Ejector device and fuel cell gas path system having the same

Abstract

The application provides an ejector device and a fuel cell gas path system with the same. The ejector device comprises a casing having an air inlet, a containing cavity and an air outlet, the air inlet being communicated with the air outlet through the containing cavity; an ejector assembly rotatably arranged in the containing cavity, the ejector assembly comprising a plurality of ejectors, the plurality of ejectors being arranged at intervals around a pivot axis of the ejector assembly; each ejector comprising a nozzle, a mixing chamber and a diffusion part communicated in sequence, the nozzle being used for communication with the air inlet, and the diffusion part being used for communication with the air outlet; and a driving device drivingly connected with the ejector assembly to drive the ejector assembly to rotate around the pivot axis; wherein at least one of the inner diameter of the nozzle and the inner diameter of the mixing chamber of at least two ejectors is different; and the nozzles of the plurality of ejectors are selectively communicated with the air inlet. The application effectively solves the problem of narrow power coverage range of the ejector in the prior art.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically, to an ejector device and a fuel cell gas path system having the same. Background Technology

[0002] Currently, hydrogen recirculation systems in hydrogen fuel cell systems typically use hydrogen circulation pumps or ejectors as hydrogen recirculation devices. Ejectors, due to their advantages such as simple structure, high reliability, and low cost, are increasingly widely used in hydrogen recirculation systems. During the use of ejectors, to ensure their proper ejection performance, the ejector's power range must exceed the operating power variation range of the hydrogen fuel cell system. However, with the continuous development of high-power fuel cells, the maximum power of fuel cell systems is increasing, and their operating power variation range is also expanding. Once the actual operating power of the fuel cell deviates from the ejector's power range, the ejector's ejection performance will rapidly decrease, severely affecting the normal operation of the fuel cell.

[0003] In existing technologies, there are generally two methods to increase the power coverage of an ejector:

[0004] I. Structural parameter optimization of a single ejector

[0005] Optimizing the structural parameters of the ejector can improve its ejection performance and thus increase its power coverage. However, the ejection performance depends on the overall structural combination (especially the ejector nozzle diameter and the ejector mixing chamber diameter). Optimizing a single structural parameter has limited effect on improving the ejector's power coverage and cannot meet the operational requirements of high-power fuel cells in the current technology.

[0006] II. Switching between the two ejectors

[0007] By modifying the ejector connected to the hydrogen fuel cell gas path system, the power range of the ejector can be matched to the operating power of the fuel cell. However, to achieve automatic switching between the two ejectors, additional pipelines and solenoid valves are required to control the flow of hydrogen, resulting in a complex pipeline and control circuit structure. Furthermore, with the continuous development of high-power fuel cells, two ejectors are no longer sufficient to meet the operational requirements of fuel cells, and adding more ejectors would further increase the complexity of the pipeline and control circuits, making the proposed solution difficult to implement. Summary of the Invention

[0008] The main objective of this invention is to provide an ejector device and a fuel cell gas path system having the same, so as to solve the problem of the narrow power coverage range of ejectors in the prior art.

[0009] To achieve the above objectives, according to one aspect of the present invention, an ejector device is provided, comprising: a housing having an air inlet, a receiving cavity, and an exhaust port, the air inlet communicating with the exhaust port through the receiving cavity; an ejector assembly rotatably disposed within the receiving cavity, the ejector assembly including a plurality of ejectors spaced apart about a pivot axis of the ejector assembly; each ejector including a nozzle, a mixing chamber, and a diffuser connected in sequence, the nozzle communicating with the air inlet and the diffuser communicating with the exhaust port; and a drive device drivenly connected to the ejector assembly to drive the ejector assembly to rotate about the pivot axis; wherein at least two ejectors have different inner diameters of the nozzles and at least one of the inner diameters of the mixing chambers; and the nozzles of the plurality of ejectors are selectively connected to the air inlet.

[0010] Furthermore, the drive unit is located outside the housing, which also has mounting holes. The drive shaft of the drive unit passes through the mounting holes and is connected to the ejector assembly. The drive shaft is coaxial with the pivot axis. The air inlet and exhaust outlet are located on one side of the drive shaft.

