Ejector unit, heat exchange unit and refrigerant short-circuit detecting method

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2010-054298 filed on Mar. 11, 2010, the contents of which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an ejector unit, a heat exchange unit with the ejector unit, and a refrigerant short-circuit detecting method in an ejector unit.

BACKGROUND OF THE INVENTION

Conventionally, an ejector-type refrigerant cycle device having an ejector, provided with functions of a refrigerant decompression means and a refrigerant circulating means, is known. The ejector-type refrigerant cycle device can be suitably used for a vehicle air conditioner or a vehicle refrigeration device for freezing and refrigerating a load mounted to a vehicle. Furthermore, the ejector-type refrigerant cycle device is also suitably used for a fixed-type refrigeration system such as an air conditioner, a refrigerator or a freezer.

For example, in an ejector-type refrigerant cycle device described in JP 2009-58221A (corresponding to US 2008/0264097A1), gas refrigerant flowing out of an evaporator is drawn into an ejector by using a high-speed jet flow in expansion, and a speed energy of the refrigerant in the expansion is converted to a pressure energy in a diffuser portion of the ejector, thereby increasing a refrigerant pressure to be drawn into a compressor and reducing power consumed in the compressor. Thus, operation efficiency in the refrigerant cycle can be increased.

More specifically, in the ejector, the refrigerant passage sectional area of a nozzle portion is throttled so that refrigerant is decompressed and expanded in the nozzle portion, and a refrigerant suction port is provided to communicate with a space in the ejector, where the refrigerant jet port of the nozzle portion is provided, so as to draw the refrigerant flowing out of the evaporator.

A mixing portion is provided in the ejector on a downstream side of the nozzle portion and the refrigerant suction port in the refrigerant flow, so as to mix the high-speed refrigerant flow jetted from the nozzle portion with the suction refrigerant drawn from the refrigerant suction port. The diffuser portion is provided in the ejector downstream of the mixing portion.

The diffuser portion is formed in such a shape to gradually increase the passage sectional area of the refrigerant, and has an effect of reducing the velocity of the refrigerant flow so as to increase the refrigerant pressure. That is, the diffuser portion has an effect of converting the speed energy of the refrigerant to the pressure energy of the refrigerant.

JP 2009-58221A proposed that the ejector may be located in a tank for distributing refrigerant into tubes or for joining the refrigerant from the tubes of the evaporator, or the ejector may be located in a separated special space in the tank.

JP 2010-181136A (corresponding to US 2010/0175422 A1) proposes an evaporator unit in which an ejector, a cylindrical ejector case (container) for accommodating the ejector and an evaporator are integrally assembled.

In the evaporator unit proposed in JP 2010-181136A, the refrigerant pressure at the refrigerant inlet of the nozzle portion of the ejector, the refrigerant pressure at, the refrigerant suction port of the ejector and the refrigerant pressure at the refrigerant outlet of the diffuser portion of the ejector are different from each other. That is, the refrigerant pressure at the refrigerant inlet of the nozzle portion of the ejector is larger than the refrigerant pressure at the refrigerant outlet of the diffuser portion of the ejector, and the refrigerant pressure at the refrigerant outlet of the diffuser portion of the ejector is larger than the refrigerant pressure at the refrigerant suction port of the ejector. According to experiments by the inventors of the present application, if the brazing between the ejector and a container for containing the ejector is insufficient, the refrigerant may flow in short-circuit in the container between the refrigerant inlet of the nozzle portion, the refrigerant suction port and the refrigerant outlet of the diffuser portion of the ejector.

If the refrigerant short-circuit path is generated, the ejector efficiency may be decreased, and thereby reducing the refrigeration cycle efficiency when the ejector is used for a refrigerant cycle device.

Thus, it is necessary to examine a refrigerant short-circuit path between the refrigerant inlet of the nozzle portion, the refrigerant suction port and the refrigerant outlet portion of the diffuser portion of the ejector. However, it is generally difficult to confirm whether the refrigerant short-circuit path is generated because the refrigerant short-circuit path is caused in the ejector inside of the container.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is an object of the present invention to provide an ejector unit and a heat exchange unit, in which a refrigerant short-circuit path can be easily detected.

It is another object of the present invention to provide a method for easily detecting a refrigerant short-circuit in an ejector unit.

According to an aspect of the present invention, an ejector unit is provided with an ejector that includes a nozzle portion configured to decompress refrigerant, a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle portion, and a diffuser portion in which the refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed and the mixed refrigerant is pressurized. The ejector is accommodated in a container and bonded to the container, to define in the container an inlet space in which an inlet of the nozzle portion is open, a suction space in which the refrigerant suction port of the ejector is open and an outlet space in which an outlet of the diffuser portion is open. The inlet space, the suction space and the outlet space are partitioned from each other by bonding portions between the ejector and the container. The container is provided with a short-circuit detection hole exposed to an exterior of the container at least at one position of a first position between the inlet space and the suction space, and a second position between the suction space and the outlet space. Furthermore, the bonding portion around the short-circuit detection hole encloses the short circuit detection hole. Therefore, the inlet space, the suction space and the outlet space can be air-tightly partitioned from each other.

Thus, if at least one of a short circuit between the inlet space and the suction space, and a short circuit between the suction space and the outlet space is caused, the short circuit can be easily detected by detecting a leakage from the short circuit detection hole. As a result, the short circuit caused in the ejector unit can be easily detected.

For, example, an outer surface of the ejector may be provided with a groove portion extending in a circumferential direction of the ejector. In this case, the groove portion of the ejector is overlapped with the short-circuit detection hole, and extends in the circumferential direction in a range larger than the short-circuit detection hole.

The container may continuously extend in a longitudinal direction of the ejector, or the container may be divided into plural members in a longitudinal direction of the ejector.

A heat exchange unit such as an evaporator unit may be configured by the ejector unit, and a heat exchanger connected to the ejector. In this case, the heat exchanger is brazed integrally with the ejector unit without closing the short-circuit detection hole.

The heat exchanger may include a plurality of tubes in which the refrigerant flows, and a tank portion located at one longitudinal end side of the tubes to distribute the refrigerant into the tubes or to joint the refrigerant from the tubes. In this case, the tank portion may be adapted as the container, and the short-circuit detection hole may be provided in the tank portion at a position where the tank portion is adapted as the container.

Alternatively, a heat exchanger may be connected to the ejector unit via a refrigerant pipe. In this case, the heat exchanger may be spaced from the ejector unit without closing the short-circuit detection hole.

