Pressure-control unit for a hydrogen supply system of an internal combustion engine, and hydrogen supply system

Abstract

A pressure control unit (30) for a hydrogen supply system (10) for controlling the pressure of gaseous hydrogen from a high-pressure tank (12) and feeding same to a consumer (42), the pressure control unit comprising a housing (52), an inlet port (54) and an outlet port (56), a fluid duct (58) which extends through the housing (52) from the inlet port (54) to the outlet port (56), and at least one valve (32, 36), by which a throughflow of the hydrogen through the fluid duct (58) can be restricted or shut off, wherein: the valve (32, 36) has a valve body (101) which fixes a valve seat (102) and in which a valve element (103) is received movably; the valve body (101) has a first portion which is arranged in a bore (104), connected fluidically to the fluid duct (58), of the housing (52); the valve body (101) has a second portion which is arranged outside of the bore (104), connected fluidically to the fluid duct (58), of the housing (52); a first sealing point (111) is provided between the bore (104) and the first portion and comprises a first O-ring (121), and a second sealing point (112) is provided which comprises a second O-ring (122); and a third sealing point (113) is provided between the housing (52) and the second portion and comprises a third O-ring (123).

Description

[0001] Description

[0002] title

[0003] Pressure control unit for a hydrogen supply system of an internal combustion engine, as well as hydrogen supply system

[0004] State of the art

[0005] The invention relates to a pressure control unit for a hydrogen supply system of an internal combustion engine for supplying and controlling the pressure of hydrogen.

[0006] From the subsequently published DE 102022 213 374 A1 of the applicant, a pressure control unit for a fuel supply system of an internal combustion engine for controlling the pressure of a gaseous fuel is already known, which has a housing with an opening in which a pressure control valve is accommodated.

[0007] Disclosure of the invention

[0008] The present invention is based on the objective of providing an effective seal between the valve and the housing in a pressure control unit for a hydrogen supply system for pressure control and supply of gaseous hydrogen from a high-pressure tank to a consumer, which comprises a housing and an inlet nozzle and an outlet nozzle and a fluid channel extending from the inlet nozzle to the outlet nozzle through the housing, and at least one valve by means of which a flow of hydrogen through the fluid channel can be throttled or blocked, wherein the valve has a valve body which fixes a valve seat and in which a valve element is movably received,which, on the one hand, prevents a shunt of hydrogen within the housing parallel to the valve and, in addition, reliably prevents the escape of hydrogen from the housing in the area of ​​the valve over the entire service life of the pressure control unit.

[0009] According to the invention, this object is achieved in that the valve body comprises a first section which is arranged in a bore of the housing which is fluidically connected to the fluid channel, and a second section which is arranged outside the bore of the housing which is fluidically connected to the fluid channel, wherein a first sealing point is provided between the bore and the first section, which comprises a first sealing ring, and a second sealing point is provided which comprises a second sealing ring, and wherein a third sealing point is provided between the housing and the second section, which has a third sealing ring.

[0010] While the first sealing point and the second sealing point can in principle already prevent a bypass of hydrogen within the housing parallel to the valve and a leakage of hydrogen from the housing in the area of ​​the valve, long-term tests by the applicant, which also simulate adverse environmental conditions, for example salt spray tests, have shown that the mere provision of the first and second sealing points may not yet be able to ensure sufficiently long-lasting function.

[0011] Only by providing the third sealing point according to the invention, which has a third sealing ring, between the housing and the second section of the valve body, i.e. outside the bore, is sufficiently durable function ensured under all circumstances.

[0012] By locating the third sealing point or third sealing ring outside the bore between the housing and the second section of the valve body, it shields the area within the bore where the first and second sealing points, or the first and second sealing rings, are located from potentially adverse environmental influences, thus increasing their longevity. The third sealing point or third sealing ring can therefore also be referred to as an "environmental seal."

[0013] The inlet nozzle provided according to the invention and the outlet nozzle provided according to the invention can, for example, be mounted directly on the housing or on a component which in turn is fixed directly or indirectly to the housing.

