Pressure regulator for gaseous fuel, in particular hydrogen gas

Abstract

The present application relates to a pressure regulator for a gaseous fuel, in particular hydrogen gas, comprising: an inlet for the gaseous fuel at an inlet pressure; an outlet for the gaseous fuel, a main valve comprising a main valve inlet, a main valve outlet, a main valve secondary inlet and a regulating piston, in a housing, which regulates the fuel flow from the inlet through the main valve to the outlet, and an electronically controllable valve which is configured to provide the inlet pressure via the main valve secondary inlet onto the regulating piston of the main valve as control pressure and as a result to regulate the fuel flow based at least on a pressure sensor signal that indicates the pressure of the gaseous fuel at the outlet of the pressure regulator, wherein the main valve further comprises a passage for the gaseous fuel that is configured to reduce the control pressure acting on the regulating piston. The present application also relates to a multi-stage safety system for the described pressure regulator.

Description

[0001] Pressure regulator for gaseous fuel, especially hydrogen gas

[0002] 1. Technical area

[0003] The invention relates to a pressure regulator for a gaseous fuel, in particular for hydrogen gas.

[0004] 2. State of the art

[0005] Gaseous fuel, particularly hydrogen gas, is used as an energy carrier in mobile applications, either in gaseous form in high-pressure tanks or in liquid form in cooled low-pressure tanks. Depending on the filling level of the storage containers, decreasing pressure conditions exist starting from the maximum fill level of the storage tank, which continuously decreases as gas is withdrawn, e.g., during ferry operations. Tank pressures of 200, 350, or 700 bar at 100% tank filling are common today in the compressed gas storage sector. Tank pressures of less than 20 bar are used in cryogenic liquefied gas storage.

[0006] In order to be able to make the stored fuel, e.g. hydrogen, available to a consumer, the gas must be taken from the storage facility at a variable pressure level of approximately 10 bar to 875 bar and conditioned to a pressure specific to the consumer. This conditioning typically takes the form of pressure release, which must be adapted to the respective consumer, e.g. a fuel cell or a hydrogen combustion engine. Fuel cells typically operate with a hydrogen supply pressure of approximately 9 bar, while hydrogen combustion engines operate at pressures of up to 60 bar. It is of crucial importance that the medium is made available to the consumer within a small pressure tolerance window, regardless of the often strongly fluctuating or falling gas mass flow, for example when the driver accelerates or brakes sharply.Particularly when the tank is empty or there are high gas mass flows in the full load range, pressure drops in the...

[0007] supply line, optimal efficiency of the fuel cell or the combustion engine cannot be achieved.

[0008] Pressure conditioning in the supply line is typically achieved or implemented by a mechanical pressure regulator. Such a mechanical pressure regulator responds to the applied tank pressure through a fixed spring-to-area ratio by opening the spring-loaded valve opposite the downstream side in the low-pressure range, which also exerts a force on the spring-loaded valve. As long as these forces, generated by different sized effective areas on the high-pressure and low-pressure sides, are not balanced, the valve opens and gas flows from the high-pressure side to the low-pressure side, where the consumer is located and continuously draws fuel / hydrogen. Since the areas in these mechanical pressure regulators are not variable during operation, the falling pressure in the reservoir causes a proportionally falling pressure on the low-pressure side.Thus, mechanical regulators without pressure compensation are often unable to achieve a control quality of more than 90%.

[0009] A pressure-balanced regulator has a unique technical feature. It eliminates the problem of falling tank pressure by flushing the surface of the valve element facing the tank pressure with low pressure. This type of mechanical pressure control is independent of the reservoir's fill level, but is characterized by the fact that additional sealing elements between the high- and low-pressure areas of the regulator can negatively impact the regulator's service life and internal leakage. Such regulators can achieve a control performance of 95%, but are often unreliable and therefore frequently fail prematurely.

[0010] Mechanical control valves are also characterized by the fact that they cannot directly influence the medium flowing to the consumer during operation. In addition, these regulators are often limited to small mass flow rates or fuel flows such as 3 g / s, as is common in the light vehicle sector (cars). This limitation arises from the design-related force-area ratio of the control valve in combination with the preloading spring element. For larger flow rates such as 7 g / s (light duty) or 16 g / s (heavy duty), very large surfaces and very strong spring elements would be necessary in view of the pressure condition in the tank at 350 bar or 700 bar in order to be able to press the valves closed against the full tank pressure despite the large valve cross-section. This increases the complexity, manufacturing effort and therefore costs.

[0011] There are also control valves with electronic control that are designed in such a way that an inaccurate, mechanical control is connected upstream to reduce the tank pressure to an intermediate pressure level acceptable for the electronic regulator. The inlet pressure for the series-connected electronic regulator is subject to particularly large pressure fluctuations, which depend on the fill level of the storage vessel / tank. Due to the low inlet pressure despite this, the electronic control is able to provide fine control for the consumer. A major disadvantage of this configuration is a limited gas mass flow and a complex design. Output pressure changes, including mass flow changes, can only be handled to a limited extent via the control unit, since the mechanical regulator operates depending on the tank pressure and cannot be controlled separately.The use of such valves is therefore essentially limited to the natural gas sector with maximum tank pressures of 200 to 300 bar.

