Hydrogen supply system for an internal combustion engine

Abstract

The invention relates to a hydrogen supply system for an internal combustion engine with an inlet-side high-pressure region (A), with an outlet-side low-pressure region (C) and with a medium-pressure region (B) which is arranged fluidically between the high-pressure region (A) and the low-pressure region (C), wherein a mechanical pressure-reducing device (15) is provided to lower a high pressure in the high-pressure region (A) to a medium pressure in the medium-pressure region (B), and wherein an electrically actuable pressure-reducing device (23) is provided to lower the medium pressure in the medium-pressure region (B) to a low pressure in the low-pressure region (C).

Description

[0001] Description

[0002] title

[0003] Hydrogen supply system for an internal combustion engine

[0004] State of the art

[0005] From DE 10 2016 205 713 A1 of the applicant, a pressure control system for gas-powered internal combustion engines is already known, comprising a gas line for supplying a gas valve with gaseous fuel, wherein a pressure regulator for setting a constant gas pressure is arranged in the gas line, and comprising a shut-off valve which is located between the pressure regulator and a tank container in which gas is located under high pressure.

[0006] Disclosure of the invention

[0007] The invention is based on the inventors' desire to provide an optimized hydrogen supply system for an internal combustion engine.

[0008] The invention shows different configurations for this purpose.

[0009] According to the invention, it is first provided that the hydrogen supply system is provided with a high-pressure region on the inlet side, with a low-pressure region on the outlet side and with a medium-pressure region fluidly arranged between the high-pressure region and the low-pressure region, wherein a mechanical pressure reducing device is provided for reducing a high pressure in the high-pressure region to a medium pressure in the medium-pressure region and wherein an electrically controllable pressure reducing device is provided for reducing the medium pressure in the medium-pressure region to a low pressure in the low-pressure region.

[0010] The high pressure can, for example, be a pressure in the range of 200 to 700 bar, for example corresponding to a pressure in a hydrogen tank of the hydrogen supply system, or a hydrogen tank to which the hydrogen supply system is connected on the high-pressure side. The medium pressure can, for example, be a pressure in the range between 35 bar and 200 bar, for example a pressure of 40 bar. The low pressure can, for example, be a pressure that can fluctuate dynamically between 15 bar and 35 bar depending on the operating state of the internal combustion engine and that is intended for injecting the hydrogen into a combustion chamber of the internal combustion engine.

[0011] To protect the medium-pressure region from excessively high gas pressure, a pressure relief valve can be arranged in the medium-pressure region. This pressure relief valve can be designed as a check valve that opens from the medium-pressure region toward the environment of the hydrogen supply system when the difference between the pressure in the medium-pressure region and the pressure in the environment of the hydrogen supply system exceeds a limit value.

[0012] A pressure sensor may also be provided in the medium pressure range, for example upstream of the pressure relief valve.

[0013] It can be provided that at least the mechanical pressure reducing device, the pressure sensor, and the pressure relief valve are integrated into a pressure reducing unit in or on a common pressure reducing housing, in which a fluid channel extends from an inlet connection to an outlet connection. Such a unit is easy to handle and can be integrated into a more comprehensive system simply by mechanical fixation and fluidic connection via the connection points.

[0014] In a further development, the pressure reducing unit can have a high-pressure shut-off valve downstream of the inlet nozzle and upstream of the mechanical pressure reducing device in order to be able to shut off the part located in the flow direction from the high-pressure area. In this case and within the scope of the entire application, the shut-off valve or a shut-off valve can be designed in particular as an electrically controllable, normally closed switching valve. This is therefore a valve that has only two switching states, open and closed, but due to its design cannot remain in intermediate states. In this respect, it differs from proportional valves, which due to their design can remain in intermediate states if they are electrically controlled accordingly. Proportional valves are therefore in particular not shut-off valves within the meaning of the invention.

[0015] Furthermore, the pressure reducing unit can have a flow limiting valve downstream of the inlet nozzle and upstream of the mechanical pressure reducing device. Such a valve is characterized here and throughout the application by the fact that it remains open as long as the amount of gas flowing through it is less than a certain limit. If this flow continues to increase, it closes or subsequently prevents a further increase in the flow rate.

[0016] The electrically controllable pressure reducing device may be or comprise an electrically controllable proportional valve; alternatively, the electrically controllable pressure reducing device may also comprise two electrically controllable proportional valves connected in parallel to one another, or may consist of two electrically controllable proportional valves connected in parallel to one another.

