WO2024074257A1

WO2024074257A1 - Shut-off valve device for a fuel supply system for supplying an internal combustion engine with, in particular, gaseous fuel, pressure regulating device for such a fuel supply system, and fuel supply system

Info

Publication number: WO2024074257A1
Application number: PCT/EP2023/074556
Authority: WO
Inventors: Uwe Richter; Markus Schetter; Stephan Wehr
Original assignee: Robert Bosch Gmbh
Priority date: 2022-10-07
Filing date: 2023-09-07
Publication date: 2024-04-11
Also published as: DE102022210615A1

Abstract

A shut-off valve device (32) for a fuel supply system for supplying an internal combustion engine with, in particular, gaseous fuel, comprises an inlet (54), an outlet (56), a first valve (58) with a first valve element, which is acted upon in the closing direction by a first biasing device (62) and can be acted upon in the opening direction by a controllable actuator (64), characterised in that the shut-off valve device (32) further comprises a second valve (60) hydraulically parallel to the first valve (58) and having a second valve element, which is acted upon by an inlet-side fluid pressure in the closing direction and by an outlet-side fluid pressure in the opening direction, and which is mechanically coupled (70) to the first valve (58) in the closing direction in such a way that it closes when the first valve (58) closes.

Description

Title

Shut-off valve device for a fuel supply system for supplying an internal combustion engine with, in particular, gaseous fuel, pressure control device for such a fuel supply system, and fuel supply system

State of the art

The invention relates to a shut-off valve device for a fuel supply system for supplying an internal combustion engine with, in particular, gaseous fuel, a pressure control device for such a fuel supply system, and a fuel supply system with the features of the preambles of the independent claims.

Internal combustion engines whose fuel is gaseous hydrogen are well known on the market. Such internal combustion engines can be used, for example, to drive motor vehicles. The hydrogen can be stored in liquid form in a tank-like fuel storage tank under relatively high pressure, for example 700 bar. From there it passes through a high-pressure pressure control device to a low-pressure pressure control device and then to a distribution chamber, which is functionally similar to the fuel rail in an internal combustion engine with gasoline or diesel direct injection. The high-pressure pressure control device typically regulates the gas pressure down to, for example, around 40 bar, while the low-pressure pressure control device regulates the gas pressure further down, typically to a pressure of around 15 bar. Several injectors are usually connected to the distribution chamber, which inject the gaseous fuel directly into the combustion chambers of the internal combustion engine (H2 direct injection) or into a prechamber (port fuel injection). The low-pressure pressure regulator is also abbreviated as HIPR (“Hydrogen Injection Pressure Regulator”). It regulates the pressure and thus the mass or volume flow in the distribution chamber or to the distribution chamber according to the specific requirements. Depending on the size of the required mass or volume flow, the HIPR currently comprises one or two modified so-called “HGIs”, which are proportional valves. The two HGIs are hydraulically arranged parallel to one another between an inlet of the low-pressure pressure regulator facing the gas reservoir and an outlet of the low-pressure pressure regulator facing the distribution chamber. The low-pressure pressure regulator typically also includes a pressure sensor and a safety valve. The safety valve is designed as a shut-off valve device. When the internal combustion engine is switched off, the shut-off valve device is closed and the shut-off valve device opens when the internal combustion engine is to be started. When the internal combustion engine is switched off, the shut-off valve device is intended to prevent unwanted gas from escaping into the distribution chamber in the event of a leak.

Disclosure of the invention

The problem underlying the invention is solved by a shut-off valve device, a pressure control device and a fuel supply system with the features of the independent claims. Advantageous further developments are mentioned in subclaims.

One advantage of the present invention is that the shut-off valve device can open against high pressure. At the same time, only comparatively little energy is required to control the actuator in order to be able to keep the shut-off valve device in the open state. If the actuator is not actuated, the shut-off valve device is closed. A fuel supply system with such a shut-off valve device therefore works very safely and reliably.

Specifically, a shut-off valve device is proposed which is designed and arranged to be used in a fuel supply system for supplying a Internal combustion engine with, in particular, gaseous fuel. The fuel can be, for example, hydrogen, in particular gaseous hydrogen. The hydrogen is therefore used for internal engine combustion. The internal combustion engine can essentially be a typical piston internal combustion engine, such as those used in motor vehicles or stationary generators.

