-side expansion valve 14b and the blown air that has passed through the outlet-side evaporator 17a. The suction-side evaporator 17b is an evaporation unit that causes the refrigerant decompressed by the suction-side expansion valve 14b to absorb heat from the blown air, thereby evaporating the refrigerant.

[0042] The refrigerant outlet of the suction-side evaporator 17b is connected to a suction port 621 of the ejector 16. The detailed configuration of the ejector 16 will be described with reference to Fig. 2. The ejector 16 has a nozzle portion 61 and a body portion 62.

[0043] Nozzle portion 61 accelerates the refrigerant flowing in from refrigerant inlet 611 to supersonic speed and sprays it into mixing portion 622 formed in body portion 62. Nozzle portion 61 is formed by applying plastic working or cutting to a cylindrical member made of metal (stainless steel in this embodiment).

[0044] A refrigerant inlet 611, through which the refrigerant flowing out from the nozzle-side expansion valve 14a flows, is formed at the most upstream portion of the refrigerant passage formed inside the nozzle portion 61. An injection port 615, through which the refrigerant is injected, is formed at the most downstream portion of the refrigerant passage of the nozzle portion 61.

[0045] The refrigerant passage of the nozzle 61 is formed with a tapered portion 612, a throat portion 613, and a divergent portion 614. The tapered portion 612 is a portion that reduces the cross-sectional area of ​​the passage for the refrigerant flowing in from the refrigerant inlet 611 as the refrigerant flows downstream. The throat portion 613 is the portion where the cross-sectional area of ​​the passage for the refrigerant is the smallest. The divergent portion 614 is a portion where the cross-sectional area of ​​the passage for the refrigerant increases as the refrigerant flows from the throat portion 613 toward the injection port 615.

[0046] That is, the ejector 16 employs a so-called Laval nozzle as the nozzle portion 61. The dimensions and shape of the nozzle portion 61 are set so that the refrigerant can be accelerated to the speed of sound or faster during normal operation of the ejector-type refrigeration cycle 10.

[0047] The body 62 is a cylindrical member that forms the outer shell of the ejector 16 and defines a refrigerant passage therein. The nozzle 61 is fixed to one longitudinal end of the body 62 by press-fitting, screw fastening, or other means. The central axis of the refrigerant passage of the nozzle 61 and the central axis of the refrigerant passage of the body 62 are coaxially arranged.

[0048] The body 62 is made of metal (specifically, aluminum alloy). Alternatively, the body 62 may be made of resin. The body 62 is provided with a suction port 621, a mixing section 622, an area enlargement section 623, a refrigerant outlet 624, and the like.

[0049] The suction port 621 is formed on the cylindrical side surface of the body portion 62, at a portion on the outer circumferential side of the nozzle portion 61. The suction port 621 is a through-hole that draws the refrigerant flowing out from the suction-side evaporator 17b into the ejector 16. The ejector 16 draws the refrigerant through the suction port 621 by utilizing a pressure drop caused by an expansion wave generated by the injected refrigerant.

[0050] The mixing section 622 is a refrigerant passage that mixes the sprayed refrigerant and the suctioned refrigerant to increase the pressure of the mixed refrigerant. The mixing section 622 is formed in a rotational shape. Therefore, at the inlet of the mixing section 622, the sprayed refrigerant flows toward the central axis of the mixing section 622, and the suctioned refrigerant flows toward the inner wall surface of the mixing section 622. Therefore, the axial velocity and temperature of the refrigerant at the inlet of the mixing section 622 are in a non-equilibrium state.

[0051] The mixing section 622 is formed with a tapered mixing section 622a and a divergent mixing section 622b. The tapered mixing section 622a is located upstream of the divergent mixing section 622b in the refrigerant flow direction. The tapered mixing section 622a forms a refrigerant passage with a truncated cone shape whose cross-sectional area decreases toward the downstream side in the mixed refrigerant flow direction. The tapered mixing section 622a forms a refrigerant passage that accelerates the mixed refrigerant of the injected refrigerant and the suctioned refrigerant to two-phase sonic speed or faster.

[0052] The divergent mixing section 622b is connected downstream of the convergent mixing section 622a. The divergent mixing section 622b forms a refrigerant passage having a truncated cone shape whose cross-sectional area increases toward the downstream side in the flow direction of the mixed refrigerant. The divergent mixing section 622b generates shock waves in the mixed refrigerant flowing out of the convergent mixing section 622a and further forms a refrigerant passage that eliminates the generated shock waves.

[0053] For this reason, a neck portion 622c is formed at the connection between the convergent mixing portion 622a and the divergent mixing portion 622b, which minimizes the cross-sectional area of ​​the refrigerant passage formed in the mixing portion 622. The neck portion 622c serves as the outlet of the convergent mixing portion 622a and the inlet of the divergent mixing portion 622b.

[0054] In order to effectively increase the pressure of the mixed refrigerant in the divergent mixing section 622b, the mixed refrigerant needs to be made to move at or above the two-phase sonic velocity in the convergent mixing section 622a. Therefore, in the convergent mixing section 622a of this embodiment, the passage cross-sectional area is reduced so that the pressure of the mixed refrigerant in the neck section 622c is lower than the pressure Pnout of the injected refrigerant immediately after it is injected from the injection port 615 of the nozzle section 61.

[0055] In the tapered mixing section 622a, it is desirable to sufficiently mix the mixed refrigerant and the suction refrigerant to achieve an equilibrium state. Here, the equilibrium state in the tapered mixing section 622a means a state in which the mixed refrigerant does not have temperature distribution, pressure distribution, or velocity distribution. Therefore, in the ejector 16, the tapered mixing length LMIX1, which is the axial length of the tapered mixing section 622a, is set to satisfy the following formulas F1 and F2.

[0056]

[0057]

[0058] u ｓｎｉｎ is the mass average velocity of the refrigerant at the inlet of the tapered mixing section 622a. In other words, is the average axial velocity of the refrigerant at the inlet of the tapered mixing section 622a. ｌ１ is the density of droplets in the mixed refrigerant at the inlet of the tapered mixing section 622a. ｌ１ is the average diameter of the droplets at the inlet of the convergent mixing section 622a. ｇ１ is the viscosity of the gas phase refrigerant in the mixed refrigerant at the inlet of the tapered mixing section 622a.

[0059] Lv1 is the mass average velocity u of the mixed refrigerant at the inlet of the tapered mixing section 622a. ｓｎｉｎ The first relaxation distance Lv1 is calculated by multiplying the mass average velocity u ｓｎｉｎ This is a value obtained by multiplying the first velocity relaxation time τv1 required for the velocity of the gas phase refrigerant in the mixed refrigerant to become equal to the velocity of the droplets.

[0060] According to the test and investigation by the inventors, if the tapered mixing distance LMIX1 is set so as to satisfy the formulas F1 and F2, the dryness fraction X at the inlet of the tapered mixing section 622a can be ｓｎｉｎ It has been confirmed that the refrigerant mixture in the neck portion 622c is in equilibrium even if the dryness fraction X ｓｎｉｎIt has been confirmed that even if the flow rate of the mixed refrigerant in the axial direction in the neck portion 622c is equal to or greater than the two-phase sonic velocity, that is, it is supersonic, even if the flow rate of the mixed refrigerant in the axial direction in the neck portion 622c is changed within a wide range.

[0061] The mixed refrigerant, which has reached equilibrium and supersonic speed in the neck portion 622c, generates a shock wave with its leading edge on the inner wall surface of the body portion 62. The shock wave increases the pressure of the refrigerant. Furthermore, the mixed refrigerant flowing through the divergent mixing portion 622b generates pseudo-shock waves, in which multiple shock waves and expansion waves are repeatedly generated depending on the Mach number of the mixed refrigerant. The mixed refrigerant increases its pressure and enthalpy as it passes through the repeatedly generated shock waves.

[0062] When pseudo-shock waves are generated, the central shaft static pressure, which is the refrigerant pressure on the central shaft side of the divergent mixing section 622b, and the wall static pressure, which is the refrigerant pressure on the wall side, change to different values, which causes energy loss due to friction of the mixed refrigerant. Therefore, in order to improve the pressure-boosting capacity of the ejector 16, it is desirable to eliminate the pseudo-shock waves in the divergent mixing section 622b.

[0063] It is known that the pseudo-shock waves can be eliminated by reducing the velocity of the mixed refrigerant to subsonic velocity. Therefore, in the divergent mixing section 622b of this embodiment, the passage cross-sectional area is enlarged so that the velocity of the mixed refrigerant at the outlet of the divergent mixing section 622b becomes subsonic velocity.

[0064] In addition, it is desirable to shorten the distance over which the pseudo-shock waves disappear from the generation of the divergent mixing section 622b. Therefore, in this embodiment, the divergent mixing distance LMIX2, which is the axial length of the divergent mixing section 622b, is set to satisfy the following formulas F3 and F4.

[0065]

[0066]

[0067] u ｎｅｃｋ is the mass average velocity of the refrigerant in the neck 622c. In other words, is the average axial velocity of the refrigerant in the neck 622c. ｌ２ is the density of the droplets in the mixed refrigerant at the neck portion 622c. ｌ２is the average diameter of the droplet at the neck 622c. ｇ２ is the viscosity of the vapor phase refrigerant in the mixed refrigerant at the neck portion 622c.

[0068] Lv2 is the mass average velocity u of the mixed refrigerant in the neck portion 622c. ｎｅｃｋ The second relaxation distance Lv2 is calculated by multiplying the mass average velocity u ｎｅｃｋ represents the distance obtained by integrating the second velocity relaxation time τv2 required until the flow velocity of the gas phase refrigerant in the mixed refrigerant becomes equal to the flow velocity of the droplets.

[0069] According to the test and investigation by the inventors, if the divergent mixing distance LMIX2 is set so as to satisfy the formulas F3 and F4, the dryness fraction X ｎｅｃｋ It has been confirmed that even if the flow rate varies over a wide range, the pseudo shock wave disappears in the divergent mixing section 622b.