[0011] Furthermore, the distance between the central axis of each nozzle and the pivot axis is consistent; and / or, the distance between the central axis of each mixing chamber and the pivot axis is consistent.

[0012] Furthermore, along the rotation direction of the ejector assembly, the inner diameter of each nozzle gradually increases or decreases; and / or, along the rotation direction of the ejector assembly, the inner diameter of each mixing chamber gradually increases or decreases; wherein the inner diameter of the nozzle of each ejector assembly is adapted to the inner diameter of the mixing chamber.

[0013] Furthermore, the diffuser has a conical diffuser cavity, one end of which is connected to the mixing chamber. Each ejector also includes an outlet equal volume cavity connected to the exhaust port, and the other end of the conical diffuser cavity is connected to the exhaust port through the outlet equal volume cavity. The inner diameter of the conical diffuser cavity gradually increases along the direction from the mixing chamber to the outlet equal volume cavity, and the cross-sections of the outlet equal volume cavities of at least two ejectors are different. The cross-sections are arranged perpendicular to the gas flow direction in the outlet equal volume cavity.

[0014] Furthermore, the housing also has: a return air port communicating with the receiving cavity, and each ejector also includes a return air chamber, the return air port communicating with the mixing chamber through the return air chamber; wherein, the return air port and the exhaust port are located on the same side.

[0015] Furthermore, there are n ejectors, evenly distributed within the housing. The ejector device also includes an encoder, mounted on the drive shaft, for detecting the rotation angle of the drive shaft. When the Nth ejector needs to be used, the encoder's detection value is acquired, and when the detection value is... When this happens, the control drive device stops operating.

[0016] Furthermore, the ejector device also includes: a bearing disposed in a mounting hole, with a drive shaft passing through the bearing; wherein the outer ring of the bearing is connected to the wall of the mounting hole, and the inner ring of the bearing is connected to the drive shaft.

[0017] According to another aspect of the present invention, a fuel cell gas path system is provided, comprising: a gas supply device; an injector connected to the gas supply device; an ejector device located downstream of the injector, the injector being used to input gas into the gas inlet of the ejector device; a fuel cell stack, the exhaust port of the ejector device being connected to the stack inlet of the fuel cell stack; wherein the ejector device is the aforementioned ejector device.

[0018] Furthermore, the fuel cell gas path system also includes: a first pipeline, the two ends of which are respectively connected to the electric ejection port of the fuel cell stack and the return gas port of the ejector device; a gas-liquid separator, which is installed on the first pipeline; a shut-off valve, which is installed between the gas supply device and the ejector; and a pressure reducing valve, which is installed between the shut-off valve and the ejector.

[0019] Furthermore, the ejector device to be used is determined based on the power of the fuel cell stack; wherein, the inner diameter of the nozzle and the inner diameter of the mixing chamber of the ejector device to be used are positively correlated with the power of the fuel cell stack.

[0020] According to the technical solution of this invention, the housing of the ejector device has an air inlet, a receiving cavity, and an exhaust port. The air inlet communicates with the exhaust port through the receiving cavity. The ejector assembly is rotatably disposed within the receiving cavity and includes multiple ejectors. The multiple ejectors are spaced apart around the pivot axis of the ejector assembly. Each ejector includes a nozzle, a mixing chamber, and a diffuser that are connected in sequence. The nozzle communicates with the air inlet to inject gas into the mixing chamber, which is used to mix the gas. The diffuser communicates with the exhaust port to diffuse the mixed gas. A driving device is drivenly connected to the ejector assembly to drive the ejector assembly to rotate around the pivot axis. At least two ejectors have different inner diameters of their nozzles and mixing chambers, so that the power coverage ranges of the at least two ejectors are different, thereby improving the power coverage range of the ejector device. In this way, the gas entering the ejector through the inlet flows sequentially through the nozzle, mixing chamber, and diffuser. The gas pressure, velocity, flow rate, and other parameters are adjusted to match the operating power of the fuel cell. The gas is then fed into the fuel cell through the exhaust port to ensure normal operation. When the operating power of the fuel cell changes beyond the power coverage range of the ejector currently in use, the drive device drives the ejector assembly to rotate around the pivot axis to change the ejector connected to the fuel cell gas path system. This ensures that the power coverage range of the ejector device matches the actual operating power of the fuel cell, thereby solving the problem of the narrow power coverage range of the ejector in the prior art and improving the operational stability of the fuel cell.

