ejector

Abstract

An ejector (1) ejects a working fluid supplied to a first working fluid supply port (11) and a second working fluid supply port (12) from an outer nozzle (21) and an inner nozzle (22) respectively corresponding thereto, generates negative pressure in a negative pressure generating chamber (14) to suck in a target fluid, and discharges the target fluid together with the working fluid from a discharge port (16). Either one of a first working fluid flow passage (23) between the outer nozzle (21) and the inner nozzle (22) and a second working fluid flow passage (24) within the inner nozzle (22) has a larger flow passage cross-sectional area than the other. A body casing (10) is provided with an LSV (31) in a corresponding manner with respect to the first working fluid supply port (11) or the second working fluid supply port (12) connected to either the first working fluid flow passage (23) or the second working fluid flow passage (24) whichever has the larger flow passage cross-sectional area, and that is capable of linearly adjusting the flow rate of the working fluid in a region where the required flow rate increases.

Description

Ejector

[0001] The technology disclosed in this specification relates to an ejector configured to generate negative pressure by supplying a working fluid, and to suck in and cause a target fluid to flow by the action of the negative pressure.

[0002] A known example of this type of technology is an ejector described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-129999). This ejector includes a main casing and two nozzles that inject a working fluid from within the main casing. Each nozzle receives a working fluid from two supply ports (a first working fluid supply port and a second working fluid supply port) formed in the main casing. One of the two nozzles is an outer nozzle, and the other is an inner nozzle disposed within the outer nozzle. A gap is formed between the tip of the outer nozzle and the tip of the inner nozzle. This gap forms a first working fluid flow path through which the working fluid flows. The inner nozzle also forms a second working fluid flow path through which the working fluid flows. Each working fluid supply port receives a working fluid from a different injector. These injectors are driven by duty control that alternately opens and closes their valves. The working fluid supplied to each working fluid supply port flows through the first working fluid flow path and the second working fluid flow path, respectively, and is then injected from the corresponding nozzle. This injection of the working fluid generates negative pressure in a negative pressure generating chamber. This negative pressure causes the target fluid to be drawn into the negative pressure generating chamber through the target fluid supply port, and then the target fluid flows together with the working fluid to the diffuser and is discharged from the discharge port.

[0003] Japanese Patent Application Laid-Open No. 2020-56365

[0004] In the ejector described in Patent Document 1, the required flow rate of the working fluid supplied to each supply port may be increased in order to increase the flow rate of the fluid discharged from the discharge port of the ejector. In this case, each injector is duty-controlled, so the working fluid supplied to each nozzle pulsates, causing the fluid discharged from the ejector to pulsate. This raises concerns that downstream equipment, to which the target fluid is supplied, may be adversely affected by the fluid pulsation.

[0005] This disclosed technology has been made in consideration of the above circumstances, and its purpose is to provide an ejector that can suppress the pulsation of the working fluid and the fluid released from the ejector, even when the required flow rate of the working fluid supplied to each working fluid supply port is large.

[0006] (1) In order to achieve the above object, one aspect of the technology disclosed in the present application includes a main body casing, the main body casing including a first working fluid supply port and a second working fluid supply port for receiving a supply of working fluid, a target fluid supply port for receiving a supply of target fluid, a negative pressure generating chamber for generating negative pressure by the working fluid, a diffuser communicating with the negative pressure generating chamber and through which the working fluid and the target fluid flow, and one discharge port for discharging the working fluid and the target fluid that have flowed through the diffuser to the outside, an outer nozzle provided corresponding to the first working fluid supply port and having a tip located in the negative pressure generating chamber for injecting the working fluid, an inner nozzle provided corresponding to the second working fluid supply port and located within the outer nozzle for injecting the working fluid, a first working fluid flow path through which the working fluid supplied from the first working fluid supply port flows, and a second working fluid flow path through which the working fluid supplied from the second working fluid supply port flows. the first working fluid flow path is formed between an outer nozzle and an inner nozzle, and the second working fluid flow path is formed within the inner nozzle; negative pressure is generated in a negative pressure generating chamber by working fluid supplied to each working fluid supply port and sprayed from the corresponding nozzle, the negative pressure causes target fluid to be sucked from a target fluid supply port into the negative pressure generating chamber, and the target fluid flows together with the working fluid to a diffuser and is discharged from a discharge port; one of the first working fluid flow path and the second working fluid flow path has a larger flow cross-sectional area than the other; and the main casing is provided with a linear solenoid valve that is capable of adjusting the flow rate of the working fluid with a linear characteristic in a region where the required flow rate is large, corresponding to the first working fluid supply port or the second working fluid supply port that is connected to the first working fluid flow path or the second working fluid flow path having the larger flow cross-sectional area.