[0012] 3. Summary

[0013] As discussed above, the pressure regulators known from the prior art exhibit deficiencies at high mass flow rates / fuel flows and / or in terms of reliability. Furthermore, they are poorly able to respond to variability, such as strongly varying fuel consumption during fluctuating driving behavior. The problem addressed by the present application is to at least partially mitigate these and similar disadvantages of the prior art.

[0014] This problem is at least partially solved by the subject matter of the independent claims of the present application. Exemplary embodiments are described in the dependent claims. Unless otherwise stated, material properties are to be determined according to the relevant standards. Furthermore, the term "substantially" is to be understood below as "within typical design, measurement, and / or manufacturing tolerances."

[0015] The present application relates to a pressure regulator for a gaseous fuel, in particular hydrogen gas, comprising an inlet for the gaseous fuel at an inlet pressure, an outlet for the gaseous fuel, a main valve comprising a main valve inlet, a main valve outlet, a main valve secondary inlet, and a control piston in a housing that controls the fuel flow from the inlet through the main valve to the outlet, and an electronically controllable valve, in particular a proportional valve, configured to deliver inlet pressure via the main valve secondary inlet to the control piston of the main valve as a control pressure and thereby control the fuel flow based on at least one pressure sensor signal indicating the pressure of the gaseous fuel at the outlet of the pressure regulator, wherein the main valve further comprises a passage for the gaseous fuel that is configured to reduce the control pressure.which acts on the control piston and is preferably arranged in the control piston and / or the housing.

[0016] For example, the passage can be located in the control piston crown, in the circumference of the control piston, and / or as a bypass in a guide ring system. Such a passage integrated in or on the control piston improves the response of the control piston to changes in the control pressure without complicating the design of the pressure regulator. A further advantage of this arrangement is that the mechanical design of the control piston significantly influences the dynamic response of the pressure regulator. This allows pressure regulators to be adapted to different requirements by installing control pistons with different passages.

[0017] Alternatively or additionally, the passage can also be implemented via a check valve integrated in the control piston, via a filter, a gap between the control piston and the housing wall and / or via one or more channels in the wall of the control piston or in the housing wall, and / or via a flow pad due to a surface roughness of the wall of the control piston and / or the housing wall.

[0018] The pressure regulator described herein can thus operate essentially independently of the inlet pressure, which is not the case with mechanical regulators or mechanical control stages, for example. Furthermore, the pressure regulator can be controlled and configured via an engine control unit to regulate the pressure and mass flow, or the fuel flow, according to adjustable setpoints for the pressure and mass flow.

[0019] During operation, increased fuel consumption by the consumer (e.g., a fuel cell) leads to a pressure drop at the outlet of the pressure regulator, which is indicated by the pressure sensor signal, and to the opening of the electronically controlled valve. This controls the control piston to increase the flow through the main valve until the outlet pressure again corresponds to the setpoint. Accordingly, reduced fuel consumption leads to a pressure increase at the outlet, thus closing the electronically controlled valve. In this case, the passage of the control piston allows the control piston to react as quickly as possible to the reduced pressure control signal, thereby improving the responsiveness, bandwidth, and step response of the control loop.

[0020] The pressure regulator described herein also exhibits a particularly fast response during load changes. This property is achieved, among other things, by the control piston design described here. The control piston is preferably located in a cylinder guide with minimal volume above the piston, whereby control in the form of gas addition via the electronically controllable valve directly results in a change in the position of the piston. If the flow through the electronically controllable control valve (preferably designed as an electromagnetic proportional valve) decreases, the control pressure can be quickly reduced again via the passage of the control piston.

[0021] The pressure regulator described here can provide high mass or fuel flows with simultaneously highly variable pressure ranges and maintain the outlet pressure constant with high accuracy even with widely varying mass or fuel flows. Unlike previously known pressure regulators, it is not limited to mass flow rates of 3 g / s. Its capacity is above 10 g / s, depending on the residual tank pressure. At residual tank pressures of 30 bar or more, mass flows of up to 20 g / s are possible without having to make any structural changes to the existing assembly. The pressure regulator described here has a single-stage design and therefore does not require an upstream mechanical pressure control valve.

[0022] The pressure regulator described here can utilize the pressure of the pressurized gaseous fuel by metering the tank pressure via the electronically controllable valve as control pressure to the control piston of the main valve. This type of pneumatic valve control ensures particularly precise control of the output pressure signal. In real gas tests, the pressure regulator described here achieved a control accuracy of over 99% at inlet pressures of up to 860 bar and typical outlet pressures between 9 bar and 40 bar. At very low outlet pressures of less than 3 bar, control accuracies of approximately 90-95% were achieved. The pressure regulator described here can operate with variable outlet pressure levels from 1 bar to 60 bar.

[0023] A further advantage of the pressure regulator described here is that it can be designed in such a way that it can be adapted to the application-specific conditions such as material and / or installation space requirements, as well as the integration of additional components, e.g. as described here, without having to replace an unnecessarily large number of components or having to change the basic design of the pressure regulator. By adapting it to the respective conditions, control qualities of over 99% can be achieved even with very low output pressures or mass flows. The design of the control piston and the passage also means that the pressure regulator can react very quickly to changing pressure and flow requirements. This increases the control bandwidth, which improves the control quality, reduces pressure oscillations and improves the step response behavior of the regulator or the control loop, e.g. in the case of strong and instantaneous load requirements.

