Hydrogen supply system for internal combustion engine

Abstract

The invention relates to a hydrogen supply system for an internal combustion engine, comprising a high-pressure region (A) on the inlet side, a low-pressure region (C) on the outlet side, and a medium-pressure region (B) arranged fluidically between the high-pressure region (A) and the low-pressure region (C), a mechanical pressure reducing device (15) is provided for reducing a high pressure in the high-pressure region (A) to a medium pressure in the medium-pressure region (B), and wherein an electrically actuatable pressure reducing device (23) is provided for reducing a medium pressure in the medium-pressure region (B) to the low pressure in the low-pressure region (C). In this case, a pressure-limiting valve (17) is arranged in the medium-pressure region (B) and / or the low-pressure region (C) and a shut-off valve (22) is arranged downstream of the pressure-limiting valve. The hydrogen supply system according to the invention can in particular consist of only one hydrogen supply unit ("single cartridge solution").

Description

BACKGROUND

[0001] A pressure regulating system for a gas-driven internal combustion engine is known from the applicant's DE 10 2016 205 713 A1, having a gas line which supplies a gas valve with gaseous fuel, wherein a pressure regulator for setting a constant gas pressure is arranged in the gas line, and having a shut-off valve which is between the pressure regulator and a tank container in which the gas is under high pressure. SUMMARY

[0002] The present application proceeds from the wish of the inventor to provide a hydrogen supply system for an internal combustion engine which is as simple as possible.

[0003] To this end according to the application it is initially provided that the hydrogen supply system has a high-pressure region on the inlet side, a low-pressure region on the outlet side and a medium-pressure region arranged fluidically between the high-pressure region and the low-pressure region, wherein a mechanical pressure-reducing device for reducing the high pressure in the high-pressure region to the medium pressure in the medium-pressure region is provided, and wherein an electrically controllable pressure-reducing device for reducing the medium pressure in the medium-pressure region to the low pressure in the low-pressure region is provided.

[0004] The high pressure can be a pressure in the range from 200 to 700 bar, corresponding to the pressure in a hydrogen tank of the hydrogen supply system or in a hydrogen tank connected to the high-pressure side of the hydrogen supply system. The medium pressure can be a pressure in the range from 35 bar to 200 bar, for example a pressure of 40 bar. The low pressure can be a pressure which can fluctuate dynamically between 15 bar and 35 bar depending on the operating state of the internal combustion engine and is set for blowing hydrogen into the combustion chamber of the internal combustion engine.

[0005] For safety reasons it is mandatory in a hydrogen supply system of this type to provide at least one shut-off valve in order to at least completely fluidically separate the part of the low-pressure region located in the flow direction from the high-pressure region.

[0006] Here the shut-off valve can be a switch valve which is electrically controllable, closed in the absence of current. This is a valve which has only two switching states: open and closed, but which by its construction cannot be stopped in an intermediate state. This distinguishes the switch valve from a proportional valve which by its construction can be stopped in an intermediate state when it is correspondingly electrically controlled. A proportional valve is therefore not a shut-off valve in the sense of the present application.

[0007] The shut-off valve of the hydrogen supply system or hydrogen supply unit (see below) can differ from a proportional valve which is also included in the hydrogen supply system or hydrogen supply unit in that the shut-off valve has a larger fluid cross section than the proportional valve.

[0008] In order to be able to provide a hydrogen supply system for an internal combustion engine under this boundary condition which is as simple as possible, according to the application it is further provided that a shut-off valve is arranged in the medium-pressure region or in the low-pressure region.

[0009] By arranging the shut-off valve in the medium-pressure region or in the low-pressure region, it is possible in principle first of all to technically significantly simplify the shut-off valve, since it has to be suitable only for shutting off against the medium pressure or the low pressure and not against the high pressure. It is thus possible to provide a medium-pressure shut-off valve or a low-pressure shut-off valve, and a high-pressure shut-off valve in the hydrogen supply system is dispensable.