[0021] Compared to existing ejectors, the ejector assembly in this application features multiple ejectors. By changing the ejectors connected to the fuel cell gas path system, the power coverage range of the ejector device can be matched to the operating power variation range of the fuel cell, thereby improving the operational stability of the fuel cell. Furthermore, the method of switching ejectors by driving the ejector assembly to rotate using a drive device eliminates the need for additional piping and solenoid valves, significantly reducing the structural complexity of the ejector device and making it simpler, easier to manufacture, and easier to implement. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 A cross-sectional schematic diagram of an embodiment of the ejector device according to the present invention is shown;

[0024] Figure 2 It shows Figure 1 A partially enlarged schematic diagram of point D of the ejector device in the diagram;

[0025] Figure 3 It shows Figure 1 A schematic cross-sectional view of the ejector device along the AA direction;

[0026] Figure 4 It shows Figure 1 A schematic cross-sectional view of the ejector device along the BB direction;

[0027] Figure 5 It shows Figure 1 A schematic cross-sectional view of the ejector device along the CC direction;

[0028] Figure 6 A schematic diagram of the overall structure of an embodiment of the fuel cell gas circuit system according to the present invention is shown;

[0029] Figure 7 It shows Figure 6 The graph shows the functional relationship between the number of ejector stages and the stack power in the fuel cell gas path system.

[0030] The above figures include the following reference numerals:

[0031] 1. Ejector assembly; 10. Housing; 11. Air inlet; 12. Receiving cavity; 13. Exhaust port; 15. Mounting hole; 16. Return port; 20. Ejector assembly; 21. Ejector; 211. Nozzle; 212. Mixing chamber; 213. Diffusion section; 214. Outlet cavity; 215. Return chamber; 30. Drive unit; 31. Drive shaft; 3. First pipeline; 4. Gas supply device; 5. Shut-off valve; 6. Pressure reducing valve; 7. Injector; 8. Fuel cell stack; 9. Gas-liquid separator. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0034] In this invention, unless otherwise stated, directional terms such as "up" and "down" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" are generally used in relation to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0035] To address the issue of the narrow power coverage of ejectors in existing technologies, this application provides an ejector device and a fuel cell gas path system incorporating it.

[0036] like Figures 1 to 5 As shown, the ejector device includes a housing 10, an ejector assembly 20, and a drive unit 30. The housing 10 has an air inlet 11, a receiving cavity 12, and an exhaust port 13. The air inlet 11 communicates with the exhaust port 13 through the receiving cavity 12. The ejector assembly 20 is rotatably disposed within the receiving cavity 12 and includes a plurality of ejectors 21, which are spaced apart around a pivot axis of the ejector assembly 20. Each ejector 21 includes a nozzle 211, a mixing chamber 212, and a diffuser 213 connected in sequence. The nozzle 211 communicates with the air inlet 11, and the diffuser 213 communicates with the exhaust port 13. The drive unit 30 is drivenly connected to the ejector assembly 20 to drive the ejector assembly 20 to rotate around the pivot axis. Among them, at least one of the inner diameters of the nozzles 211 of at least two ejectors 21 and the inner diameter of the mixing chamber 212 is different; the nozzles 211 of the plurality of ejectors 21 may selectively communicate with the air inlet 11.