[0014] The fluid channel provided according to the invention, which extends from the inlet nozzle to the outlet nozzle through the housing, can, for example, be straight or angled, i.e. with deflection points.

[0015] The valve provided according to the invention, by which a flow of hydrogen through the fluid channel can be throttled or blocked, can be a shut-off valve, for example a switching valve, or a pressure control valve, for example a proportional valve. Alternatively, the pressure control unit can also comprise a pressure control valve and a shut-off valve, or two pressure control valves, which are connected in parallel, for example, and additionally comprise a shut-off valve. All of these valves, or only a subset of these valves, can have the properties, in particular the bores, sealing points, and sealing rings, which are explained here only with reference to the component referred to as "the valve."

[0016] The invention further provides that the valve has a valve body that fixes a valve seat. The valve seat can thus be part of the valve body or rigidly connected to the valve body. The invention further provides that a valve element is movably accommodated in the valve body. For example, the valve element can be acted upon by an elastic spring and / or can experience forces in the opening and / or closing direction from an electromagnet enclosed by the valve, resulting in corresponding movements of the valve element.

[0017] The housing can be detachably connected to the valve, for example by means of a screw connection which, for example, fixes a flange encompassed by the valve to the outside of the housing, or with an internal thread machined into the bore into which an external thread provided on the first section of the valve body engages.

[0018] Of course, a permanent connection between the housing and the valve is also possible.

[0019] The first sealing point seals, in particular, between the valve body and the fluid channel in such a way that a bypass around the valve within the fluid channel is reliably prevented. For this purpose, the first sealing point can be provided in the fluid channel. The first sealing ring can be designed, for example, as an O-ring, i.e., it can have a circular cross-section in the absence of a compressive force acting on it.

[0020] The second sealing point contributes in particular to sealing the bore and the fluid channel to the outside so that the hydrogen passed through the pressure control unit cannot escape from the hydrogen supply system. For this purpose, the second sealing point can be provided in particular in the area of ​​the bore outlet, i.e. at the location on the outer surface of the housing where a twist drill would have first machined the housing during the imagined production of the bore. The bore starts from there - this is the area of ​​its outlet. The second sealing ring can, for example, be designed as an O-ring, i.e. have a circular cross-section in the absence of a pressing force acting on it.

[0021] The third sealing point also contributes to sealing the bore and fluid channel from the outside and also shields the second sealing point from adverse environmental influences, which also ensures that the hydrogen passing through the pressure control unit cannot escape from the hydrogen supply system. The third sealing ring can also be an O-ring. Alternatively, it can also be a rectangular sealing ring or a flat gasket.

[0022] The cascaded arrangement of the three sealing points simplifies valve assembly if the diameter of the first sealing ring is smaller than the diameter of the second sealing ring and the diameter of the second sealing ring is smaller than the diameter of the third sealing ring. When assembling the valve to the pressure control unit housing, the first section of the valve body can then, for example, first be inserted over the second sealing point and then over the first sealing point into the bore of the pressure control unit housing, before the second section of the valve body comes into contact with the outside of the pressure control unit housing, thus forming the third sealing point.

[0023] To facilitate the insertion of the valve body into the bore, the bore can, for example, have a chamfer in its exit area.

[0024] The housing and valve body can be made of steel, for example, stainless steel. However, the housing can also be made of aluminum and only the valve body made of steel. In this case, the weight of the housing and the machining effort are reduced.

[0025] The aluminum / steel material combination does potentially lead to a tendency for corrosion, especially upon contact with salt water. However, in the context of the present invention, this is counteracted by the provision of an environmental seal, particularly if at least all areas of the valve body where aluminum / steel metal contact occurs are sealed from the environment by the third sealing ring.

[0026] In addition, it may be provided to provide at least these areas, or the area in which the environmental seal rests against the valve body, and / or the areas of the valve body made of steel, with a corrosion-reducing layer, e.g. with a ZnNi layer.

[0027] It can be provided that the third sealing point is located radially outside the bore.

