Hydrogen supply device for bench test of hydrogen energy engine

Abstract

The utility model discloses a hydrogen supply device for a bench test of a hydrogen energy engine. The hydrogen supply device comprises a hydrogen supply unit, a high-pressure pipeline unit and a low-pressure pipeline unit which are connected in sequence, the high-pressure pipeline unit is used for enabling hydrogen from the hydrogen supply unit to flow into the high-pressure pipeline unit when a high-pressure in-cylinder injection test with the injection pressure larger than or equal to 10 MPa needs to be carried out; the low-pressure pipeline unit is used for enabling hydrogen from the hydrogen supply unit to flow into the low-pressure pipeline unit when a low-pressure in-cylinder injection test with the injection pressure smaller than 10 MPa is carried out; when a high-pressure cylinder internal injection test is carried out, the second ball valve and the pressure reducing valve are opened, and the third ball valve and other valves are kept closed; when the low-pressure pipeline unit carries out a low-pressure cylinder inner injection test, the first ball valve, the fifth ball valve and the pressure reducing valve are opened, and other valves are kept closed. A low-pressure large-flow hydrogen supply system and a high-pressure medium-small-flow hydrogen supply system are integrated in the same rack, and two kinds of gas supply equipment do not need to be installed at the same time when different engines are replaced.

Description

Technical Field

[0001] The utility model belongs to the field of engine bench test, and in particular relates to a hydrogen supply device for hydrogen engine bench test. Background Art

[0002] As people pay more attention to environmental issues and traditional energy is increasingly depleted, hydrogen, an efficient, clean, and renewable alternative fuel for internal combustion engines, has attracted people's attention. Hydrogen has high energy density, wide flammability range, low ignition energy, and no carbon emissions when burned. At present, there are two injection strategies for direct injection hydrogen internal combustion engines: high pressure and low pressure. Low pressure direct injection mostly uses large flow direct injection injectors. Therefore, if the hydrogen engine air supply pipeline is designed to take into account both high pressure and medium flow and low pressure and large flow, it will lead to very high costs, and there is a possibility that the high pressure and medium flow pipeline cannot meet the hydrogen demand under low pressure and large flow conditions. Summary of the invention

[0003] In order to overcome the problems existing in the prior art, the utility model provides a hydrogen supply device for a hydrogen engine bench test, which can integrate low-pressure, high-flow and high-pressure, medium- and small-flow hydrogen supply systems in the same bench, does not require replacement of equipment and gas source when operating conditions change, and is simple, convenient, safe and reliable to operate.

[0004] The purpose of this utility model is achieved through the following technical solutions:

[0005] A hydrogen supply device for a hydrogen engine bench test, comprising a hydrogen supply unit, a high-pressure pipeline unit and a low-pressure pipeline unit connected in sequence; the hydrogen supply unit is used to provide hydrogen, and the high-pressure pipeline unit is used to allow hydrogen from the hydrogen supply unit to flow into the high-pressure pipeline unit when a high-pressure in-cylinder injection test with an injection pressure of ≥10MPa is required;

[0006] The low-pressure pipeline unit is used to allow hydrogen from the hydrogen supply unit 1 to flow into the low-pressure pipeline unit when performing a low-pressure in-cylinder injection test with an injection pressure of less than 10 MPa;

[0007] The high-pressure pipeline unit includes a second ball valve, a pressure reducing valve, a third pressure gauge, a hydrogen flow meter, a third ball valve, a safety valve, a flame arrester and a vent connected in sequence; a first ball valve is connected in parallel between the inlet of the second ball valve and the outlet of the pressure reducing valve; the third pressure gauge and the hydrogen flow meter are used to measure the current pressure value and flow value in the pipeline respectively; the third ball valve is used to open when it is necessary to evacuate the high-pressure hydrogen in the high-pressure pipeline unit; when performing a high-pressure in-cylinder injection test, the second ball valve, the pressure reducing valve and the third ball valve are opened, and the other valves remain closed;

[0008] The low-pressure pipeline unit includes a fourth ball valve, a fifth ball valve, a pressure reducing valve, and an air rail, and each component is connected by a pipeline; when performing a low-pressure cylinder injection test, the first ball valve, the fifth ball valve, and the pressure reducing valve are opened, and the remaining valve components remain closed.