[0037] Using the technical solution of this embodiment, the housing 10 of the ejector device has an air inlet 11, a receiving cavity 12, and an exhaust port 13. The air inlet 11 is connected to the exhaust port 13 through the receiving cavity 12. The ejector assembly 20 is rotatably disposed in the receiving cavity 12 and includes a plurality of ejectors 21. The plurality of ejectors 21 are spaced apart around the pivot axis of the ejector assembly 20. Each ejector 21 includes a nozzle 211, a mixing chamber 212, and a diffuser 213 connected in sequence. The nozzle 211 is used to communicate with the air inlet 11 to inject gas into the mixing chamber 212. The mixing chamber 212 is used to mix the gas. The diffuser 213 is connected to the exhaust port 13 to diffuse the mixed gas. The driving device 30 is drivenly connected to the ejector assembly 20 to drive the ejector assembly 20 to rotate around the pivot axis. In this design, at least one of the inner diameters of the nozzles 211 and the inner diameter of the mixing chamber 212 of at least two ejectors 21 is different, so that the power coverage range of the at least two ejectors 21 is different, thereby improving the power coverage range of the ejector device. In this way, the gas entering the ejector 21 through the air inlet 11 flows through the nozzle 211, the mixing chamber 212 and the diffuser 213 in sequence. The parameters such as the pressure, velocity and flow rate of the gas are adjusted to match the operating power of the fuel cell, and the gas is input into the fuel cell through the exhaust port 13 to ensure that the fuel cell can operate normally. When the operating power of the fuel cell changes to outside the power coverage range of the currently used ejector 21, the drive device 30 drives the ejector assembly 20 to rotate around the pivot axis to change the ejector 21 connected to the fuel cell gas path system, so that the power coverage range of the ejector device matches the actual operating power of the fuel cell, thereby solving the problem of the narrow power coverage range of the ejector in the prior art and improving the operating stability of the fuel cell.

[0038] Compared to ejectors in the prior art, the ejector assembly 20 of the ejector device in this embodiment is provided with multiple ejectors 21. By changing the ejectors 21 connected to the fuel cell gas path system, the power coverage range of the ejector device can be matched with the operating power variation range of the fuel cell, thereby improving the operating stability of the fuel cell. Simultaneously, the method of driving the ejector assembly 20 to rotate via the drive device 30 to switch the ejectors 21 eliminates the need for additional pipelines and solenoid valves, significantly reducing the structural complexity of the ejector device and making its structure simpler, easier to manufacture, and easier to implement.

[0039] In this embodiment, the ejector device can accommodate four ejectors 21 of different sizes and structures, and depending on the situation, five or six ejectors 21 of different sizes can even be arranged circumferentially. Compared with the dual ejectors in the prior art, the ejector device in this embodiment has a much wider range of fuel cell power. With the continuous increase in fuel cell power (such as the development of 200kW fuel cell stacks), this design has an undeniable role and advantage now and in the future.

[0040] In this embodiment, there are four ejectors 21, and the inner diameters of the nozzles 211 and the mixing chambers 212 of the four ejectors 21 are different to further increase the power coverage of the ejector device. Among them, the inner diameter of the nozzle 211 of each ejector 21 is matched with the inner diameter of the mixing chamber 212, that is, the two are positively correlated.

[0041] It should be noted that the number of ejectors 21 is not limited to this and can be adjusted according to the working conditions and usage requirements. Optionally, there may be two, three, five, six, seven, eight, or more ejectors 21.

[0042] like Figures 1 to 6 As shown, the drive unit 30 is located outside the housing 10, which also has a mounting hole 15. The drive shaft 31 of the drive unit 30 passes through the mounting hole 15 and is connected to the ejector assembly 20. The drive shaft 31 is coaxial with the pivot axis. The air inlet 11 and the exhaust port 13 are located on one side of the drive shaft 31. Thus, by rotating the drive shaft 31, the ejector assembly 20 is driven to rotate around the pivot axis, thereby achieving automatic switching between the four ejectors 21 and improving the automation level of the ejector device. Simultaneously, the air inlet 11 and the exhaust port 13 located on one side of the drive shaft 31 can communicate with the ejectors 21 to allow gas to enter and exit. After selecting an ejector 21, gas enters the ejector 21 through the air inlet 11 and exits through the exhaust port 13.

[0043] Specifically, the housing 10 is cylindrical, with the air inlet 11 located on the bottom surface of the housing 10 and the exhaust outlet 13 located on the circumferential surface of the housing 10.

[0044] Optionally, the distance between the central axis of each nozzle 211 and the pivot axis is the same; and / or, the distance between the central axis of each mixing chamber 212 and the pivot axis is the same. In this way, the above arrangement ensures that each nozzle 211 can communicate with the air inlet 11 and the exhaust port 13, thereby reducing the number of air inlets 11 and exhaust ports 13, and making the structure of the housing 10 simpler and easier to process and implement.