[0007] According to the configuration (1) above, the working fluid supplied to the first working fluid supply port flows through the first working fluid flow path to the outer nozzle, is injected from its tip into the negative pressure generating chamber, flows through the diffuser, and is discharged from the discharge port. The working fluid supplied to the second working fluid supply port flows through the second working fluid flow path to the inner nozzle, is injected from its tip into the negative pressure generating chamber, flows through the diffuser, and is discharged from the discharge port. This injection of the working fluid generates negative pressure in the negative pressure generating chamber. This negative pressure draws the target fluid from the target fluid supply port into the negative pressure generating chamber. The target fluid then flows together with the working fluid into the diffuser and is discharged from the discharge port. One of the first working fluid flow path and the second working fluid flow path has a larger cross-sectional area than the other. The main casing is also provided with a linear solenoid valve corresponding to the first working fluid supply port or the second working fluid supply port, which is connected to the first working fluid flow path or the second working fluid flow path with the larger cross-sectional area. This linear solenoid valve can adjust the flow rate of the working fluid with a linear characteristic in a range where the required flow rate increases. Therefore, even when the required flow rate of the working fluid supplied to the first working fluid supply port or the second working fluid supply port increases, the linear solenoid valve adjusts the flow rate of the working fluid with a linear characteristic, so that pulsation does not occur in the working fluid supplied to the first working fluid supply port or the second working fluid supply port.

[0008] (2) To achieve the above object, in the configuration of (1) above, it is preferable that the first working fluid supply port and the second working fluid supply port are arranged in the main casing along the axial direction of the outer nozzle and the inner nozzle, the first working fluid supply port is arranged adjacent to the tip side of the outer nozzle and the inner nozzle relative to the second working fluid supply port, the first working fluid supply port is connected to the first working fluid flow path, the second working fluid supply port is connected to the second working fluid flow path, and a linear solenoid valve is provided in the main casing corresponding to the first working fluid supply port.

[0009] According to the configuration (2) above, in addition to the effects of the configuration (1), the first working fluid supply port and the second working fluid supply port are arranged in the main casing along the axial direction of the outer nozzle and the inner nozzle. The first working fluid supply port is arranged adjacent to the tip of the outer nozzle and the inner nozzle relative to the second working fluid supply port. The first working fluid supply port is connected to the first working fluid flow path, and the second working fluid supply port is connected to the second working fluid flow path. The main casing is provided with a linear solenoid valve corresponding to the first working fluid supply port. Therefore, even when the required flow rate of the working fluid supplied to the first working fluid supply port increases, the linear solenoid valve adjusts the flow rate of the working fluid with a linear characteristic, preventing pulsation from occurring in the working fluid supplied to the first working fluid supply port.

[0010] (3) In order to achieve the above object, in the configuration of (2) above, it is preferable that the main casing is provided with an injector that corresponds to the second working fluid supply port and is capable of intermittently injecting working fluid in an area where the required flow rate is small.

[0011] According to the configuration (3), in addition to the effects of the configuration (2), the main casing is provided with an injector corresponding to the second working fluid supply port. This injector is capable of intermittently injecting working fluid in a region where the required flow rate of working fluid supplied to the second working fluid supply port is small. Therefore, when the required flow rate of working fluid supplied to the second working fluid supply port is small, the injector intermittently injects working fluid, but since the flow rate of working fluid supplied to the second working fluid supply port is small, pulsation of the working fluid is small.

[0012] According to the configuration (1) above, even when the required flow rate of the working fluid supplied to the first working fluid supply port or the second working fluid supply port increases, the pulsation of the working fluid can be suppressed, and the pulsation of the fluid released from the ejector can be suppressed.

[0013] According to the configuration (2) above, even when the required flow rate of the working fluid supplied to the first working fluid supply port increases, the pulsation of the working fluid can be suppressed, and the pulsation of the fluid released from the ejector can be suppressed.

[0014] According to the configuration (3) above, in addition to the effect of the configuration (2) above, when the required flow rate of the working fluid to be supplied to the second working fluid supply port becomes small, the pulsation of the working fluid can be suppressed, and the pulsation of the fluid released from the ejector can be suppressed.