According to another aspect of the present invention, a method is for detecting a refrigerant short circuit in an ejector unit in which an ejector is contained in a container and brazed to the container to form an inlet space in which an inlet of a nozzle portion is open, a suction space in which a refrigerant suction port of the ejector is open and an outlet space in which an outlet of a diffuser portion of the ejector is open. Here, the inlet space, the suction space and the outlet space are partitioned from each other by bonding portions between the ejector and the container. The method includes a step of filling a detection fluid in the ejector unit with an inner pressure, and a step of detecting a leakage of the detection fluid from a short-circuit detection hole enclosed by the bonding portion and exposed to outside. The short-circuit detection hole is provided at least at one position of a first position between the inlet space and the suction space, and a second position between the suction space and the outlet space. Thus, a short-circuit path in the ejector unit can be easily detected.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments when taken together with the accompanying drawings. In which:

FIG. 1 is an entire schematic diagram showing an ejector-type refrigerant cycle device according to a first embodiment of the invention;

FIG. 2 is a schematic perspective view showing an integrated unit according to the first embodiment;

FIG. 3 is a partially sectional view showing a part of the integrated unit according to the first embodiment;

FIG. 4 is a side view of an ejector according to the first embodiment;

FIG. 5 is a schematic perspective view showing the ejector located in a container according to the first embodiment;

FIG. 6 is an enlarged view showing a part of the ejector according to the invention;

FIGS. 7A and 7B are disassembled views showing container members for receiving the ejector, according to the first embodiment;

FIG. 8 is a graph showing relationships between a cooling capacity ratio and a short-circuit area ratio, according to the first embodiment;

FIG. 9 is a schematic perspective view showing an ejector unit according to a first modification example of the first embodiment of the present invention;

FIG. 10 is a sectional view showing an upper tank portion with a container in an integrated unit, according to a second modification example of the first embodiment of the present invention;

FIG. 11A is a side view showing an ejector according to a third modification example of the first embodiment of the present invention, FIG. 11B is an enlarged view showing the part XIB of FIG. 11A, and FIG. 11C is a sectional view showing a part of an ejector unit with the ejector shown in FIG. 11A;

FIG. 12A is a top view showing a container according to a fourth modification example of the first embodiment of the present invention, FIG. 12B is an enlarged view showing the container of FIG. 12A, and FIG. 12C is a sectional view showing a part of an ejector unit having the container shown in FIG. 12A;

FIG. 13 is an entire schematic diagram of an ejector-type refrigerant cycle device according to a second embodiment of the invention;

FIG. 14 is a side view of an ejector according to the second embodiment;

FIG. 15 is a schematic perspective view showing an integrated unit according to the second embodiment;

FIG. 16 is a sectional view showing a part of the integrated unit according to the second embodiment;

FIG. 17 is a perspective view showing an integrated unit with an ejector and an evaporator, in which first and second refrigerant short-circuit detection holes are provided in an upper tank portion; and

FIG. 18 is a schematic perspective view showing an integrated unit according to a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

First Embodiment

A first embodiment of the present invention will be described with reference to FIGS. 1 to 12. In the present embodiment, an ejector-type refrigerant cycle device 10 is typically applied to a vehicle air conditioner.

In the ejector-type refrigerant cycle device 10, a compressor 11 for drawing and compressing refrigerant is driven and rotated by a vehicle engine via an electromagnetic clutch 11a, a belt or the like.

As the compressor 11, a variable capacity compressor or a fixed displacement compressor may be used. The variable capacity compressor is adapted to adjust a refrigerant discharge capacity by changing refrigerant discharge amount of the compressor. Furthermore, the fixed displacement compressor is adapted to adjust a refrigerant discharge capacity by changing an operation rate of the compressor using interruption of the electromagnetic clutch 11a. When an electrical compressor is used as the compressor 11, the refrigerant discharge capacity of the compressor 11 can be adjusted by adjusting the rotational speed of the electrical motor.

A refrigerant radiator 12 is connected to a refrigerant discharge side of the compressor 11. The radiator 12 is a heat-radiation heat exchanger in which high-pressure refrigerant discharged from the compressor 11 is heat-exchanged with outside air (i.e., air outside of a vehicle compartment) blown by a cooling fan, thereby cooling the high-pressure refrigerant discharged from the compressor 11.

In the present embodiment, a fluoro-based refrigerant or HC-based refrigerant is used as the refrigerant, thereby forming a sub-critical refrigerant cycle in the ejector-type refrigerant cycle device. In the sub-critical refrigerant cycle, the pressure of the high-pressure refrigerant discharged from the compressor 11 is lower than the critical pressure of the refrigerant. Thus, the radiator 12 is adapted as a condenser in which refrigerant is cooled and condensed.

A thermal expansion valve 13 is arranged at a refrigerant outlet side of the radiator 12. The thermal expansion valve 13 is a decompression device configured to decompress liquid refrigerant flowing out of the radiator 12. The thermal expansion valve 13 is provided with a temperature sensing portion 13a located at a refrigerant suction side of the compressor 11.

For example, the thermal expansion valve 13 is a variable throttle mechanism, in which a super-heat degree at the refrigerant suction side of the compressor 11 is detected based on temperature and pressure of the refrigerant, at the refrigerant suction side of the compressor 11, and its valve-open degree (refrigerant flow amount) is adjusted so that the super-heat degree at the refrigerant suction side of the compressor 11 is approached to a predetermined value. In the present embodiment, the refrigerant suction side of the compressor 11 corresponds to a refrigerant outlet side of a first evaporator 15.

An ejector 14 is arranged at a refrigerant outlet side of the thermal expansion valve 13. The ejector 14 is adapted as a refrigerant decompression portion for further decompressing and expanding the refrigerant flowing from the thermal expansion valve 13, and as a refrigerant circulation portion for circulating the refrigerant by the suction action of a high-speed refrigerant flow jetted from a nozzle portion 14a.

The ejector 14 is provided with the nozzle portion 14a, a refrigerant suction port 14b, a mixing portion 14c and a diffuser portion 14d. The nozzle portion 14a has therein a throttle passage area in which the refrigerant (middle-pressure refrigerant) after passing through the thermal expansion valve 13 is further decompressed and expanded. The refrigerant suction port 14b is arranged to communicate with a space around the refrigerant jet port of the nozzle portion 14a in the ejector 14, such that gas refrigerant flowing out of a second evaporator 18 is drawn into the ejector 14 from the refrigerant suction port 14b.

The mixing portion 14c is provided in the ejector 14 on a downstream side of the nozzle portion 14a and the refrigerant suction port 14b in the refrigerant flow, so as to mix the high-speed refrigerant flow jetted from the nozzle portion 14a with the suction refrigerant drawn from the refrigerant suction port 14b. The diffuser portion 14d is provided in the ejector 14 downstream of the mixing portion 14c in the refrigerant flow. The diffuser portion 14d is formed in such a shape to gradually increase the passage sectional area of the refrigerant, and has an effect of reducing the velocity of the refrigerant flow so as to increase the refrigerant pressure. That is, the diffuser portion 14d has an effect of converting the speed energy of the refrigerant to the pressure energy of the refrigerant.

The first evaporator 15 is connected to a refrigerant outlet portion of the diffuser portion 14d of the ejector 14, and the refrigerant outlet side of the first evaporator 15 is coupled to the refrigerant suction side of the compressor 11.

The middle-pressure refrigerant flowing out of the thermal expansion valve 13 flows into a flow distribution portion 18, and is divided by the flow distribution portion 18 into a flow amount Gn of the refrigerant flowing into the nozzle portion 14a of the ejector 14 and a flow amount Ge of the refrigerant flowing toward the refrigerant suction port 14b of the ejector 14.

Thus, the flow of the refrigerant after passing through the thermal expansion valve 13 is branched by the flow distribution portion 16 into a first flow of the refrigerant flowing toward an inlet side of the nozzle portion 14a of the ejector 14, and a second flow of the refrigerant flowing toward the refrigerant suction port 14b of the ejector 14.

The throttle mechanism 17 and the second evaporator 18 are arranged in a refrigerant passage between the refrigerant distribution portion 16 and the refrigerant suction port 14b of the ejector 14. The throttle mechanism 17 is a decompression device, which further decompresses the refrigerant flowing into the second evaporator 18 so as to adjust a refrigerant flow amount flowing into the second evaporator 18.