[0024] The pressure regulator described here can also be installed in any position. In particular, it can be used in parallel for stationary or mobile applications with particularly high consumption throughputs without negatively affecting the other regulators or the output pressure signal. The pressure regulator can be used in compressed gas storage systems, liquefied gas storage systems, and all other types of hydrogen or alternative gas treatment. Across all applications, the regulator represents a very robust solution, meaning no regular maintenance is required.

[0025] In order to keep the response time of the control piston to a change in the control pressure as short as possible and thus to increase the control bandwidth of the control circuit, a volume between a surface of the control piston, on which the control pressure acts, and a housing in which the control piston moves, in the closed state, in a range of too mmA 3 to 1000 mm A 3, preferably in a range between 300 mm A 3 and 700 mm A 3. Alternatively or additionally, the volume of a connecting bore from the outlet of the electronically controlled valve to the secondary inlet of the main valve can be in the range between 40 mm A 3 and 500 mm A 3, preferably in the range between 100 mm A 3 and 250 mm A 3. Alternatively or additionally, the output volume of the electronically controlled valve can be in the range between 400 mm A 3 and 1200 mm A 3, preferably in the range between 650 mm A 3 and 950 mm A 3 lie.

[0026] The pressure regulator can further be designed such that a diameter of a surface of the control piston that is exposed to the control pressure is in the range of 30 mm to 50 mm. This relatively large area enables precise regulation of the pressure. The shut-off body of the main valve can, for example, have a diameter of 2 mm to 6 mm. The resulting area ratio, i.e., between the control piston and the shut-off body, further improves the control quality. Embodiments of the pressure regulator described here include pressure regulators with non-circular control piston and / or shut-off body cross-sections. Their cross-sections have comparable area sizes as described herein with reference to exemplary cylindrical control pistons and shut-off bodies with a circular cross-section.

[0027] The pressure regulator can further be designed so that the passage

[0028] throttle element that influences how the control pressure is reduced, whereby the

[0029] The throttle element can preferably be adjustable, allowing, for example, the effective cross-section of the passage to be changed. This allows the response of the control piston to be precisely tailored to the intended use of the pressure regulator.

[0030] The main valve of the pressure regulator can, for example, be configured to set a variable fuel flow rate in the range of 0.02 g / s to 50 g / s. A variable fuel flow rate allows the regulator to be operated in a situation-dependent manner and adapted to the potentially highly fluctuating demand of a downstream fuel-consuming element, e.g., a fuel cell, a gas turbine, or an internal combustion engine.

[0031] In one exemplary embodiment, the pressure regulator may further comprise a device for temperature control by means of heating and / or cooling. Such temperature control represents an advantageous additional safety mechanism. Particularly when working with gaseous fuels, unwanted temperature changes can occur, which can be prevented and / or counteracted with a suitable temperature control device. Maintaining a temperature that is as constant as possible reduces mechanical expansion / contraction of the pressure regulator's components and thus leads to improved operational stability of the regulator.

[0032] For example, two components can be cooled and / or heated: firstly, the pressure regulator itself to ensure functionality at low media temperatures at the inlet or low / high ambient temperatures due to engine heat or atmospheric conditions, and secondly, the escaping gas at the outlet for preconditioning to ensure the highest possible effectiveness / efficiency of the energy generator.

[0033] The pressure regulator can, for example, be configured such that the temperature control device comprises cooling channels in the area of ​​a main valve body of the main valve for liquid-based cooling of the main valve and / or an electric heater for heating the main valve. The optional temperature control of the pressure regulator made possible in this way can, for example, be achieved via an attached flange, which optionally also represents the cover of the main valve housing. This cover can, for example, be either electrically heated or conditioned via cooling fins and liquid channels connected to the cooling circuit of the vehicle / unit. Temperature conditioning as described above can, in a special type of housing design, be implemented directly via cooling fins and cooling channels in the housing area, similar to the structure of a liquid-cooled cylinder head in an internal combustion engine.

[0034] An exemplary embodiment of the pressure regulator can further comprise a control unit that controls the electronically controllable valve, at least partially based on the at least one pressure sensor signal, preferably using pulse width modulation (PWM). A PWM signal generated by the control unit can be used, for example, to adjust the stroke of the valve. Preferably, a proportional valve is used, and the frequency of the PWM is high enough (e.g., >300 Hz or >1 kHz) that the proportional valve can act as a low-pass filter for the PWM signal. This prevents the PWM signal from causing fluctuations in the pressure control signal acting on the control piston.The use of a proportional valve has the additional advantage that the shut-off body of the proportional valve rarely touches the sealing seat during operation, thus significantly reducing wear – for example, compared to an electronically controlled shut-off valve. In addition to at least one pressure sensor signal indicating the outlet pressure, the pressure regulator can also consider other signals such as an inlet pressure signal. Furthermore, the control unit can adjust its control parameters (e.g., control gain, control type, etc.) based on a signal indicating the mass or fuel flow requested by a consumer.

[0035] Such a control unit allows the pressure regulator to be adapted to specific operating conditions (e.g., full load in a hydrogen combustion engine). For example, by increasing the pressure in the low-pressure range upstream of the injector, more fuel can be supplied to the engine for a short time. For example, for range extender programming, the maximum available fuel consumption can be adjusted. Furthermore, the pressure regulator can be electronically pre-controlled during load changes, for example, to close the main valve early and thus save fuel.