[0045] In this embodiment, each mixing chamber 212 is a circular hole, and within each ejector 21, the central axis of the nozzle 211 is coaxially arranged with the central axis of the mixing chamber 212. The distance between the central axis of each nozzle 211 and the pivot axis is the same, and the distance between the central axis of each mixing chamber 212 and the pivot axis is also the same. This arrangement ensures that the injection position of the nozzle 211 is located on the central axis of the mixing chamber 212, guaranteeing that the gas can collide more evenly with the inner wall of the mixing chamber 212, thereby improving the degree of gas mixing. Furthermore, it ensures that the central axes of each nozzle 211 and each mixing chamber 212 are located on the same circumferential surface, reducing the processing difficulty for operators.

[0046] Optionally, along the rotation direction of the ejector assembly 20, the inner diameter of each nozzle 211 gradually increases or decreases; and / or, along the rotation direction of the ejector assembly 20, the inner diameter of each mixing chamber 212 gradually increases or decreases. The inner diameter of each nozzle 211 in the ejector assembly 20 is adapted to the inner diameter of the mixing chamber 212. In this way, along the rotation direction of the ejector assembly 20, the power coverage range of each ejector 21 increases progressively. This allows for step-by-step switching of the power coverage range of the ejector device, reducing the difficulty of switching power coverage ranges; it also facilitates the selection of a suitable ejector 21 by the operator. Simultaneously, the above arrangement makes the selection of the inner diameter of the nozzle 211 and the inner diameter of the mixing chamber 212 more flexible and diverse, adapting to different working conditions and usage requirements, and also improving the processing flexibility of the operator.

[0047] In this embodiment, along the rotation direction of the ejector assembly 20, the inner diameters of the four nozzles 211 gradually increase, and the inner diameters of the four mixing chambers 212 gradually increase, so that the gas injection volume of each nozzle 211 matches the volume of its corresponding mixing chamber 212, thereby improving the uniformity of gas mixing.

[0048] In other embodiments not shown in the accompanying drawings, the inner diameter of each nozzle gradually decreases along the rotation direction of the ejector assembly, and the inner diameter of each mixing chamber gradually decreases.

[0049] Specifically, the ejector device has four power coverage levels, which increase sequentially along the rotation direction of the ejector assembly 20.

[0050] like Figures 1 to 5As shown, the diffuser 213 has a conical diffuser cavity, one end of which is connected to the mixing chamber 212. Each ejector 21 also includes an outlet equal volume cavity 214, which is connected to the exhaust port 13. The other end of the conical diffuser cavity is also connected to the exhaust port 13 via the outlet equal volume cavity 214. Along the direction from the mixing chamber 212 to the outlet equal volume cavity 214, the inner diameter of the conical diffuser cavity gradually increases, and the cross-sections of the outlet equal volume cavities 214 of at least two ejectors 21 are different. The cross-sections are perpendicular to the gas flow direction within the outlet equal volume cavity 214. Thus, as the gas flows from the mixing chamber 212 to the outlet equal volume cavity 214, the smaller inner diameter of the conical diffuser cavity near the mixing chamber 212 results in more intense collisions between the gas and the cavity wall, causing the gas to diffuse rapidly towards the outlet equal volume cavity 214, thereby increasing the gas diffusion rate. Meanwhile, the above-mentioned arrangement of the outlet cavity 214 makes the power coverage range of at least two ejectors 21 different, thereby increasing the power coverage range of the ejector device 1.

[0051] In this embodiment, the outlet equal volume cavity 214 of the four ejectors 21 are all different. In each ejector 21, the inner diameter of the nozzle 211, the inner diameter of the mixing chamber 212, and the cross-section of the outlet equal volume cavity 214 are positively correlated, that is, the larger the inner diameter of the nozzle 211, the larger the inner diameter of the mixing chamber 212 and the larger the cross-section of the outlet equal volume cavity 214.

[0052] In this embodiment, the outlet equal volume cavity 214 is a circular hole.

[0053] like Figure 1 and Figure 2 As shown, the housing 10 also has a return air port 16, which communicates with the receiving cavity 12. Each ejector 21 also includes a return air chamber 215, through which the return air port 16 communicates with the mixing chamber 212. The return air port 16 and the exhaust port 13 are located on the same side. In this way, unburned gas in the fuel cell can enter the mixing chamber 212 through the return air port 16 and the return air chamber 215, where it is fully mixed with the gas in the mixing chamber 212 and then reintroduced into the fuel cell for further combustion, thereby increasing gas utilization and reducing the operating cost of the fuel cell. Simultaneously, the above arrangement allows the return air pipeline and the exhaust pipeline to be located on the same side, resulting in a more compact and rational pipeline layout.