[0028] For this purpose, the housing can further be provided with a collar at the outlet of the bore, extending in the direction of the bore and surrounding the bore, and the third sealing ring can be arranged radially on the outside of this collar. The third sealing ring can then be pre-assembled on the housing before the valve is mounted to the housing. If the third sealing ring protrudes in the direction of the bore before the valve is installed, its defined compression is achieved by the valve coming into contact with the collar of the housing during assembly, and the third sealing ring is compressed accordingly.

[0029] Basically, regardless of whether the housing has a further collar pointing in the direction of the bore at the outlet of the bore, which together with the collar forms a groove in which the third sealing ring is arranged, or whether the third sealing ring is exposed on its radial outer side, the third sealing ring then protects the area in which the valve rests against the collar of the housing from environmental influences.

[0030] While the provision of the additional collar (or a resulting groove in which the third sealing ring is then arranged) can mechanically protect the third sealing ring, its omission has the advantage of saving material and avoiding an exposed contact surface between the housing and the valve body and a possible associated tendency to corrosion, see above.

[0031] The invention also relates to a hydrogen supply system with such a pressure control unit. A high-pressure tank can be provided upstream of the pressure control unit, and a consumer, for example, a fuel distribution device with one or more injectors, can be provided downstream of the pressure control unit.

[0032] Embodiments of the present invention are explained below with reference to the drawings, in which:

[0033] Figure 1 is a schematic representation of a fuel supply system for supplying an internal combustion engine with gaseous fuel, comprising a pressure control unit with two pressure control valves; Figure 2 is a schematic perspective representation of the pressure control unit of Figure 1;

[0034] Figure 3 shows a detail of the areas of the pressure control unit from Figure 2 in which valves are connected to the housing according to the invention;

[0035] Figure 4 shows an alternative embodiment.

[0036] A fuel supply system is designated overall by reference numeral 10 in Figure 1. It serves to supply an internal combustion engine (not shown) with a gaseous fuel, in this case, for example, with gaseous hydrogen.

[0037] The hydrogen is stored under high pressure, for example, below 700 bar, in a tank-like fuel storage unit 12. This can be filled via a filling connection 14. Furthermore, an integrated unit 16 consisting of a tank valve for filling and discharging hydrogen into and from the fuel storage unit 12 and a temperature sensor for detecting the temperature of the hydrogen coming from the fuel storage unit 12 is arranged on the fuel storage unit 12.

[0038] The hydrogen first flows via a pressure line 18 to a filter 20 and from there to a high-pressure pressure regulator 22. This reduces the pressure of the gaseous hydrogen to, for example, a pressure in the range of 40 bar. The pressure line 18 leads from the high-pressure pressure regulator 22 to a pressure sensor 24, another filter 26, and an optional temperature control device 28, finally to a low-pressure pressure regulator unit 30 (short: "pressure regulator unit").

[0039] The low-pressure pressure control unit 30 comprises, in this example, two hydraulically parallel pressure control valves 32, a low-pressure pressure sensor 34, and a safety valve in the form of a shut-off valve device 36. The two pressure control valves 32 are identically constructed and, in this case, are proportional control valves. The low-pressure pressure control unit 30 further reduces the pressure in the pressure line 18 from the inlet-side pressure of approximately 40 bar, in this example, to a pressure of approximately 15 bar, for example.

[0040] Downstream of the low-pressure pressure control unit 30, the pressure line 18 leads to a fuel distribution device 38, which can be designed, for example, as an elongated tube similar to a typical fuel rail, as is known from gasoline and diesel fuel systems. The gas pressure prevailing in the fuel distribution device 38 is detected by a pressure sensor 40.

[0041] Connected to the fuel distribution device 38 are several injectors 42, which inject the gaseous hydrogen directly into combustion chambers 44 of the internal combustion engine, as an example here. The gaseous hydrogen is mixed with atmospheric oxygen in the combustion chambers 44, and this mixture is ignited by a respective ignition device 46. Typically, the internal combustion engine is a 2-stroke or 4-stroke piston internal combustion engine of a largely conventional design. For example, such an internal combustion engine is used to power a motor vehicle. However, it can also be used stationary, for example, to drive a generator for power generation.