[0070] The enlarged area section 623 is connected to the downstream side of the mixing section 622. The enlarged area section 623 is formed in a truncated cone shape that expands the passage cross-sectional area toward the downstream side in the refrigerant flow direction. The enlarged area section 623 forms a refrigerant passage that smoothly connects the outlet of the diverging mixing section 622b and the refrigerant outlet 624.

[0071] The refrigerant passage formed by the area enlargement portion 623 may be formed in a cylindrical shape with a constant passage cross-sectional area, as long as the shape does not cause the passage cross-sectional area to decrease in the flow direction of the mixed refrigerant.

[0072] Next, the electrical control unit of the vehicle air conditioner 1 will be described. The control device 20 has a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 20 performs various calculations and processes based on control programs stored in the ROM. The control device 20 then controls the operation of various control target devices connected to the output side based on the results of the calculations and processes.

[0073] A group of various control sensors is connected to the input side of the control device 20. The group of control sensors includes an inside air temperature sensor, an outside air temperature sensor, a solar radiation sensor, a discharge pressure sensor, a high-pressure temperature sensor, an evaporator pressure sensor, an evaporator temperature sensor, and the like (not shown).

[0074] The inside air temperature sensor is an inside air temperature detector that detects the temperature inside the vehicle cabin (inside air temperature) Tr. The outside air temperature sensor is an outside air temperature detector that detects the temperature outside the vehicle cabin (outside air temperature) Tam. The solar radiation sensor is an solar radiation amount detector that detects the amount of solar radiation As irradiating the vehicle cabin.

[0075] The discharge pressure sensor is a discharge pressure detection unit that detects a discharge pressure Pd, which is the pressure of the refrigerant discharged from the compressor 11. The high-pressure temperature sensor is a high-pressure temperature detection unit that detects a high-pressure temperature Td, which is the temperature of the refrigerant flowing out from the outdoor heat exchanger 12.

[0076] The evaporator pressure sensor is an evaporator pressure detection unit that detects the suction side pressure Pe, which is the pressure of the suction side refrigerant flowing out from the suction side evaporator 17b. The evaporator temperature sensor is an evaporator temperature detection unit that detects the suction side temperature Te, which is the temperature of the suction side refrigerant.

[0077] An operation panel (not shown) is connected to the input side of the control device 20 via wire or wireless. The operation panel is located near the instrument panel at the front of the vehicle interior. Operation signals are input to the control device 20 from various operation switches provided on the operation panel. Specific examples of the various operation switches include an auto switch, an air conditioning switch, and a temperature setting switch.

[0078] The auto switch is an automatic control setting unit that sets or cancels automatic control operation of the automotive air conditioning system 1. The air conditioner switch is a cooling request unit that requests the outlet-side evaporator 17 a and the suction-side evaporator 17 b to cool the blown air. The temperature setting switch is a temperature setting unit that sets the set temperature Tset in the vehicle cabin.

[0079] The control device 20 is an integrated unit that controls various control target devices connected to the output side. Therefore, the components (hardware and software) that control the operation of each control target device constitute the control unit that controls the operation of each control target device. For example, the component of the control device 20 that controls the refrigerant discharge capacity of the compressor 11 constitutes the discharge capacity control unit.

[0080] Next, we will explain the operation of the above-configured vehicle air conditioner 1. When the auto switch and air conditioner switch are turned on while the start switch (so-called ignition switch) of the vehicle system is turned on, the control device 20 executes an air conditioning control program that is pre-stored in a memory circuit.

[0081] The control program reads the detection signals from the control sensors and the operation signals from the operation panel. Based on the read detection signals and operation signals, the control program calculates a target outlet temperature TAO, which is the target temperature of the air to be blown into the vehicle cabin. Furthermore, the control device 20 controls the operation of various controlled devices based on the detection signals, operation signals, target outlet temperature TAO, etc.

[0082] Thereafter, the control routine of reading the detection signals and operation signals, calculating the target blow-out temperature TAO, and controlling the various controlled devices is repeated at each predetermined control cycle until the termination condition of the control program is met. The target blow-out temperature TAO is calculated using the following formula F5.

[0083]

[0084] Tset is the set temperature inside the vehicle cabin set by the temperature setting switch. Tr is the inside air temperature detected by the inside air temperature sensor. Tam is the outside air temperature detected by the outside air temperature sensor. As is the amount of solar radiation detected by the solar radiation sensor. Kset, Kr, Kam, and Ks are control gains, and C is a correction constant.

[0085] The control device 20 also controls the refrigerant discharge capacity of the compressor 11 so that the suction side temperature Te detected by the evaporator temperature sensor approaches the target evaporator temperature TEO.

[0086] The target evaporator temperature TEO is determined based on the target outlet temperature TAO by referring to a control map stored in advance in the control device 20. In the control map, the target evaporator temperature TEO is decreased as the target outlet temperature TAO decreases. The target evaporator temperature TEO is determined within a range that does not cause frost formation on the suction side evaporator 17b.

[0087] Furthermore, the control device 20 controls the throttle opening of the nozzle-side expansion valve 14a so that the discharge pressure Pd detected by the discharge pressure sensor approaches the target high pressure PDO.

[0088] The target high-pressure PDO is determined based on the discharge pressure Pd and the high-pressure temperature Td detected by the high-pressure temperature sensor, with reference to a control map previously stored in the control device 20. In the control map, the target high-pressure PDO is determined so that, in a Mollier diagram of the refrigerant, the line drawn by the refrigerant from the outlet of the outdoor heat exchanger 12 to the injection port 615 of the ejector 16 passes through either the critical point or the saturated gas line.

[0089] For this reason, the control device 20 controls the throttle opening of the nozzle-side expansion valve 14a so that the line drawn by the refrigerant from the outlet of the outdoor heat exchanger 12 to the injection port 615 of the ejector 16 passes through either the critical point or the saturated gas line on the Mollier diagram of the refrigerant.

[0090] More specifically, in the control map of this embodiment, the target high-pressure PDO is determined so that the line drawn by the refrigerant from the refrigerant inlet 611 of the nozzle portion 61 to the injection port 615 passes through the saturated gas line in the Mollier diagram of the refrigerant.

[0091] For this reason, the control device 20 controls the aperture of the nozzle-side expansion valve 14a so that the line drawn by the refrigerant from the refrigerant inlet 611 of the nozzle portion 61 to the injection port 615 passes through the saturated gas line in the Mollier diagram of the refrigerant. In other words, the control device 20 controls the aperture of the nozzle-side expansion valve 14a so that the specific enthalpy when the line drawn by the refrigerant flowing through the refrigerant passage of the nozzle portion 61 passes through the saturated gas line is larger than the specific enthalpy at the critical point.

[0092] The controller 20 controls the throttle opening of the suction-side expansion valve 14b so that the superheat degree SHE of the refrigerant on the outlet side of the suction-side evaporator 17b approaches a predetermined reference superheat degree KSHE (0°C in this embodiment). The controller 20 detects the superheat degree SHE based on the suction-side pressure Pe and the suction-side temperature Te detected by the evaporator pressure sensor.

[0093] Therefore, in the ejector refrigeration cycle 10, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 3. That is, the discharged refrigerant (point a3 in Fig. 3) pressurized to or above the critical pressure by the compressor 11 flows into the outdoor heat exchanger 12. The discharged refrigerant that has flowed into the outdoor heat exchanger 12 releases heat to the outside air blown by the outdoor air fan, thereby reducing the enthalpy (from point a3 to point b3 in Fig. 3).

[0094] The flow of the supercritical refrigerant flowing out of the outdoor heat exchanger 12 is branched at the branching section 13. One of the refrigerant branches at the branching section 13 flows into the nozzle-side expansion valve 14a and is decompressed (from point b3 to point c3 in FIG. 3 ).

[0095] As shown in the Mollier diagram of Fig. 3, the throttle opening of the nozzle side expansion valve 14a is adjusted so that the line drawn by the refrigerant from the refrigerant inlet 611 of the nozzle portion 61 to the injection port 615 (the line drawn from point c3 to point d3 in Fig. 3) passes through the saturated gas line. Therefore, the refrigerant at the outlet portion of the nozzle side expansion valve 14a (point c3 in Fig. 3) is in a supercritical state.

[0096] The refrigerant flowing out of the nozzle-side expansion valve 14a flows as a driving-side fluid into the refrigerant inlet 611 of the nozzle portion 61. The refrigerant flowing into the refrigerant inlet 611 of the nozzle portion 61 is isentropically decompressed in a refrigerant passage formed in the nozzle portion 61, accelerated to a speed faster than the speed of sound, and injected from the injection port 615 into the mixing portion 622 (from point c3 to point d3 in Figure 3). In Figure 3, the amount of energy recovered in the nozzle portion 61 is represented by Δh1.

[0097] The other refrigerant branched at the branching portion 13 flows into the high-pressure passage of the internal heat exchanger 15. The refrigerant flowing into the high-pressure passage of the internal heat exchanger 15 exchanges heat with the refrigerant flowing through the low-pressure passage, thereby reducing its enthalpy (from point b3 to point e3 in FIG. 3). The refrigerant flowing out of the high-pressure passage of the internal heat exchanger 15 flows into the suction-side expansion valve 14b and is decompressed isenthalpically (from point e3 to point f3 in FIG. 3).

[0098] The refrigerant in a gas-liquid two-phase state decompressed by the suction-side expansion valve 14b flows into the suction-side evaporator 17b. In the suction-side evaporator 17b, the refrigerant absorbs heat from the blown air that has passed through the outlet-side evaporator 17a and evaporates (from point f3 to point g3 in FIG. 3). This cools the blown air. The refrigerant flowing out of the suction-side evaporator 17b (point g3 in FIG. 3) is drawn into the suction port 621 of the ejector 16 as a suction-side fluid.

[0099] Inside the ejector 16, the injected refrigerant injected from the nozzle portion 61 (point d3 in Figure 3) and the suction refrigerant sucked from the suction port 621 (point g3 in Figure 3) join together in the tapered mixing portion 622a to form a mixed refrigerant (from point d3 to point h3, and from point g3 to point h3 in Figure 3).