[0054] In this embodiment, at any given time of operation, the return port 16 of the ejector device can only be connected to one ejector 21, and the return port 16 does not need to select from multiple ejector return ports. During the operation of the ejector device, the airflow path of the basic hydrogen path system inside the ejector device is completely consistent with the airflow path of the hydrogen path system of a conventional ejector. The airflow path is simple and the flow resistance is small, which in turn benefits the performance of the ejector device.

[0055] Optionally, there are n ejectors 21, evenly distributed within the housing 10. The ejector device also includes an encoder mounted on the drive shaft 31 for detecting the rotation angle of the drive shaft 31. Specifically, when the Nth ejector needs to be used, the encoder's detection value is obtained, and the value is... When the time comes, the control drive device 30 stops operating. In this way, the above settings enable the ejector device to automatically switch the ejector 21 that needs to be put into use, thereby improving the intelligence level and switching accuracy of the ejector device.

[0056] In this embodiment, there are four ejectors 21, which are evenly distributed within the housing 10. When the Nth ejector 21 needs to be used, the encoder's detection value is obtained, and the drive device 30 is stopped when the detection value is N*90°. For example, when the second ejector 21 needs to be used, the drive device 30 is stopped when the encoder's detection value is 180°.

[0057] In this embodiment, the ejector device also includes a bearing, which is disposed within the mounting hole 15, and the drive shaft 31 passes through the bearing. The outer ring of the bearing is connected to the wall of the mounting hole 15, and the inner ring of the bearing is connected to the drive shaft 31. Thus, by supporting the drive shaft 31 with the bearing, friction between the drive shaft 31 and the mounting hole 15 can be prevented, which not only improves the operational stability of the ejector device but also extends its service life.

[0058] like Figure 6 As shown, this application also provides a fuel cell gas path system, which includes a gas supply device 4, an injector 7, an ejector device 1, and a fuel cell stack 8. The injector 7 is connected to the gas supply device 4. The ejector device 1 is located downstream of the injector 7, and the injector 7 is used to input gas into the gas inlet 11 of the ejector device. The exhaust port 13 of the ejector device 1 is connected to the stack inlet of the fuel cell stack 8. The ejector device 1 is the aforementioned ejector device. In this way, the ejector device 1 can switch the connection of the ejector 21 within the fuel cell gas path system in a timely manner according to the actual operating power of the fuel cell stack 8, ensuring that the power coverage range of the ejector device 1 matches the operating power of the fuel cell stack 8, thereby improving the operational stability of the fuel cell.

[0059] In this embodiment, the gas supply device 4 is a hydrogen cylinder.

[0060] Specifically, the injector 7 injects hydrogen from the hydrogen cylinder into the ejector 21 according to the needs of the fuel cell stack 8. Under the ejection action of the ejector 21, the physical states of the hydrogen, such as pressure, flow rate, and velocity, are adjusted to match the operating power of the fuel cell stack 8. The hydrogen is then input into the fuel cell stack 8 for combustion through the exhaust port 13 and the stack inlet to achieve normal operation of the fuel cell.

[0061] like Figure 6 As shown, the fuel cell gas path system also includes a first pipeline 3, a gas-liquid separator 9, a shut-off valve 5, and a pressure reducing valve 6. The two ends of the first pipeline 3 are connected to the electric ejection port of the fuel cell stack 8 and the return port 16 of the ejector device, respectively. The gas-liquid separator 9 is installed on the first pipeline 3. The shut-off valve 5 is installed between the gas supply device 4 and the ejector 7. The pressure reducing valve 6 is installed between the shut-off valve 5 and the ejector 7. In this way, the aforementioned arrangement of the first pipeline 3 and the gas-liquid separator 9 allows unburned hydrogen in the fuel cell stack 8 to be reintroduced into the ejector device 1 for reuse, thereby improving the hydrogen utilization rate and making the fuel cell gas path system more energy-efficient and environmentally friendly.

[0062] In this embodiment, the gas-liquid separator 9 is a gas-water separator.