In such a fuel supply system, the hydrogen can be stored in liquid form in a fuel storage tank under relatively high pressure, for example 700 bar. From there it can pass through a high-pressure pressure control device to a low-pressure pressure control device and then to a distribution chamber, which is functionally similar to the fuel rail in an internal combustion engine with gasoline or diesel direct injection. The high-pressure pressure control device typically regulates the gas pressure down to, for example, around 40 bar, while the low-pressure pressure control device regulates the gas pressure further down, typically to a pressure of around 15 bar. Several injectors can be connected to the distribution chamber, which inject the fuel directly into the combustion chambers of the internal combustion engine (H2 direct injection) or into a prechamber (port fuel injection).

The low-pressure pressure control device (HIPR) just mentioned regulates the pressure and thus the mass or volume flow in the distribution chamber or to the distribution chamber according to the specific requirements. For this purpose, the HIPR can comprise at least one proportional valve. The low-pressure pressure control device typically also includes a pressure sensor and a safety valve. The safety valve can, for example, be designed as the shut-off valve device proposed here. When the internal combustion engine is switched off, the shut-off valve device is closed, and the shut-off valve device opens when the internal combustion engine is to be started.

The shut-off valve device comprises an inlet which faces, for example, the fuel reservoir of the fuel supply system. At the inlet of the shut-off valve device, there is thus a certain pressure which typically adjusted by means upstream of the shut-off valve device, for example a high pressure pressure regulating device. A typical pressure at the inlet of the shut-off valve device is, for example, approximately in the range of 40 bar.

The shut-off valve device further comprises an outlet which faces, for example, proportional valves of a pressure control device and further downstream a distribution chamber. Such a pressure control device can, for example, be a low-pressure pressure control device which further reduces the pressure, for example to a pressure of approximately 15 bar.

The shut-off valve device also includes a first valve with a first valve element, which is acted upon in the closing direction by a first pre-tensioning device and can be acted upon in the opening direction by a controllable actuator. The first valve is therefore "normally closed". It is therefore a typical switching valve with one switching position "open" and one switching position "closed".

According to the invention, the shut-off valve device further comprises a second valve which is hydraulically parallel to the first valve and has a second valve element which is acted upon by an inlet-side fluid pressure in the closing direction and by an outlet-side fluid pressure in the opening direction. The second valve is therefore opened solely by the pressure difference between the inlet and the outlet of the shut-off valve device. However, the pressure at the outlet of the shut-off valve device increases or the pressure at the inlet of the shut-off valve device decreases when the first valve is opened by a corresponding control of the actuator. By opening the first valve, the pressure difference between the inlet and outlet and thus across the second valve element is influenced in such a way that the second valve opens.

The flow cross-section of the second valve is typically significantly larger than that of the first valve. If the second valve is open, the shut-off valve device can be considered to be fully open, so that the fuel can reach the low-pressure pressure control device of the fuel supply system, for example, largely unthrottled. Since the second valve is the "main valve" with a correspondingly large opening cross-section, the first valve ("pilot valve") can have a correspondingly small opening cross-section, so that the actuator only has to apply a comparatively small force to open the first valve, and also only has to apply a comparatively small force to keep the first valve open. Accordingly, the actuator can be comparatively small, and only comparatively little energy is required to operate it.

Furthermore, the second valve element is mechanically coupled to the first valve in the closing direction in such a way that it closes when the first valve closes. The first valve element in turn closes when the energy supply to the actuator of the first valve is stopped. This ensures that the entire shut-off valve device of the fuel supply system closes when the energy supply to the actuator of the first valve is stopped. A separate closing mechanism for the second valve can therefore be dispensed with. For example, the first valve could have a driver that only acts in the closing direction and that in turn interacts with the second valve element.

Overall, the shut-off valve device according to the invention creates a switching valve that can open against a comparatively high pressure and requires relatively little energy to remain open when open. This is made possible by a 2-stage opening principle. The first stage or the first valve is a pilot valve that is opened by an actuator, and the second stage or the second valve is the main valve that is opened independently via the pressure difference between the inlet and outlet influenced by the pilot valve.

In a further development, it is provided that the second valve element is additionally acted upon in the opening direction by a second pre-tensioning device. This further simplifies the opening of the second valve, as the dependency of the opening of the second valve on a sufficient reduction in the pressure difference between the inlet and the outlet by opening the first valve is reduced. It is sufficient that the hydraulic force acting in the opening direction together with the pre-tensioning force acting in the opening direction are greater than those in the closing direction. acting hydraulic force. The structure of the shut-off valve device according to the invention is thereby further simplified.