[0036] The pressure regulator may further comprise at least one temperature sensor for detecting the temperature of the gaseous fuel in the pressure regulator. Such temperature measurement is particularly advantageous in combination with the devices herein for temperature control by means of heating and / or cooling. Alternatively or additionally, such temperature detection represents an advantageous safety mechanism, for example, to be able to issue a warning signal and / or otherwise react in the event of overheating or an unwanted drop in temperature.

[0037] In another example, the electronically controllable valve of the pressure regulator can have a maximum stroke of up to 15 mm, preferably up to 10 mm, and even more preferably up to 5 mm. This allows for controlled gas supply without pulsation disturbances in the control line.

[0038] For example, the electronically controlled valve can be configured to accommodate pressures of up to 1500 bar, up to 1200 bar, up to 1000 bar, or up to 700 bar within the proportional valve housing itself. The electronically controlled valve can thus be capable of withstanding corresponding internal pressures without bursting, and the inlet pressure can be delivered directly to the control piston via the electronically controlled valve as control pressure.

[0039] The pressure regulator may further comprise one or more of the following components: a pressure relief valve arranged downstream of the main valve in the flow path and opening at a pressure greater than the controllable outlet pressure of the pressure regulator, preferably at a pressure of over 30 bar or over 70 bar; a service interface unit (SIU) arranged downstream of the main valve in the flow path; and an electronically controllable venting valve arranged downstream of the main valve in the flow path. This also allows the pressure regulator to be automatically vented, ensuring that in the event of a fault, the outlet pressure does not become so high that it could damage downstream components, such as a fuel cell. To further improve the safety of the pressure regulator, all valves of the pressure regulator can be in an NC (normally closed) configuration.

[0040] To further improve control accuracy and quality and functional integration and / or to enable online diagnostics, the pressure regulator may further comprise one or more of the following components: a pressure sensor for measuring a pressure of the gaseous fuel at the outlet, which provides the pressure sensor signal, a pressure sensor for measuring the pressure of the gaseous fuel at the inlet, which provides a further pressure sensor signal that can be used to regulate the fuel flow; and / or a further pressure sensor for measuring a pressure of the gaseous fuel at the outlet, which provides a further pressure sensor signal for signal backup.

[0041] 4. Brief description of the drawings

[0042] Fig. i shows a schematic representation of an embodiment of a pressure regulator;

[0043] Fig. 2a shows a schematic detailed view of the proportional valve of the embodiment of a pressure regulator from Fig. 1;

[0044] Fig. 2b shows a schematic detailed view of the main valve of the embodiment of a pressure regulator from Fig. 1;

[0045] Fig. 3 shows a schematic representation of another embodiment of a pressure regulator according to the present application;

[0046] Fig. 4 shows a schematic detailed view of the main valve of the embodiment of a pressure regulator from Fig. 3;

[0047] Fig. 5 shows a further schematic detailed view of the main valve of the embodiment of a pressure regulator from Fig. 3; Fig. 6 shows a further schematic detailed view of the main valve of the embodiment of a pressure regulator from Fig. 3. Description of an exemplary embodiment

[0048] In the following, an embodiment of the present disclosure is described by way of example. Various combinations of features are described with reference to the illustrated embodiments. Naturally, not all features of the described embodiments need to be present to implement the present invention. Furthermore, the embodiments can be modified by combining certain features of one embodiment with one or more features of another embodiment - if this is technically compatible and reasonable - without deviating from the disclosure and the scope of the present invention, which is defined by the patent claims. Some features, functions, and properties of the pressure regulator that have already been generally described in Section 3 are only briefly mentioned below or not described at all to avoid repetition.

[0049] Fig. 1 shows a schematic representation of an embodiment of a pressure regulator 1 comprising an inlet 11, an outlet 12, a first pressure sensor 13 for measuring the pressure of the gaseous fuel at the outlet 12, a second pressure sensor 14 for measuring the pressure of the gaseous fuel at the inlet 11, and a temperature sensor 15, each of which is attached to the base body of the pressure regulator 1. Embodiments without some or all of the illustrated sensors are also possible. For example, the outlet pressure can also be measured at the inlet of a downstream consumer or in a distributor assembly.

[0050] The inlet 11 and the outlet 12 are connected to a main valve 16 by a line through the base body of the pressure regulator 1. The main valve 16 comprises a main valve inlet 17, a main valve outlet 18, a main valve secondary inlet (not in the sectional plane), and a control piston 20 movable within the main valve 16 for regulating the fuel flow through the main valve 16. In a closed position, the control piston 20 blocks a path between the main valve inlet 17 and the main valve outlet 18, so that no gas can flow from the main valve inlet 17 to the main valve outlet 18. In an open position, the control piston 20 opens a path between the main valve inlet 17 and the main valve outlet 18, so that gas can flow from the main valve inlet 17 to the main valve outlet 18.

[0051] The control piston 20 controls the fuel flow by moving a shut-off body 23 against the spring 24. The shut-off body 23 thereby detaches from the sealing seat of the main valve 16 and opens a flow path from the main valve inlet 17 to the main valve outlet 18. During operation, the shut-off body 23 is pressed against the sealing seat of the main valve not only by the spring 24, but also by the pressure of the fuel at the inlet 17. The further the control piston 20 is displaced in the direction of the spring 24, the larger the effective flow cross-section through the main valve. The main valve 16 is thus configured to control the gas flow between the inlet 11 and outlet 12 of the pressure regulator 1. The illustrated pressure regulator 1 further comprises an electromagnetic proportional valve 22 which is designed to deliver the inlet pressure via the main valve secondary inlet to the control piston 20 of the main valve 16 as control pressure (see also Fig. 2a).