[0009] Furthermore, the hydrogen supply unit comprises an outer frame and a plurality of gas cylinders arranged in an array in the outer frame, wherein the outer frame is provided with a support leg at the bottom and a lifting lug at the top; the outlet of each gas cylinder is connected to an air pipe, one end of the air pipe is connected to a main pipe, and a valve assembly is provided on the main pipe;

[0010] The valve assembly is used to regulate hydrogen when the hydrogen supply unit supplies gas, and includes a hydrogen venting port, a hydrogen charging port, a primary pressure regulating valve, an charging ball valve, a main valve, and a venting valve; the hydrogen venting port and the venting valve are connected to the main pipe through a pipeline, and the hydrogen charging port and the charging ball valve are connected to the main pipe through pipelines in turn.

[0011] Furthermore, the valve assembly also includes a first pressure gauge and a second pressure gauge, the first pressure gauge displays the pressure after the first-stage decompression; the second pressure gauge is used to display the inflation pressure when the hydrogen supply unit is inflated.

[0012] Furthermore, when it is necessary to exhaust the hydrogen in the air cylinder, the vent valve is opened to exhaust the hydrogen through the hydrogen vent port; when it is necessary to inflate the hydrogen supply unit, the hydrogen filling port is connected to the hydrogen source, and the filling ball valve is opened to allow hydrogen to be introduced into the main pipe.

[0013] Furthermore, a filter and a solenoid valve are provided between the hydrogen supply unit and the high-pressure pipeline unit. The filter is used to filter impurities in the hydrogen from the hydrogen supply unit, and the solenoid valve is used to cut off the gas supply of the device when necessary to avoid danger to the upstream gas source.

[0014] Furthermore, the gas rail of the hydrogen supply device for the hydrogen engine bench test is connected to the hydrogen engine through a pipeline.

[0015] Furthermore, the mass flow rate of hydrogen in the pipeline in the high-pressure pipeline unit is ≤10kg / h, and the mass flow rate of hydrogen in the pipeline in the low-pressure pipeline unit is >10kg / h.

[0016] Furthermore, when conducting a high-pressure in-cylinder injection test, the flow path of the device is as follows: hydrogen from the hydrogen supply unit passes through a filter, a solenoid valve, a second ball valve, a pressure reducing valve, and a fourth ball valve in sequence before entering the gas rail;

[0017] When conducting a low-pressure in-cylinder injection test, the flow path of the device is as follows: hydrogen from the hydrogen supply unit passes through a filter, a solenoid valve, a first ball valve, a fifth ball valve, and a pressure reducing valve in sequence before entering the gas rail.

[0018] Furthermore, a safety valve is connected in parallel between the outlet of the fourth ball valve and the outlet of the third ball valve, and a pipeline is connected in parallel between the outlet of the pressure reducing valve and the inlet of the safety valve, so as to open the safety valve immediately to exhaust hydrogen in the air rail in an emergency and ensure the safety of the experiment.

[0019] Compared with the prior art, the beneficial effects brought about by the technical solution of the utility model are:

[0020] The device described in the utility model integrates low-pressure and high-flow and high-pressure and medium- and small-flow hydrogen supply systems in the same frame. When replacing different engines, there is no need to install two gas supply devices or arrange two sets of pipelines at the same time, which reduces the floor space. Moreover, more than half of the high-pressure and low-flow pipelines can be used to conduct low-pressure and high-flow hydrogen internal combustion engine experiments, which reduces costs and equipment space.

[0021] The gas cylinders in the hydrogen supply unit are arranged in a 3*3 array with 9 carbon fiber wrapped gas cylinders, which occupies a smaller area and has a large gas storage capacity, and can support the test of hydrogen internal combustion engines for a longer period of time;

[0022] Moreover, the valve assembly of the air supply device realizes charging and discharging, and the first-level pressure reduction is integrated, which reduces the volume and is simple to operate; the high-pressure, medium-small flow pipeline and the low-pressure, large-flow pipeline are deflated through the same pipeline through the safety valve, which is safe, reliable and cost-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the hydrogen supply device for the hydrogen engine bench test of the utility model;

[0024] Figure 2a yes Figure 1 The front view of the hydrogen supply unit structure of the hydrogen supply device shown, Figure 2b yes Figure 2a Side view of

[0025] Figure 3 2 is a schematic diagram of a valve assembly of the hydrogen supply unit.