[0010] It is then seen in this case, however, that mechanical pressure-reducing devices have an unavoidable leakage, so that in the case of a shut-off valve which shuts off in the medium-pressure region or in the low-pressure region, a pressure can gradually build up in the medium-pressure region or in the low-pressure region as a result of this leakage, which corresponds to the high pressure and for which the medium-pressure shut-off valve or the low-pressure shut-off valve is not designed.

[0011] According to the application it is further provided that a pressure-limiting valve is arranged in the medium-pressure region or in the low-pressure region, by means of which the pressure in the medium-pressure region or in the low-pressure region can be limited to the medium pressure or to the low pressure even when the shut-off valve in the medium-pressure region or in the low-pressure region is closed and at the same time the mechanical pressure-reducing device has a non-negligible leakage.

[0012] The pressure-limiting valve can be configured, for example, as a bleed valve, by means of which hydrogen can be controllably discharged into the surroundings of the hydrogen supply system when the pressure in the medium-pressure region or in the low-pressure region exceeds the medium pressure or the low pressure. The bleed valve can be, for example, a spring-loaded non-return valve.

[0013] In a further development of the application, the possibility of simplifying the hydrogen supply system can be achieved in such a way that the hydrogen supply system is configured with a hydrogen tank, and the high-pressure region extends fluidically from the hydrogen tank to the mechanical pressure-reducing device without an intermediate connection shut-off valve, and if necessary the medium-pressure region also extends fluidically from the mechanical pressure-reducing device to the electrically controllable pressure-reducing device without an intermediate connection shut-off valve. In other words, the hydrogen supply system is implemented without a high-pressure shut-off valve and possibly even without a medium-pressure shut-off valve. This is a significant technical simplification, since the technical complexity of the shut-off valve decreases from the high-pressure shut-off valve via the medium-pressure shut-off valve to the low-pressure shut-off valve.

[0014] In a further development of the application, a fuel distributor and a plurality of injectors fluidically connected to the fuel distributor are further provided in the low-pressure region, by means of which hydrogen can be blown into the combustion chamber of the internal combustion engine.

[0015] On the other hand, the hydrogen supply system can also be a hydrogen supply unit, which has a housing with a fluid channel arranged inside the housing, and a mechanical pressure reducing device, an electrically operable pressure reducing device, a pressure limiting valve and a shut-off valve arranged in the fluid channel.

[0016] The housing can be, in particular, a one-piece housing, which is, for example, made as a cast body or by cutting, for example, aluminum or steel.

[0017] Alternatively, the shell may consist of two or more partial shells, which are in particular inseparably connected to each other. The partial shells may also be, for example, cast or machined from, for example, aluminum or steel.

[0018] In this type of hydrogen supply unit, a high-pressure connecting pipe can be provided on the high-pressure side, communicating with a fluid channel for connection to a high-pressure pipeline. For example, the high-pressure connecting pipe can be a short pipe for releasable connection, such as a threaded connection, to a high-pressure pipeline.

[0019] In this type of hydrogen supply unit, a low-pressure connecting pipe can be provided on the low-pressure side, communicating with a fluid channel for connection to a low-pressure pipeline. For example, the low-pressure connecting pipe can be a short pipe for releasable connection, such as a threaded connection, to a low-pressure pipeline.

[0020] The hydrogen supply unit can be a particularly compact component, which extends a maximum of 40 cm in length, width, and height, particularly a maximum of 30 cm, or even a maximum of only 25 cm.

[0021] The hydrogen supply unit can be part of a comprehensive hydrogen supply system, which also includes the components described above: tanks, high-pressure lines, low-pressure lines, fuel distributors, and / or injectors.

[0022] The hydrogen supply unit or hydrogen supply system or comprehensive hydrogen supply system may have pressure sensors and / or filtration devices in high-pressure areas, medium-pressure areas and / or low-pressure areas. Attached Figure Description

[0023] Exemplary embodiments of the present invention will be explained below with reference to the accompanying drawings. The drawings show: Figure 1 The first embodiment of the present invention.

[0024] Figure 2 The second embodiment of the present invention. Detailed Implementation

[0025] exist Figure 1The first embodiment of the invention is shown in the figure. The hydrogen supply system 10 for an internal combustion engine includes a hydrogen tank 12 in which hydrogen is stored at a high pressure (e.g., 700 bar) and the hydrogen tank is releasably connected to a first pressure reducing unit 14 via a high-pressure line 13 and its high-pressure short pipe 141.

