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

Abstract

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) by means of 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 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) includes a second section,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.

Description

Prior ArtThe invention relates to a pressure regulating unit for a hydrogen supply system of an internal combustion engine for supplying and regulating the pressure of hydrogen.From the post-published DE 10 2022 213 374 A1 of the applicant, a pressure regulating unit for a fuel supply system of an internal combustion engine for pressure regulating a gaseous fuel is already known, which has a housing with an opening in which a pressure regulating valve is accommodated.Disclosure of the InventionThe present invention starts from the object of providing, in a pressure regulating unit for a hydrogen supply system for pressure regulation and supply of gaseous hydrogen from a high-pressure tank to a consumer, which comprises a housing and an inlet connection and an outlet connection and a fluid channel which extends from the inlet connection to the outlet connection through the housing, and at least one valve by means of which a throughflow of the hydrogen through the fluid channel can be restricted or shut off, wherein the valve has a valve body which fixes a valve seat and in which a valve element is movably accommodated, an effective seal between the valve and the housing which, on the one hand, prevents a bypass of the hydrogen within the housing parallel to the valve and, moreover, also in the region of the valve, reliably prevents an outlet of hydrogen from the housing over the entire service life of the pressure regulating unit.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 comprises 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 which comprises a first sealing ring and a second sealing point which comprises a second sealing ring is provided between the bore and the first section, and wherein a third sealing point which comprises a third sealing ring is provided between the housing and the second section.While the first sealing point and the second sealing point can in principle already prevent a shunt of the hydrogen within the housing parallel to the valve and an escape of hydrogen from the housing in the region of the valve, long-term experiments by the applicant, which also simulate adverse environmental conditions, for example salt mist spray tests, have provided the realization that the merely provision of the first and the second sealing point may not yet be able to ensure a sufficiently permanent function.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, that is to say outside the bore, is the sufficiently permanent function ensured under all circumstances.By virtue of the third sealing point or the third sealing ring being arranged outside the bore between the housing and the second section of the valve body, it shields the region within the bore in which the first and the second sealing point or the first and the second sealing ring are arranged from potentially adverse environmental influences and thus increases the longevity thereof. The third sealing point or the third sealing ring can therefore also be referred to as an "environmental seal".The inlet connector provided according to the invention and the outlet connector provided according to the invention can be mounted, for example, directly on the housing or on a component which is in turn fixed directly or indirectly on the housing.The fluid channel provided according to the invention, which extends from the inlet connection to the outlet connection through the housing, can extend, for example, straight or angled, i.e. with deflection points.The valve provided according to the invention, by means of which a throughflow of the hydrogen through the fluid channel can be throttled or shut off, can be a shut-off valve, for example a switching valve, or a pressure regulating valve, for example a proportional valve. On the other hand, it can also be provided that the pressure regulating unit has a pressure regulating valve and a shut-off valve or has two pressure regulating valves which are connected, for example, in parallel with one another and additionally has a shut-off valve, wherein all these valves or only a portion of these valves can have the properties, in particular the bores, sealing points and sealing rings, which are explained in the present case only with reference to the component designated as "the valve".It is furthermore provided according to the invention that the valve has a valve body which fixes a valve seat. The valve seat can thus be part of the valve body or be rigidly connected to the valve body. It is furthermore provided according to the invention that a valve element is movably accommodated in the valve body. For example, the valve element can be loaded by an elastic spring and / or be subjected to forces in the opening and / or closing direction by an electromagnet comprised by the valve, so that corresponding movements of the valve element result.The housing can be detachably connected to the valve, for example by means of a screw connection which fixes a flange encompassed by the valve on the outside of the housing, for example, or with an internal thread worked into the bore, into which an external thread provided on the first section of the valve body engages.Of course, a non-detachable connection between the housing and the valve is also possible.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 is safely excluded within the fluid channel. 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., in the absence of a pressing force acting on it, it can have a circular cross section.The second sealing point contributes in particular to sealing off the bore and the fluid channel from the outside, so that the hydrogen passed through the pressure regulating unit cannot escape from the hydrogen supply system. For this purpose, the second sealing point can be provided in particular in the region of the exit of the bore, that is to say at the location on the outer surface of the housing where a twist drill would have first machined the housing during the imaginary production of the bore. From there the bore starts-there is the region of its exit. The second sealing ring can be designed, for example, as an O-ring, i.e., in the absence of a pressing force acting on it, it can have a circular cross section.The third sealing point also contributes to sealing the bore and the fluid channel from the outside and moreover effects to shield the second sealing point from adverse environmental influences, which also ensures that the hydrogen passed through the pressure regulating 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 seal.The cascaded arrangement of the three sealing points has the consequence that the assembly of the valve is simplified if it is provided that a diameter of the first sealing ring is smaller than a diameter of the second sealing ring and the diameter of the second sealing ring is smaller than a diameter of the third sealing ring. The first section of the valve body can then, during the assembly of the valve on the housing of the pressure regulating unit, be introduced, for example, first into the bore of the housing of the pressure regulating unit via the second sealing point and then into the bore of the housing of the pressure regulating unit via the first sealing point, before the second section of the valve body comes to bear on the outside of the housing of the pressure regulating unit and the third sealing point is thus formed.In order to facilitate the introduction of the valve body into the bore, the bore can have a chamfer, for example, in its outlet region.The housing and the valve body may be made of steel, for example stainless steel. However, it can also be provided that the housing is made of aluminum and only the valve body consists of steel. In this case, the weight of the housing and the effort involved in its machining are reduced.The aluminum / steel material combination potentially causes a tendency to corrosion, especially when in contact with salt water. However, in the context of the present invention, this is counteracted by the provision according to the invention of an environmental seal, in particular if at