[0026] In the figure:

[0027] 1. Hydrogen supply unit, 2. Filter, 3. Explosion-proof solenoid valve, 4. First ball valve, 5. Second ball valve, 6, 14. Pressure reducing valve, 7. Third pressure gauge, 8. Hydrogen flow meter, 9. Third ball valve, 10. Safety valve, 11. Flame arrester, 12. Fourth ball valve, 13. Fifth ball valve, 15, 16. Gas rail, 17. Main pipe, 18. Gas cylinder, 19. Lifting ear, 20. Outer frame, 22. Valve assembly, 23. Gas pipe, 24. Gas cylinder fixing plate, 25. Support foot, 26. Valve control panel, 27. First pressure gauge, 28. First-stage pressure regulating valve, 29. Second pressure gauge, 30. Inflating ball valve, 31. Main valve, 32. Deflation valve, 33. Hydrogen venting port, 34. Hydrogen filling port, 35. Low-pressure first branch, 36. Low-pressure second branch. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme, beneficial effects and significant progress of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model is clearly and completely described below in combination with the drawings provided in the examples of the utility model. Obviously, all the described embodiments are only partial embodiments of the utility model, rather than all embodiments; based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0029] In the description of this application, unless otherwise clearly specified and limited, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more; unless otherwise specified or explained, the terms "connected", "fixed", etc. should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] like Figure 1 As shown, a hydrogen supply device for a hydrogen engine bench test includes a hydrogen supply unit 1, a high-pressure pipeline unit and a low-pressure pipeline unit. The hydrogen supply unit 1 is connected to a filter 2, a solenoid valve 3, a high-pressure pipeline unit and a low-pressure pipeline unit in sequence, and each component is connected by a pipeline. The hydrogen supply unit 1 is used to supply hydrogen, and the filter 2 is used to filter impurities in the hydrogen. Once blocked, subsequent equipment may be dangerous; the solenoid valve 3 is an explosion-proof solenoid valve, which is used to close the upstream gas source to protect the upstream gas source when the engine backfires, and can cut off the gas supply in an emergency, cut off the hydrogen from the source, and avoid danger to the upstream gas source.

[0031] The high-pressure pipeline unit includes a first ball valve 4, a second ball valve 5, a pressure reducing valve 6, a third pressure gauge 7, a hydrogen flow meter 8, a third ball valve 9, a safety valve 10, a flame arrester 11, and a vent, and each component is connected by a pipeline. The second ball valve 5, the pressure reducing valve 6, the third pressure gauge 7, the hydrogen flow meter 8, the third ball valve 9, the flame arrester 11 and the vent are connected in series between the inlet and the outlet of the high-pressure pipeline unit; the first ball valve 4 is connected in parallel between the inlet of the second ball valve 5 and the outlet of the pressure reducing valve 6. The pressure reducing valve 6 is used to adjust the pipeline pressure to the required pressure in the gas rail 15; the third ball valve 9 is used to open when it is necessary to evacuate the high-pressure hydrogen in the high-pressure pipeline unit.

[0032] The low-pressure pipeline unit includes: a fourth ball valve 12, a fifth ball valve 13, a pressure reducing valve 14, and gas rails 15 and 16. Each component is connected by a pipeline; the gas rails 15 and 16 are connected to the hydrogen engine through a pipeline. The inlet and outlet of the low-pressure pipeline unit are divided into two branches, namely a low-pressure first branch 35 and a low-pressure second branch 36. The low-pressure first branch 35 is connected in series with the fourth ball valve 12 and the gas rail 15 in sequence; the low-pressure second branch 36 is connected in series with the fifth ball valve 13, the pressure reducing valve 14 and the gas rail 16 in sequence.

[0033] A safety valve 10 is connected in parallel between the outlet of the fourth ball valve 12 and the outlet of the third ball valve 9, so that when an emergency occurs, the safety valve 10 can be opened immediately to exhaust the hydrogen in the air rail 15 to ensure the safety of the experiment; a pipeline is connected in parallel between the outlet of the pressure reducing valve 14 and the inlet of the safety valve 10, so that when an emergency occurs, the safety valve 10 can be opened immediately to exhaust the hydrogen in the air rail 16 to ensure the safety of the experiment.