[0063] Specifically, after the shut-off valve 5 is opened, the hydrogen in the hydrogen cylinder is depressurized by the pressure reducing valve 6 and then introduced into the injector 7. The injector 7 injects a certain amount of hydrogen into the ejector device 1 according to the needs of the fuel cell stack 8. To ensure the operational stability of the fuel cell stack 8, the injector 7 injects an excess of hydrogen into the fuel cell stack 8. The unburned hydrogen, mixed with small droplets and water vapor generated during the gas combustion process, is discharged from the stack outlet, forming a circulating airflow to be ejected. The circulating airflow passes through the gas-liquid separator 9 to filter out the small droplets in the airflow to prevent the small droplets from clogging the ejector 21. The separated circulating airflow is input into the ejector 21 and fully mixed with the dry hydrogen injected from the nozzle 211 in the mixing chamber 212 before re-entering the fuel cell stack 8 for combustion.

[0064] like Figure 7 As shown, the ejector 21 of the ejector device 1 is determined according to the power of the fuel cell stack. Specifically, the inner diameter of the nozzle 211, the inner diameter of the mixing chamber 212, and the cross-section of the outlet equal volume cavity 214 of the ejector 21 are positively correlated with the stack power. This allows the ejector device to accurately and quickly switch the ejector 21 from the currently used ejector 21 to the one required for operation, ensuring that the power coverage of the ejector 21 matches the actual operating power of the fuel cell, further improving the operational stability of the fuel cell.

[0065] In this embodiment, the four-level power coverage of the ejector device 1 covers the idle point and peak point of the fuel cell power, further improving the operational stability of the fuel cell.

[0066] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0067] The ejector assembly has an air inlet, a receiving cavity, and an exhaust port. The air inlet communicates with the exhaust port through the receiving cavity. The ejector assembly is rotatably disposed within the receiving cavity and includes multiple ejectors. The multiple ejectors are spaced apart around the pivot axis of the ejector assembly. Each ejector includes a nozzle, a mixing chamber, and a diffuser connected in sequence. The nozzle communicates with the air inlet to inject gas into the mixing chamber, which mixes the gas. The diffuser communicates with the exhaust port to diffuse the mixed gas. A drive device is drivenly connected to the ejector assembly to drive the ejector assembly to rotate around the pivot axis. At least two ejectors have different inner diameters of either the nozzle or the mixing chamber, so that the power coverage range of the at least two ejectors is different, thereby improving the power coverage range of the ejector assembly. In this way, the gas entering the ejector through the inlet flows sequentially through the nozzle, mixing chamber, and diffuser. The gas pressure, velocity, and flow rate are adjusted to match the operating power of the fuel cell, and then fed into the fuel cell through the exhaust port to ensure normal operation. When the operating power of the fuel cell changes to outside the power coverage range of the ejector currently in use, the drive device drives the ejector assembly to rotate around the pivot axis to change the ejector connected to the fuel cell gas path system. This makes the power coverage range of the ejector device match the actual operating power of the fuel cell, thereby solving the problem of the narrow power coverage range of the ejector in the prior art and improving the operating stability of the fuel cell.

[0068] Compared to existing ejectors, the ejector assembly in this application features multiple ejectors. By changing the ejectors connected to the fuel cell gas path system, the power coverage range of the ejector device can be matched to the operating power variation range of the fuel cell, thereby improving the operational stability of the fuel cell. Furthermore, the method of switching ejectors by driving the ejector assembly to rotate using a drive device eliminates the need for additional piping and solenoid valves, significantly reducing the structural complexity of the ejector device and making it simpler, easier to manufacture, and easier to implement.