In the present embodiment, the first and second evaporators 15, 18 are integrally assembled to form an integrated structure. Both the first and second evaporators 15, 18 are accommodated in an air conditioning case defining an air passage through which air blown by an electrical blower 19 flows. Air blown by the electrical blower 19 passes through both the first and second evaporators 15, 18 in the air conditioning case as in the arrow F1 shown in FIG. 1, so that air to be blown into the vehicle compartment is cooled by the first and second evaporators 15, 18.

The cool air cooled by the first and second evaporators 15, 18 is blown to a space to be cooled (e.g., vehicle compartment), so that the space is cooled by the first and second evaporators 15, 18. In the first and second evaporators 15, 18, the first evaporator 15 connected to a refrigerant outlet side of the ejector 14 is arranged upstream in the air flow F1, and the second evaporator 18 connected to the refrigerant suction port 14b of the ejector 14 is arranged downstream in the air flow F1.

For example, the space to be cooled is the vehicle compartment when the ejector-type refrigerant cycle device 10 is applied to a vehicle air conditioner. Alternatively, the space to be cooled is a space of a refrigerator, when the ejector-type refrigerant cycle device 10 is applied to the refrigerator mounted to a vehicle or the like.

In the present embodiment, the ejector 14, the first and second evaporators 15, 18, the flow distribution portion 16 and the throttle mechanism 17 are integrally assembled to form an integrated unit 20. The integrated unit 20 may be adapted as a heat exchange unit. Specific examples of the integrated unit 20 will be described with reference to FIGS. 2 to 7B.

FIG. 2 is a schematic perspective view showing the integrated unit 20 of an example of the first embodiment. FIG. 3 is a sectional view showing a part of the integrated unit 20 in FIG. 2.

In the present embodiment, the first and second evaporators 15, 18 are integrally assembled to form an integrated heat exchanging structure. Thus, in the integrated unit 20, the first evaporator 15 is positioned at an upstream side in the air flow F1, and the second evaporator 18 is positioned at a downstream side in the air flow F1.

The basic structure of the first evaporator 15 is the same as that of the second evaporator 18. The first evaporator 15 includes a heat exchanging core portion 15a, and a pair of tank portions 15b, 15c located at two sides of the heat exchanging core portion 15a. Similarly, the second evaporator 18 includes a heat exchanging core portion 18a, and a pair of tank portions 18b, 18c located at two sides of the heat exchanging core portion 18a.

The heat exchanging core portion 15a includes a plurality of tubes 21 extending in a tube longitudinal direction (top-bottom direction in FIG. 2), and the heat exchanging core portion 18 includes a plurality of tubes 21 extending in the tube longitudinal direction. A fluid (e.g., air) to be cooled passes through the heat exchanging core portions 15a, 18a, between adjacent tubes 21.

Corrugated fins 22 are arranged between the tubes 21 to facilitate heat exchange between the refrigerant flowing inside of the tubes 21 and air passing outside of the tubes 21. The tubes 21 and the fins 22 are alternately stacked in a 20, stack direction (e.g., left-right direction in FIG. 2), thereby forming the heat exchanging core portions 15a, 18a, respectively. The fins 22 may be omitted from the structure of the heat exchanging core portion 15a, 18a, or may have different shapes.

In FIG. 2, a part of the fins 22 is indicated. However, actually, the fins 22 are arranged in an entire area of the heat exchanging core portions 15a, 18a, such that the tubes 21 and the fins 22 are stacked in the stack direction. The stack structure of the heat exchanging core portions 15a, 18a is provided to have clearances between the tubes 21 and the fins 22, through which air blown by the electrical blower 19 passes.

The tubes 21 may be flat tubes having flat surfaces along the air flow direction F1. The fin 22 is a corrugated fin formed by bending a thin plate into a wave shape. The fins 22 are disposed to be bonded to outer flat surfaces of the tubes 21, so as to increase heat transmitting areas on the air side.

The tank portions 15b, 15c extend in the tube stack direction and communicate with the tubes 21 in the heat exchanging core portion 15a to form a refrigerant passage of the first evaporator 15. Similarly, the tank portions 18b, 18c extend in the tube stack direction and communicate with the tubes 21 in the heat exchanging core portion 18a to form a refrigerant passage of the second evaporator 18 independent from that of the first evaporator 15.

As shown in FIG. 3, the upper and lower end portions of the tubes 21 of the heat exchanging core portion 15a are inserted into and bonded to the upper and lower tank portions 15b, 15c of the first evaporator 15, to respectively communicate with the inner spaces of the tank portions 15b, 15c.

Similarly, the upper and lower end portions of the tubes 21 of the heat exchanging core portion 18a are inserted into and bonded to the upper and lower tank portions 18b, 18c of the second evaporator 18, to respectively communicate with the inner spaces of the tank portions 18b, 18c.

Thus, the tank portions 15b, 15c, 18b, 18c are adapted to distribute the refrigerant into the plural tubes 21 of the heat exchanging core portions 15a, 18a, or to join the refrigerant from the plural tubes 21.

In the present embodiment, the two upper tank portions 15b, 18b arranged adjacent to each other are molded integrally. Similarly, the two lower tank portions 15c, 18c arranged adjacent to each other are molded integrally. However, the two upper tank portions 15b, 18b and the two lower tank portions 15c, 18c may be molded respectively independently from each other.

The ejector 14, the flow distribution portion 16 and the throttle mechanism 17 are arranged on a side (e.g., upper side in FIG. 3) of the upper tank portions 15b, 18b, opposite to the tubes 21. As shown in FIG. 4, the ejector 14 has an elongated shape extending in the axial direction of the nozzle portion 14a.

In the present embodiment, the flow distribution portion 16 and the throttle mechanism 17 are integrally provided in the ejector 14. For example, as shown in FIGS. 3 to 5, the flow distribution portion 16 is integrated in the ejector 14, and is positioned at an inlet side of the nozzle portion 14a. The throttle mechanism 17 is configured by a throttle hole opened in a cylindrical surface of the flow distribution portion 16 of the ejector 14. As shown in FIG. 4, a cylindrical surface of the flow distribution portion 16 is continuously extended as the cylindrical surface of the ejector 14.

As shown in FIGS. 3 and 5, the ejector 14 with the flow distribution portion 11 is accommodated in a cylindrical container 23, and the cylindrical container 23 having therein the ejector 14 is arranged at the upper side of the upper tank portions 15b, 18b such that the longitudinal direction of the ejector 14 is parallel with a tank longitudinal direction.

The components of the evaporators 15, 18, such as the tubes 21, the fins 22 and the tank portions 15b, 15c, 18b, 18c are made of metal such as aluminum having a sufficient heat conductivity and brazing performance. The components of the evaporators 15, 18 are integrally brazed, after being respectively molded from the metal such as aluminum.

An ejector unit is configured by the ejector 14 and the container 23. The ejector 14 with the flow distribution portion 16 is formed separately from the container 23, and then is inserted and fixed to the container 23. The container 23 having therein the ejector 14 is brazed to the first and second evaporators 15, 18, thereby forming the integrated unit 20.

As shown in FIG. 2, a refrigerant inlet 24 and a refrigerant outlet 25 of the integrated unit 20 are formed in a connection joint 26 assembled to the first and second evaporators 15, 18. The refrigerant inlet 24 is provided in the connection joint 26 to communicate with a refrigerant inlet of the flow distribution portion 16, and the refrigerant outlet 25 is provided in the connection joint 26 to communicate with the upper tank portion 15b of the first evaporator 15.

The connection joint 26 is formed from an aluminum material, similarly to the components of the evaporators 15, 18. For example, as shown in FIG. 2, the connection joint 26 is brazed and fixed to an end surface of the upper tank portions 15b, 18b at one end side in the tank longitudinal direction.