[0034] like Figure 2a-2b As shown, the hydrogen supply unit 1 includes an outer frame 20, and 9 carbon fiber wrapped gas cylinders 18 are arranged in a 3*3 array inside the outer frame 20. The gas cylinders 8 are high-pressure hydrogen cylinders, and the 9 gas cylinders are fixed by the outer frame 20 and the gas cylinder fixing plate 24; the carbon fiber wrapped gas cylinders used have a higher hydrogen storage density than ordinary steel cylinders. The total hydrogen storage capacity of the hydrogen supply unit 1 is 450Nm 3 , and the floor space occupied is only the space of two ordinary steel cylinder groups. The hydrogen supply unit 1 can support 15MPa direct injection test and a running time of up to 2 hours.

[0035] The outer frame 20 is provided with a plurality of legs 25 at the bottom. Since the legs 25 have a certain height from the ground, they can also be moved by a forklift, which is more convenient for transportation. The outer frame 20 is provided with a plurality of lifting ears 19 at the top for connecting with a crane hook so as to lift and move the outer frame 20 by the crane. A gas cylinder fixing plate 24 is fixed on the inner side wall of the outer frame 20. The outer wall of each gas cylinder 18 is provided with a ring. The ring is fixed to the gas cylinder fixing plate 24 and the outer frame 20 through a bracket. The outlet of each gas cylinder 18 is connected to an air pipe 23. One end of the air pipe is connected to the outlet of the gas cylinder 18, and the other end is connected to the main pipe 17. A valve assembly 22 is provided on the main pipe 17.

[0036] like Figure 3 As shown, the valve assembly 22 is used to regulate hydrogen when the hydrogen supply unit 1 supplies gas, and includes a valve control panel 26. The valve control panel 26 has two holes, namely a hydrogen venting port 33 and a hydrogen charging port 34. The valve control panel 26 is also provided with a first-stage pressure regulating valve 28, an charging ball valve 30, a main valve 31, a venting valve 32, and a first pressure gauge 27 and a second pressure gauge 29. The first pressure gauge 27 displays the pressure after the first-stage pressure reduction; the second pressure gauge 29 is used to display the charging pressure when the hydrogen supply unit 1 is charged.

[0037] The hydrogen venting port 33 is connected to the main pipe 17 through a pipeline, and a venting valve 32 is provided on the pipeline. When it is necessary to exhaust the hydrogen in the air cylinder 18, the venting valve 32 is opened to discharge the hydrogen through the hydrogen venting port 33; the hydrogen charging port 34 is connected to the main pipe 17 through a pipeline, and an inflation ball valve 30 is provided on the pipeline. When it is necessary to inflate the hydrogen supply unit 1, the hydrogen charging port 34 is connected to the hydrogen source (i.e., the hydrogen inflation device), and the inflation ball valve 30 is opened to allow hydrogen to be introduced into the main pipe 17.

[0038] When the hydrogen supply unit 1 needs to supply gas, the valve assembly 22 is used for regulation, and the main valve 31 is opened on the valve assembly panel 26. The first-level pressure reduction is performed by controlling the first-level pressure regulating valve 28, and the first pressure gauge 27 displays the pressure after the first-level pressure reduction; when the hydrogen in the gas cylinder 18 needs to be vented, the vent valve 32 is opened, and the hydrogen is discharged from the vent port 33; when the hydrogen supply unit 1 needs to be inflated, the hydrogen source is connected to the inflation port 34 through a pipeline, the inflation ball valve 30 is opened, and the second pressure gauge 29 displays the inflation pressure.