[0017] This electrically controllable pressure reducing device can be integrated together with a shut-off valve in or on a common pressure regulator housing in which a fluid channel extends from an inlet nozzle to an outlet nozzle, to form a pressure regulator unit.

[0018] Such a unit is easy to handle and can be integrated into a more comprehensive system simply by mechanical fixation and fluidic connection via the nozzles.

[0019] The pressure regulator housing can be separated from the pressure reducer housing mentioned above. A fluid line, for example, is then located fluidically between the outlet port of the pressure reducer unit and the inlet port of the pressure regulator unit, which is, for example, detachably connected to the outlet port of the pressure reducer unit and / or the inlet port of the pressure regulator unit; and / or at least one further component of the hydrogen supply system is located there, which is, for example, detachably connected to the outlet port of the pressure reducer unit and / or the inlet port of the pressure regulator unit.

[0020] On the other hand, it can also be provided that the mechanical pressure reducing device and the electrically controllable pressure reducing device are integrated into a complete unit in or on a common overall housing in which a fluid channel extends from an inlet nozzle to an outlet nozzle.

[0021] The overall unit therefore simultaneously represents a pressure reducing unit and a pressure regulator unit in the sense of the preceding statements and has only a single overall housing in which a fluid channel extends from an inlet nozzle to an outlet nozzle, without any further connection points, such as nozzles or the like, being provided between the inlet nozzle and the outlet nozzle.

[0022] Such a complete unit, which can also be referred to as a “single-housing solution,” has the advantage of being easy to handle and can be integrated into a more comprehensive system simply by mechanical fixing and fluidic connection via the nozzles.

[0023] In this case, a pressure relief valve can be arranged in the medium-pressure region, i.e., downstream of the mechanical pressure reducing device and upstream of the electrically controlled pressure reducing device, to protect the medium-pressure region from excessively high gas pressure. This pressure relief valve can be designed as a check valve that opens from the medium-pressure region toward the environment of the hydrogen supply system when the difference between the pressure in the medium-pressure region and the pressure in the environment of the hydrogen supply system exceeds a limit value.

[0024] A pressure sensor can also be provided in the medium-pressure range, for example, upstream of the pressure relief valve. Optionally, a flow-limiting valve can be provided in the high-pressure range. It can either be integrated into the overall unit or located upstream of the overall unit.

[0025] Even within the overall unit, the electrically controllable pressure reducing device can be or comprise an electrically controllable proportional valve; or comprise two electrically controllable proportional valves connected in parallel to one another or consist of two electrically controllable proportional valves connected in parallel to one another.

[0026] A shut-off valve can be integrated into the overall unit. It can preferably be located in the low-pressure area, i.e., downstream of the electrically controlled pressure reducing device.

[0027] Alternatively, the shut-off valve can also be located in the medium-pressure range within the overall unit, preferably downstream of a pressure relief valve that limits the pressure in the medium-pressure range to the medium pressure. In this case, the shut-off valve can be designed with the principle that the occurrence of a pressure greater than the medium pressure is reliably excluded, even if a leak occurs at the mechanical pressure reducer in the closed position. The shut-off valve can then be structurally simplified.

[0028] The hydrogen supply system can comprise a hydrogen tank, with the high-pressure region extending fluidically from the hydrogen tank to the mechanical pressure reducing device without the interposition of a shut-off valve. The shut-off function can be implemented particularly in the medium-pressure region, particularly downstream of a pressure relief valve. The shut-off valve can be designed in a significantly simpler manner there, since it only needs to shut off medium pressure, not high pressure.

[0029] The hydrogen supply system may further comprise a fuel distributor and at least one injector fluidly connected thereto in the low-pressure region. Exemplary embodiments of the invention are explained below with reference to the drawing. The drawing shows:

[0030] Figure 1 shows a first embodiment of the invention,

[0031] Figure 2 shows a second embodiment of the invention,

[0032] Figure 3 shows a third embodiment of the invention,

[0033] Figure 4 shows a fourth embodiment of the invention,

[0034] Fig. 5 to 9 further embodiments of the invention,

[0035] Figure 10 shows a fifth embodiment of the invention,

[0036] Figure 11 shows a sixth embodiment of the invention,

[0037] Figure 12 shows an alternative to the sixth embodiment and

[0038] Fig. 13 and 14 potential modifications.