In a further development, it is provided that the first valve element is acted upon in the opening direction by the fluid pressure on the outlet side and that the hydraulically effective area of the first valve element acting in the opening direction is smaller than the hydraulically effective area of the second valve element acting in the opening direction. Thus, despite a possibly large pressure difference between inlet and outlet, only comparatively little force is required to open the first valve, and at the same time a comparatively small change in the pressure difference between inlet and outlet is sufficient to open the second valve.

In a further development, the second valve element has a valve seat for the first valve element. The second valve element therefore has a dual function. Such a shut-off valve device has particularly compact, i.e. small, dimensions.

In a further development of this, it is provided that the first valve element comprises a valve tappet with an end face, that the second valve element comprises a valve plate with a fluid passage and that a valve seat for the first valve element is formed on the second valve element and interacts with the end face of the first valve element when closed. This development has the advantage that essential components of the first valve of so-called "quantity control valves" can be adopted unchanged or with only minor changes, for example the actuator, at least part of a valve housing, the valve tappet, etc. Such quantity control valves are used in high-pressure fuel pumps, which are designed as piston pumps, in gasoline or diesel fuel systems to control the fuel delivered by the high-pressure fuel pump.

Such high-pressure fuel pumps typically have a classic spring-loaded check valve as the inlet valve, for example with a plate-shaped valve element. The valve element of the inlet valve can be temporarily forced open by a valve tappet that is connected to an actuator. into the open position. At least the valve tappet and actuator components - typically an electromagnetic actuator - can now be used to implement the shut-off valve device according to the invention. Since the first valve only works as a pilot valve and therefore only comparatively low hydraulic forces act on the first valve element, the valve tappet and actuator components of a classic quantity control valve can be adopted without any or at least without significant changes to the actuator and valve tappet. This saves considerable costs and existing production facilities can be used.

Together with the two pre-tensioning devices mentioned above, the first pre-tensioning device in this development then acts in the closing direction of both valves, and the second pre-tensioning device acts in the opening direction of both valves. In this case, it is advantageous if a pre-tensioning force of the first pre-tensioning device acting in the closing direction is greater than a pre-tensioning force of the second pre-tensioning device acting in the opening direction.

In a further development of this, it is provided that the end face of the first valve element is spherical and/or the valve seat on the second valve element comprises a conical surface. This enables a good sealing effect and self-centering of the first valve element on the valve seat of the second valve element, and also a comparatively small diameter of the sealing cross section, i.e. the sealing line by means of which the first valve element rests on the second valve element when the first valve is closed, is achieved. Accordingly, the value of the hydraulic force resultant that acts on the first valve element is relatively low even with a comparatively high pressure difference between the inlet and the outlet, so that the actuator only has to apply a comparatively small force to open the first valve.

It is also conceivable that the second valve element has a conical sealing surface which, when the second valve is closed, rests against a corresponding conical valve seat which is formed, for example, on a - possibly multi-part - valve housing of the shut-off valve device. In a further development of this, it is provided that the second valve element is guided in a sliding seat on the first valve element. This simplifies assembly and increases the reliability of the shut-off valve device during operation. It is possible, for example, for the second valve element to be cylindrical and pot-shaped overall and to be guided on the cylindrical valve tappet by means of its cylindrical side wall. In this case, the valve seat for the first valve element would be formed on the "bottom" of the second pot-shaped valve element. The flow path for the fluid when the first valve is open could then be provided, for example, by at least one opening in the peripheral wall of the second valve element and at least one - preferably central - opening in the bottom of the second valve element.

In a further development, the second valve element is made from a sealing plastic. This also increases the reliability of the shut-off valve device during operation. For example, the second valve element can comprise an elastomer material, PEEK, PTFE, Vespel, or a similar sealing material or can be made from such a material.

As already mentioned above, the present invention also relates to a pressure control device for a fuel supply system for supplying an internal combustion engine with gaseous fuel, for example gaseous hydrogen, as described at the beginning. The pressure control device is in particular a low-pressure pressure control device which in particular controls the pressure in a distribution chamber arranged downstream of it, to which in turn several injectors are connected. According to the invention, the pressure control device has a shut-off valve device of the above type. The pressure control device can form a coherent, for example modular, component together with the shut-off valve device and one or more pressure control valves and/or one or more pressure sensors.