[0100] Here, the refrigerant mixed in the convergent mixing section 622a is in a non-equilibrium state, making it difficult to represent it as a single point on a Mollier diagram. Therefore, point h3 in Figure 3 shows the state of the refrigerant on the central axis side near the neck section 622c. This also applies to the following embodiments.

[0101] The mixed refrigerant flowing from the convergent mixing section 622a to the divergent mixing section 622b reaches an equilibrium state and is effectively pressurized by the action of the shock waves (from point h3 to point i3 in FIG. 3). The refrigerant pressurized in the divergent mixing section 622b flows through the expanded area section 623, flows out of the refrigerant outlet 624, and into the outlet-side evaporator 17a.

[0102] In the outlet-side evaporator 17a, the refrigerant flowing out from the ejector 16 absorbs heat from the air being blown into the vehicle cabin and evaporates (from point i3 to point j3 in FIG. 3). This cools the air. The refrigerant flowing out from the outlet-side evaporator 17a flows into the accumulator 18 and is separated into gas and liquid.

[0103] The gas phase refrigerant flowing out of the accumulator 18 flows into the low-pressure passage of the internal heat exchanger 15. The refrigerant flowing into the low-pressure passage of the internal heat exchanger 15 exchanges heat with the refrigerant flowing through the high-pressure passage, increasing the enthalpy (from point j3 to point k3 in FIG. 3). The refrigerant flowing out of the low-pressure passage of the internal heat exchanger 15 is drawn into the compressor 11 and compressed again (from point k3 to point a3 in FIG. 3).

[0104] In the interior air conditioning unit, the air blown toward the vehicle cabin is cooled as it passes through the outlet-side evaporator 17a. The air cooled by the outlet-side evaporator 17a is further cooled as it passes through the suction-side evaporator 17b. The air cooled by the suction-side evaporator 17b is placed in the interior air conditioning unit, where its temperature is adjusted by a reheating unit such as a heater core, and then blown out to an appropriate location in the vehicle cabin. This achieves air conditioning in the vehicle cabin.

[0105] In the ejector-type refrigeration cycle 10, the refrigerant evaporation temperature of the suction-side evaporator 17b is lower than the refrigerant evaporation temperature of the outlet-side evaporator 17a. Therefore, in the vehicle air conditioner 1, the air blown into the passenger compartment can be efficiently cooled in the order from the outlet-side evaporator 17a to the suction-side evaporator 17b.

[0106] As described above, the vehicle air conditioner 1 can cool the blown air to condition the interior of the vehicle cabin. Furthermore, the ejector-type refrigeration cycle 10 of this embodiment can reliably and sufficiently improve the COP by configuring a supercritical refrigeration cycle.

[0107] To increase the amount of energy recovered in the ejector, the refrigerant flow must be phase-changed to a mist flow in the refrigerant passage formed in the nozzle, and the droplets contained in the mist flow must be atomized in the refrigerant passage of the nozzle to bring the gas phase refrigerant and the droplets closer to an equilibrium state.

[0108] However, in an ejector-type refrigeration cycle in which a liquid-phase refrigerant flows into the nozzle, it is difficult to bring the gas-phase refrigerant and liquid droplets contained in the mist flow into an equilibrium state because, when the operating conditions change, the axial length of the refrigerant passage in the nozzle or the time the refrigerant flows through the refrigerant passage in the nozzle becomes insufficient.

[0109] In contrast, in the ejector-type refrigeration cycle 10 of this embodiment, as explained using the Mollier diagram of Figure 3, the line drawn by the refrigerant from the outlet of the outdoor heat exchanger 12 to the injection port 615 of the nozzle portion 61 of the ejector 16 passes through the saturated gas line.

[0110] According to this, the refrigerant that flows from the outlet of the outdoor heat exchanger 12 to the injection port 615 of the nozzle portion 61 of the ejector 16 does not become a liquid phase, but changes from a supercritical state to a gas-liquid two-phase state. In other words, the flow state of the supercritical refrigerant that flows out of the outdoor heat exchanger 12 can be changed into a mist flow in the refrigerant passage of the nozzle portion 61 without changing into a liquid phase flow or a bubble flow.

[0111] Furthermore, the decompression process of the refrigerant in the refrigerant passage of the nozzle portion 61 after passing either the critical point or the saturated gas line is a condensation process in which the quality of the refrigerant decreases. The droplets generated by the decrease in quality of the refrigerant are smaller in size than the droplets contained in the mist flow that has undergone a phase change from the liquid phase flow or the bubbly flow. Therefore, immediately after generation, the droplets generated by the decrease in quality of the refrigerant are rapidly broken down into fine particles by the shear force of the surrounding gas phase refrigerant flow.

[0112] Therefore, compared to a cycle in which liquid-phase refrigerant flows into the nozzle, even if the operating conditions change, it is easier to bring the gas-phase refrigerant and liquid droplets closer to an equilibrium state in the refrigerant passage of the nozzle 61. Furthermore, both the gas-phase refrigerant and the liquid droplets can be accelerated equally in the refrigerant passage of the nozzle 61.

[0113] As a result, in the ejector refrigeration cycle 10 of this embodiment, the decompression process of the refrigerant in the nozzle portion 61 of the ejector 16 (the process from point c3 to point d3 in Figure 3) can be made to approach an isentropic line determined by the refrigerant properties.

[0114] This increases the amount of energy recovered in the nozzle portion 61 of the ejector 16, thereby sufficiently improving the COP. That is, the COP improvement effect achieved by configuring a supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0115] In this embodiment, the nozzle-side expansion valve 14a is provided as a pressure reducing section. By adjusting the throttle opening of the nozzle-side expansion valve 14a, the pressure of the refrigerant on the outlet side of the outdoor heat exchanger 12 can be adjusted so that the line drawn by the refrigerant from the outlet of the outdoor heat exchanger 12 to the injection port 615 of the nozzle section 61 passes through the saturated gas line.

[0116] Furthermore, in this embodiment, the throttle opening of the suction side expansion valve 14b is adjusted so that the line drawn by the refrigerant from the refrigerant inlet 611 of the nozzle portion 61 to the injection port 615 passes through the saturated gas line. In other words, the throttle opening of the suction side expansion valve 14b is adjusted so that the refrigerant flowing into the refrigerant inlet 611 of the nozzle portion 61 becomes supercritical.

[0117] This makes it possible to increase the pressure difference between the refrigerant pressure at the refrigerant inlet 611 of the nozzle portion 61 and the refrigerant pressure at the injection port 615, compared to when the refrigerant flowing into the refrigerant inlet 611 of the nozzle portion 61 is in a gas-liquid two-phase state. As a result, the amount of recovered energy can be further increased.

[0118] The ejector-type refrigeration cycle 10 of this embodiment also includes an internal heat exchanger 15 as an auxiliary heat dissipation unit. This reduces the enthalpy of the refrigerant flowing into the suction-side evaporator 17b, thereby increasing the refrigeration capacity of the suction-side evaporator 17b. This further improves the COP of the ejector-type refrigeration cycle 10.

[0119] The refrigeration capacity of the suction side evaporator 17b can be defined as the enthalpy difference obtained by subtracting the enthalpy of the inlet side refrigerant from the enthalpy of the outlet side refrigerant of the suction side evaporator 17b multiplied by the refrigerant flow rate flowing through the suction side evaporator 17b.

[0120] Second Embodiment This embodiment describes a modification of the ejector-type refrigeration cycle 10 described in the first embodiment. Specifically, in the ejector-type refrigeration cycle 10 of this embodiment, as shown in the overall configuration diagram of Fig. 4, the internal heat exchanger 15 is eliminated and an auxiliary exterior heat exchanger 12a is adopted.

[0121] Therefore, in the ejector refrigeration cycle 10 of this embodiment, the refrigerant inlet side of the auxiliary exterior heat exchanger 12a is connected to the other outlet of the branch portion 13. The auxiliary exterior heat exchanger 12a is an auxiliary exterior air heat exchange portion that exchanges heat between the other refrigerant branched at the branch portion 13 and outside air blown by an outside air fan (not shown), thereby dissipating heat from the refrigerant. Therefore, the auxiliary exterior heat exchanger 12a is an auxiliary heat dissipation portion that dissipates heat from the other refrigerant branched at the branch portion 13.

[0122] The refrigerant outlet of the auxiliary exterior heat exchanger 12a is connected to the inlet side of the nozzle expansion valve 14a. The gas phase refrigerant outlet of the accumulator 18 is connected to the suction port side of the compressor 11. Other configurations of the ejector-type refrigeration cycle 10 and the vehicle air conditioner 1 are the same as those of the first embodiment.

[0123] Next, a description will be given of the operation of the vehicle air conditioner 1 of this embodiment having the above-described configuration. The basic operation of the vehicle air conditioner 1 of this embodiment is the same as that of the first embodiment.

[0124] Therefore, in the ejector refrigeration cycle 10, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 5. In Fig. 5, the states of the refrigerant at locations equivalent in the cycle configuration to those in Fig. 3 described in the first embodiment are indicated by the same reference characters (alphabet), and only the subscripts (numbers) have been changed to match the diagram numbers. This also applies to the following Mollier diagrams.

[0125] That is, the discharged refrigerant (point a5 in FIG. 5 ) that has been pressurized to or above the critical pressure by the compressor 11 dissipates heat to the outside air in the outdoor heat exchanger 12 to reduce the enthalpy (from point a5 to point b5 in FIG. 5 ), as in the first embodiment. The flow of the supercritical refrigerant that has flowed out of the outdoor heat exchanger 12 is branched at the branching section 13.

[0126] One of the refrigerant branches at the branching portion 13 flows into the nozzle-side expansion valve 14a and is decompressed (from point b5 to point c5 in FIG. 5 ). The refrigerant flowing out of the nozzle-side expansion valve 14a flows into the refrigerant inlet 611 of the nozzle portion 61 as a driving-side fluid, similar to the first embodiment.