[0039] Figure 1 shows a first embodiment of the invention. A hydrogen supply system 10 for an internal combustion engine comprises a hydrogen tank 12 in which hydrogen is stored under high pressure (e.g., 700 bar) and which is detachably connected via a high-pressure line 13 to a pressure reducer unit 14 via its inlet connection 141.

[0040] The pressure reducer unit 14 further comprises a mechanical pressure reducing device 15 for reducing the high pressure to a medium pressure, for example, to 40 bar. The first pressure reducer unit 14 is detachably connected downstream via its outlet connection 142 to a medium-pressure line 20 (shown only symbolically in Figure 1), which in turn is detachably connected downstream to the inlet connection 211 of a pressure regulator unit 21. Of course, the medium-pressure line 20 can also comprise other components of the hydrogen supply system not shown here.

[0041] The pressure regulator unit 21 has an electrically controllable

[0042] Pressure reducing device 23, which in the example is designed as a proportional valve, serves to dynamically reduce the intermediate pressure to a low pressure.

[0043] Via its outlet connection 212, the pressure regulator unit 21 is detachably connected to a low-pressure line 25, which is further connected to a fuel distributor 26, which supplies hydrogen to a plurality of injectors 27 fluidly connected to it.

[0044] According to the first exemplary embodiment (Figure 1), the pressure reducer unit 14 and the pressure regulator unit 21 are implemented as two separate units, each having its own housing ("two-housing solution"), namely a pressure reducer housing 14' and a pressure regulator housing 21', each of which can be manufactured in one piece, for example, from aluminum or steel, for example by machining. Within these housings 14', 21', a fluid channel 14", 21" extends from nozzles 141, 211 to nozzles 142, 212.

[0045] The hydrogen supply system 10 is divided accordingly into a high-pressure region A, which extends upstream of the mechanical pressure reducing device 15, a low-pressure region C, which extends downstream of the electrically controllable pressure reducing device 23, and a medium-pressure region B, which extends fluidly between the high-pressure region A and the low-pressure region C.

[0046] Figure 2 shows a second embodiment of the invention. A hydrogen supply system 10 for an internal combustion engine comprises a hydrogen tank 12 in which hydrogen is stored under high pressure (e.g., 700 bar) and which is detachably connected via a high-pressure line 13 to an overall unit 30 via its inlet connection 301. On the opposite side, the overall unit 30 is detachably connected via its outlet connection 302 to a low-pressure line 25, which is further connected to a fuel distributor 26 that supplies hydrogen to a plurality of injectors 27 fluidly connected to it.

[0047] The overall unit 30 comprises a one-piece housing 30', which is machined from aluminum or steel, for example. Inside the housing 30' of the overall unit 30, a fluid channel 30" extends from the high-pressure area A through the medium-pressure area B to the low-pressure area C, from nozzle 301 to nozzle 302.

[0048] In the fluid channel 30', in the order of the flow direction, a mechanical pressure reducing device 15 for reducing the high pressure to a medium pressure, for example to 40 bar, and an electrically controllable pressure reducing device 23 for dynamically variable reduction of the medium pressure to a low pressure, for example 15 bar to 35 bar, are provided.

[0049] The electrically controllable pressure reducing device 23 is designed as a proportional valve in the example.

[0050] According to the second embodiment (Figure 2), an overall unit 30 is realized as a single unit which reduces a pressure of the hydrogen in two stages from high pressure via medium pressure to low pressure and has a single housing (“single-housing solution”).

[0051] The hydrogen supply system 10 is divided accordingly into a high-pressure region A, which extends upstream of the mechanical pressure reducing device 15, a low-pressure region C, which extends downstream of the electrically controllable pressure reducing device 23, and a medium-pressure region B, which extends fluidly between the high-pressure region A and the low-pressure region C.

[0052] The third exemplary embodiment (Figure 3) differs from the first exemplary embodiment in that the pressure reducer unit 14 is further developed by a pressure relief valve 17 branching off from the fluid channel 14" of the pressure reducer unit 14 downstream of the mechanical pressure reducing device 15. The pressure relief valve 17 is designed as a check valve and opens from the medium-pressure region B toward the environment of the hydrogen supply system 10 when the difference between the pressure in the medium-pressure region B and the pressure in the environment of the hydrogen supply system 10 exceeds a limit value. The excess hydrogen is then discharged, for example, through a discharge opening 18 of the pressure reducer unit 14.