[0015] 1 is a front cross-sectional view of an ejector according to an embodiment of the present invention;

[0016] Hereinafter, an embodiment of an ejector will be described in detail with reference to the drawings.

[0017] [Ejector Configuration] FIG. 1 shows a front cross-sectional view of an ejector 1. This ejector 1 is used, for example, in a fuel cell system to supply hydrogen gas to a fuel cell. The ejector 1 shown in FIG. 1 is properly positioned upside down. However, the ejector 1 can also be positioned tilted relative to the horizontal position shown in FIG. 1. As shown in FIG. 1, the ejector 1 includes a tubular main casing 10 for carrying a working fluid and a target fluid. For example, in a fuel cell system, hydrogen gas corresponds to the working fluid, and hydrogen off-gas corresponds to the target fluid. The main casing 10 includes an upstream section 10a and a downstream section 10b. In FIG. 1, the upstream section 10a corresponds to approximately the right half of the main casing 10, and the downstream section 10b corresponds to approximately the left half of the main casing 10.

[0018] The upstream section 10a is provided with a first working fluid supply port 11 and a second working fluid supply port 12 for receiving a supply of working fluid, a target fluid supply port 13 for receiving a supply of target fluid, and a negative pressure generating chamber 14 for generating negative pressure by the working fluid. The upstream section 10a is provided with two coaxial nozzles 21, 22 for injecting the working fluid into the negative pressure generating chamber 14. The two nozzles 21, 22 are provided corresponding to the first working fluid supply port 11 and the second working fluid supply port 12, respectively. The tip of each nozzle 21, 22 is positioned corresponding to the negative pressure generating chamber 14.

[0019] The downstream portion 10b is provided with a diffuser 15 that communicates with the negative pressure generating chamber 14 and through which the working fluid and the target fluid flow, and a single discharge port 16 for discharging the working fluid and the target fluid that have flowed through the diffuser 15 to the outside.

[0020] The ejector 1 injects the working fluid supplied to each of the working fluid supply ports 11 and 12 from each of the nozzles 21 and 22, and this injection generates negative pressure in the negative pressure generating chamber 14. The ejector 1 also uses the generated negative pressure to draw the target fluid from the target fluid supply port 13 into the negative pressure generating chamber 14. The ejector 1 then flows the drawn target fluid together with the working fluid into the diffuser 15 and discharges it from the discharge port 16 toward downstream equipment.

[0021] In this embodiment, the two nozzles 21, 22 include an outer nozzle 21 and an inner nozzle 22. In this embodiment, the outer nozzle 21 and the inner nozzle 22 are arranged such that their axes coincide with the axis of the diffuser 15. The outer nozzle 21 is provided corresponding to the first working fluid supply port 11 for injecting the working fluid. The tip of the outer nozzle 21 opens into the negative pressure generating chamber 14. The inner nozzle 22 is provided corresponding to the second working fluid supply port 12 for injecting the working fluid. The inner nozzle 22 is arranged inside the outer nozzle 21, and its tip opens into the negative pressure generating chamber 14.

[0022] The first working fluid supply port 11 and the second working fluid supply port 12 are arranged in the main casing 10 along the axial direction of the nozzles 21, 22. The first working fluid supply port 11 is arranged adjacent to the tip side of each nozzle 21, 22 relative to the second working fluid supply port 12. The second working fluid supply port 12 is arranged away from each nozzle 21, 22.

[0023] Figure 2 shows an enlarged cross-sectional view of the upstream portion 10a of Figure 1. As shown in Figures 1 and 2, a gap is formed between the outer nozzle 21 and the inner nozzle 22. This gap communicates with the first working fluid supply port 11 and serves as a first working fluid flow path 23 through which the working fluid supplied from the first working fluid supply port 11 flows. The outer nozzle 21 is formed with an inlet hole 29 that communicates with the first working fluid supply port 11 and through which the working fluid flows into the first working fluid flow path 23. The first working fluid flow path 23 has an annular cross section.

[0024] The inside of the inner nozzle 22 is connected to the second working fluid supply port 12 and forms a second working fluid flow path 24 through which the working fluid supplied from the second working fluid supply port 12 flows.

[0025] 1, the main casing 10 is generally cylindrical, and its hollow 25 has a different inner diameter in the longitudinal direction. The hollow 25 in the downstream portion 10b includes the negative pressure generating chamber 14, the diffuser 15, and the discharge port 16.