[0069] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0070] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0071] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ejector device, characterized in that, include: The housing (10) has an air inlet (11), a receiving cavity (12) and an exhaust port (13), wherein the air inlet (11) is connected to the exhaust port (13) through the receiving cavity (12); An ejector assembly (20) is rotatably disposed within the receiving cavity (12). The ejector assembly (20) includes a plurality of ejectors (21), which are spaced apart about the pivot axis of the ejector assembly (20). Each ejector (21) includes a nozzle (211), a mixing chamber (212), and a diffuser (213) connected in sequence. The nozzle (211) is used to communicate with the air inlet (11), and the diffuser (213) is used to communicate with the exhaust port (13). A drive device (30) is driven to the ejector assembly (20) to drive the ejector assembly (20) to rotate about the pivot axis; Among them, at least one of the inner diameter of the nozzle (211) of at least two of the ejectors (21) and the inner diameter of the mixing chamber (212) is different; the nozzles (211) of the plurality of ejectors (21) may be selectively connected to the air inlet (11); The diffuser (213) has a conical diffuser cavity, one end of which is connected to the mixing chamber (212). Each ejector (21) further includes an outlet equal volume cavity (214) connected to the exhaust port (13). The other end of the conical diffuser cavity is connected to the exhaust port (13) through the outlet equal volume cavity (214). The inner diameter of the conical diffuser cavity gradually increases along the direction from the mixing chamber (212) to the outlet equal volume cavity (214). The cross-sections of the outlet equal volume cavities (214) of at least two ejectors (21) are different. The cross-sections are perpendicular to the gas flow direction in the outlet equal volume cavity (214). Along the rotation direction of the ejector assembly (20), the inner diameter of each nozzle (211) gradually increases or decreases; and / or, along the rotation direction of the ejector assembly (20), the inner diameter of each mixing chamber (212) gradually increases or decreases; wherein the inner diameter of the nozzle (211) of each ejector assembly (20) is adapted to the inner diameter of the mixing chamber (212).

2. The ejector device according to claim 1, characterized in that, The drive device (30) is located outside the housing (10), and the housing (10) also has a mounting hole (15). The drive shaft (31) of the drive device (30) passes through the mounting hole (15) and is connected to the ejector assembly (20). The drive shaft (31) is coaxial with the pivot axis. The air inlet (11) and the exhaust port (13) are located on one side of the drive shaft (31).

3. The ejector device according to claim 1, characterized in that, The distance between the central axis of each nozzle (211) and the pivot axis is the same; and / or, The distance between the central axis of each of the mixing chambers (212) and the pivot axis is the same.

4. The ejector device according to claim 1, characterized in that, The housing (10) also has: The return air port (16) is connected to the receiving cavity (12), and each ejector (21) also includes a return air cavity (215). The return air port (16) is connected to the mixing chamber (212) through the return air cavity (215); wherein the return air port (16) and the exhaust port (13) are located on the same side.

5. The ejector device according to claim 2, characterized in that, The ejector (21) is indivual, The ejectors (21) are evenly distributed within the housing (10), and the ejector device further includes: An encoder is mounted on the drive shaft (31) for detecting the rotation angle of the drive shaft (31); Among them, when the first When an ejector is put into use, the detection value of the encoder is acquired, and the detection value is... When the time comes, the drive device (30) is controlled to stop operating.

6. The ejector device according to claim 2, characterized in that, The ejector device further includes: A bearing is disposed in the mounting hole (15), and the drive shaft (31) passes through the bearing; wherein, the outer ring of the bearing is connected to the wall of the mounting hole (15), and the inner ring of the bearing is connected to the drive shaft (31).

7. A fuel cell gas path system, characterized in that, include: Gas supply device (4); The injector (7) is connected to the air supply device (4); An ejector device (1) is located downstream of the injector (7), which is used to input gas into the air inlet (11) of the ejector device; The fuel cell stack (8) has its exhaust port (13) connected to the stack inlet of the fuel cell stack (8). Wherein, the ejector device (1) is the ejector device according to any one of claims 1 to 6.

8. The fuel cell gas path system according to claim 7, characterized in that, The fuel cell gas path system also includes: The first pipeline (3) is connected at both ends to the electric ejection port of the fuel cell stack (8) and the return gas port (16) of the ejector device, respectively. A gas-liquid separator (9) is installed on the first pipeline (3); A shut-off valve (5) is provided between the gas supply device (4) and the injector (7); A pressure reducing valve (6) is disposed between the shut-off valve (5) and the injector (7).

9. The fuel cell gas path system according to claim 7, characterized in that, The ejector (21) of the ejector device (1) to be put into use is determined according to the power of the fuel cell stack; wherein the inner diameter of the nozzle (211) and the inner diameter of the mixing chamber (212) of the ejector (21) to be put into use are positively correlated with the power of the fuel cell stack.

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