[0039] When conducting a hydrogen engine bench test, the working process is as follows:

[0040] Open the main valve 31 and the primary pressure regulating valve 28 of the hydrogen supply unit 1 in sequence to reduce the pressure once;

[0041] When a high-pressure in-cylinder injection test with an injection pressure ≥10MPa is required, a high-pressure pipeline unit (hydrogen mass flow rate ≤10kg / h) shall be used;

[0042] The hydrogen from the hydrogen supply unit 1 enters the filter 2 through the pipeline to filter the impurities in the hydrogen, and enters the high-pressure pipeline unit after passing through the solenoid valve 3;

[0043] Close the first ball valve 4, close the fifth ball valve 13, open the second ball valve 5 and the pressure reducing valve 6, adjust the pressure reducing valve 6 to the target pressure (i.e., the pressure required in the gas rail 15), and allow the hydrogen to flow through the second ball valve 5 and the pressure reducing valve 6 for secondary pressure reduction; at this time, the third pressure gauge 7 displays the pressure in the pipeline at this time, and the hydrogen flowmeter 8 measures and displays the hydrogen flow in the pipeline at this time; at this time, close the third ball valve 9, the fourth ball valve 12, and the fifth ball valve 13 to prevent high-pressure hydrogen from entering the low-pressure pipeline and damaging the pipeline and equipment;

[0044] If it is necessary to exhaust the high-pressure hydrogen in the high-pressure pipeline unit, the third ball valve 9 can be opened to exhaust and release the pressure.

[0045] When a low-pressure in-cylinder injection test with an injection pressure of less than 10 MPa is required, a low-pressure pipeline unit (hydrogen mass flow rate> 10 kg / h) is used;

[0046] The hydrogen from the hydrogen supply unit 1 enters the filter 2 through the pipeline to filter the impurities in the hydrogen, and after passing through the solenoid valve 3, the first ball valve 4, the fifth ball valve 13, and the pressure reducing valve 14 are opened, and the second ball valve 5 and the pressure reducing valve 6 remain closed, and enter the low-pressure pipeline unit;

[0047] At this time, close the third ball valve 9 and the fourth ball valve 12, open the fifth ball valve 13, and allow the hydrogen to flow through the fifth ball valve 13 and the pressure reducing valve 14 for secondary pressure reduction; set the pressure to a target value of 10-25 Bar, and the hydrogen that reaches the target value enters the gas rail 16; Figure 1 The inner diameter of the pipeline in the low-pressure pipeline unit shown by the middle dotted line is larger than the inner diameter of the pipeline in the high-pressure pipeline unit, and the pipeline in the low-pressure pipeline unit is made of stainless steel pipe, which is sufficient to support the low-pressure and high-flow hydrogen internal combustion engine bench test.

[0048] When the hydrogen nozzle at the stand end sprays normally, the safety valve 10 is opened to exhaust the hydrogen in the air rails 15 and 16, so that the hydrogen in the air rails 15 and 16 is discharged from the vent after passing through the safety valve 10 and the flame arrester 11.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A hydrogen gas supply device for a hydrogen engine bench test, characterized in that: It comprises a hydrogen supply unit (1), a high-pressure pipeline unit and a low-pressure pipeline unit which are connected in sequence; the hydrogen supply unit (1) is used to supply hydrogen to the high-pressure pipeline unit through a main pipe (17); the high-pressure pipeline unit is used to allow hydrogen from the hydrogen supply unit (1) to flow into the high-pressure pipeline unit when a high-pressure in-cylinder injection test with an injection pressure of ≥10 MPa is required; The low-pressure pipeline unit is used to make hydrogen from the hydrogen supply unit (1) flow into the low-pressure pipeline unit through part of the high-pressure pipeline unit when performing a low-pressure in-cylinder injection test with an injection pressure of less than 10 MPa; The high-pressure pipeline unit comprises a second ball valve (5), a pressure reducing valve (6, 14), a third pressure gauge (7), a hydrogen flow meter (8), a third ball valve (9), a safety valve (10), a flame arrester (11) and a vent which are connected in sequence; a first ball valve (4) is connected in parallel between the inlet of the second ball valve (5) and the outlet of the pressure reducing valve (6, 14); the third pressure gauge (7) and the hydrogen flow meter (8) are used to measure the current pressure value and flow value in the pipeline respectively; the third ball valve (9) is used to open when it is necessary to evacuate the high-pressure hydrogen in the high-pressure pipeline unit; when performing a high-pressure in-cylinder injection test, the second ball valve (5), the pressure reducing valve (6, 14) and the third ball valve (9) are opened, and the other valve components remain closed; The low-pressure pipeline unit comprises a fourth ball valve (12), a fifth ball valve (13), a pressure reducing valve (6, 14), and an air rail (15, 16), and each component is connected by a pipeline; when performing a low-pressure in-cylinder injection test, the first ball valve (4), the fifth ball valve (13), and the pressure reducing valve (6, 14) are opened, and the other valve components remain closed.