[0127] The other refrigerant branched at the branch portion 13 flows into the auxiliary exterior heat exchanger 12a. The refrigerant that has flowed into the auxiliary exterior heat exchanger 12a dissipates heat to outside air blown by the outside air fan, thereby reducing its enthalpy (from point b5 to point e51 in FIG. 5). The refrigerant that has flowed out of the auxiliary exterior heat exchanger 12a flows into the suction side expansion valve 14b and is isenthalpic-depressurized (from point e51 to point f5 in FIG. 5), as in the first embodiment.

[0128] Furthermore, in the ejector-type refrigeration cycle 10 of this embodiment, the gas-phase refrigerant flowing out from the accumulator 18 is drawn into the compressor 11 and compressed again (from point j5 to point a5 in FIG. 5). Other operations are the same as those of the first embodiment.

[0129] As described above, the vehicle air conditioner 1 of this embodiment can condition the air inside the vehicle cabin in the same manner as in the first embodiment. Furthermore, the ejector-type refrigeration cycle 10 of this embodiment can provide the same effects as in the first embodiment. That is, the COP improvement effect achieved by configuring a supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0130] The ejector-type refrigeration cycle 10 of this embodiment also includes an auxiliary exterior heat exchanger 12a as an auxiliary heat dissipation unit. This reduces the enthalpy of the refrigerant flowing into the suction-side evaporator 17b, thereby increasing the refrigeration capacity of the suction-side evaporator 17b. This further improves the COP of the ejector-type refrigeration cycle 10.

[0131] Third Embodiment This embodiment describes a modification of the ejector-type refrigeration cycle 10 described in the first embodiment. Specifically, the ejector-type refrigeration cycle 10 of this embodiment employs the auxiliary exterior heat exchanger 12a described in the second embodiment in addition to the internal heat exchanger 15, as shown in the overall configuration diagram of FIG.

[0132] Therefore, in the ejector-type refrigeration cycle 10 of this embodiment, the refrigerant inlet side of the auxiliary exterior heat exchanger 12a is connected to the other outlet of the branch portion 13. The refrigerant outlet of the auxiliary exterior heat exchanger 12a is connected to the inlet side of the high-pressure passage of the internal heat exchanger 15. Other configurations of the ejector-type refrigeration cycle 10 and the vehicle air conditioner 1 are similar to those of the first embodiment.

[0133] Next, a description will be given of the operation of the vehicle air conditioner 1 of this embodiment having the above-described configuration. The basic operation of the vehicle air conditioner 1 of this embodiment is the same as that of the first embodiment.

[0134] Therefore, in the ejector refrigeration cycle 10, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0135] That is, the discharged refrigerant (point a7 in FIG. 7 ) that has been pressurized to or above the critical pressure by the compressor 11 dissipates heat to the outside air in the outdoor heat exchanger 12 to reduce the enthalpy (from point a7 to point b7 in FIG. 5 ), as in the first embodiment. The flow of the supercritical refrigerant that has flowed out of the outdoor heat exchanger 12 is branched at the branching section 13.

[0136] One of the refrigerant branches at the branching portion 13 flows into the nozzle-side expansion valve 14a and is decompressed (from point b7 to point c7 in FIG. 7 ). The refrigerant flowing out of the nozzle-side expansion valve 14a flows into the refrigerant inlet 611 of the nozzle portion 61 as a driving-side fluid, similar to the first embodiment.

[0137] The other refrigerant branched at the branch portion 13 flows into the auxiliary exterior heat exchanger 12a. As in the second embodiment, the refrigerant that has flowed into the auxiliary exterior heat exchanger 12a dissipates heat to the outside air, thereby reducing the enthalpy (from point b7 to point e71 in FIG. 7 ).

[0138] The refrigerant flowing out of the auxiliary exterior heat exchanger 12a flows into the high-pressure passage of the internal heat exchanger 15. As in the first embodiment, the refrigerant flowing into the high-pressure passage of the internal heat exchanger 15 exchanges heat with the refrigerant flowing through the low-pressure passage, thereby reducing the enthalpy (from point e71 to point e7 in FIG. 7). The refrigerant flowing out of the high-pressure passage of the internal heat exchanger 15 flows into the suction-side expansion valve 14b and is decompressed isenthalpically (from point e7 to point f7 in FIG. 7). Other operations are the same as those in the first embodiment.

[0139] As described above, the vehicle air conditioner 1 of this embodiment can condition the air inside the vehicle cabin in the same manner as in the first embodiment. Furthermore, the ejector-type refrigeration cycle 10 of this embodiment can provide the same effects as in the first embodiment. That is, the COP improvement effect achieved by configuring a supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0140] The ejector-type refrigeration cycle 10 of this embodiment also includes an auxiliary exterior heat exchanger 12a and an internal heat exchanger 15 as auxiliary heat dissipation units, which can reduce the enthalpy of the refrigerant flowing into the suction-side evaporator 17b, thereby increasing the refrigeration capacity of the suction-side evaporator 17b.

[0141] In the ejector-type refrigeration cycle 10 of this embodiment, the temperature of the refrigerant flowing through the low-pressure passage of the internal heat exchanger 15 is lower than the outside air temperature. Therefore, in the auxiliary heat dissipation section of this embodiment, the other refrigerant branched at the branch section 13 can be efficiently dissipated heat in the order from the auxiliary exterior heat exchanger 12 a to the internal heat exchanger 15.

[0142] Fourth Embodiment This embodiment describes a modification of the ejector-type refrigeration cycle 10 described in the first embodiment. Specifically, in the ejector-type refrigeration cycle 10 of this embodiment, as shown in the overall configuration diagram of FIG. 8, the outlet-side evaporator 17a is eliminated.

[0143] Therefore, in the ejector-type refrigeration cycle 10 of this embodiment, the inlet side of the low-pressure passage of the internal heat exchanger 15 is connected to the refrigerant outlet 624 of the ejector 16. The inlet side of the accumulator 18 is connected to the outlet of the low-pressure passage of the internal heat exchanger 15. The suction port side of the compressor 11 is connected to the gas-phase refrigerant outlet of the accumulator 18. Other configurations of the ejector-type refrigeration cycle 10 and the vehicle air conditioner 1 are similar to those of the first embodiment.

[0144] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. The basic operation of the vehicle air conditioner 1 of this embodiment is the same as that of the second embodiment. In this embodiment, the internal heat exchanger 15 exchanges heat between the other refrigerant branched at the branch portion 13 and the refrigerant flowing out from the refrigerant outlet 624 of the ejector 16. Other operations are the same as those of the second embodiment.

[0145] As described above, the vehicle air conditioner 1 of this embodiment can condition the air inside the vehicle cabin in the same manner as in the first embodiment. Furthermore, the ejector-type refrigeration cycle 10 of this embodiment can provide the same effects as in the first embodiment. That is, the COP improvement effect achieved by configuring a supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0146] Fifth Embodiment In this embodiment, a modification of the ejector-type refrigeration cycle 10 described in the first embodiment will be described. Specifically, as shown in the overall configuration diagram of Fig. 9, the ejector-type refrigeration cycle 10 of this embodiment employs a water-refrigerant heat exchanger 12b instead of the exterior heat exchanger 12. The vehicle air conditioner 1 of this embodiment also includes a high-temperature side heat medium circuit 30.

[0147] Therefore, in the ejector-type refrigeration cycle 10 of this embodiment, the inlet side of the refrigerant passage of the water-refrigerant heat exchanger 12b is connected to the discharge port of the compressor 11. The inlet side of the branching portion 13 is connected to the outlet of the refrigerant passage of the water-refrigerant heat exchanger 12b.

[0148] The water-refrigerant heat exchanger 12b is a heat exchanger that exchanges heat between the refrigerant discharged from the compressor 11 and the high-temperature heat medium circulating through the high-temperature heat medium circuit 30. The water-refrigerant heat exchanger 12b heats the high-temperature heat medium by dissipating heat from the discharged refrigerant to the high-temperature heat medium. The other configurations of the ejector refrigeration cycle 10 are the same as those of the first embodiment.

[0149] Next, the high-temperature side heat medium circuit 30 will be described. The high-temperature side heat medium circuit 30 is a heat medium circuit that circulates the high-temperature side heat medium. In this embodiment, an ethylene glycol aqueous solution is used as the high-temperature side heat medium. The high-temperature side heat medium circuit 30 includes a high-temperature side pump 31, a high-temperature side radiator 32, and a heat medium passage of the water-refrigerant heat exchanger 12b.

[0150] The high-temperature side pump 31 is a high-temperature side heat medium pumping unit that sucks in the high-temperature side heat medium that has flowed out from the heat medium passage of the water-refrigerant heat exchanger 12b and pumps it to the heat medium inlet side of the high-temperature side radiator 32. The high-temperature side pump 31 is an electric water pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 20.

[0151] The high-temperature side radiator 32 is a heat exchanger that exchanges heat between the high-temperature side heat medium flowing out of the water-refrigerant heat exchanger 12b and outside air blown by an outside air fan (not shown). The high-temperature side radiator 32 has a heat medium outlet connected to an inlet side of the heat medium passage of the water-refrigerant heat exchanger 12b.

[0152] Therefore, in the high-temperature side heat medium circuit 30, when the high-temperature side pump 31 is operated, the high-temperature side heat medium pumped from the high-temperature side pump 31 circulates through the high-temperature side radiator 32, the heat medium passage of the water-refrigerant heat exchanger 12b, and the suction side of the high-temperature side pump, in that order.

[0153] In the high-temperature side heat medium circuit 30, the high-temperature side heat medium that has flowed into the heat medium passage of the water-refrigerant heat exchanger 12b is heated by heat exchange with the discharged refrigerant flowing through the refrigerant passage of the water-refrigerant heat exchanger 12b. The high-temperature side heat medium heated in the water-refrigerant heat exchanger 12b is drawn into the high-temperature side pump 31 and pumped to the inlet side of the high-temperature side radiator 32.