A partition plate (not shown) is located in and brazed to the upper tank portion 15b of the first evaporator 15, to partition an inner space of the upper tank portion 15b into a first space 27 at one end side in the tank longitudinal direction, and a second space 28 at the other end side in the tank longitudinal direction.

The first space 27 is adapted as a joining tank to which the refrigerant passing through the tubes 21 of the first evaporator 15 is joined, and the second space 28 is adapted as a distribution tank from which the refrigerant is distributed to the tubes 21 of the first evaporator 15.

A partition plate (not shown) is located in and brazed to the upper tank portion 18b of the second evaporator 18, to partition an inner space of the upper tank portion 18b into a first space 29 at one end side in the tank longitudinal direction, and a second space 30 at the other end side in the tank longitudinal direction.

The first space 29 is adapted as a distribution tank from which the refrigerant is distributed into the tubes 21 of the second evaporator 18; and the second space 30 is adapted as a join tank into which the refrigerant passing through the tubes 21 of the second evaporator 18 is joined.

One end portion of the container 23, positioned at the inlet side of the ejector 14, is opened and communicates with the refrigerant inlet 24 of the connection joint 26. On the other hand, the other end portion of the container 23, positioned at the outlet side of the ejector 14, is closed.

Furthermore, as shown in FIG. 5, an inlet space portion 31, a suction space portion 32 and an outlet space portion 33 are provided in the container 23. The three space portions of the inlet space portion 31, the suction space portion 32 and the outlet space portion 33 are respectively partitioned from each other by bonding portions between the container 23 and the ejector 14. For example, a brazing material layer is formed on the container 23, so that the container 23 and the ejector 14 are integrally bonded to each other by using the brazing material, thereby defining the inlet space portion 31, the suction space portion 32 and the outlet space portion 33.

As shown in FIG. 5, a refrigerant inlet of the nozzle portion 14a of the ejector 14, that is; a refrigerant inlet of the flow distribution portion 16, is open in the inlet space portion 31. The refrigerant suction port 14b of the ejector 14 is open in the suction space portion 32. An outlet portion of the diffuser portion 14d of the ejector 14 is open in the outlet space portion 33.

The container 23 is provided with a first communication hole 34 through which a throttle hole as the throttle mechanism 17 formed in the cylindrical surface of the ejector 14 communicates with the first space 29 of the upper tank portion 18b, a second communication hole 35 through which the suction space portion 32 communicates with the second space portion 30 of the upper tank portion 18b, and a third communication hole 36 through which the outlet space portion 33 communicates with the second space portion 28 of the upper tank portion 15b.

A first short-circuit detection hole 37 and a second short-circuit detection hole 38 are provided in the container 23 at the bonding portions bonded to the ejector 14.

The first short-circuit detection hole 37 is provided in the bonding portion of a partition portion for partitioning the inlet space portion 31 and the suction space portion 32 from each other. The second short-circuit detection hole 38 is provided in the bonding portion of a partition portion for partitioning the suction space portion 32 and the outlet space portion 33 from each other.

Each of the first and second short-circuit detection holes 37, 38 is formed into a slit hole extending in a circumferential direction of the container 23. In the example of FIG. 5, two first short-circuit detection holes 37 are formed by a pair of slit holes elongated in the circumferential direction of the container 23, and two second short-circuit detection holes 38 are formed by a pair of slit holes elongated in the circumferential direction of the container 23. The two first short-circuit detection holes 37 are provided at the same position in the longitudinal direction of the container 23. The two second short-circuit detection holes 38 are provided at the same position in the longitudinal direction of the container 23.

As shown in FIG. 3, the first and second evaporators 15, 18 are brazed integrally with the container 23 without closing the first and second short-circuit detection holes 37, 38. That is, the first and second short-circuit detection holes 37, 38 are open and exposed outside of the integrated unit 20.

As shown in FIG. 3, one of the first short-circuit detection holes 37 and one of the second short-circuit detection holes 38 of the container 23 arranged on the upper tank portions 15b, 18b are open toward the upper tank portions 15b, 18b (i.e., toward the tubes 22), and is exposed to outside of the integrated unit 20 via a space provided a valley portion between the adjacent upper tank portions 15b, 18b. In the example of FIG. 3, the one of the first short-circuit detection holes 37 and the one of the second short-circuit detection holes 38 of the container 23 arranged on the upper tank portions 15b, 18b are open downwardly.

FIG. 6 shows a bonding portion 40 between the ejector 14 and the container 23, around the first or second short-circuit detection hole 37, 38. In FIG. 6, the hatching area indicates the bonding portion 40 between the ejector 14 and the container 23.

As shown in FIG. 6, the bonding portion between the ejector 14 and the container 23 is formed into a rectangular frame shape enclosing each of the first and second short-circuit detection holes 37, 38. Thus, each of the first and second short-circuit detection holes 37, 38 is enclosed by the bonding portion between the ejector 14 and the container 23.

The entire periphery of each of the first and second short-circuit detection holes 37, 38 of the container 23 is air-tightly bonded to the ejector 14. It is desired to set the width of the bonding portion 40 surrounding the detection hole 37, 38 to be equal to or larger than 1 mm.

In the present embodiment, as shown in FIGS. 7A and 7B, the container 23 can be formed by a pair of semi-cylindrical members 23a, 23b to be divided. Each of the semi-cylindrical members 23a, 23b is provided with one first short-circuit detection hole 37 and one second short-circuit detection hole 38. More specifically, the semi-cylindrical member 23a is provided with the one first short-circuit detection hole 37 and the one second short-circuit detection hole 38. In contrast, the semi-cylindrical member 23a is provided with one first communication hole 34, plural second communication holes 35 (e.g., two), and plural third communication holes 36 (e.g., four), in addition to the one first short-circuit detection hole 37 and the one second short-circuit detection hole 38.

Next, a refrigerant flow in the entire structure of the integrated unit 20 will be described in detail with reference to FIG. 2. The flow of the refrigerant flowing into the flow distribution portion 16 in the container 23 from the refrigerant inlet 24 of the connection joint 26 as in the arrow a1 is branched into a main flow of the refrigerant flowing toward the nozzle portion 14a of the ejector 14, and a branch flow of the refrigerant flowing toward the throttle mechanism 17.

The main flow of the refrigerant flowing toward the nozzle portion 14a of the ejector 14 passes through the ejector 14 as in the arrow a2, in this order of the nozzle portion 14a, the mixing portion 14c and the diffuser portion 14d. The low-pressure refrigerant decompressed by the ejector 14 flows into the second space portion 28 of the upper tank portion 15b of the first evaporator 15 as in the arrow a3, via an inner space of the container 23.

The refrigerant in the second space portion 28 of the upper tank portion 15b flows downwardly in the tubes 21 of the right side portion of the heat exchanging core portion 15a, as in the arrow a4. Because the lower tank portion 15c does not have a partition plate, the refrigerant flowing into the lower tank portion 15c from the tubes 21 flows as in the arrow a5 from the right side portion of the lower tank portion 15c to the left side portion thereof.

The refrigerant in the left side portion of the lower tank portion 15c flows through the tubes 21 upwardly, flows into the first space portion 27 of the upper tank portion 15b, and flows out of the refrigerant outlet 25 as in the arrow a7.