Finally, as already mentioned above, the present invention relates to a fuel supply system for supplying an internal combustion engine with preferably gaseous fuel, for example Hydrogen, comprising a fuel storage device, at least one pressure control device, for example a high-pressure pressure control device and/or a low-pressure pressure control device arranged downstream of the high-pressure pressure control device, a distribution chamber arranged downstream of the at least one pressure control device and a plurality of injectors connected to the distribution chamber. It is advantageous if at least one pressure control device comprises a shut-off valve device of the above type.

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

Figure 1 is a schematic representation of a fuel supply system for supplying an internal combustion engine with gaseous fuel, with a pressure control device, which in turn comprises a shut-off valve device;

Figure 2 is a perspective view of a first embodiment of the pressure control device of Figure 1;

Figure 3 is a perspective view of a second embodiment of the pressure control device of Figure 1;

Figure 4 is a hydraulic equivalent circuit diagram of the shut-off valve device of Figure 1;

Figure 5 is a section through the shut-off valve device of Figure 1;

Figure 6 is a perspective view of a second valve element of the shut-off valve device of Figure 1; and

Figure 7 is a sectional perspective view through the shut-off valve device of Figure 1. In the following, functionally equivalent elements and areas in different figures and in different embodiments have the same reference symbols. They are normally only described in detail when they are first mentioned. In addition, for the sake of simplicity, not all reference symbols are entered in all figures.

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 fuel, in particular a gaseous fuel, in this case for example gaseous hydrogen.

The hydrogen is stored in liquid form under high pressure, for example approximately 700 bar, in a tank-like fuel storage unit 12.

This can be filled via a filling connection 14. An integrated unit 16 comprising a tank valve for filling and dispensing hydrogen into or out of the fuel storage 12 and a temperature sensor for detecting the temperature of the gaseous hydrogen coming from the fuel storage 12 is also arranged on the fuel storage 12.

The gaseous hydrogen first reaches a filter 20 via a pressure line 18 and from there to a high-pressure pressure control device 22. This reduces the pressure of the gaseous hydrogen to a pressure in the range of 40 bar, for example. The pressure line 18 leads from the high-pressure pressure control device 22 to a pressure sensor 24, another filter 26 and an optional temperature control device 28 and finally to a low-pressure pressure control device 30.

The low-pressure pressure control device 30 comprises a shut-off valve device 32, downstream of this two hydraulically parallel pressure control valves 34 and between the shut-off valve device 32 and the two pressure control valves 34 a low-pressure pressure sensor 35. The two pressure control valves 34 are identically constructed and are typically proportional valves. The low-pressure pressure control device 30 reduces the pressure in the pressure line 18 again from the inlet-side pressure of approximately 40 bar to a pressure of approximately 15 bar, for example. The pressures supplied to the pressure control valves 34 The upstream shut-off valve device 32 is closed when the fuel supply system 10 is not in operation. This prevents unwanted gas leakage.

Downstream of the low-pressure pressure control device 30, the pressure line 18 leads to a distribution chamber 36, which can be designed, for example, as an elongated tube in the manner of a typical fuel rail, as is known from gasoline and diesel fuel systems. The gas pressure prevailing in the distribution chamber 36 is detected by a pressure sensor 37.

Several injectors 38 are connected to the distribution chamber 36, which in this case blow the gaseous hydrogen directly into combustion chambers 40 of the internal combustion engine. The gaseous hydrogen is mixed with atmospheric oxygen in the combustion chambers 40, and this mixture is ignited by a respective ignition device 42. The internal combustion engine is typically 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 drive a motor vehicle. However, it can also be used stationary, for example, to drive a generator to generate electricity.

The fuel supply system 10 and its components are controlled by an electronic control and regulating device 44, which has one or more corresponding microprocessors, a memory for program code, etc. This receives signals from, among others, the temperature sensor 16, the pressure sensor 24, the pressure sensor 37, etc. The control and regulating device 44 controls various components of the fuel supply system 10, including the low-pressure pressure control device 30 and the ignition devices 42. Furthermore, a control device 46 is also controlled by the control and regulating device 44, which in turn specifically controls or regulates the operation of the fuel storage device 12.