[0154] The high-temperature side heat medium that flows into the high-temperature side radiator 32 exchanges heat with the outside air and is cooled. The high-temperature side heat medium that flows out of the high-temperature side radiator 32 flows into the heat medium passage of the water-refrigerant heat exchanger 12b. In other words, the water-refrigerant heat exchanger 12b and the components of the high-temperature side heat medium circuit 30 in this embodiment are heat radiating units that radiate heat from the refrigerant to the outside air via the high-temperature side heat medium.

[0155] Furthermore, by adjusting the rotation speed, the high-temperature side pump 31 can adjust the amount of heat exchange between the refrigerant and the high-temperature side heat medium in the water-refrigerant heat exchanger 12b and the amount of heat exchange between the high-temperature side heat medium and the outside air in the high-temperature side radiator 32. This allows the high-temperature side pump 31 to adjust the state of the refrigerant (i.e., pressure and enthalpy) at the outlet of the refrigerant passage of the water-refrigerant heat exchanger 12b. Therefore, the high-temperature side pump 31 is a heat dissipation capacity adjustment unit that adjusts the heat dissipation capacity of the heat dissipation unit.

[0156] The high-pressure temperature sensor of this embodiment detects the temperature of the refrigerant flowing out of the refrigerant passage of the water-refrigerant heat exchanger 12b as the high-pressure temperature Td. The remaining configuration of the vehicle air conditioner 1 is the same as that of the first embodiment.

[0157] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. In this embodiment, the control device 20 controls the throttle opening of the nozzle-side expansion valve 14a so that the throttle opening becomes a target throttle opening. The target throttle opening is determined based on the target outlet temperature TAO by referring to a control map stored in advance in the control device 20.

[0158] Furthermore, the control device 20 controls the pumping capacity of the high-temperature side pump 31 so that the discharge pressure Pd approaches the target high pressure PDO.

[0159] As in the first embodiment, the target high-pressure PDO is determined based on the discharge pressure Pd and the high-pressure temperature Td by referring to a control map previously stored in the control device 20. In the control map, the target high-pressure PDO is determined so that the line drawn by the refrigerant from the outlet of the refrigerant passage of the water-refrigerant heat exchanger 12b to the injection port 615 of the ejector 16 passes through either the critical point or the saturated gas line in a Mollier diagram of the refrigerant.

[0160] Therefore, the control device 20 controls the pumping capacity of the high-temperature side pump 31 so that the line drawn by the refrigerant from the outlet of the refrigerant passage of the water-refrigerant heat exchanger 12b to the injection port 615 of the ejector 16 passes through either the critical point or the saturated gas line in the Mollier diagram of the refrigerant.

[0161] More specifically, in the control map of this embodiment, the target high-pressure PDO is determined so that the line drawn by the refrigerant from the refrigerant inlet 611 of the nozzle portion 61 to the injection port 615 passes through the saturated gas line in the Mollier diagram of the refrigerant.

[0162] Therefore, the control device 20 controls the pumping capacity of the high-temperature side pump 31 so that the line drawn by the refrigerant from the refrigerant inlet 611 of the nozzle portion 61 to the injection port 615 passes through the saturated gas line in the Mollier diagram of the refrigerant. Other operations are the same as those in the first embodiment.

[0163] Therefore, in the ejector refrigeration cycle 10 of this embodiment, the state of the refrigerant changes, similarly to the first embodiment.

[0164] In the high-temperature side heat medium circuit 30, the high-temperature side heat medium pumped from the high-temperature side pump 31 flows into the high-temperature side radiator 32 and dissipates heat to the outside air. The high-temperature side heat medium flowing out of the high-temperature side radiator 32 flows into the heat medium passage of the water-refrigerant heat exchanger 12b. The high-temperature side heat medium flowing into the heat medium passage of the water-refrigerant heat exchanger 12b absorbs heat from the discharged refrigerant flowing through the refrigerant passage. This reduces the enthalpy of the discharged refrigerant. The refrigerant flowing out of the heat medium passage of the water-refrigerant heat exchanger 12b is drawn into the high-temperature side pump 31. Other operations are the same as those in the first embodiment.

[0165] As described above, the vehicle air conditioner 1 of this embodiment can condition the air inside the vehicle cabin in the same manner as in the first embodiment. Furthermore, the ejector-type refrigeration cycle 10 of this embodiment can provide the same effects as in the first embodiment. That is, the COP improvement effect achieved by configuring a supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0166] Sixth Embodiment In this embodiment, as shown in Fig. 10, an example will be described in which an ejector-type refrigeration cycle 10a according to the present disclosure is applied to a vehicle cooling device 1a mounted on an electric vehicle. An electric vehicle is a vehicle that obtains driving power for running from an electric motor. The vehicle cooling device 1a is mounted on the vehicle and cools on-board devices that generate heat during operation.

[0167] The vehicle cooling device 1a cools a battery 50 as an on-board device. The battery 50 is a secondary battery that stores power to be supplied to multiple on-board devices that operate electrically. The battery 50 is an assembled battery formed by electrically connecting multiple stacked battery cells in series or parallel. The battery cells in this embodiment are lithium-ion batteries.

[0168] The battery 50 generates heat during operation (i.e., during charging and discharging). The battery 50 is prone to a decrease in output when the temperature is low, and prone to deterioration when the temperature is high. For this reason, the temperature of the battery 50 needs to be maintained within an appropriate temperature range (in this embodiment, 15°C or higher and 55°C or lower).

[0169] The vehicle cooling system 1a includes an ejector refrigeration cycle 10a, a low-temperature side heat medium circuit 40, a control device 20, and the like.

[0170] The ejector refrigeration cycle 10a does not have the branching portion 13 and the internal heat exchanger 15, as compared with the ejector refrigeration cycle 10 described in the first embodiment. Therefore, in the ejector refrigeration cycle 10a, the inlet side of the nozzle-side expansion valve 14a is connected to the refrigerant outlet of the outdoor heat exchanger 12. Also, the inlet side of the suction-side expansion valve 14b is connected to the liquid-phase refrigerant outlet of the accumulator 18.

[0171] The outlet of the suction side expansion valve 14b is connected to the inlet side of the refrigerant passage of the chiller 17c. The chiller 17c is a heat exchanger that exchanges heat between the refrigerant flowing out of the suction side expansion valve 14b and the low-temperature side heat medium circulating through the low-temperature side heat medium circuit 40. The chiller 17c is an evaporation unit that causes the refrigerant flowing out of the suction side expansion valve 14b to absorb heat contained in the low-temperature side heat medium, thereby evaporating the refrigerant. This cools the low-temperature side heat medium.

[0172] The outlet of the refrigerant passage of the chiller 17c is connected to the suction port 621 side of the ejector 16. Other configurations of the ejector refrigeration cycle device 10a are similar to those of the ejector refrigeration cycle device 10 described in the first embodiment.

[0173] Next, the low-temperature side heat medium circuit 40 will be described. The low-temperature side heat medium circuit 40 is a heat medium circuit that circulates a low-temperature side heat medium. In this embodiment, the same type of fluid as the high-temperature side heat medium is used as the low-temperature side heat medium. The low-temperature side heat medium circuit 40 includes a low-temperature side pump 41, a coolant passage for the chiller 17c, a coolant passage for the battery 50, and the like.

[0174] The low-temperature side pump 41 is a low-temperature side heat medium pumping unit that sucks in the low-temperature side heat medium that has flowed out from the coolant passage of the battery 50 and pumps it to the inlet side of the heat medium passage of the chiller 17 c. The basic configuration of the low-temperature side pump 41 is similar to that of the high-temperature side pump 31 described in the fourth embodiment.

[0175] The inlet side of the cooling water passage of the chiller 17c is connected to the discharge port of the low-temperature side pump 41. The inlet side of the cooling water passage of the battery 50 is connected to the outlet side of the cooling water passage of the chiller 17c. The cooling water passage of the battery 50 is a passage through which the low-temperature side heat medium flowing out from the chiller 17c circulates to cool the battery 50. In other words, the cooling water passage of the battery 50 cools the battery 50 by exchanging heat between the low-temperature side heat medium and the battery cells.

[0176] The cooling water passages of the battery 50 are formed inside a battery case that houses multiple stacked battery cells. The cooling water passages of the battery 50 are configured so that multiple passages are connected in parallel inside the battery case so that all battery cells can be cooled evenly. The outlet of the cooling water passages of the battery 50 is connected to the suction port side of the low-temperature side pump 41.

[0177] Therefore, in the low-temperature side heat medium circuit 40, when the low-temperature side pump 41 is operated, the low-temperature side heat medium pressurized from the low-temperature side pump 41 circulates through the cooling water passage of the chiller 17c, the cooling water passage of the battery 50, and the intake port of the low-temperature side pump 41 in that order.

[0178] In the low-temperature side heat medium circuit 40, the low-temperature side heat medium that has flowed into the coolant passage of the chiller 17c is cooled by absorbing heat from the refrigerant flowing through the refrigerant passage of the chiller 17c. The low-temperature side heat medium cooled by the chiller 17c flows into the coolant passage of the battery 50. This cools the battery 50. The low-temperature side heat medium that has flowed out of the coolant passage of the battery 50 is sucked into the low-temperature side pump 41 and pumped to the inlet side of the refrigerant passage of the chiller 17c.

[0179] In addition, a low-temperature side heat medium temperature sensor is connected to the input side of the control device 20 of this embodiment as a group of control sensors. The low-temperature side heat medium temperature sensor is a low-temperature side heat medium temperature detection unit that detects the low-temperature side heat medium temperature TwB, which is the temperature of the low-temperature side heat medium flowing out from the coolant passage of the battery 50.

[0180] The evaporator pressure sensor of this embodiment detects the pressure of the suction-side refrigerant flowing out of the refrigerant passage of the chiller 17c as the suction-side pressure Pe, and the evaporator temperature sensor detects the temperature of the suction-side refrigerant as the suction-side temperature Te. The remaining configuration of the vehicle air conditioner 1 is the same as that of the first embodiment.

[0181] Next, the operation of the vehicle cooling device 1a of this embodiment configured as described above will be described. The control device 20 of this embodiment executes a cooling control program pre-stored in a memory circuit when a predetermined execution condition is met. In this embodiment, the execution condition is met when the start switch (also known as the ignition switch) of the vehicle system is turned on to start the vehicle system, or when the charging connector of the battery 50 is connected to the vehicle.