[0042] The fuel supply system 10 and its components are controlled by an electronic control and regulating device 48, which has one or more corresponding microprocessors, a memory for program code, etc. The control and regulating device 48 receives signals from, among others, the temperature sensor (installed in the integrated unit 16), the pressure sensor 24, the pressure sensor 34, the pressure sensor 40, etc. The control and regulating device 48 controls various components of the fuel supply system 10, including the low-pressure pressure regulating device 30, the safety valve 36, and the ignition devices 46. Furthermore, a control device 50 is also controlled by the control and regulating device 48, which in turn specifically controls or regulates the operation of the fuel storage device 12. The low-pressure pressure regulating unit 30 is shown in greater detail in Figure 2.It comprises a block-like housing 52 with an inlet-side connection piece 54 and an outlet-side connection piece 56. The two pressure control valves 32 are arranged, in the illustrated installation position, with their longitudinal direction essentially vertical. Hydraulically, the two pressure control valves 32 are connected in parallel. The outlet-side connection 56 leads to the fuel distribution device 38. It can be seen that in the exemplary embodiment shown here, the low-pressure pressure control unit 30 forms an integrated unit that includes the two pressure control valves 32, the shut-off valve device 36, and the pressure sensor 34. This integrated unit is also referred to as a HIPR (Hydrogen Injection Pressure Regulator).

[0043] The housing 52 is made of steel or aluminum. The two pressure control valves 32 are fluid-tightly connected to the housing 52 of the pressure control unit 30, as will be shown below.

[0044] Figure 3 shows in more detail the connection of a valve (namely one of the two pressure control valves 32 from Figure 2 or the shut-off valve device 36 from Figure 2 or all of these valves) to the housing 52 of the pressure control unit 30.

[0045] Accordingly, the valve 32, 36 is provided with a valve body 101 that fixes a valve seat body 102K and in which a valve element 103 is movably received. The valve seat body 102K has an axially central passage 106, and a valve seat 102 is formed thereon.

[0046] In the valve body 101, the valve element 103 is displaceable between a lower position in Figure 3, in which the valve element 103 rests against the valve seat 102 of the valve seat body 102K and thus closes the passage 106, and an upper position in Figure 3, in which the valve 32, 36 is open

[0047] The valve body 101 is arranged in a bore 104 of the housing 52 which is fluidically connected to the fluid channel 58 and which, in Figure 3, extends vertically into the housing 52, starting from the outer surface 52E of the housing 52.

[0048] Between the bore 104 and the valve body 101 there is a first sealing point

[0049] 111 is provided, which comprises a first O-ring 121. This sealing point 111 is located in a part of the fluid channel 58 that runs vertically in Figure 3 and ensures that there is no shunt to the valve 32, 36 within the fluid channel 58.

[0050] Between the bore 104 and the valve body 101 there is a second sealing point

[0051] 112 is provided, which includes a second O-ring 122. This sealing point 112 is located in Figure 3 above the fluid channel 58 at the outlet 104A of the bore 104 and seals the fluid channel 58 against the exterior 100 of the pressure control unit 30.

[0052] The valve body 101 is widened by an annular shoulder 101 R pointing towards the housing 52, wherein an electromagnet 105, which is encompassed by the valve 32, 36, is located, viewed in the longitudinal direction, only at the level of the widened part of the valve body 101 of the valve 32, 36.

[0053] The pressure control unit 30 has a third sealing point 113, which is provided radially outside the bore 104. The third sealing point 113 has a third sealing ring 123, which can be an O-ring.

[0054] The third sealing ring 123 is provided radially outside the bore 104 by being arranged radially on the outside of a collar 130 surrounding the bore 104. On its radial outer side, the third sealing ring 123 is exposed and is thus exposed to the environmental conditions prevailing in the exterior 100.