In contrast, the branch refrigerant branched from the flow distribution portion 16 to the throttle mechanism 17 is decompressed while passing through the throttle mechanism 17, and the decompressed low-pressure refrigerant (e.g., gas-liquid two-phase refrigerant) flows into the first space portion 29 of the upper tank portion 18b of the second evaporator 18 as in the arrow a8.

The refrigerant of the first space portion 29 of the upper tank portion 18b flows downwardly in the tubes 21 of the left side portion of the heat exchanging core portion 18a as in the arrow a9, and flows into the left side portion within the lower tank portion 18c. Because the lower tank portion 18c does not have a partition plate, the refrigerant flowing into the lower tank portion 18c from the tubes 21 flows as in the arrow a10 from the left side portion of the lower tank portion 18c to the right side portion thereof.

The refrigerant of the right side portion in the lower tank portion 18c flows upwardly in the tubes 21 of the right side portion of the heat exchanging core portion 18a as in the arrow a11, and flows into the second space portion 30 of the upper tank portion 18b. Because the refrigerant suction port 14b of the ejector 14 communicates with the second space portion 30 of the upper tank portion 18b, the refrigerant in the second space portion 30 of the upper tank portion 18b is drawn into the ejector 14 from the refrigerant suction port 14b as in the arrow a12.

Because the integrated unit 20 has the above refrigerant flow structure, the integrated unit 20 can be configured entirely by using the single refrigerant inlet 24 and the single refrigerant outlet 24.

Operation of the ejector-type refrigerant cycle device of the present embodiment will be described. When the compressor 11 is driven by a vehicle engine, high-temperature and high-pressure refrigerant compressed by the compressor 11 flows into the radiator 12. The radiator 12 is configured to cool and condense the high-temperature refrigerant by using outside air. The high-press refrigerant flowing out of the radiator 12 flows into the thermal expansion valve 13.

Therefore, the high-pressure refrigerant is decompressed by the thermal expansion valve 13 to a middle-pressure refrigerant, thereby adjusting the flow amount of the refrigerant circulating in the refrigerant cycle. The valve open degree of the thermal expansion valve 13 is adjusted so that the super-heat degree of the refrigerant at the outlet of the first evaporator 15 becomes a predetermined value. The middle-pressure refrigerant after passing through the thermal expansion valve 13 flows into the refrigerant inlet 24 of the integrated unit 20, and then flows into the flow distribution portion 16.

The flow of the refrigerant flowing into the flow distribution portion 16 in the container 23 from the refrigerant inlet 24 is branched into a main flow of the refrigerant flowing toward the nozzle portion 14a of the ejector 14, and a branch flow of the refrigerant flowing to the throttle mechanism 17.

The refrigerant flowing into the nozzle portion 14a of the ejector 14 is decompressed and expanded by the nozzle portion 14a. In the nozzle portion 14a, the pressure energy of the refrigerant is converted to the speed energy of the refrigerant, and the refrigerant is jetted with a high speed from the refrigerant jet port of the nozzle portion 14a. Because the refrigerant pressure is reduced around the refrigerant jet port of the nozzle portion 14a in the ejector 14 by the jet flow from the refrigerant jet port of the nozzle portion 14a, the refrigerant flowing out of the second evaporator 18 is drawn into the ejector 14 from the refrigerant suction port 14b.

Furthermore, the jet refrigerant jetted from the nozzle portion 14a and the suction refrigerant drawn from the refrigerant suction port 14b are mixed in the mixing portion 14c of the ejector 14, and then the mixed refrigerant is pressurized in the diffuser portion 14d of the ejector 14. The passage sectional area is enlarged in the diffuser portion 14d as toward downstream in the ejector 14, so that the speed energy of the refrigerant is converted to the pressure energy thereof, thereby increasing the pressure of the refrigerant in the diffuser portion 14d.

The refrigerant flowing out of the diffuser portion 14d of the ejector 14 flows into the first evaporator 15, and flows in the refrigerant passage of the first evaporator 15 as in the arrows a4 to a7 in FIG. 2. In the heat exchanging core portion 15a of the first evaporator 15, the low-pressure refrigerant flowing therein is evaporated by absorbing heat from air blown by the blower fan 19. The gas refrigerant flowing out of the refrigerant outlet 15 of the integrated unit 20 is drawn into the compressor 11, and is compressed again.

The branch refrigerant flowing into the throttle mechanism 17 is further decompressed and expanded by the throttle mechanism 17 to become a low-pressure refrigerant, and the low-pressure refrigerant from the throttle mechanism 17 flows in the second evaporator 18 as in the arrows a9 to a11 shown in FIG. 2. In the heat exchanging core portion 18a of the second evaporator 18, the low-pressure refrigerant flowing therein is evaporated by absorbing heat from air after passing through the first evaporator 15 as in the arrow F1. The gas refrigerant flowing out of the second evaporator 18 is drawn into the ejector 14 from the refrigerant suction port 14b, as described above.

In the present embodiment, as described above, the refrigerant downstream of the diffuser portion 14d of the ejector 14 is supplied to the first evaporator 15, while the branch refrigerant flowing out of the throttle mechanism 17 is supplied to the second evaporator 18. Thus, cooling action can be obtained at the same time in both the first and second evaporators 15, 18. Therefore, cool air cooled by both the first and second evaporators 15, 18 can be blown into the space to be cooled (e.g., the vehicle compartment).

The refrigerant evaporation pressure at the first evaporator 15 is the refrigerant pressure after being pressurized in the diffuser portion 14d of the ejector 14. In contrast, because the refrigerant outlet side of the second evaporator 18 is connected to the refrigerant suction port 14b of the ejector 14, the refrigerant pressure immediately after the decompression in the nozzle portion 14a is applied to the second evaporator 18.

Thus, the refrigerant evaporation pressure (refrigerant evaporation temperature) of the first evaporator 15 can be made higher than the refrigerant evaporation pressure (the refrigerant evaporation temperature) of the second evaporator 18. In the present embodiment, the first evaporator 15 having relatively high refrigerant evaporation temperature is arranged at an upstream air side in the air flow direction F1, and the second evaporator 18 having relatively low refrigerant evaporation temperature is arranged at a downstream air side in the air flow direction F1. Thus, it is possible to secure both of a temperature difference between the blown air and the refrigerant evaporation temperature in the first evaporator 15, and a temperature difference between the blown air and the refrigerant evaporation temperature in the second evaporator 18.

Accordingly, cooling performance can be effectively improved in both the first and second evaporators 15, 18. As a result, the space to be cooled can be effectively cooled by the combination of the first and second evaporators 15, 18. Because the suction pressure of the compressor 11 can be increased by the pressurizing action of the diffuser portion 14d, the driving power of the compressor 11 can be reduced.

Next, the effects of the first and second short-circuit detection holes 37, 38 of the present embodiment will be described. In the ejector 14, a refrigerant inlet pressure P0 at the inlet side of the nozzle portion 14a, a refrigerant suction pressure P1 at the refrigerant suction port 14b and a refrigerant outlet pressure P2 at the outlet of the diffuser portion 14d have the following relationship of P0>P2>P1.

If the bonding between the container 23 and the ejector 14 is insufficient, the inlet space portion 31, the suction space portion 32 and the outlet space portion 33 may be not air-tightly partitioned from each other. In this case, the refrigerant flows from a high-pressure side to a low-pressure side among the inlet space portion 31, the suction space portion 32 and the outlet space portion 32, thereby cause a short-circuit path in the ejector unit.