[0182] When the control program is executed, the control device 20 operates the low-temperature side pump 41 so as to achieve a predetermined reference pumping capacity. Furthermore, the control program reads detection signals from the control sensors at predetermined control cycles. Then, based on the read control signals, it determines whether cooling of the battery 50 is necessary.

[0183] In the control program of this embodiment, when the low-temperature side heat medium temperature TwB is equal to or higher than a predetermined reference cooling start temperature KTwBH while no refrigerant is flowing into the chiller 17c, it is determined that cooling of the battery 50 is necessary. Also, when the low-temperature side heat medium temperature TwB is equal to or lower than a predetermined reference cooling stop temperature KTwBL while refrigerant is flowing into the chiller 17c, it is determined that cooling of the battery 50 is not necessary.

[0184] When it is determined that cooling of the battery 50 is necessary, the control device 20 controls the operation of various components of the ejector refrigeration cycle 10 to cool the battery. Specifically, the control device 20 controls the rotation speed of the compressor 11 so that the suction-side temperature Te approaches a predetermined reference cooling temperature KTe. In addition, the control device 20 controls the throttle opening of the nozzle-side expansion valve 14a and the suction-side expansion valve 14b, as in the first embodiment.

[0185] Therefore, in the ejector refrigeration cycle 10a, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0186] That is, the discharged refrigerant (point a11 in FIG. 11 ) pressurized to or above the critical pressure by the compressor 11 flows into the outdoor heat exchanger 12. The discharged refrigerant that has flowed into the outdoor heat exchanger 12 releases heat to the outside air blown by the outdoor air fan, thereby reducing its enthalpy (from point a11 to point b11 in FIG. 11 ). The supercritical refrigerant that has flowed out of the outdoor heat exchanger 12 flows into the nozzle-side expansion valve 14a and is decompressed in the same manner as in the first embodiment (from point b11 to point c11 in FIG. 11 ).

[0187] The refrigerant flowing out of the nozzle expansion valve 14a flows as a driving fluid into the refrigerant inlet 611 of the nozzle portion 61. The refrigerant flowing into the nozzle portion 61 is isentropically decompressed in a refrigerant passage formed in the nozzle portion 61, accelerated to a speed faster than the speed of sound, and injected from the injection port 615 into the mixing portion 622 (from point c11 to point d11 in FIG. 11 ). In FIG. 11 , the amount of energy recovered in the nozzle portion 61 is represented by Δh2.

[0188] Inside the ejector 16, the injected refrigerant (point d11 in Figure 11) and the suction refrigerant (point g11 in Figure 11) sucked from the suction port 621 join together in the tapered mixing section 622a to become a mixed refrigerant (from point d11 to point h11, and from point g11 to point h11 in Figure 11).

[0189] The mixed refrigerant that flows from the convergent mixing section 622a to the divergent mixing section 622b reaches an equilibrium state and is effectively pressurized by the action of shock waves (from point h11 to point i11 in FIG. 11 ). The refrigerant pressurized in the divergent mixing section 622b flows through the expanded area section 623, flows out of the refrigerant outlet 624, and flows into the accumulator 18. The refrigerant that flows into the accumulator 18 is separated into gas and liquid (from point i11 to point j11 and from point i11 to point m11 in FIG. 11 ).

[0190] The gas-phase refrigerant separated in the accumulator 18 (point j11 in FIG. 11 ) is drawn into the compressor 11 and compressed again (from point j11 to point a11 in FIG. 11 ). The liquid-phase refrigerant separated in the accumulator 18 (point m11 in FIG. 11 ) flows into the suction-side expansion valve 14b and is decompressed in the same manner as in the first embodiment (from point m11 to point f11 in FIG. 11 ). The gas-liquid two-phase refrigerant decompressed by the suction-side expansion valve 14b flows into the refrigerant passage of the chiller 17c.

[0191] In the chiller 17c, the refrigerant decompressed by the suction-side expansion valve 14b absorbs heat from the low-temperature heat medium flowing through the cooling water passage and evaporates (from point f11 to point g11 in FIG. 11 ). This cools the low-temperature heat medium. The refrigerant flowing out of the chiller 17c (point g11 in FIG. 11 ) is drawn into the suction port 621 of the ejector 16 as a suction-side fluid.

[0192] In the low-temperature side heat medium circuit 40, the low-temperature side heat medium pumped from the low-temperature side pump 41 flows into the coolant passage of the chiller 17c and is cooled. The low-temperature side heat medium cooled in the chiller 17c flows into the coolant passage of the battery 50. The low-temperature side heat medium that flows into the coolant passage of the battery 50 exchanges heat with the battery 50, thereby cooling the battery 50. The low-temperature side heat medium that flows out from the coolant passage of the battery 50 is sucked into the low-temperature side pump 41.

[0193] As described above, the vehicle cooling device 1a can cool the battery 50. Furthermore, the ejector-type refrigeration cycle 10a can provide the same effects as those of the first embodiment. That is, the COP improvement effect due to the supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0194] Seventh Embodiment In this embodiment, an ejector-type refrigeration cycle 10b according to the present disclosure is applied to a vehicle air conditioner 1b mounted on an electric vehicle. The vehicle air conditioner 1b is an air conditioner with an in-vehicle equipment cooling function that has a function of cooling in-vehicle equipment.

[0195] 12, the ejector refrigeration cycle 10b of this embodiment does not include the outdoor heat exchanger 12 of the ejector refrigeration cycle 10a described in the sixth embodiment, and instead employs a water-refrigerant heat exchanger 12b. Furthermore, the ejector refrigeration cycle 10b further includes an auxiliary outdoor heat exchanger 12a, a branch section 13, a junction section 13a, a cooling expansion valve 14c, a cooling evaporator 17d, and the like.

[0196] Therefore, in the ejector-type refrigeration cycle 10b of this embodiment, the inlet side of the branch part 13 is connected to the outlet of the refrigerant passage of the water-refrigerant heat exchanger 12b. One outlet of the branch part 13 is connected to the inlet side of the nozzle-side expansion valve 14a. The other outlet of the branch part 13 is connected to the refrigerant inlet side of the auxiliary exterior heat exchanger 12a.

[0197] The refrigerant outlet of the auxiliary exterior heat exchanger 12a is connected to the inlet side of a cooling expansion valve 14c. The cooling expansion valve 14c is a variable throttle mechanism that reduces the pressure of the refrigerant flowing out of the auxiliary exterior heat exchanger 12a. The cooling expansion valve 14c is a cooling flow rate adjustment unit that adjusts the flow rate of refrigerant flowing into the cooling evaporator 17d.

[0198] The cooling expansion valve 14c has a basic configuration similar to that of the nozzle expansion valve 14a. Furthermore, the nozzle expansion valve 14a and the cooling expansion valve 14c of this embodiment have a full-closing function that closes the refrigerant passage by fully closing the throttle opening.

[0199] The outlet of the cooling expansion valve 14c is connected to the refrigerant inlet side of the cooling evaporator 17d. The cooling evaporator 17d is a heat exchanger that exchanges heat between the refrigerant flowing out from the cooling expansion valve 14c and the blown air. As in the first embodiment, the cooling evaporator 17d is disposed in an air passage formed in the indoor air conditioning unit. The cooling evaporator 17d causes the refrigerant, whose pressure has been reduced by the cooling expansion valve 14c, to absorb heat from the blown air, thereby evaporating the refrigerant.

[0200] One inlet side of a junction section 13a is connected to the refrigerant outlet of the cooling evaporator 17d. The junction section 13a is a three-way joint having the same configuration as the branch section 13. The other inlet side of the junction section 13a is connected to the gas phase refrigerant outlet side of the accumulator 18. The outlet side of the junction section 13a is connected to the suction port side of the compressor 11. The other configuration of the ejector refrigeration cycle device 10b is the same as that of the ejector refrigeration cycle device 10a described in the sixth embodiment.

[0201] The vehicle air conditioning system 1b also includes a high-temperature side heat medium circuit 30 similar to that of the fifth embodiment. The water-refrigerant heat exchanger 12b and the components of the high-temperature side heat medium circuit 30 are heat radiating units that radiate heat from the refrigerant to the outside air via the high-temperature side heat medium.

[0202] In addition, a cooling evaporator temperature sensor and a high-pressure pressure sensor are connected to the input side of the control device 20 of this embodiment as a group of control sensors. The cooling evaporator temperature sensor is a cooling evaporator temperature detection unit that detects an evaporator-side refrigerant temperature Te2, which is the temperature of the refrigerant in the cooling evaporator 17d. The high-pressure pressure sensor is a high-pressure pressure detection unit that detects a high-pressure temperature T2, which is the temperature of the refrigerant flowing out from the auxiliary exterior heat exchanger 12a.

[0203] The high-pressure temperature sensor of this embodiment detects the temperature of the refrigerant flowing out of the refrigerant passage of the water-refrigerant heat exchanger 12b as the high-pressure temperature Td. The evaporator pressure sensor of this embodiment detects the pressure of the suction-side refrigerant flowing out of the refrigerant passage of the chiller 17c as the suction-side pressure Pe. The evaporator temperature sensor detects the temperature of the suction-side refrigerant as the suction-side temperature Te. The remaining configuration of the vehicle air conditioner 1 is the same as that of the first embodiment.

[0204] Next, the operation of the vehicle air conditioner 1b of this embodiment configured as described above will be described. The control program of this embodiment switches the operation mode based on the detection signal and the operation signal. The operation modes include (a) standalone air conditioning mode, (b) standalone cooling mode, and (c) air conditioning cooling mode. Each operation mode will be described below.

[0205] (a) Single Air Conditioning Mode The single air conditioning mode is an operating mode that is selected when an occupant requests air conditioning of the vehicle interior and when it is not determined that cooling of the battery 50 is necessary.