The low-pressure pressure control device 30 is shown in a first embodiment in Figure 2 with a single pressure control valve 34. The low-pressure pressure control device 30 includes a housing 48 with an inlet-side connection piece 50 and an outlet-side connection piece 52. The Housing 48 integrates the pressure control valve 34, the shut-off valve device 32 and the low-pressure pressure sensor 35 into a single structural unit. The housing 48 can be a milled aluminum block. The low-pressure pressure control device 30 shown in Figure 3, which is a second embodiment, has - as shown in Figure 1 - two pressure control valves 34 that are connected in parallel to one another.

The very basic structure of the shut-off valve device 32 is shown in Figure 4. The shut-off valve device 32 comprises an inlet 54 and an outlet 56. The inlet 54 is, for example, identical to the inlet-side connection piece 50. The outlet 56 leads, for example, to the low-pressure pressure sensor 35 and further to the pressure control valve 34 or to the pressure control valves 34. Furthermore, the shut-off valve device 32 includes two valves arranged hydraulically parallel to one another, namely a first valve 58 and a second valve 60. Both valves 58 and 60 are designed as switching valves, each with a closed and an open switching position.

The first valve 58 has a first valve element, not yet shown in Figure 4, which is acted upon in the closing direction by a first pre-tensioning device 62 and which can be acted upon in the opening direction by a controllable actuator 64. As will be explained further below, the actuator 64 can be, for example, an electromagnetic actuator, as is known from quantity control valves for controlling the delivery quantity of piston pumps in diesel and gasoline fuel systems.

The first valve element of the first valve 58 is also subjected to the fluid pressure prevailing at the inlet 54 in the closed position and the fluid pressure prevailing at the outlet 56 in the open position, which is indicated by corresponding dashed lines. As will also be explained further below, the flow cross section of the first valve 58 is relatively small in the open position, which is indicated in Figure 4 by a throttle 66. The second valve 60 has a second valve element, also not shown in Figure 4, which is acted upon in the opening direction by a second prestressing device 68 and which is also acted upon in the closing direction by the fluid pressure prevailing at the inlet 54 and in the opening direction by the fluid pressure prevailing at the outlet 56, which in turn is indicated by corresponding dashed lines. A prestressing force F1 of the first prestressing device 62 is greater than a prestressing force F2 of the second prestressing device 68. The second valve 60 is mechanically coupled to the first valve 58 in the closing direction such that it closes or is closed when the first valve 58 closes or is closed. The coupling is such, however, that the first valve 58 can open without the second valve 60 being mechanically forced into the open position. The mechanical coupling is indicated in Figure 4 by a dash-dotted line 70.

The shut-off valve device 32 functions as follows: if the internal combustion engine is not in operation and the fuel supply system 10 is switched off, the actuator 64 is not actuated, i.e. without current. The preload force F1 of the first preload device 62 pushes the first valve 58 into the closed position, and this also forces the second valve 60 into the closed position. The shut-off valve device 32 is therefore closed as a whole. The above-mentioned exemplary fluid pressure of approximately 40 bar prevails at the inlet 54, and the above-mentioned exemplary fluid pressure of approximately 15 bar prevails at the outlet 56.

If the actuator 64 is energized, the first valve element is opened against the preload force F1 of the first preload device 62 and against the hydraulic force of the fluid pressure prevailing at the inlet 54. Hydrogen gas thus flows through the throttle 66 to the outlet 56, whereby the pressure there increases and the pressure at the inlet 54 decreases. Due to this changing pressure difference between the inlet 54 and outlet 56 and the preload force F2 of the second preload device 68, the second valve element of the second valve 60 is pressed into the open position. This releases the comparatively large opening cross-section of the second valve 60, so that hydrogen gas can now flow largely unhindered from the inlet 54 to the outlet 56. can flow. The pressure at the outlet 56 is now only slightly lower than at the inlet 54.

If the shut-off valve device 32 is to be closed again, the activation of the actuator 64 is terminated, i.e. it is de-energized, for example. Due to the preload force F1 of the first preload device 62, the first valve element of the first valve 58 is now pushed into the closed position. Due to the mechanical coupling 70, it takes the second valve element of the second valve 60 with it into the closed position against the preload force F2 of the second preload device 68.