[0055] In an alternative, which is shown in Figure 4, the housing 52 has at the outlet 104A of the bore 104 a further collar 131 pointing in the bore direction, which together with the collar 130 forms a groove 132 in which the third sealing ring 123 is arranged.

Claims

Claims 1. A pressure control unit (30) for a hydrogen supply system (10) for pressure control and supply of gaseous hydrogen from a high-pressure tank (12) to a consumer (42), comprising a housing (52), an inlet nozzle (54) and an outlet nozzle (56), a fluid channel (58) extending from the inlet nozzle (54) to the outlet nozzle (56) through the housing (52), and at least one valve (32, 36) through which a flow of hydrogen through the fluid channel (58) can be throttled or blocked, wherein the valve (32, 36) has a valve body (101) which fixes a valve seat (102) and in which a valve element (103) is movably received, wherein the valve body (101) comprises a first section (101A) which is arranged in a bore (104) of the housing (52) which is fluidically connected to the fluid channel (58), wherein the valve body (101) comprises a second portion (101B),which is arranged outside the bore (104) of the housing (52) which is fluidically connected to the fluid channel (58), and wherein a first sealing point (111) comprising a first sealing ring (121) and a second sealing point (112) comprising a second sealing ring (122) are provided between the bore (104) and the first section, and wherein a third sealing point (113) comprising a third sealing ring (123) is provided between the housing (52) and the second section.

2. Pressure control unit (30) according to claim 1, wherein the valve (32, 36) is a shut-off valve or a proportional valve.

3. Pressure control unit (30) according to claim 1 or 2, wherein the second sealing point (112) is provided in the region of the outlet (104A) of the bore (104).

4. Pressure control unit (30) according to claim 1, 2 or 3, wherein the first sealing point (111) is provided in the fluid channel (58).

5. Pressure control unit (30) according to one of the preceding claims, wherein the third sealing point (113) is provided radially outside the bore (104).

6. Pressure control unit (30) according to claim 5, wherein the housing (52) has a collar (130) at the outlet of the bore (104) pointing in the bore direction and encircling the bore (104), and the third sealing ring (123) is arranged radially outwardly on this collar (130).

7. Pressure control unit (30) according to claim 6, wherein the housing (52) has at the outlet of the bore (104) a further collar (131) pointing in the direction of the bore, which together with the collar (130) forms a groove (132) in which the third sealing ring (123) is arranged.

8. Pressure control unit (30) according to claim 6, wherein the third sealing ring (123) is exposed on its radial outer side.

9. Pressure control unit (30) according to one of the preceding claims, wherein a diameter of the first sealing ring (121) is smaller than a diameter of the second sealing ring (122) and the diameter of the second sealing ring (122) is smaller than a diameter of the third sealing ring (123).

10. Pressure control unit (30) according to one of the preceding claims, wherein the first sealing ring (121) is an O-ring and the second sealing ring (122) is also an O-ring, while the third sealing ring (123) is an O-ring or a rectangular sealing ring or a flat seal.

11. Pressure control unit (30) according to one of the preceding claims, wherein the third sealing ring (123) consists of a solid material or a foamed material.

12. Pressure control unit (30) according to one of the preceding claims, wherein the bore (104) has a chamfer (104F) in its outlet region (104A).

13. Pressure control unit (30) according to one of the preceding claims, wherein the housing (52) is made of aluminum and the valve body (101) is made of steel.

14. Pressure control unit (30) according to one of the preceding claims, wherein the valve body (101) widens over an annular shoulder (101 R) pointing towards the housing (52), wherein the valve (32, 36) comprises an electromagnet (105) which, viewed in the longitudinal direction, is formed only at the level of the widened part of the valve body (101).

15. Hydrogen supply system (10) with a pressure control unit (30) according to one of the preceding claims, wherein a high-pressure tank (12) is provided upstream of the pressure control unit (30) and a consumer, for example a fuel distribution device (38) with one or more injectors (42), is provided downstream of the pressure control unit (30).

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