[0052] The control piston 20 further comprises a passage 21 (in the embodiment shown comprising an adjustable throttle element) for the gaseous fuel, which is configured to reduce the control pressure acting on the control piston 20 so that it can move back into the closed position when the control pressure is reduced. This is shown in detail in Fig. 2b. A stronger electrical current flow through the solenoid coils of the proportional valve 22 results in a greater control pressure acting on the control piston 20, which thereby increases the flow through the main valve. Advantageous dimensions of the control piston 22 and the shut-off body 23 as well as further possibilities for implementing the flow are described in Section 3.

[0053] The pressure regulator 1 may further comprise (or be connected to) a control unit (not shown) that controls the proportional valve 22, at least partially based on a pressure sensor signal generated by the pressure sensor 13 in the outlet region of the pressure regulator. The control unit compares the pressure sensor signal with a setpoint for the outlet pressure and, if there is a deviation from the setpoint, changes the current flow through the solenoid coils of the proportional valve 22 to increase or reduce the control pressure on the control piston 22. This also increases or reduces the fuel flow through the main valve 16 to reduce the deviation from the setpoint. During operation and with the control loop closed, for example, increased fuel consumption by a consumer leads to a lower pressure in the outlet region 18.

[0054] The proportional valve 22 is controlled, for example, via pulse width modulation (PWM). The stroke of the proportional valve 22 and thus the control pressure on the control piston 22 can be adjusted via the pulse width of the PWM signal generated by the control unit. A change in the pulse width of the PWM signal causes the shut-off body of the proportional valve 22 to be moved towards or away from the sealing seat. In this way, the adjustable control pressure can be applied to the control piston. Preferably, the frequency of the PWM signal is high enough (e.g., >300 Hz or >1 kHz) that the proportional valve 22 can act as a low-pass filter for the PWM signal. This prevents the PWM signal from causing fluctuations in the control pressure acting on the control piston 20.

[0055] The use of a proportional valve 22 has the additional advantage that the shut-off body of the proportional valve 22 rarely touches the sealing seat during operation, thus significantly reducing wear – for example, compared to an electronically controlled shut-off valve that is either closed or open. In addition to the signal from pressure sensor 13, pressure regulator 1 can also consider other signals, such as an inlet pressure signal from sensor 14. Furthermore, the control unit can adjust its control parameters and thus the transfer function based on a signal indicating the mass or fuel flow requested by a consumer.

[0056] The pressure regulator 1 can further comprise a pressure relief valve 26 on the outlet side, the trigger pressure of which can be adjusted according to the area of ​​application of the pressure regulator 1. The pressure regulator 1 can also comprise a Service Interface Unit (SIU) 25. In the embodiment of Fig. 1, the SIU 25 is provided with a removable cap. After removing the cap, a standard hose can be attached to the SIU 25, e.g., with a thread. The standard hose can have a centrally and axially positioned mandrel which is configured to move a spring-loaded sealing element of the SIU 25 from its basic position, so that gas from the outlet region of the pressure regulator can be discharged through the hose in a controlled manner.

[0057] The pressure regulator 1 can further comprise an active purge valve (not shown). The active purge valve can be arranged in the position of the SIU 25 as an alternative to the latter. The active purge valve can, for example, be electromagnetically activated and can, for example, be opened for a short period of time, e.g., a few seconds, after an engine connected to the pressure regulator 1 has been stopped, in order to drain any remaining fuel from the pressure regulator 1. By integrating the SIU 25 and / or the purge valve (not shown), the pressure regulator 1 enables targeted ventilation of the low- and high-pressure areas for servicing purposes. The pressure regulator 1 can thus be provided with a shut-off mechanism.

[0058] Through the integration of the SIU 25, pressure regulator 1 also enables targeted pressure reduction in the low-pressure line between pressure regulator 1 and the consumer after the system is shut down, as well as controlled pressure reduction during extended downtimes. The example pressure regulator 1 is designed such that all integrated valves are in an NC (normally closed) configuration, which leads to increased safety in the event of a failure. The function and use of temperature sensor 15 are described in more detail in Section 3.

[0059] Fig. 2a shows a schematic detailed view of the proportional valve 22 of the embodiment of a pressure regulator 1 from Fig. 1. The proportional valve inlet 30 is connected to the inlet 11 of the pressure regulator 1 via a vertical supply line 31. As described above in Section 3 and in Fig. 1, the proportional valve 22 is designed to direct the pressure present at the inlet 30 via a line in the base body of the pressure regulator 1 (not in the sectional plane) as control pressure to the top side of the control piston 20 of the main valve 16. Fig. 2b shows a schematic detailed view of the main valve 16 of the pressure regulator 1 from Fig. 1. In Fig. 2b it can be seen in particular that the passage 21 is arranged with a throttle element in the piston bottom of the control piston 20, via which throttle element the flow cross-section of the passage 21 can be adjusted. Other embodiments of the passage 21 of the control piston 20 are described above in Section 3.For example, the passage 21 could also be integrated into the guide ring system 33 of the control piston 20, or the control piston 20 can have elongated channels on its outer wall, or the housing wall can have elongated channels. Furthermore, Fig. 2b shows the shut-off body 23 in the closed position and the spring 24. Since the surface of the control piston 20, as described in more detail in Section 3, is considerably larger than the surface of the shut-off body 23, the control pressure can be considerably lower than the inlet pressure pressing the shut-off body 23 against the sealing seat of the main valve 16. In particular, the diameter of the surface of the control piston 20 exposed to the control pressure can be in the range of 30 mm to 50 mm and / or the effective diameter of the surface of a shut-off body 23 of the main valve 16 exposed to the inlet pressure can be in the range of 1 mm to 10 mm, preferably in the range of 2 mm to 6 mm.The volume between the surface of the control piston 20, on which the control pressure acts, and the housing in which the control piston 20 moves can be in a range of 100 mm in the closed state. A 3 to 1000 mm A 3 and preferably in a range between 300 mm A 3 and 700 mm A 3 lie.