A possible concrete embodiment of the shut-off valve device 32 will now be explained with reference to Figures 5-7: the actuator 64 comprises a magnet assembly 72, which is identical to the magnet assemblies of the above-mentioned quantity control valves of gasoline and diesel fuel pumps. It comprises a fluid-tight housing 74 with an electromagnet 76, which is an annular electromagnet in the present example, which is connected to an electrical connection 78. The magnet assembly 72 also comprises an annular armature 80, one end of which is adjacent to a pole body 81. This is firmly connected to a needle-like valve tappet 82 (hence also referred to as a "valve needle"), which can also be designed to be largely identical to typical valve tappets of the said quantity control valves.

An annular collar 84 is provided on the valve tappet 82, and a counterholder 88 is pressed into a connecting piece 86, which connects the housing 74 to the housing 48. The above-mentioned first pretensioning device 62 is clamped in the form of a spiral spring between the annular collar 84 and the counterholder 88. The connecting piece 86 also contains a stop plate 90, which interacts with a section of the annular collar 84 in such a way that an upward movement of the valve tappet 82 in the figures is thereby limited.

A pot-shaped element 92 is placed on the lower end of the valve tappet 82 in Figures 5 and 7, which comprises a plate-like base 94, a cylindrical peripheral wall 96 and an annular collar 98 extending radially outward from the upper edge of the peripheral wall 94 in the figures. In A comparatively small central through-opening 100 is present in the plate-like base 94. As can be seen from Figure 6, there are through-openings 102 in the cylindrical peripheral wall 962 which are diametrically opposite and have a substantially circular cross-section in plan view.

As can be seen in particular from Figure 7, an annular surface 104 of the base 94 facing the valve tappet 82 is slightly conical, and an end face 106 of the valve tappet 82 facing the base 94 is slightly spherical. In the relative position of the valve tappet 82 to the cup-shaped element 92 shown in Figures 5 and 7, the face 106 rests linearly on the annular surface 104 in an area just radially outside of the central through-opening 100.

A valve body 108 is inserted into the housing 48 and is sealed from the housing 48 by an O-ring 110, for example. A valve seat body 112 is pressed into the valve body 108 and is sealed from the valve body 108 by an O-ring 114. A radial bore in the valve body 108 forms the inlet 54, for example, and an axial bore in the valve seat body 112 forms the outlet 56, for example. At the upper edge of the axial bore 56 in the valve seat body 112, the latter has a conical bevel 116, which can interact with a corresponding conical bevel 118 on the cup-shaped element 92 or on its base 94.

The second pre-tensioning device 68, which in the present case is also formed by a spiral spring, is clamped between the valve seat body 112 and the annular collar 98. An upward movement of the cup-shaped element 92 in Figures 5 and 7 is limited by the valve body 108. While the valve tappet 82 is made of metal, the cup-shaped element 92 in the present case is made of a sealing plastic, for example an elastomer material, PEEK, PTFE, Vespel or similar sealing materials. The connecting piece 86 is preferably welded to the housing 48, for example by KEEP welding or laser welding. The same applies to the connecting piece 86 to the housing 48. In the present example, the electrical connection 78 is encapsulated in the housing 74.

The valve tappet 82 forms the above-mentioned first valve element, the bottom 94 of the cup-shaped element 92 forms the above-mentioned second valve element. The cup-shaped element 92 and with it the second valve element 94 are guided through the inside of the peripheral wall 96 in a sliding seat on the first valve element or the valve tappet 82. The annular surface 104 on the cup-shaped element 92 forms a valve seat for the first valve element 82. The conical bevel 116 on the valve seat body 112 forms a valve seat for the second valve element 94.

The shut-off valve device 32 shown in Figures 5-7 functions as follows: when the shut-off valve device 32 is closed, the electromagnet 76 is de-energized. The valve tappet 82 is thus pressed downwards with its spherical end face 106 by the first pre-tensioning device 62 in Figures 5 and 7 against the conical annular surface 104 on the bottom 94 of the pot-shaped element 92, and this in turn is pressed with the conical slope 118 against the conical slope 116 on the valve seat body 112. This realizes the above-mentioned mechanical coupling 70 between the first valve element 82 of the first valve 58 and the second valve element 94 of the second valve 60 in the closing direction. As already mentioned in connection with Figure 4, the preload force F1 of the first preload device 62 acting in the closing direction is greater than the preload force F2 of the second preload device 68 acting in the opening direction.