[0206] In the ejector refrigeration cycle 10b in the standalone air conditioning mode, the control device 20 fully closes the nozzle expansion valve 14a and throttles the cooling expansion valve 14c. Therefore, in the ejector refrigeration cycle 10b in the standalone air conditioning mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the water-refrigerant heat exchanger 12b, the auxiliary exterior heat exchanger 12a, the cooling expansion valve 14c, the chiller 17c, and the suction port of the compressor 11 in this order. In other words, in the standalone air conditioning mode, a normal vapor compression refrigeration cycle is configured that does not use the ejector 16.

[0207] The control device 20 also controls the refrigerant discharge capacity of the compressor 11 so that the evaporator-side refrigerant temperature Te2 detected by the cooling evaporator temperature sensor approaches the target evaporator temperature TEO. The control device 20 also controls the throttle opening of the cooling expansion valve 14c so that the discharge pressure Pd approaches the target high-pressure PDO2. The target high-pressure PDO2 is determined based on the outside air temperature Tam and the high-pressure temperature T2, by referring to a control map previously stored in the control device.

[0208] In the high-temperature side heat medium circuit 30 in the single air-conditioning mode, the control device 20 operates the high-temperature side pump 31 so as to exert a predetermined reference pumping capacity.

[0209] Therefore, in the ejector-type refrigeration cycle 10b in the single air-conditioning mode, refrigerant is not circulated through the ejector 16, and the water-refrigerant heat exchanger 12b and the auxiliary exterior heat exchanger 12a function as radiators. Furthermore, a vapor compression refrigeration cycle is configured in which the cooling evaporator 17d functions as an evaporator. As a result, the cooling evaporator 17d cools the blown air.

[0210] In the high-temperature side heat medium circuit 30 in the single air-conditioning mode, the heat of the refrigerant discharged from the compressor 11 is dissipated to the outside air via the high-temperature side heat medium, as in the fifth embodiment.

[0211] In the interior air conditioning unit in the single air conditioning mode, the air blown toward the interior of the vehicle is cooled as it passes through the cooling evaporator 17d. The air cooled by the cooling evaporator 17d is temperature-adjusted by a reheating unit such as a heater core and then blown out to an appropriate location in the vehicle cabin. This achieves air conditioning in the vehicle cabin.

[0212] (b) Single Cooling Mode The single cooling mode is an operating mode that is selected when the air conditioning of the vehicle interior is not requested by the occupant and it is determined that cooling of the battery 50 is necessary.

[0213] In the ejector refrigeration cycle 10b in the sole cooling mode, the control device 20 throttles the nozzle expansion valve 14a and fully closes the cooling expansion valve 14c. Therefore, in the ejector refrigeration cycle 10b in the sole air conditioning mode, the refrigerant is switched to a refrigerant circuit in which the refrigerant circulates in the same order as in the sixth embodiment.

[0214] The control device 20 controls the operation of the compressor 11 and the suction side expansion valve 14b, as in the sixth embodiment. The control device 20 controls the operation of the nozzle side expansion valve 14a, as in the fifth embodiment.

[0215] In the high-temperature side heat medium circuit 30 in the single cooling mode, the control device 20 controls the pumping capacity of the high-temperature side pump 31, as in the fifth embodiment. In the low-temperature side heat medium circuit 40 in the single cooling mode, the control device 20 controls the pumping capacity of the low-temperature side pump 41, as in the sixth embodiment.

[0216] Therefore, in the ejector-type refrigeration cycle 10b in the single cooling mode, the state of the refrigerant changes substantially in the same manner as in the sixth embodiment. More specifically, the ejector-type refrigeration cycle is configured in which the water-refrigerant heat exchanger 12b functions as a radiator and the chiller 17c functions as an evaporator. As a result, the low-temperature side heat medium is cooled in the chiller 17c.

[0217] In the high-temperature side heat medium circuit 30 in the single cooling mode, the heat of the discharged refrigerant is dissipated to the outside air via the high-temperature side heat medium, as in the single cooling mode. In the low-temperature side heat medium circuit 40 in the single cooling mode, the low-temperature side heat medium cooled by the chiller 17c is caused to flow into the coolant passage of the battery 50, thereby cooling the battery 50, as in the sixth embodiment.

[0218] (c) Air Conditioning Cooling Mode The air conditioning cooling mode is an operation mode that is selected when an occupant requests air conditioning in the vehicle cabin and it is determined that cooling of the battery 50 is necessary.

[0219] In the ejector refrigeration cycle 10b in the air conditioning / cooling mode, the control device 20 throttles the nozzle expansion valve 14a and throttles the cooling expansion valve 14c. Therefore, in the ejector refrigeration cycle 10b in the standalone air conditioning mode, the refrigerant circulates in the same order as in the standalone cooling mode, and is switched to a refrigerant circuit in which the refrigerant circulates in the same order as in the standalone cooling mode.

[0220] The control device 20 also controls the operation of the compressor 11 and the cooling expansion valve 14c in the same manner as in the single cooling mode. The control device 20 also controls the operation of the suction side expansion valve 14b and the nozzle side expansion valve 14a in the same manner as in the single cooling mode.

[0221] In the high-temperature side heat medium circuit 30 in the air conditioning cooling mode, the control device 20 controls the pumping capacity of the high-temperature side pump 31, as in the fifth embodiment. In the low-temperature side heat medium circuit 40 in the air conditioning cooling mode, the control device 20 controls the pumping capacity of the low-temperature side pump 41, as in the sixth embodiment.

[0222] Therefore, in the ejector refrigeration cycle 10b in the air-conditioning cooling mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0223] That is, the discharged refrigerant (point a13 in FIG. 13 ) pressurized to or above the critical pressure by the compressor 11 flows into the refrigerant passage of the water-refrigerant heat exchanger 12 b. As in the fifth embodiment, the discharged refrigerant dissipates heat to the high-temperature side heat medium, reducing the enthalpy (from point a13 to point b13 in FIG. 13 ). The flow of the supercritical refrigerant flowing out of the refrigerant passage of the water-refrigerant heat exchanger 12 b is branched at the branching section 13.

[0224] One of the refrigerant branches at the branch unit 13 flows into the nozzle expansion valve 14a and is decompressed (from point b13 to point c13 in FIG. 13 ). The refrigerant flowing out of the nozzle expansion valve 14a flows into the refrigerant inlet 611 of the nozzle unit 61 as a driving side fluid, similar to the first embodiment.

[0225] The other refrigerant branched at the branching portion 13 flows into the auxiliary exterior heat exchanger 12a. The refrigerant that has flowed into the auxiliary exterior heat exchanger 12a dissipates heat to the outside air blown by the outside air fan, thereby reducing its enthalpy (from point b13 to point e131 in FIG. 13). The refrigerant that has flowed out of the auxiliary exterior heat exchanger 12a flows into the cooling expansion valve 14c and is decompressed isenthalpically (from point e131 to point k13 in FIG. 13).

[0226] The gas-liquid two-phase refrigerant decompressed by the cooling expansion valve 14c flows into the cooling evaporator 17d. In the cooling evaporator 17d, the refrigerant decompressed by the cooling expansion valve 14c absorbs heat from the air being blown into the vehicle cabin and evaporates (from point k13 to point j13 in FIG. 13). This cools the air being blown. The refrigerant flowing out of the cooling evaporator 17d merges with the gas-phase refrigerant flowing out of the accumulator 18 and is drawn into the compressor 11. Other operations of the ejector refrigeration cycle 10b are the same as those of the sixth embodiment.

[0227] In the high-temperature side heat medium circuit 30 in the air-conditioning cooling mode, the heat of the discharged refrigerant is dissipated to the outside air via the high-temperature side heat medium, as in the single cooling mode. In the low-temperature side heat medium circuit 40 in the air-conditioning cooling mode, the low-temperature side heat medium cooled by the chiller 17c is caused to flow into the coolant passage of the battery 50, as in the single cooling mode, to cool the battery 50. Other operations are the same as in the single cooling mode.

[0228] As described above, the vehicle air conditioner 1b can provide comfortable air conditioning for the vehicle cabin and adequately cool the battery 50. Furthermore, in the single cooling mode and the air conditioning cooling mode of the ejector-type refrigeration cycle 10b, the same effects as those of the first embodiment can be obtained. That is, the COP improvement effect due to the configuration of the supercritical refrigeration cycle can be reliably and sufficiently obtained.

[0229] 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.

[0230] 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 device that cools an object to be cooled, such as ventilation air, a low-temperature heat medium, or an in-vehicle device. However, the application of the ejector-type refrigeration cycle device according to the present disclosure is not limited thereto. For example, the ejector-type refrigeration cycle device may be applied to a heat pump cycle device in which a refrigerant absorbs heat from outside air in an evaporator and then radiates the heat absorbed from the outside air by the refrigerant to an object to be heated in a heat radiator. The object to be heated may be ventilation air or water for daily use.

[0231] More specifically, when the ejector refrigeration cycle 10 described in the second and third embodiments is applied to a heating device that heats air to be blown into a room as an object to be heated, the air can be heated by passing it through the auxiliary outdoor heat exchanger 12a and then the outdoor heat exchanger 12. In the ejector refrigeration cycle 10, the temperature of the refrigerant flowing through the outdoor heat exchanger 12 is higher than the temperature of the refrigerant flowing through the auxiliary outdoor heat exchanger 12a. Therefore, the air can be efficiently heated in the order from the auxiliary outdoor heat exchanger 12a to the outdoor heat exchanger 12.

[0232] Furthermore, in the first to third and fifth embodiments, examples have been described in which the ejector-type refrigeration cycle 10 is applied to a vehicle air conditioning system in which the same cooling object, that is, blown air, is cooled by both the outlet-side evaporator 17a and the suction-side evaporator 17b, but the present invention is not limited to this.

[0233] For example, the outlet-side evaporator 17 a and the suction-side evaporator 17 b may be configured to cool different objects to be cooled. Specifically, one of the outlet-side evaporator 17 a and the suction-side evaporator 17 b may cool the blown air, and the other evaporator may cool the low-temperature heat medium, similar to the chiller 17 c described in the second embodiment.