2. The hydrogen gas supply device for hydrogen engine bench test according to claim 1 is characterized in that: The hydrogen supply unit (1) comprises an outer frame (20) and a plurality of gas cylinders (18) arranged in an array and fixed inside the outer frame, wherein the outer frame (20) is provided with a support foot at the bottom and a lifting lug (19) at the top; the outlet of each gas cylinder (18) is connected to an air pipe (23), one end of the air pipe is connected to the main pipe (17), and a valve assembly (22) is provided on the main pipe (17); The valve assembly (22) is used to regulate hydrogen when the hydrogen supply unit (1) supplies gas, and comprises a hydrogen venting port (33), a hydrogen charging port (34), a primary pressure regulating valve (28), a charging ball valve (30), a main valve (31), and a venting valve (32); the hydrogen venting port (33) and the venting valve (32) are connected to the main pipe (17) via a pipeline, and the hydrogen charging port (34) and the charging ball valve (30) are connected to the main pipe (17) via a pipeline in turn.

3. The hydrogen gas supply device for hydrogen engine bench test according to claim 2 is characterized in that: The valve assembly (22) further comprises a first pressure gauge (27) and a second pressure gauge (29), wherein the first pressure gauge (27) displays the pressure after the first stage of decompression; and the second pressure gauge (29) is used to display the inflation pressure when the hydrogen supply unit (1) is inflated.

4. The hydrogen gas supply device for hydrogen engine bench test according to claim 2 is characterized in that: When it is necessary to exhaust the hydrogen in the air cylinder (18), the exhaust valve (32) is opened to exhaust the hydrogen through the hydrogen exhaust port (33); when it is necessary to inflate the hydrogen supply unit (1), the hydrogen inflation port (34) is connected to the hydrogen source, and the inflation ball valve (30) is opened to allow hydrogen to flow into the main pipe (17).

5. The hydrogen gas supply device for hydrogen engine bench test according to claim 2, characterized in that: A filter (2) and a solenoid valve (3) are also provided between the hydrogen supply unit (1) and the high-pressure pipeline unit; the filter (2) is used to filter impurities in the hydrogen from the hydrogen supply unit (1); and the solenoid valve (3) is used to cut off the gas supply of the device when necessary to avoid danger to the upstream gas source.

6. The hydrogen gas supply device for hydrogen engine bench test according to claim 2, characterized in that: The gas rails (15, 16) of the hydrogen supply device for the hydrogen engine bench test are connected to the hydrogen engine through pipelines.

7. The hydrogen gas supply device for hydrogen engine bench test according to claim 2, characterized in that: The hydrogen mass flow rate of the pipeline in the high-pressure pipeline unit is ≤10kg / h, and the hydrogen mass flow rate of the pipeline in the low-pressure pipeline unit is >10kg / h.

8. The hydrogen gas supply device for hydrogen engine bench test according to claim 2, characterized in that: When conducting a high-pressure in-cylinder injection test, the flow path of the device is as follows: hydrogen from a hydrogen supply unit (1) passes through a filter (2), a solenoid valve (3), a second ball valve (5), a pressure reducing valve (6, 14), and a fourth ball valve (12) in sequence before entering a gas rail (15); When conducting a low-pressure in-cylinder injection test, the flow path of the device is as follows: hydrogen from a hydrogen supply unit (1) passes through a filter (2), a solenoid valve (3), a first ball valve (4), a fifth ball valve (13), and pressure reducing valves (6, 14) in sequence before entering a gas rail (16).

9. The hydrogen gas supply device for hydrogen engine bench test according to claim 2, characterized in that: A safety valve (10) is connected in parallel between the outlet of the fourth ball valve (12) and the outlet of the third ball valve (9), and a pipeline is connected in parallel between the outlet of the pressure reducing valve (6, 14) and the inlet of the safety valve (10), so as to open the safety valve (10) immediately to exhaust hydrogen in the air rail (15, 16) in an emergency.

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