[0026] The first pressure-reducing unit 14 is implemented as a one-piece unit and also includes a mechanical pressure-reducing device 15 for reducing the high pressure to a medium pressure, for example, to 40 bar. The first pressure-reducing unit 14 also includes a particulate filter 16 on the inlet side and a pressure-limiting valve 17 configured as a check valve downstream of the mechanical pressure-reducing device 15. Once the pressure-limiting valve is loaded at the inlet side with a pressure greater than the medium pressure, the pressure-limiting valve opens, and hydrogen gas is then released from the hydrogen supply system 10 through a vent 18. In this respect, the pressure-limiting valve 17 can also be referred to as a vent valve. A medium pressure sensor 19 is also provided in the first pressure-reducing unit 14 downstream of the mechanical pressure-reducing device 15.

[0027] The first pressure reducing unit 14 is releasably connected downstream to the medium pressure pipeline 20 via a medium pressure short pipe 142, and the medium pressure pipeline is releasably connected downstream to the inlet short pipe 211 of the second pressure reducing unit 21.

[0028] The second pressure reducing unit 21 is implemented as a single unit. In sequence according to the flow direction, the second pressure reducing unit 21 also includes a shut-off valve 22, another intermediate pressure sensor 19, a particulate filter 16, and an electrically operable pressure reducing device 23, configured as a proportional valve in this example. This electrically operable pressure reducing device is used to reduce the intermediate pressure to a low pressure.

[0029] The second pressure reduction unit 21 is releasably connected to the low-pressure line 25 via its low-pressure short pipe 212, which is also connected to the fuel distributor 26, which supplies hydrogen to a plurality of injectors 27 in fluid connection thereto.

[0030] In this example, shut-off valve 22 is a medium-pressure shut-off valve, meaning that it is designed by its construction to shut off hydrogen gas at a medium pressure, such as 40 bar. However, it is not a high-pressure shut-off valve and therefore, by its construction, it is not designed to shut off hydrogen gas at a high pressure, such as 250 bar or 700 bar. Shut-off valve 22 can thus be a component that is relatively simple to implement.

[0031] In this example, the intermediate pressure relief valve 17 is connected before the shut-off valve 22, thereby reliably eliminating pressures greater than the intermediate pressure at the shut-off valve 22, specifically even in the shut-off condition and when there is some leakage at the mechanical pressure reducing device 15.

[0032] According to the first embodiment ( Figure 1The first decompression unit 14 and the second decompression unit 21 are implemented as two separate units, each with its own housing (“Two-Box-Lösung”, a two-box solution).

[0033] exist Figure 2 The second embodiment of the invention is shown below. A hydrogen supply system 10 for an internal combustion engine includes a hydrogen tank 12 in which hydrogen is stored at a high pressure (e.g., 700 bar), and this tank is releasably connected to a hydrogen supply unit 30 via a high-pressure line 13 and its high-pressure short pipe 301. On the opposite side, the hydrogen supply unit 30 is releasably connected to a low-pressure line 25 via its low-pressure short pipe 302, which is also connected to a fuel distributor 26 that supplies hydrogen to a plurality of injectors 27 in fluid connection thereto.

[0034] The hydrogen supply unit 30 has a one-piece housing 303 in the example, which is machined from aluminum or steel, for example by casting or cutting. Inside the housing 303 of the hydrogen supply unit 30, a fluid passage 304 extends from a high-pressure region A through a medium-pressure region B to a low-pressure region C, that is, from a short pipe 301 to a short pipe 302.

[0035] In the fluid channel 304, arranged in sequence according to the flow direction are a high-pressure sensor 31, a mechanical pressure reducing device 15 for reducing high pressure to medium pressure, for example, to 40 bar, an electrically operable pressure reducing device 23 for dynamically and variably reducing medium pressure to low pressure, for example, from 15 bar to 35 bar, a pressure limiting valve 17, and a shut-off valve 22.