least all regions of the valve body in which a metal contact aluminum / steel occurs are sealed from the environment by the third sealing ring.In addition, it can be provided that at least these regions, or rather the region in which the environmental seal abuts the valve body and / or the regions of the valve body made of steel, are provided with a corrosion-reducing layer, for example a ZnNi layer.It can be provided that the third sealing point is provided radially outside the bore.For this purpose, it can furthermore be provided that the housing has a collar which points in the bore direction and which extends around the bore, and the third sealing ring is arranged radially on the outside of this collar. The third sealing ring can then already be pre-assembled on the housing before the valve is mounted on the housing.If the third sealing ring projects in the bore direction before the valve is mounted, its defined compression results from the valve coming to rest on the collar of the housing during its mounting and the third sealing ring being compressed accordingly.Fundamentally, regardless of whether the housing has a further collar pointing in the bore direction at the outlet of the bore, which collar 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 region in which the valve abuts against the collar of the housing from environmental influences.While provision of the further 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 possibly associated tendency to corrosion, see above.The invention also relates to a hydrogen supply system having a pressure regulating unit of this type. In this case, a high-pressure tank can be provided upstream of the pressure regulating unit and a consumer, for example a fuel distribution device having one or more injectors, can be provided downstream of the pressure regulating unit.Hereinafter, embodiments of the present invention will be explained with reference to the drawings. In these show: FIG. 1 shows a schematic illustration of a fuel supply system for supplying an internal combustion engine with gaseous fuel, having a pressure regulating unit having two pressure regulating valves; FIG. 2 shows a schematic perspective illustration of the pressure regulating unit from FIG. 1 ; FIG. 3 shows a detail of the regions of the pressure regulating unit from FIG. 2 in which valves are connected to the housing according to the invention; FIG. 4 shows an alternative embodiment.A fuel supply system in FIG. 1 overall has the reference numeral 10.The hydrogen is stored under high pressure, for example under 700 bar, in a tank-like fuel store 12. This can be filled via a filling connection 14. Furthermore, an integrated unit 16 comprising a tank valve for filling and discharging hydrogen into or from the fuel accumulator 12 and a temperature sensor for detecting the temperature of the hydrogen coming from the fuel accumulator 12 is arranged on the fuel accumulator 12.The hydrogen passes via a pressure line 18 first to a filter 20 and from there further to a high-pressure pressure pressure regulating device 22, which reduces the pressure of the gaseous hydrogen, for example, to a pressure in the range of 40 bar. The pressure line 18 leads from the high-pressure pressure regulating device 22 further to a pressure sensor 24, a further filter 26 and an optional temperature regulating device 28 finally to a low-pressure pressure regulating unit 30 ("pressure regulating unit" for short).The low-pressure pressure regulating unit 30 comprises in the present case, by way of example, two hydraulically parallel pressure regulating valves 32, a low-pressure pressure sensor 34 and a safety valve in the form of a shut-off valve device 36. The pressure in the pressure line 18 is once again lowered by the low-pressure pressure regulating unit 30 from the pressure, which is exemplary at the input side, of approximately 40 bar to a pressure, for example of approximately 15 bar.Downstream of the low pressure pressure regulating unit 30, the pressure line 18 leads to a fuel distribution device 38, which can be designed, for example, as an elongate tube in the manner of a typical fuel rail, as is known from petrol and diesel fuel systems. The gas pressure prevailing in the fuel distribution device 38 is detected by a pressure sensor 40.A plurality of injectors 42 are connected to the fuel distribution device 38 and, in the present case, directly blow the gaseous hydrogen into combustion chambers 44 of the internal combustion engine, for example. The gaseous hydrogen is mixed with atmospheric oxygen in the combustion chambers 44, and this mixture is ignited by a respective igniter 46. Typically, the internal combustion engine is a 2-stroke or 4-stroke piston internal combustion engine of a widely customary design. For example, such an internal combustion engine is used to drive a motor vehicle. However, it can also be used, for example, in a stationary manner for driving a generator for power generation.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 other things, 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, among other things, the low-pressure 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 accumulator 12.In FIG. 2, the low-pressure pressure control unit 30 is shown in greater detail. It comprises a block-like housing 52 with an inlet-side connection piece 54 and an outlet-side connection piece 56. the two pressure regulating valves 32 are arranged with their longitudinal direction substantially vertically in the installation position shown. The two pressure regulating valves 32 are hydraulically connected in parallel. The outlet-side connection 56 leads to the fuel distribution device 38. This integrated structural unit is also referred to as a HIPR (Hydrogen Injection Pressure Regulator).The housing 52 is made of a steel material or aluminum. As will be shown below, the two pressure regulating valves 32 are connected to the housing 52 of the pressure regulating unit 30 in a fluid-tight manner.FIG. 3 shows in more detail the connection of a valve (namely one of the two pressure regulating valves 32 from FIG. 2 or the shut-off valve device 36 from FIG. 2 or all of these valves) to the housing 52 of the pressure regulating unit 30.Accordingly, it is provided that the valve 32, 36 has a valve body 101 which fixes a valve seat body 102K and in which a valve element 103 is movably accommodated. The valve seat body 102K has an axially central through-passage 106 and a valve seat 102 is formed on it.In the valve body 101, the valve element 103 is displaceable between a position which is lower in FIG. 3 and in which the valve element 103 bears against the valve seat 102 of the valve seat body 102K and thus closes the through-passage 106, and an upper position in FIG. 3 in which the valve 32, 36 is openThe valve body 101 is arranged in a bore 104 of the housing 52 which is fluidically connected to the fluid channel 58 and which extends vertically into the housing 52 in FIG. 3 starting from the outer surface 52E of the housing 52.Between the bore 104 and the valve body 101 a first sealing point 111 is provided, which comprises a first O-ring 121. This sealing point 111 is located in a part of the fluid channel 58 which runs vertically in FIG. 3 and has the effect that there is no bypass to the valve 32, 36 within the fluid channel 58.Between the bore 104 and the valve body 101 a second sealing point 112 is provided, which comprises a second O-ring 122. In FIG. 3, this sealing point 112 is located 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.The valve body 101 is widened by an annular shoulder 101R facing the housing 52, wherein an electromagnet 105 which is surrounded by the valve 32, 36 is located, as seen in the longitudinal direction, only at the height of the widened part of the valve body 101 of the valve 32, 36.The pressure regulating 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.The third sealing ring 123 is provided radially outside the bore 104 by being arranged radially outside on 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.In an alternative, which is shown in FIG. 4, housing 52 has at the outlet 104A of bore 104 a further collar 131 pointing in the bore direction, which collar, together with collar 130, forms a groove 132, in which third sealing ring 123 is arranged.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2022 213 374 A1