[0026] As shown in FIGS. 1 and 2 , the hollow 25 of the upstream section 10 a includes a nozzle accommodating section 27 and an assembly space 28 with an inner diameter larger than that of the nozzle accommodating section 27. The nozzle accommodating section 27 includes the negative pressure generating chamber 14 and accommodates the outer nozzle 21 and the inner nozzle 22. The assembly space 28 is an operating space for assembling the nozzles 21 and 22 into the nozzle accommodating section 27. After the nozzles 21 and 22 are assembled into the nozzle accommodating section 27, a plug 41 is assembled into the assembly space 28 to close the space 28. The plug 41 has a cylindrical shape with a bottom and a multi-step outer diameter. The plug 41, assembled into the assembly space 28, is fastened to the main casing 10 with bolts 43. A communication flow path 30 that connects the second working fluid flow path 24 and the second working fluid supply port 12 is formed between the inner wall of the assembly space 28 and the plug 41. In addition, a spring 44 is provided in the assembly space 28 between the plug 41 and the base end of the outer nozzle 21 to press the outer nozzle 21 against the step of the nozzle accommodating portion 27 .

[0027] In this embodiment, the first working fluid flow path 23 between the outer nozzle 21 and the inner nozzle 22 has a larger flow path cross-sectional area than the second working fluid flow path 24 in the inner nozzle 22. The first working fluid flow path 23 communicates with the first working fluid supply port 11 via an inlet 29. A linear solenoid valve (LSV) 31 is provided in the main casing 10 in correspondence with the first working fluid supply port 11. An outlet 31a of the LSV 31 is provided so as to communicate with the first working fluid supply port 11. The working fluid is supplied to an inlet 31b of the LSV 31. The LSV 31 is a solenoid valve capable of linearly adjusting the flow rate of the working fluid in a range where the required flow rate is high. In this embodiment, the LSV 31 has a well-known configuration, so a detailed description of the configuration will be omitted.

[0028] The second working fluid supply port 12 communicates with the second working fluid flow path 24 via a communication flow path 30. An injector 32 is provided in the main casing 10, corresponding to the second working fluid supply port 12, for injecting working fluid into the supply port 12. An outlet 32a of the injector 32 is provided to communicate with the second working fluid supply port 12. The working fluid is supplied to an inlet 32b of the injector 32. The injector 32 is a solenoid valve that is driven to alternately open and close by duty control in a region where the required flow rate is small. In other words, the injector 32 is a solenoid valve that can intermittently inject working fluid in a region where the required flow rate is small. In this embodiment, the injector 32 has a well-known configuration, so a detailed description of the configuration will be omitted.

[0029] [Regarding Actions and Effects of the Ejector] According to the configuration of the ejector 1 of this embodiment described above, the working fluid supplied to the first working fluid supply port 11 flows through the first working fluid flow path 23 to the outer nozzle 21, is injected from its tip into the negative pressure generating chamber 14, flows through the diffuser 15, and is discharged from the discharge port 16. The working fluid supplied to the second working fluid supply port 12 flows through the second working fluid flow path 24 to the inner nozzle 22, is injected from its tip into the negative pressure generating chamber 14, flows through the diffuser 15, and is discharged from the discharge port 16. Negative pressure is generated in the negative pressure generating chamber 14 by this injection of the working fluid. This negative pressure causes the target fluid to be drawn from the target fluid supply port 13 into the negative pressure generating chamber 14. The target fluid then flows together with the working fluid to the diffuser 15 and is discharged from the discharge port 16.

[0030] Here, of the first working fluid flow path 23 and the second working fluid flow path 24, the first working fluid flow path 23 has a larger flow path cross-sectional area than the second working fluid flow path 24. Furthermore, the main casing 10 is provided with an LSV 31 corresponding to the first working fluid supply port 11 connected to the first working fluid flow path 23, which has a larger flow path cross-sectional area. The LSV 31 is capable of adjusting the flow rate of the working fluid with a linear characteristic in a range where the required flow rate increases. Therefore, even when the required flow rate of the working fluid supplied to the first working fluid supply port 11 increases, the LSV 31 adjusts the flow rate of the working fluid with a linear characteristic, so that pulsation does not occur in the working fluid supplied to the first working fluid supply port 11. Therefore, even when the required flow rate of the working fluid supplied to the first working fluid supply port 11 increases, pulsation of the working fluid can be suppressed, and pulsation of the fluid discharged from the ejector 1 can be suppressed.