[0060] Essential aspects of the functioning of some embodiments of the pressure regulator 1 described here can also be characterized as follows using similar terms:

[0061] Pressure regulator 1 with an inlet 11 and an outlet 12, between which a first flow path and a second flow path are arranged, a shut-off body 23 for opening and closing the first flow path and a controllable valve device 22 for opening and closing the second flow path, a control piston 20 with an effective direction from the outlet 12 to the inlet 11 to move the shut-off body 23 from a closed position to an open position in which the first flow path is open and a closing spring 24 with the effective direction from the inlet 11 to the outlet 12 to move the shut-off body 23 from an open position to a closed position in which the first flow path is closed, wherein the control piston 20 connects the first and the second flow path and the control piston 20 generates a pressure drop between the valve device and the outlet of the pressurized side of the control piston 20 when the second flow path is open,to move the shut-off body 23 from the closed position to the open position by the control piston against the force of the closing spring 24 and against the pressure in the outlet.

[0062] The control piston 20 described here thus functions as a control device that transmits the differential pressure force from the control pressure and the output pressure to the shut-off body 23, thereby opening the main valve 16. Other control devices, such as a diaphragm with a passage, are also possible. Furthermore, the passage described here functions as a throttling device, allowing a pressure difference between the control pressure and the output pressure. Other throttling devices, such as a porous material for the control piston, are also conceivable.

[0063] Fig. 3 shows a further embodiment of a pressure regulator 1 according to the present application. Only essential design differences from the previously described embodiments are described below. In particular, the pressure regulator 1 illustrated in Fig. 3 comprises a further development of the electronically controllable valve 22. The electronically controllable valve 22 can be connected, in particular, to a housing of the pressure regulator 1 using a union nut 40 such that, when the union nut 40 is fixed to the housing, a sealing needle of the electronically controllable valve 22 can be moved essentially torsion-free toward an associated sealing seat of the housing. Such a design reduces the likelihood of damage and / or leaks during assembly, maintenance, and / or operation.

[0064] Furthermore, it has been shown that it can be advantageous for sealing to manufacture the sealing needle of the electronically controllable valve 22 from a metal, preferably a copper-based alloy such as brass or bronze, and the associated sealing seat of the housing from a polyamide-based plastic, preferably Vespel. Furthermore, the sealing needle can be manufactured in one piece with a valve piston of the electronically controllable valve 22. The valve piston of the electronically controllable valve 22 can also be supported on two sides, with the valve piston bearings being arranged such that they are not exposed to the flow of gaseous fuel. Such an arrangement improves the operation of the electronically controllable valve 22. In particular, vibrations of the valve piston can be reduced and the control quality improved.

[0065] The control piston 20 of the main valve 16 of the pressure regulator 1 can furthermore, as shown in Fig. 4, be movably mounted in the housing via two bearing elements 43a, 43b, and can preferably be made of a metal, preferably a copper-based alloy such as brass or bronze. Alternatively or additionally, the control piston 20 of the main valve 16 can have a spring-loaded piston ring (not shown). For example, such bearing elements provide an additional sealing and damping function for the control piston 20.

[0066] In other implementations, the control piston 20 of the main valve 16 can also be made of a plastic with suitable friction properties, such as PTFE, and feature integrated plain bearings. These design improvements of the control piston improve the vibration characteristics of the control piston 20 during operation, especially with large pressure differences and mass flows.

[0067] Furthermore, the pressure regulator 1 can have a temperature sensor 51 for measuring the temperature of the gaseous fuel as it flows toward the control piston 20. It has been shown that this measurement can be used to improve the control quality of the pressure regulator.

[0068] Furthermore, it has been shown that it is advantageous for safety during operation to design the pressure relief valve 26 such that, in the open state, it has an effective flow cross-section that is greater than the sum of the effective flow cross-section of the main valve 16 and the effective flow cross-section of the passage 21. This ensures that, in the event of a fault, strong overpressures cannot occur in the pressure regulator. To further improve safety, a bursting disc can be arranged in the medium-pressure range downstream of the main valve, e.g. in a further interface, and bursts at a pressure that is significantly greater than the normal system pressure during operation, e.g. > too bar. Alternatively or additionally, a further pressure relief valve can be provided as alternative / further protection. This further pressure relief valve has a higher opening pressure than the first pressure relief valve 26 and opens additionally if the pressure increases further.To improve the maintenance characteristics of the pressure regulator, the pressure regulator may include a manual valve 52 with which the SIU 53 can be closed and opened. The manual valve 52 may allow the SIU to be depressurized during operation, e.g., to relieve stress on this component and additionally reduce the risk of connecting a quick-release coupling under applied high pressure.