[0234] Although the second embodiment has been described with reference to an example in which the battery 50 is cooled as the in-vehicle device to be cooled, the in-vehicle device to be cooled is not limited to this. The in-vehicle device to be cooled may be a motor generator, an inverter, a sensor processing unit, a transaxle, an ADAS control device, or other device that generates a relatively large amount of heat during operation.

[0235] A motor generator is an electric motor that functions as both a motor that outputs driving force for driving and a generator. An inverter is an electric circuit device that supplies power to the motor generator, etc. A sensor processing unit is a control device that integrates environmental sensor interfaces and communication functions for autonomous driving and energy-saving driving. A transaxle is a power transmission mechanism that integrates a transmission, differential gear, etc. An ADAS control device is a control device for an advanced driver assistance system.

[0236] The configuration of the ejector refrigeration cycle according to the present disclosure is not limited to the configurations disclosed in the above-described embodiments, and may be configured, for example, to be capable of switching the refrigerant circuit depending on the operation mode.

[0237] In the fifth embodiment, the high-temperature-side pump 31 is used as the heat dissipation capacity adjustment unit, but the present invention is not limited to this. For example, an air volume adjustment unit such as a shutter mechanism or a blower that adjusts the volume of outside air flowing into the exterior heat exchanger 12 or the high-temperature-side radiator 32 may be used as the heat dissipation capacity adjustment unit.

[0238] For example, a bypass passage may be arranged in the high-temperature side heat medium circuit 30, which allows the high-temperature side heat medium pumped from the high-temperature side pump 31 to flow around the high-temperature side radiator 32. In this case, a flow rate ratio adjustment unit may be employed as the heat dissipation capacity adjustment unit, which adjusts the flow rate ratio between the flow rate of the high-temperature side heat medium flowing out to the high-temperature side radiator 32 side and the flow rate of the high-temperature side heat medium flowing out to the bypass passage side.

[0239] In the above embodiment, an example has been described in which the nozzle-side expansion valve 14a, which is the pressure reducing section, and the ejector 16 are configured as separate bodies, but the nozzle-side expansion valve 14a and the ejector 16 may be integrated (i.e., modularized). Specifically, a needle-shaped or conical valve element may be disposed in the refrigerant passage of the nozzle portion 61, and by displacing the valve element, the same function as the nozzle-side expansion valve 14a may be achieved.

[0240] Furthermore, the group of control sensors connected to the input side of the control device 20 is not limited to the detection units disclosed in the above-described embodiment, and various detection units may be added as necessary.

[0241] In the seventh embodiment, the confluence unit 13a is disposed in the refrigerant flow path extending from the gas-phase refrigerant outlet of the accumulator 18 to the suction port of the compressor 11. However, the present invention is not limited to this. For example, the confluence unit 13a may be disposed in the refrigerant flow path extending from the refrigerant outlet 624 of the ejector 16 to the inlet of the accumulator 18. In this case, a gas-liquid separator that separates the refrigerant into gas and liquid may be disposed in the refrigerant flow path extending from the refrigerant outlet 624 to the confluence unit 13a, and the separated liquid-phase refrigerant may flow into the suction-side expansion valve 14b.

[0242] In addition, in the above-described embodiment, an example has been described in which carbon dioxide (R744) is used as the refrigerant for the ejector-type refrigeration cycle 10 of the first embodiment, but the refrigerant is not limited to this as long as it is a refrigerant that constitutes a supercritical refrigeration cycle.

[0243] In the above embodiment, an example in which an ethylene glycol aqueous solution is used as the low-temperature heat medium is described, but the present invention is not limited to this. For example, dimethylpolysiloxane, a solution containing nanofluid, antifreeze, a water-based liquid refrigerant containing alcohol, or a liquid medium containing oil may be used as the heating heat medium and the low-temperature heat medium.

[0244] The control aspects of the ejector refrigeration cycle according to the present disclosure are not limited to the control aspects disclosed in the above-described embodiments.

[0245] For example, the control device 20 may control the throttle opening of the nozzle-side expansion valve 14a, which is the pressure reducing section, so that the line drawn by the refrigerant from the outlet of the outdoor heat exchanger 12 to the injection port 615 of the ejector 16 passes through the critical point on the Mollier diagram of the refrigerant.

[0246] The means disclosed in each of the above embodiments may be combined as appropriate within the scope of feasibility.

[0247] For example, the water-refrigerant heat exchanger 12b and the high-temperature side heat medium circuit 30 may be employed as the heat radiating section of the ejector refrigeration cycle 10 described in the first to fourth embodiments and the ejector refrigeration cycle 10a described in the sixth embodiment. The outdoor heat exchanger 12 may be employed as the heat radiating section of the ejector refrigeration cycle 10b described in the seventh embodiment.

[0248] The ejector refrigeration cycle disclosed in this specification has the following features. a nozzle section (61) for reducing the pressure of the refrigerant flowing out of the heat radiating section and spraying it from an injection port (615); a suction port (621) for sucking the refrigerant flowing out of the evaporation section; a mixing section (622) for mixing the injected refrigerant sprayed from the injection port and the sucked refrigerant sucked from the suction port; and a body section (62) having a refrigerant outlet (624) for letting the mixed refrigerant mixed in the mixing section flow out to a suction port side of the compression section, wherein in a Mollier diagram of the refrigerant, a line drawn by the refrigerant from the outlet of the heat radiating section to the injection port passes through either a critical point or a saturated gas line. (Item 2) The ejector refrigeration cycle according to item 1, further comprising: a pressure reduction unit (14a) that reduces the pressure of the refrigerant flowing out of the heat radiating unit and flowing into the nozzle unit, wherein a throttle opening of the pressure reduction unit is adjusted so that, in a Mollier diagram of the refrigerant, a line drawn by the refrigerant from an outlet of the heat radiating unit to the injection port passes through either a critical point or a saturated gas line. (Item 3) The ejector refrigeration cycle according to item 1 or 2, further comprising: a heat radiation capacity adjustment unit (31) that adjusts the heat radiation capacity of the heat radiating unit, wherein the heat radiation capacity of the heat radiating unit is adjusted so that, in a Mollier diagram of the refrigerant, a line drawn by the refrigerant from the outlet of the heat radiating unit to the injection port passes through either a critical point or a saturated gas line. (Item 4) The ejector refrigeration cycle according to any one of items 1 to 3, wherein, in a Mollier diagram of the refrigerant, a line drawn by the refrigerant from a refrigerant inlet (611) of the nozzle unit to the injection port passes through a saturated gas line. (Item 5) The ejector-type refrigeration cycle according to any one of Items 1 to 4, further comprising: a branching section (13) that branches the flow of the refrigerant flowing out from the heat dissipation section and causes one of the branched refrigerant to flow toward an inlet side of the nozzle section; and an auxiliary heat dissipation section (15, 12a) that dissipates heat from the other of the refrigerant branched at the branching section.(Item 6) The ejector-type refrigeration cycle according to Item 5, wherein the auxiliary heat dissipation unit is an internal heat exchange unit (15) that exchanges heat between the other refrigerant branched at the branch unit and the refrigerant drawn into the compression unit. (Item 7) The ejector-type refrigeration cycle according to Item 5 or 6, wherein the auxiliary heat dissipation unit is an auxiliary outside-air heat exchange unit (12a) that exchanges heat between the other refrigerant branched at the branch unit and outside air.

[0249] 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 (16) comprising: a compression section (11) for pressurizing a refrigerant above its critical pressure; a heat dissipation section (12, 12b, 30) for dissipating heat from the refrigerant discharged from the compression section; an evaporation section (17b, 17c) for evaporating the refrigerant; a nozzle section (61) for decompressing the refrigerant flowing out of the heat dissipation section and spraying it from an injection port (615); a suction port (621) for sucking the refrigerant flowing out of the evaporation section; a mixing section (622) for mixing the injected refrigerant sprayed from the injection port with the sucked refrigerant sucked from the suction port; and a body section (62) having a refrigerant outlet (624) for discharging the mixed refrigerant mixed in the mixing section to the suction port side of the compression section, wherein in a Mollier diagram of the refrigerant, a line drawn by the refrigerant from the outlet of the heat dissipation section to the injection port passes through either a critical point or a saturated gas line.

2. An ejector-type refrigeration cycle as described in claim 1, further comprising a pressure reducing section (14a) that reduces the pressure of the refrigerant flowing out of the heat dissipation section and flowing into the nozzle section, and the throttle opening of the pressure reducing section is adjusted so that, in a Mollier diagram of the refrigerant, the line drawn by the refrigerant from the outlet of the heat dissipation section to the injection port passes through either the critical point or the saturated gas line.

3. An ejector-type refrigeration cycle as described in claim 1, further comprising a heat dissipation capacity adjusting section (31) for adjusting the heat dissipation capacity of the heat dissipation section, wherein the heat dissipation capacity of the heat dissipation section is adjusted so that, in a Mollier diagram of the refrigerant, the line drawn by the refrigerant from the outlet of the heat dissipation section to the injection port passes through either the critical point or the saturated gas line.

4. The ejector-type refrigeration cycle according to claim 1, wherein in a Mollier diagram of the refrigerant, the line drawn by the refrigerant from the refrigerant inlet (611) of the nozzle portion to the injection port passes through a saturated gas line.

5. An ejector-type refrigeration cycle as described in claim 1, comprising: a branching section (13) that branches the flow of the refrigerant flowing out from the heat dissipation section and causes one of the branched refrigerant to flow toward the inlet side of the nozzle section; and an auxiliary heat dissipation section (15, 12a) that dissipates heat from the other of the refrigerant branched at the branching section.

6. An ejector-type refrigeration cycle as described in claim 5, wherein the auxiliary heat dissipation section is an internal heat exchange section (15) that exchanges heat between the other refrigerant branched at the branch section and the refrigerant drawn into the compression section.

7. An ejector-type refrigeration cycle according to claim 5 or 6, wherein the auxiliary heat dissipation section is an auxiliary outside air heat exchange section (12a) that exchanges heat between the other of the refrigerants branched at the branch section and outside air.

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