[0053] Optionally, within the third exemplary embodiment, a pressure sensor 19 can be included in the pressure reducer unit 14, which measures the pressure, for example, in the area between the mechanical pressure reducer 15 and the pressure relief valve 17. Alternatively, the pressure sensor 19 included in the pressure reducer unit 14 can also be fluidically arranged between the pressure relief valve 17 and the outlet connection 142 of the pressure reducer unit 14, as shown in Figure 3.

[0054] In addition, the pressure reducer unit 14 can include a particle filter 16, for example fluidically between the inlet nozzle 141 of the pressure reducer unit 14 and the mechanical pressure reducer 15 of the pressure reducer unit 14. Alternatively, the particle filter 16 can be omitted in this example.

[0055] A fourth embodiment (Figure 4) emerges from the third embodiment in that a shut-off valve 22 is provided between the inlet connection 141 of the pressure reducer unit 14 and the mechanical pressure reducer 15 of the pressure reducer unit 14 and a flow limiting valve 24 is provided downstream of the shut-off valve 22.

[0056] In an alternative of the fourth embodiment, the shut-off valve 22 can also be arranged downstream of the flow limiting valve 24 between the inlet nozzle 141 of the pressure reducer unit 14 and the mechanical pressure reducer 15 of the pressure reducer unit 14.

[0057] In two further alternatives of the fourth embodiment, one of the two components, shut-off valve 22 and flow limiting valve 24, can also be omitted within the pressure reducing unit 14.

[0058] Further embodiments, to which no specific ordinal numbers are assigned here, emerge from the first, third and fourth embodiments (including the alternatives given above) in that the pressure regulator unit 21 is modified compared to the pressure regulator unit 21 shown in Figure 1 as explained below with reference to Figures 5 to 9.

[0059] Figure 5 shows a pressure regulator unit 21 which differs from the one shown in Figure 1

[0060] Pressure regulator unit 21 differs in that within the

[0061] Pressure regulator unit 21, a shut-off valve 22 is fluidly arranged between the inlet nozzle 211 of the pressure regulator unit 21 and the electrically controllable pressure reducing device 23 of the pressure regulator unit 21.

[0062] Figure 6 shows a pressure regulator unit 21 which differs from the pressure regulator unit 21 shown in Figure 1 in that a shut-off valve 22 is arranged fluidically within the pressure regulator unit 21 between the pressure reducing device 23 of the pressure regulator unit 21 and the outlet nozzle 212 of the pressure regulator unit 21.

[0063] Both the pressure regulator unit 21 shown in Figure 5 and the pressure regulator unit 21 shown in Figure 6 can be modified by fluidically arranging a pressure sensor 19 between the electrically controllable pressure reducing device 23 and the shut-off valve 22, see Figures 7 and 8.

[0064] As shown in Figures 5 to 8, the electrically controllable pressure reducing device 23 can, for example, have a proportional valve or be a proportional valve.

[0065] However, as alternatives to all the previously shown embodiments, it is always possible for the electrically controllable pressure reducing device 23 to have two proportional valves or to consist of two proportional valves connected in parallel to one another, see Figure 9.

[0066] The fifth embodiment (Figure 10) is derived from the second embodiment (Figure 2) in that a pressure sensor 19 and a pressure relief valve 17 are arranged fluidically between the mechanical pressure reducer 15 and the electrically controllable pressure reducing device 23.

[0067] A sixth embodiment (Figure 11) emerges from the fifth embodiment (Figure 10) in that a shut-off valve 22 is provided between the electrically controllable pressure reducing device 23 and the outlet connection 302 of the overall unit 30.

[0068] In an alternative (Figure 12), the position of the shut-off valve 22 and the position of the electrically controllable pressure reducing device 23 are reversed. In all the illustrated forms with complete boxes 30, it is also always possible to fluidically provide a flow limiting valve 24 between the inlet connection 301 of the complete unit 30 and the mechanical pressure reducer 15 of the complete unit 30, as shown in Figure 13 as an example modification of the alternative of the sixth embodiment (Figure 12).

[0069] Alternatively, such a flow limiting valve 24 can always also be arranged upstream of the overall unit 30, for example fluidically between a hydrogen tank of the hydrogen supply system 10 and an inlet nozzle 301 of the overall unit 30, as shown in Figure 14 by way of example as a modification of the alternative of the sixth exemplary embodiment (Figure 12).

[0070] In alternatives to all embodiments shown with reference to Figures 10 to 14, it is possible for the electrically controllable pressure reducing device 23 to have not only one proportional valve, but two proportional valves or to consist of two proportional valves connected in parallel to one another, see Figure 9.