[0069] For applications with multiple consumers, e.g., trucks with multiple fuel cells, it may be useful, as shown in Fig. 6, to provide a second outlet 61 for the gaseous fuel, which is in fluid communication with the first outlet 12. This allows multiple consumption paths to be served with one pressure regulator. Another application is hydrogen combustion engines, which often require an additional connection due to their design (e.g., V-engines).

[0070] In order to further improve the safety of the pressure regulator 1 during operation and to prevent damage to the pressure regulator 1 and / or other components that are in fluid communication with the pressure regulator even in the event of unusual faults, a multi-stage safety system for the pressure regulator 1 has been developed, which has the following interacting components: a pressure relief valve 26 as described above, a rupture disc or an additional pressure relief valve as described above, and a control unit (not shown) that is designed to trigger an emergency shutdown of the electronically controllable valve 22, e.g. by resonantly short-circuiting solenoid coils of the electronically controllable valve 22 via a diode.The control unit can further be configured to detect a fault in the pressure regulator 1 based on one or more sensor signals and, in response, to trigger the emergency shutdown of the electronically controllable valve 22. Preferably, the control unit can be integrated into an engine control unit / main control unit of the system / vehicle or is implemented thereby. This allows the pressure regulator 1 with its entire sensor system to be controlled together with other valves in the system (e.g., solenoid valves of OTVs, etc.), e.g., to also be able to immediately interrupt the supply line to the pressure regulator 1 in the event of a fault.

[0071] For example, the one or more sensor signals may comprise one or more of the following: a sensor signal from one or more temperature sensors 15 for the gaseous fuel; a sensor signal from the pressure sensor 14 and / or the pressure sensor 13 and / or a difference thereof (i.e., a pressure difference before and after the main valve 16); a sensor signal from a mass flow sensor arranged in the flow path after the outlet 12, which preferably measures a mass flow of the gaseous fuel at the inlet of a fuel cell or an internal combustion engine.

[0072] In this way, typical error cases can be reliably prevented and the probability of system failure or serious damage can be greatly reduced.

Claims

Patent claims 1. A pressure regulator (i) for a gaseous fuel, in particular hydrogen gas, comprising: an inlet (11) for the gaseous fuel at an inlet pressure; an outlet (12) for the gaseous fuel; a main valve (16) comprising a main valve inlet (17), a main valve outlet (18), a main valve secondary inlet, and a control piston (20) in a housing that controls the fuel flow from the inlet (11) through the main valve (16) to the outlet (12); and an electronically controllable valve (22), in particular a proportional valve (22), configured to deliver the inlet pressure via the main valve secondary inlet to the control piston (20) of the main valve (16) as a control pressure and thereby control the fuel flow based on at least one pressure sensor signal indicating the pressure of the gaseous fuel at the outlet (12) of the pressure regulator (1);wherein the main valve (16) further comprises a passage (21) for the gaseous fuel, which is designed to reduce the control pressure acting on the control piston (20) and is preferably arranged in the control piston and / or the housing; 2. Pressure regulator (1) according to claim 1, wherein a volume between a surface of the control piston (20) on which the control pressure acts and a housing in which the control piston moves, in the closed state, in a range of 100 mm A 3 to 1000 mm A 3, preferably in a range between 300 mm A 3 and 700 mm A 3; and / or wherein a volume of a connecting bore from the outlet of the electronically controllable valve to the secondary inlet of the main valve is in the range between 40 mm A 3 and 500 mm A 3, preferably in the range between 100 mm A 3 and 250 mm A3; and / or wherein an output volume of the electronically controlled valve is in the range between 400 mm A 3 and 1200 mm A 3, preferably in the range between 650 mm A 3 and 950 mm A 3 lies. 3- Pressure regulator (1) according to one of claims 1 or 2, wherein a diameter of the surface of the control piston exposed to the control pressure is in the range of 30 mm to 50 mm; and / or wherein a diameter of a surface of a shut-off body of the main valve (16) exposed to the inlet pressure is in the range of 1 mm to 10 mm, preferably in the range of 2 mm to 6 mm.

4. Pressure regulator (1) according to one of claims 1 to 3, wherein the passage (21) is arranged in the control piston bottom, in the circumference of the control piston (20) and / or as a bypass in a guide ring system of the piston, and / or wherein the passage (21) is implemented via a check valve integrated in the control piston, via a filter, a gap between the control piston and the housing wall, via one or more channels in the wall of the control piston or in the housing wall, and / or via a flow pad due to a surface roughness of the wall of the control piston and / or the housing wall.

5. Pressure regulator (1) according to one of claims 1 to 4, wherein the passage (21) comprises a throttle element which influences how the control pressure is reduced, wherein the throttle element is preferably adjustable.

6. Pressure regulator (1) according to one of claims 1 to 5, wherein the main valve (16) is adapted to set a variable fuel flow rate in the range from 0.02 g / s to 50 g / s, wherein the pressure at the outlet (12) is adjustable in a range between 1 bar and 60 bar.

7. Pressure regulator (1) according to one of claims 1 to 6, further comprising a device for temperature control by means of heating and / or cooling.