[0002]

Claims

Pressure regulating unit (30) for a hydrogen supply system (10) for pressure regulation and supply of gaseous hydrogen from a high-pressure tank (12) to a consumer (42), comprising a housing (52), an inlet connection piece (54) and an outlet connection piece (56), a fluid channel (58) which extends from the inlet connection piece (54) to the outlet connection piece (56) through the housing (52), and at least one valve (32, 36) by means of which a throughflow of the hydrogen through the fluid channel (58) can be throttled 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 movably accommodated, 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 section (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) which comprises a first sealing ring (121) and a second sealing point (112) which comprises a second sealing ring (122) is provided between the bore (104) and the first section, and wherein a third sealing point (113) which comprises a third sealing ring (123) is provided between the housing (52) and the second section.The pressure control unit (30) according to claim 1, wherein the valve (32, 36) is a shut-off valve or a proportional valve.Pressure regulating 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).The pressure control unit (30) according to claim 1, 2 or 3, wherein the first sealing location (111) is provided in the fluid channel (58).Pressure regulating unit (30) according to one of the preceding claims, wherein the third sealing point (113) is provided radially outside the bore (104).Pressure regulating unit (30) according to Claim 5, wherein the housing (52) has, at the outlet of the bore (104), a collar (130) which points in the bore direction and runs around the bore (104), and the third sealing ring (123) is arranged radially on the outside on this collar (130).Pressure regulating unit (30) according to Claim 6, wherein the housing (52) has, at the outlet of the bore (104), a further collar (131) which points in the bore direction and which, together with the collar (130), forms a groove (132) in which the third sealing ring (123) is arranged.Pressure regulating unit (30) according to Claim 6, wherein the third sealing ring (123) is exposed on its radial outer side.The pressure control unit (30) according to any 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).Pressure regulating 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 likewise an O-ring, while the third sealing ring (123) is an O-ring or a rectangular sealing ring or a flat seal.Pressure regulating unit (30) according to one of the preceding claims, wherein the third sealing ring (123) consists of a solid material or of a foamed material.Pressure regulating unit (30) according to one of the preceding claims, wherein the bore (104) has a chamfer (104F) in its outlet region (104A).Pressure regulating unit (30) according to one of the preceding claims, wherein the housing (52) consists of aluminium and the valve body (101) consists of steel.Pressure regulating unit (30) according to one of the preceding claims, wherein the valve body (101) widens via an annular shoulder (101R) facing the housing (52), wherein the valve (32, 36) comprises an electromagnet (105) which, viewed in the longitudinal direction, is formed only at the height of the widened part of the valve body (101).Hydrogen supply system (10) having a pressure regulating unit (30) according to one of the preceding claims, wherein a high-pressure tank (12) is provided upstream of the pressure regulating unit (30) and a consumer, for example a fuel distribution device (38) having one or more injectors (42), is provided downstream of the pressure regulating unit (30).

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