[0031] According to the configuration of this embodiment, the main casing 10 is provided with an injector 32 corresponding to the second working fluid supply port 12. This injector 32 is capable of intermittently injecting working fluid in a region where the required flow rate is small. Therefore, when the required flow rate of the working fluid to be supplied to the second working fluid supply port 12 is small, the injector 32 intermittently injects the working fluid, but because the flow rate of the working fluid supplied to the second working fluid supply port 12 is small, pulsation of the working fluid is small. Therefore, when the required flow rate of the working fluid to be supplied to the second working fluid supply port 12 is small, pulsation of the working fluid can be suppressed, and pulsation of the fluid discharged from the ejector 1 can be suppressed.

[0032] <Other Embodiments> The disclosed technology is not limited to the above-described embodiments, and can be implemented by appropriately modifying part of the configuration within the scope of the disclosed technology.

[0033] (1) In the above embodiment, the LSV 31 is provided corresponding to the first working fluid supply port 11, and the injector 32 is provided corresponding to the second working fluid supply port 12. However, it is also possible to provide an LSV corresponding to the second working fluid supply port, and an injector corresponding to the first working fluid supply port. In this case, even if the required flow rate of the working fluid to be supplied to the second working fluid supply port increases, the LSV adjusts the flow rate of the working fluid with a linear characteristic, so that pulsation does not occur in the working fluid supplied to the second working fluid supply port. Therefore, even if the required flow rate of the working fluid to be supplied to the second working fluid supply port increases, pulsation of the working fluid can be suppressed, and pulsation of the fluid discharged from the ejector can be suppressed.

[0034] The disclosed technology can be applied to, for example, a fuel cell system mounted on a vehicle such as a hydrogen automobile.

[0035] REFERENCE SIGNS LIST 1 Ejector 10 Main casing 11 First working fluid supply port 12 Second working fluid supply port 13 Target fluid supply port 14 Negative pressure generating chamber 15 Diffuser 16 Discharge port 21 Outer nozzle 22 Inner nozzle 23 First working fluid flow path 24 Second working fluid flow path 31 LSV 32 Injector

Claims

1. A device comprising a main body casing, the main body casing comprising: a first working fluid supply port and a second working fluid supply port for receiving a supply of working fluid; a target fluid supply port for receiving a supply of target fluid; a negative pressure generating chamber for generating negative pressure by the working fluid; a diffuser communicating with the negative pressure generating chamber and through which the working fluid and the target fluid flow; and one discharge port for discharging the working fluid and the target fluid that have flowed through the diffuser to the outside; an outer nozzle provided corresponding to the first working fluid supply port, with its tip located in the negative pressure generating chamber, for spraying the working fluid; an inner nozzle provided corresponding to the second working fluid supply port, located within the outer nozzle, for spraying the working fluid; a first working fluid flow path through which the working fluid supplied from the first working fluid supply port flows; and a second working fluid flow path through which the working fluid supplied from the second working fluid supply port flows. the first working fluid flow path is formed between the outer nozzle and the inner nozzle, and the second working fluid flow path is formed in the inner nozzle; negative pressure is generated in the negative pressure generating chamber by the working fluid supplied to each of the working fluid supply ports and sprayed from the corresponding nozzle, the target fluid is sucked into the negative pressure generating chamber from the target fluid supply port by the negative pressure, and the target fluid flows together with the working fluid to the diffuser and is discharged from the discharge port; in this ejector, one of the first working fluid flow path and the second working fluid flow path has a larger flow cross-sectional area than the other, and a main casing is provided with a linear solenoid valve that can adjust the flow rate of the working fluid with a linear characteristic in a region where a required flow rate is large, corresponding to the first working fluid supply port or the second working fluid supply port that is connected to the first working fluid flow path or the second working fluid flow path which has the larger flow cross-sectional area.

2. An ejector as claimed in claim 1, wherein the first working fluid supply port and the second working fluid supply port are arranged in the main casing along the axial direction of the outer nozzle and the inner nozzle, and the first working fluid supply port is arranged adjacent to the tip side of the outer nozzle and the inner nozzle rather than the second working fluid supply port, the first working fluid supply port communicates with the first working fluid flow path and the second working fluid supply port communicates with the second working fluid flow path, and the main casing is provided with the linear solenoid valve corresponding to the first working fluid supply port.

3. An ejector according to claim 2, characterized in that the main body casing is provided with an injector that corresponds to the second working fluid supply port and is capable of intermittently injecting the working fluid in an area where the required flow rate is small.

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