8. Pressure regulator (1) according to claim 7, wherein the temperature control device comprises cooling channels in the region of a main valve body of the main valve (16) for liquid-based cooling of the main valve (16) and / or an electric heater for heating the main valve (16). 9- Pressure regulator (1) according to one of claims 1 to 8, further comprising a control unit which controls the electronically controllable valve (22) at least partially based on the at least one pressure sensor signal, preferably using pulse width modulation.

10. Pressure regulator (1) according to one of claims 1 to 9, further comprising at least one temperature sensor (15) for detecting the temperature of the gaseous fuel in the pressure regulator (1).

11. Pressure regulator (1) according to one of claims 1 to 10, wherein the electronically controllable valve (22) has a maximum stroke of up to 15 mm, preferably up to 10 mm, even more preferably up to 5 mm.

12. Pressure regulator (1) according to one of claims 1 to 11, wherein the electronically controllable valve (22) is designed to accommodate pressures of up to 1500 bar, up to 1200 bar, up to 1000 bar or up to 700 bar in a housing of the electronically controllable valve.

13. Pressure regulator (1) according to one of claims 1 to 12, further comprising: a pressure relief valve (26) which is arranged in the flow path downstream of the main valve (16) and opens at a pressure which is greater than the controllable output pressure of the pressure regulator, preferably at a pressure of more than 30 bar or more than 70 bar; and / or a service interface unit, SIU, (53) which is arranged in the flow path downstream of the main valve (16); and / or an electronically controllable venting valve which is arranged in the flow path downstream of the main valve (16); and / or a manual valve (52) with which the SIU (53) can be closed and opened.

14. Pressure regulator (1) according to one of claims 1 to 13, further comprising: a pressure sensor (14) for measuring a pressure of the gaseous fuel at the outlet (12), which provides the pressure sensor signal; and / or a pressure sensor (13) for measuring the pressure of the gaseous fuel at the inlet (11), which provides a further pressure sensor signal that can be used to regulate the fuel flow; and / or a further pressure sensor for measuring a pressure of the gaseous fuel at the outlet (12), which provides a further pressure sensor signal for signal protection.

15. Pressure regulator (1) according to one of claims 1 to 13, wherein all valves of the pressure regulator (1) are in an NC configuration (NC: normally closed).

16. Pressure regulator (1) according to one of claims 1 to 15, wherein the electronically controllable valve (22) can be connected to a housing of the pressure regulator by means of a union nut in such a way that, when the union nut is fixed to the housing, a sealing needle of the electronically controllable valve (22) can be moved essentially torsion-free towards an associated sealing seat of the housing; and / or wherein the sealing needle is made of a metal, preferably of a copper-based alloy, such as brass or bronze, and wherein the associated sealing seat of the housing is made of a polyamide-based plastic, preferably of Vespel; and / or wherein the sealing needle is made in one piece with a valve piston of the electronically controllable valve (22);and / or wherein the valve piston of the electronically controllable valve (22) is mounted on two sides, the bearings of the valve piston being arranged such that they are not exposed to the flow of gaseous fuel; 17. Pressure regulator (1) according to one of claims 1 to 16, wherein the control piston (20) of the main valve (16) is movably mounted in the housing via two bearing elements (43a, 43b) and is preferably made of a metal, preferably of a copper-based alloy, such as brass or bronze; and / or wherein the control piston (20) of the main valve (16) has a spring-loaded piston ring; and / or wherein the control piston (20) of the main valve (16) is made of a plastic, preferably of PTFE, and has integrated plain bearings that provide a sealing and damping function.

18. Pressure regulator (i) according to one of claims 10 to 17, wherein the one or more temperature sensors (15) comprise a temperature sensor (51) for measuring a temperature of the gaseous fuel when flowing towards the control piston (20) of the main valve (16).

19. Pressure regulator (1) according to one of claims 13 to 18, wherein the pressure relief valve (26) in the open state has an effective flow cross-section which is greater than a sum of an effective flow cross-section of the main valve (16) and an effective flow cross-section of the passage (21).

20. Pressure regulator (1) according to one of claims 1 to 19, further comprising a rupture disc in fluid communication with the flow path downstream of the main valve and bursting at a pressure of >100 bar; and / or a further pressure relief valve having a greater opening pressure than the pressure relief valve (26), which is preferably >100 bar.

21. Pressure regulator (1) according to one of claims 1 to 20, further comprising a second outlet (61) for the gaseous fuel, which is connected to the outlet (12) is in fluid communication.

22. A multi-stage safety system for the pressure regulator (1) according to one of claims 1 to 21, comprising: a pressure relief valve (26); a control unit configured to trigger an emergency shutdown of the electronically controllable valve (22); and optionally a rupture disc and / or an additional pressure relief valve.

23. Safety system according to claim 22, wherein the control unit is configured to detect a fault in the pressure regulator (1) based on one or more sensor signals and, in response thereto, to trigger the emergency shutdown of the electronically controllable valve (22). 24- Safety system according to claim 23, wherein the one or more sensor signals comprise one or more of the following: a sensor signal from one or more temperature sensors (15) for the gaseous fuel; a sensor signal from the pressure sensor (14) and / or the pressure sensor (13) and / or a difference thereof; a sensor signal from a mass flow sensor arranged in the flow path after the outlet (12), which preferably measures a mass flow of the gaseous fuel at the inlet of a fuel cell or an internal combustion engine.

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