Claims

Claims 1. Hydrogen supply system (10) for an internal combustion engine with an inlet-side high-pressure region (A), with an outlet-side low-pressure region (C) and a medium-pressure region (B) fluidly arranged between the high-pressure region (A) and the low-pressure region (C), wherein 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 controllable pressure reducing device (23) is provided for reducing the medium pressure in the medium-pressure region (B) to a low pressure in the low-pressure region (C).

2. Hydrogen supply system according to claim 1, wherein a pressure relief valve (17) is arranged in the medium pressure region (B).

3. Hydrogen supply system according to one of claims 1 or 2, wherein a pressure sensor (19) is arranged in the medium pressure region (B).

4. Hydrogen supply system according to claim 2 and 3, wherein the pressure sensor (19) is arranged upstream of the pressure relief valve (17).

5. Hydrogen supply system according to claim 2 and 3 or according to claim 4, wherein at least the mechanical pressure reducing device (15), the pressure sensor (19) and the pressure relief valve (17) are integrated into or on a common pressure reducer housing (14'), in which a fluid channel (14") extends from an inlet nozzle (141) to an outlet nozzle (142), to form a pressure reducer unit (14).

6. Hydrogen supply system according to claim 5, wherein the pressure reducer unit (14) has a shut-off valve (22) downstream of the inlet nozzle (141) and upstream of the mechanical pressure reducing device (15).

7. Hydrogen supply system according to one of claims 5 or 6, wherein the pressure reducer unit (14) has a flow limiting valve (24) downstream of the inlet nozzle (141) and upstream of the mechanical pressure reducing device (15).

8. Hydrogen supply system according to one of claims 1 to 7, wherein the electrically controllable pressure reducing device (23) is or comprises an electrically controllable proportional valve.

9. Hydrogen supply system according to one of claims 1 to 7, wherein the electrically controllable pressure reducing device (23) comprises two electrically controllable proportional valves connected in parallel to one another, or consists of two electrically controllable proportional valves connected in parallel to one another.

10. Hydrogen supply system according to one of claims 1 to 9, wherein the electrically controllable pressure reducing device (23) together with a shut-off valve (22) in or on a common pressure regulator housing (2T), in which a fluid channel (21") extends from an inlet nozzle (211) to an outlet nozzle (212), are integrated to form a pressure regulator unit (21).

11. Hydrogen supply system according to claim 1, wherein the mechanical pressure reducing device (15) and the electrically controllable pressure reducing device (23) are integrated into a complete unit (30) in or on a common overall housing (30'), in which a fluid channel (30") extends from an inlet nozzle (301) to an outlet nozzle (302).

12. Hydrogen supply system according to claim 11, wherein a pressure relief valve (17) is arranged downstream of the mechanical pressure reducing device (15) and upstream of the electrically controllable pressure reducing device (23).

13. Hydrogen supply system according to claim 11 or 12, wherein downstream of the mechanical pressure reducing device (15) and upstream of the electrically controllable pressure reducing device (23) a Pressure sensor (19) is arranged.

14. Hydrogen supply system according to claim 12 and 13, wherein the pressure sensor (19) is arranged upstream of the pressure relief valve (17).

15. Hydrogen supply system according to one of claims 11 to 14, wherein in the high-pressure region (A), a flow limiting valve (24) is provided, which is integrated into the overall unit (30) or is provided upstream of the overall unit (30).

16. Hydrogen supply system according to one of claims 11 to 15, wherein the electrically controllable pressure reducing device (23) is or comprises an electrically controllable proportional valve; or wherein the electrically controllable pressure reducing device (23) comprises two electrically controllable proportional valves connected in parallel to one another, or consists of two electrically controllable proportional valves connected in parallel to one another.

17. Hydrogen supply system according to one of claims 11 to 16, wherein a shut-off valve (22) is integrated into the overall unit (30) and is arranged in the low-pressure region (C).

18. Hydrogen supply system according to one of claims 11 to 16, wherein a shut-off valve (22) is integrated into the overall unit (30) and is arranged in the medium-pressure region (B).

19. Hydrogen supply system according to claim 14 and at the same time according to claim 18, wherein the shut-off valve (22) is arranged downstream of the electrically controllable pressure reducing device (23).

20. Hydrogen supply system according to one of the preceding claims, further comprising a hydrogen tank (12), wherein the high-pressure region (A) extends fluidically from the hydrogen tank (12) to the mechanical pressure reducing device (15) without the interposition of a shut-off valve (22).

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

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