If the electromagnet 76 is energized, the armature 80 in Figures 5 and 7 is pushed upwards and thus the valve tappet 82, which is firmly connected to the armature 80, is pushed away from the valve seat 104 on the second valve element 94 against the preloading force F1 of the first preloading device 62. The end face 106 thus lifts off the valve seat 104. This is also facilitated by the fact that the fluid pressure prevailing at the inlet 54 can act over a large area of the end face 106 on the valve tappet 82. As a result, hydrogen gas can flow from the inlet 54 via the radial through-openings 102 and the central through-opening 100 to the outlet 56, whereby the Pressure at the outlet 56, as already explained above in connection with Figure 4, increases, and as a result the pressure at the inlet 54, as also already explained above, decreases.

As a result, the pressure difference acting in the closing direction of the second valve element 94 between the annular surface 104 facing the valve tappet 82 and the annular surface (without reference symbol) on the second valve element 94 facing the outlet 56 decreases until the preload force F2 of the second preload device 68 acting in the opening direction is sufficient to lift the second valve element 94 with the conical slope 118 from the valve seat 116 on the valve seat body 112. The hydrogen gas can now also flow through the resulting annular gap between the second valve element 94 and the valve seat body 112 from the inlet 54 to the outlet 56.

In the meantime, the electromagnet 76 continues to be energized. However, in order to hold the shut-off valve device 32 in the open position, only a reduced holding current is required, since the distance between the armature 80 and the pole body 81 (i.e. the so-called residual air gap) has become minimal due to the movement of the valve tappet 82 together with the armature 80.

If the shut-off valve device 32 is to be closed again, the current supply to the electromagnet 76 is stopped, whereby the valve tappet 82 is pressed against the second valve element 94 by the preload force F1 of the first preload device 62 and the latter is thereby carried along and finally pressed against the valve seat 116.

Claims

Expectations

1. Shut-off valve device (32) for a fuel supply system (10) for supplying an internal combustion engine with, in particular, gaseous fuel, comprising an inlet (54), an outlet (56), a first valve (58) with a first valve element (82), which is acted upon in the closing direction by a first prestressing device (62) and can be acted upon in the opening direction by a controllable actuator (64), characterized in that the shut-off valve device (32) further comprises a second valve (60) hydraulically parallel to the first valve (58) with a second valve element (94), which is acted upon by an inlet-side fluid pressure in the closing direction and by an outlet-side fluid pressure in the opening direction, and which is mechanically coupled (70) to the first valve (58) in the closing direction such that it closes when the first valve (58) closes.

2. Shut-off valve device (32) according to claim 1, characterized in that the second valve element (94) is additionally acted upon in the opening direction by a second biasing device (68).

3. Shut-off valve device (32) according to at least one of the preceding claims, characterized in that the first valve element (82) is acted upon in the opening direction by the outlet-side fluid pressure and that the hydraulically effective area of the first valve element (82) acting in the opening direction is smaller than the hydraulically effective area of the second valve element (94) acting in the opening direction.

4. Shut-off valve device (32) according to at least one of the preceding claims, characterized in that the second valve element (94) has a valve seat (104) for the first valve element (82). Shut-off valve device (32) according to claim 4, characterized in that the first valve element comprises a valve tappet (82) with an end face (106), that the second valve element comprises a valve plate (94) with a fluid passage (100), and that the valve seat (104) for the first valve element (82) is formed on the second valve element (94) and, in the closed state, interacts with the end face (106) of the first valve element (82). Shut-off valve device (32) according to claim 5, characterized in that the end face (106) of the first valve element (82) is spherical and/or the valve seat on the second valve element (94) comprises a conical surface (104). Shut-off valve device (32) according to at least one of claims 4-6, characterized in that the second valve element (94) is guided in a sliding fit on the first valve element (82). Shut-off valve device (32) according to claim 7, characterized in that the second valve element (94) is made of a sealing plastic. Pressure regulating device (30) for a fuel supply system (10) for supplying an internal combustion engine with gaseous fuel, characterized in that it comprises a shut-off valve device (32) according to at least one of the preceding claims. Fuel supply system (10) for supplying an internal combustion engine with preferably gaseous fuel, comprising a fuel reservoir (12), at least one pressure regulating device (22, 30), a distribution chamber (36) arranged downstream of the pressure regulating device (30) and at least one injector (38) connected to the distribution chamber (36), characterized in that at least one pressure regulating device (30) has a shut-off valve device (32) according to at least one of claims 1-8.