For example, any short-circuit path shown by the arrow S1, S2 or S3 in FIG. 1 may be caused. If the partition between the inlet space portion 31 and the suction space portion 32 is insufficient, the refrigerant flows in short circuit from the inlet side of the nozzle portion 14a to the refrigerant suction port, as in the short-circuit path S1.

If the partition between the suction space portion 32 and the outlet space portion 33 is insufficient, the refrigerant flows in short circuit from the outlet side of the diffuser portion 14d to the refrigerant suction port 14b, as in the short-circuit path S2.

If the partition between the inlet space portion 31 and the suction space portion 32 is insufficient and at the same time the partition between the suction space portion 32 and the outlet space portion 33 is insufficient, the refrigerant flows in short circuit from the inlet side of the nozzle portion 14a to the outlet side of the diffuser portion 14d, as in the short-circuit path S3.

FIG. 8 is a graph showing relationships between a cooling capacity ratio and a short-circuit area ratio, in respective short-circuit paths S1 to S3, according to the first embodiment. Here, the short-circuit area ratio is a ratio of a short-circuited area to a bonding area of each position. The cooling capacity ratio is the cooling capacity, when the cooling capacity in a case without any short-circuit path is 100. The short-circuit area ratio is zero when the short-circuit path is not caused.

As shown in FIG. 8, in each of the short-circuit paths S1 to S3, when the short-circuit area ratio is small, a decrease of the cooling capacity due to the short-circuit path is small, and it does not affect an actual use. However, if the short-circuit area ratio becomes larger than a degree, the cooling capacity is significantly reduced in this order of the short-circuit path S3, the short-circuit path S1 and the short-circuit path S2, and thereby it is difficult to be actually used. In the present embodiment, a short-circuit path with a significant decrease of the cooling capacity in the integrated unit 20 can be detected by using the first and second short-circuit detection holes 37, 38, thereby securing the performance of the integrated unit 20.

Specifically, a short-circuit path can be detected by detecting a fluid leakage due to the inner pressure from the first and second short-circuit detection holes 37, 38. For example, in a detection room, helium as a detection fluid is filled in the integrated unit 20, so that the integrated unit 20 has a predetermined inner pressure. Then, the detection room is made to be vacuum, and a helium leakage from the first and second short-circuit detection holes 37 and 38 is checked by using a helium detector in the detection room.

The first short-circuit detection hole 37 is provided in the bonding portion of the partition portion for partitioning the inlet space portion 31 and the suction space portion 32 from each other. Thus, if a fluid leakage from the first short-circuit detection hole 37 is detected, a short-circuit in the short-circuit path 51 can be detected.

The second short-circuit detection hole 38 is provided in the bonding portion of the partition portion for partitioning the suction space portion 32 and the outlet space portion 33 from each other. Thus, if a leakage from the second short-circuit detection hole 38 is detected, a short-circuit in the short-circuit path S2 can be detected.

Furthermore, if leakage from both the first and second short-circuit detection holes 37, 38 are detected, a short-circuit in the short-circuit path S3 can be detected.

In the present embodiment, it can determine whether any short circuit in the short-circuit paths S1 to S3 is caused by detecting a leakage of a detection fluid from the first and second short-circuit detection holes 37, 38. Thus, it is possible to separate the integrated unit 20 without having a short circuit in the short-circuit paths S1 to S3 from a defective product, thereby securing the performance of the integrated unit 20.

FIG. 9 is a first modification example of the first embodiment, in which the one semi-cylindrical member 23a is further divided in the longitudinal direction, in the two semi-cylindrical members 23a, 23b configuring the cylindrical container 23.

More specifically, as shown in FIG. 9, the semi-cylindrical member 23a is further divided into three member parts, that is, a first part 23c corresponding to a forming portion of the inlet space portion 31, a second part 23d corresponding to a forming portion of the suction space portion 32, and a third part 23e corresponding to a forming portion of the outlet space portion 33. As in the example of FIG. 9, the semi-cylindrical member 23a of the container 23 may be suitably divided into plural parts in the longitudinal direction, without continuously extending in the longitudinal direction.

In the above-described first embodiment and the first modification example thereof, the container 23 is formed into a cylindrical shape. However, the container 23 may be formed into other shapes, if the inlet space portion 31, the suction space portion 32 and the outlet space portion 33 can be partitioned from each other with respect to the shape of the ejector 14.

FIG. 10 shows a second modification example of the above-described first embodiment, in which the container 23 for containing therein the ejector 14 is molded integrally with the upper tank portions 15b, 18b. That is, the container 23 is formed as a part of the upper tank portions 15b, 18b, to define the tank space portions. In this case, as shown in FIG. 10, only a part of the container 23 at a side opposite to the tubes 21 is exposed to outside of the integrated unit 20.

In the example of the integrated unit 20 shown in FIG. 10, the first and second short-circuit detection holes 37, 38 are provided only at positions of the container 23 exposed to the outside of the integrated unit 20.

FIGS. 11A, 11B and 11C show a third modification example of the above-described first embodiment, in which groove portions 39 extending in circumferential direction of the ejector 14 are provided respectively on the bonding surfaces. The bonding surfaces are provided to bond the ejector 14 with the container 23. The groove portions 39 are provided on the ejector 14 to be respectively overlapped with the first and second short-circuit detection holes 37, 38. Furthermore, the dimension of the groove portion 39 is made larger than the dimension of the first or second short-circuit detection hole 37, 38, in the circumferential direction of the ejector 14. In FIG. 11B, the hatching area indicates the bonding portion of the ejector 14 with the container 23.

According to the third modification example shown FIGS. 11A, 11B and 11C, the groove portion 39 extends larger than the first and second short-circuit detection holes 37, 38 in the circumferential direction of the ejector 14. Thus, if a short-circuit path is caused, a fluid inside of the integrated unit 20 may be easily leaked from the first or second short-circuit detection hole 37, 38 via the groove portion 39, as shown in FIG. 11C.

Thus, it is compared with a case where the groove portions 39 are not provided, a short-circuit path can be more accurately detected. In the example shown in FIGS. 11A to 11C, the groove portion 39 is formed to continuously extend along the entire periphery of the ejector 14. Thus, it is possible to detect a short-circuit path along the entire periphery of the bonding portion, thereby more accurately detecting the short-circuit path.

FIGS. 12A, 12B and 12C show a fourth modification example of the first embodiment, in which the positions, of the two first short-circuit detection holes 37 are shifted from each other in the longitudinal direction, while the two first short-circuit detection holes 37 are partially overlapped with each other in the circumferential direction of the container 23. Similarly, the positions of the two second short-circuit detection holes 38 are shifted from each other in the longitudinal direction, while the two first short-circuit detection holes 38 are partially overlapped with each other in the circumferential direction of the container 23. In FIG. 12C, the hatching area indicates, the bonding portion 40 of the ejector 14 with the container 23.

As described above, in the present embodiment, the shape and the size of the first and second short-circuit detection holes 37, 38, formed in the bonding portions for partitioning the inlet space portion 31, the suction space portion 32 and the outlet space portion 33, may be suitably changed. If the width dimension (e.g., the dimension in the longitudinal direction of the ejector 14) of the first and second short-circuit detection holes 37, 38 is too small, the first and second short-circuit detection holes 37, 38 may be filled with a brazing material in a brazing. Thus, preferably, the width dimension of the first and second short-circuit detection holes 37, 38 is equal to or larger than 0.5 mm.