[0036] The electrically operable pressure reducing device 23 is configured as a proportional valve in this example. The pressure relief valve 17 is configured as a check valve; once the pressure relief valve is loaded on the inlet side to a pressure greater than the maximum expected low pressure or greater than the intermediate pressure, the pressure relief valve opens, and hydrogen gas exits from the hydrogen supply system 10 and is released through the vent 18. In this respect, the pressure relief valve 17 can also be referred to as a vent valve.

[0037] In this example, shut-off valve 22 is a low-pressure shut-off valve, meaning that it is designed by construction to shut off hydrogen with a maximum expected low pressure, such as 35 bar, or a medium pressure, such as 40 bar. However, it is not a high-pressure shut-off valve and therefore, by construction, is not designed to shut off hydrogen with high pressure, such as 250 bar or 700 bar. Shut-off valve 22 can be a component with a relatively simple implementation.

[0038] In the example, pressure relief valve 17 is connected before shut-off valve 22, thereby reliably preventing pressures exceeding the maximum expected low or medium pressure from appearing on shut-off valve 22, specifically even in the case of shut-off and when some leakage occurs in mechanical pressure reducing device 15 and electrically operable pressure reducing device 23, respectively.

[0039] According to the second embodiment ( Figure 2 The hydrogen supply unit 30 is implemented as a single unit that reduces the hydrogen pressure in two stages from high pressure to low pressure via medium pressure, and the unit has a single housing (“One-Box-Lösung”, single-box solution).

Claims

1. A hydrogen supply system for an internal combustion engine, comprising a high-pressure region (A) at the inlet side, a low-pressure region (C) at the outlet side, and a medium-pressure region (B) arranged fluidly between the high-pressure region (A) and the low-pressure region (C), wherein, A mechanical pressure reducing device (15) is provided for reducing the high pressure in the high pressure zone (A) to the medium pressure in the medium pressure zone (B), and an electrically operable pressure reducing device (23) is provided for reducing the medium pressure in the medium pressure zone (B) to the low pressure in the low pressure zone (C), wherein a pressure limiting valve (17) is arranged in the medium pressure zone (B) and / or the low pressure zone (C) and a shut-off valve (22) is arranged downstream of the pressure limiting valve.

2. The hydrogen supply system according to claim 1 further comprises a hydrogen tank (12), wherein, The high-pressure area (A) extends fluidly from the hydrogen tank (12) to the mechanical pressure reducing device (15) without the intermediate connection shut-off valve (22).

3. The hydrogen supply system according to claim 1 or 2, wherein, The medium-pressure zone (B) extends fluidly from the mechanical pressure reducing device (15) to the electrically controlled pressure reducing device (23) without the intermediate connection shut-off valve (22).

4. The hydrogen supply system according to any one of the preceding claims, further comprising a fuel distributor (26) and at least one injector (27) fluidly connected to the fuel distributor in the low-pressure region (C).

5. The hydrogen supply system according to any one of the preceding claims is configured as a hydrogen supply unit (30) having a housing (303), a fluid passage (304) arranged inside the housing, and the mechanical pressure reducing device (15), the electrically controlled pressure reducing device (23), the pressure limiting valve (17) and the shut-off valve (22) arranged in the fluid passage.

6. The hydrogen supply system according to claim 5, wherein, A high-pressure connecting pipe (301) communicating with the fluid channel (304) is provided on the high-pressure side of the housing (303) for connecting with the high-pressure pipeline (13), and a low-pressure connecting pipe (302) communicating with the fluid channel (304) is provided on the low-pressure side of the housing (303) for connecting with the low-pressure pipeline (25).

7. The hydrogen supply system according to any one of the preceding claims, wherein, The pressure relief valve (17) is configured as a relief valve, which allows hydrogen to be discharged from the control to the surrounding environment of the hydrogen supply system (10) when the pressure in the medium pressure region (B) or the low pressure region (C) exceeds the medium pressure.

8. The hydrogen supply system according to any one of the preceding claims, wherein, Pressure sensors (19, 31) and / or filter devices (16) are provided in the high-pressure zone (A), the medium-pressure zone (B) and / or the low-pressure zone (C).

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