Second Embodiment

A second embodiment of the invention will be described with reference to FIGS. 13 to 17. In the above-described first embodiment and modification examples thereof, the throttle mechanism 17 is formed in the ejector 14 that is provided with the flow distribution portion 16. However, in the second embodiment, the throttle mechanism 17 may be provided in a member other than the ejector 14. FIG. 13 shows an ejector-type refrigerant cycle device 40 used for a vehicle air conditioner, according to the second embodiment.

In the ejector-type refrigeration cycle device 40, a liquid receiver 12a is provided at a refrigerant outlet side of the radiator 12. The liquid receiver 12a is a gas-liquid separator, in which the refrigerant flowing out of the radiator 12 is separated into gas refrigerant and liquid refrigerant, and surplus liquid refrigerant in the cycle is stored therein. For example, the liquid receiver 12a has a tank shape elongated in a vertical direction. The liquid receiver 12a has a liquid refrigerant outlet at a lower side, from which the liquid refrigerant flows toward downstream. The liquid receiver 12a is formed integrally with the radiator 12, for example.

Alternatively, as the radiator 12, a sub-cool type condenser may be used to include a condensation heat exchanging portion for cooling and condensing the refrigerant, a receiver portion in which the refrigerant introduced from the condensation heat exchanging portion is separated into gas refrigerant and liquid refrigerant, and a super-cooling heat exchanging portion in which the saturated liquid refrigerant from the receiver portion is super-cooled.

The thermal expansion valve 13 is arranged at a refrigerant outlet side of the liquid receiver 12a. The ejector 14 is arranged at a refrigerant outlet side of the thermal expansion valve 13.

The first evaporator 15 is connected to a refrigerant outlet portion of the diffuser portion 14d of the ejector 14, and a refrigerant outlet side of the first evaporator 15 is coupled to the refrigerant suction side of the compressor 11.

A refrigerant branch passage 41 is branched from a branch portion Z positioned between the refrigerant outlet side of the thermal expansion valve 13 and a refrigerant inlet side of the nozzle portion 14a of the ejector 14. A downstream side of the refrigerant branch passage 41 is connected to the refrigerant suction port 14b of the ejector 14. The point Z of FIG. 13 shows the branch portion Z of the refrigerant branch passage 41.

The throttle mechanism 17 is arranged in the refrigerant branch passage 41, and the second evaporator 18 is arranged in the refrigerant branch passage 41 at a downstream side of the throttle mechanism 17.

An integrated unit 42 of the second embodiment will be described in detail with reference to FIGS. 14 to 16. FIG. 14 shows the ejector 14 of the second embodiment, FIG. 15 is a schematic perspective view showing an entire structure of the integrated unit 42 of the second embodiment, and FIG. 16 shows an upper tank portion of the first and second evaporators 15, 18.

In the present embodiment, the throttle mechanism 17 is provided in a connection joint 26, without being provided in the ejector 14. The ejector 14 is arranged at an inner portion of the upper tank portion 18b, and is brazed and bonded to an upper-side inner wall surface of the upper tank portion 18b. The upper-side inner wall surface of the upper tank portion 18b is an inner wall surface of the upper tank portion 18b, positioned at a side opposite to the tubes 21. Thus, the upper tank portion 18b is adapted as a container member for containing the ejector 14, in the present embodiment.

First and second short-circuit detection holes 37, 38 are formed in bonding portions of the upper tank portion 18b, bonded to the ejector 14. FIG. 17 shows the outer shape of the integrated unit 42 having the first and second short-circuit detection holes 37, 38.

As shown in FIG. 15, a refrigerant passage from the refrigerant inlet 24 is branched from the branch portion Z in the connection joint 26 into a main passage 24a as a first passage extending to the inlet side of the nozzle portion 14a of the ejector 14, and a branch passage 41 as a second passage extending to the throttle mechanism 17. As shown in FIG. 15, the branch portion Z is provided within the connection joint 26.

In contrast, the refrigerant, outlet 25 is formed in the connection joint 26 as a single cylindrical hole penetrating through the connection joint 26 in a thickness direction of the connection joint 26.

The throttle mechanism 17 is provided in the branch passage 41 of the connection joint 26. The throttle mechanism 17 is configured by a fixed throttle such as an orifice or the like. A refrigerant outlet side of the throttle mechanism 17 is connected to one end side of a cylindrical connection pipe 43, so that the decompressed refrigerant in the throttle mechanism 17 flows through the cylindrical connection pipe 43.

As shown in FIG. 16, the connection pipe 43 is arranged in a valley portion between the upper tank portions 15b, 18b, to extend in the tank longitudinal direction. The connection pipe 43 is arranged to contact the outer surfaces of the upper tank portions 15b, 18b, and is brazed and fixed to the outer surfaces of the upper tank portions 15b, 18b.

The refrigerant inlet side of the connection pipe 43 is connected to the refrigerant outlet side of the throttle mechanism 17 at a position outside of the upper tank portions 15b, 18b. The refrigerant outlet side of the connection pipe 43 is made to communicate with the second space 30 of the upper tank portion 18b of the second evaporator 18.

As shown in FIG. 15, a partition plate 44 is located in and brazed to the upper tank portion 15b of the first evaporator 15 approximately at a center portion in the tank longitudinal direction, to partition the inner space of the upper tank portion 15b into the first space 27 at one end side in the tank longitudinal direction, and the second space 28 at the other end side in the tank longitudinal direction. Furthermore, a partition plate 45 is located in and brazed to the upper tank portion 18b of the second evaporator 18 approximately at a center portion in the tank longitudinal direction, to partition the inner space of the upper tank portion 18b into the first space 29 at one end side in the tank longitudinal direction, and the second space 30 at the other end side in the tank longitudinal direction.

An auxiliary tank member 46 is arranged at one longitudinal end side of the upper tank portions 15b, 18b of the first and second evaporators 15, 18, to define therein a communication space. The auxiliary tank member 46 is formed of an aluminum material, and is brazed integrally with the first and second evaporators 15, 18.

The inner space of the auxiliary tank member 46 is made to communicate with the second space 28 of the upper tank portion 15b of the first evaporator 15. On the other hand, the second space 30 of the upper tank portion 18b of the second evaporator 18 is partitioned by a partition plate (not shown) from the inner space of the auxiliary tank member 46.

A tip end portion of the ejector 14 in the longitudinal direction, corresponding to the outlet portion of the diffuser portion 14d, is fitted into an insertion hole (not shown) provided in the partition plate 45 in the upper tank portion 18b.

A communication space (not shown) is provided in the upper tank portion 18b of the second evaporator 18, such that the refrigerant outlet side of the diffuser portion 14d of the ejector 14 communicates with the inner space of the auxiliary tank member 46 via the communication space. The communication space provided in the upper tank portion 18b of the second evaporator 18 is partitioned from the second space 30 of the upper tank portion 18b.

Thus, the refrigerant outlet side of the diffuser portion 14d of the ejector 14 communicates with the inner space of the auxiliary tank member 46 via the communication space of the upper tank portion 18b, without communicating with the first and second spaces 29, 30 of the upper tank portion 18b.

Thus, the refrigerant outlet side of the ejector 14 communicates with the second space 28 of the upper tank portion 15b, via the communication space of a connection pipe in the upper tank portion 18b and the inner space of the auxiliary tank member 46.

Next, the refrigerant flow in the integrated unit 42 will be described with reference to FIG. 15. As described above, refrigerant flowing into the refrigerant inlet 24 of the connection joint 26 is branched at the branch portion Z into the main passage 24a and the branch passage 41. The refrigerant flowing into the main passage 24a passes through the ejector 14, in this order of the nozzle portion 14a, the mixing portion 14c and the diffuser portion 14d. The low-pressure refrigerant decompressed by the ejector 14 flows into the second space portion 28 of the upper tank portion 15b of the first evaporator 15 as in the arrow b1, via the communication space of the connection pipe and the inner space of the auxiliary tank member 46.

The refrigerant of the second space portion 28 of the upper tank portion 15b flows downwardly in the tubes 21 of the right side portion of the heat exchanging core portion 15a, and flows into the right side portion in the lower tank portion 15c as in the arrow b2. Because the lower tank portion 15c does not have a partition plate, the refrigerant flowing into the lower tank portion 15c from the tubes 21 flows as in the arrow b3 from the right side portion of the lower tank portion 15c to the left side portion thereof.

The refrigerant in the left side portion of the lower tank portion 15c flows through the tubes 21 upwardly as in the arrow b4, flows into the first space portion 27 of the upper tank portion 15b, and flows out of the refrigerant outlet 25 of the connection joint 26 as in the arrow b5.

In contrast, the refrigerant branched from the branch portion Z into the branch passage 41 of the connection joint 26 is decompressed while passing through the throttle mechanism 17, and the decompressed low-pressure refrigerant (e.g., gas-liquid two-phase refrigerant) flows into the second space portion 30 of the upper tank portion 18b of the second evaporator 18 as in the arrow b6.

The refrigerant of the second space portion 30 of the upper tank portion 18b flows downwardly in the tubes 21 of the right side portion of the heat exchanging core portion 18a, and flows into the right side portion in the lower tank portion 18c as in the arrow b7. Because the lower tank portion 18c does not have a partition plate, the refrigerant flowing into the lower tank portion 18c from the tubes 21 flows as in the arrow b8 from the right side portion of the lower tank portion 18c to the left side portion thereof.

The refrigerant in the left side portion of the lower tank portion 18c flows upwardly in the tubes 21 of the left side portion of the heat exchanging core portion 18a as in the arrow b9, and flows into the first space portion 29 of the upper tank portion 18b. Because the refrigerant suction port 14b of the ejector 14 communicates with the first space portion 29 of the upper tank portion 18b, the refrigerant in the first space portion 29 of the upper tank portion 18b is drawn into the ejector 14 from the refrigerant suction port 14b.

In the integrated unit 42 of the present embodiment, it can determine whether any short circuit in the short-circuit paths S1 to S3 is caused by detecting a leakage of a detection fluid from the first and second short-circuit detection holes 37, 38. Thus, it is possible to separate the integrated unit 42 without having a short circuit in the short-circuit paths S1 to S3, thereby securing the performance of the integrated unit 42.

Third Embodiment

A third embodiment of the present invention will be described with reference to FIG. 18. In the above-described embodiments, the container 23 containing therein the ejector 14 is brazed and fixed to the first and second evaporators 15, 18. However, in the third embodiment, as shown in FIG. 18, a container 50 for accommodating the ejector 14 is spaced from the first and second evaporators 15, 18 and is connected to the first and second evaporators 15, 18 via refrigerant piping.

Specifically, an outlet side pipe 51 of a thermal expansion valve 13 (see FIG. 1) is connected to one end portion of the container 50 at the inlet side of the nozzle portion 14a, and the other end portion of the container 50 at the refrigerant outlet side of the diffuser portion 14d is connected to an inlet side pipe 52 of the first evaporator 15.

Furthermore, an outlet side pipe 53 of the second evaporator 18 is connected to a portion of the container 50 at a portion corresponding to the refrigerant suction port 14.

Furthermore, a branch pipe 54 defining therein the refrigerant branch passage 41 is connected to the outlet side pipe 51 of the thermal expansion valve 13.

The first and second short-circuit detection holes 37, 38 are provided in the container 50, and the first and second evaporators 15, 18 are arranged separately from the container 50 without closing the first and second short-circuit detecting holes 37, 38.

In the present embodiment, it can determine whether any short circuit in the short-circuit paths S1 to S3 in the container 50 is caused by detecting a leakage of a detection fluid from the first and second short-circuit detection holes 37, 38. Thus, it is possible to improve the performance of the integrated unit. In the third embodiment, the other parts may be similar to those of the above-described first embodiment.

Other Embodiments

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.

(1) In the above-described embodiments, any refrigerant short circuit in the short-circuit paths S1 to S3 can be detected by using the first and second short-circuit detection holes 37, 38. However, a refrigerant short circuit in the short-circuit path S1 or the short-circuit path S2 may be detected by using any one of the first and second short-circuit detection holes 37, 38.

(2) In the above-described embodiments, the integrated unit of the present invention is used for a sub-critical refrigerant cycle in which the pressure of the refrigerant discharged from the compressor 11 is lower than the critical pressure of the refrigerant. However, the integrated unit of the present invention may be used for a super-critical refrigerant cycle in which the pressure of the refrigerant discharged from the compressor 11 becomes higher than the critical pressure of the refrigerant. For example, carbon dioxide may be used as the refrigerant.

In the super-critical refrigerant cycle, the refrigerant discharged from the compressor 11 is cooled in the radiator 12 without a condensation. Therefore, in this case, the liquid receiver 12a does not have a gas-liquid separating function and a liquid refrigerant storing function. In the super-critical refrigerant cycle, an accumulator as a low-pressure gas-liquid separator may be located at a refrigerant outlet side of the first evaporator 15.

(3) In the above-described embodiment, the throttle mechanism 17 may be configured by a fixed throttle other than the orifice. For example, a capillary tube may be used as the throttle mechanism 17. Alternatively, an electrical control valve may be used instead of the throttle mechanism 17. In this case, the valve open degree of the electrical control valve may be controlled by an electrical actuator.

(4) In the above-described embodiments, a fixed ejector having a nozzle portion with a fixed throttle passage area is used as the ejector 14. However, a variable ejector may be used as the ejector 14, in which a throttle passage area of the nozzle portion is variable.

As an example of the variable nozzle portion, a needle may be inserted into a passage of the nozzle portion. In this case, by electrically controlling the position of the needle, the throttle passage area can be adjusted.

(5) In the above-described embodiments, the space to be cooled by the first and second evaporators 15, 18 may be any space, without being limited to a vehicle compartment, a refrigerating room of a refrigerator, or the like. For example, the integrated unit may be widely used for a general refrigerant cycle device.

(6) According to above described embodiments and modification examples of the present invention, an ejector unit includes an ejector 14 and a container 23. The ejector 14 is bonded to the container 23 to define in the container 23 an inlet space portion 31 in which an inlet of the nozzle portion 14a is open, a suction space portion 32 in which the refrigerant suction port 14b of the ejector 14 is open and an outlet space portion 33 in which an outlet of the diffuser portion 14d is open. The inlet space portion 31, the suction space portion 32 and the outlet space portion are partitioned from each other by bonding portions 40 between the ejector 14 and the container 23. The container 23 is provided with a short-circuit detection hole (37, 38) exposed to an exterior of the container 23 at least at one position of a first position between the inlet space portion 31 and the suction space portion 32, and a second position between the suction space portion 32 and the outlet space portion 33. Furthermore, the bonding portion 40 around the short-circuit detection hole (37, 38) encloses the short circuit detection hole (37, 38). Thus, a short circuit path can be easily detected in the ejector unit.

The integrated unit described in the above embodiments may be adapted as a heat exchange unit (e.g., evaporator unit) including the ejector unit.

(7) Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

Ejector unit, heat exchange unit and refrigerant short-circuit detecting method

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CPC

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Abstract

Description

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Priority Claims (1)