Shut-off valve and hydrogen tank system with shut-off valve

Description

[0001] The invention relates to a shut-off valve for hydrogen tank systems. Furthermore, the invention relates to a hydrogen tank system with a shut-off valve according to the invention. State of the art

[0002] For solenoid valves with large strokes, such as shut-off valves for hydrogen tank systems, magnetic actuators with immersion armatures are typically used. This is because, with these, the magnetic force decreases less sharply with increasing distance between the armature and its fixed stop than with flat armature designs.

[0003] German patent application DE 10 2018 221 602 A1 discloses, by way of example, a hydrogen storage tank with an electromagnetically actuated valve assembly. The valve assembly has a movable valve element that interacts with a valve seat for opening and closing an outlet. The valve element is acted upon by a spring force in the direction of the valve seat, so that the valve assembly is closed when the solenoid coil is not energized. In the open position, the valve element exposes an outlet with a diameter of [diameter missing in original text] and an adjoining through-channel. The valve element also forms a magnetic armature that operates according to the plunger armature principle. When the solenoid coil is energized, a magnetic field is generated surrounding the coil, the field lines of which extend over an outer pole body, an inner pole body, and the magnetic armature.The magnetic field lines run across a radial and an axial air gap between the magnetic armature and the outer pole body. The magnetic force generated in the axial air gap lifts the magnetic armature, or the valve element, out of the sealing seat against the spring force, thus opening the solenoid valve.

[0004] US 2014 / 239207 A1 discloses a shut-off valve for hydrogen tank systems, comprising a main valve with a stroke-moving main valve piston, which at one end delimits a control chamber, at the other end interacts with a main valve seat and is acted upon in the direction of the main valve seat by the spring force of a spring, as well as an annular solenoid coil for acting on an end section of the main valve piston designed as a diving armature.

[0005] US Patent 2018 / 038507 discloses a valve device comprising: a main valve element dividing the space of a valve element of a housing into the first and second pressure chambers; a sealing element configured to isolate the first and second pressure chambers from each other; a first pilot passage having one end connected to a primary passage and the other end connected to a second pressure chamber and a first throttle.

[0006] From DE 10 2018 221600 A1 a method for operating a tank device for storing compressed fluids is known, comprising a tank, a valve device, a supply line, a flow control element arranged in the supply line and a control unit, wherein the valve device includes a magnetic device by means of which the opening and closing process of the valve device can be controlled.

[0007] WO 2020 / 158728 A1 discloses a solenoid valve for gas, which is provided with a housing having a first port, a second port and a valve opening, a main valve body which is able to move between a closed and an open position and which moves in the opening direction by means of the pressure of the gas supplied from the first port.

[0008] US 2015 / 184805 A1 discloses an arrangement for a liquid control valve, including: a main valve body with a first flow channel mounted on an inlet through which a filling source gas flows, a second flow channel through which a supply source gas flows, and a third flow channel to which the first flow channel and the second flow channel are connected.

[0009] US Patent 6,675,831 B2 discloses a high-pressure vessel device comprising: a high-pressure vessel into which high-pressure gas is introduced; and a valve mechanism provided at a gas outlet of the high-pressure vessel such that it is located inside the vessel.

[0010] In a solenoid valve with a plunger, as described by way of example in DE 10 2018 221 602 A1, the field coupling via the radial air gap leads to a weakening of the magnetic field in the axial air gap. The result is a reduction in the magnetic force acting on the armature in the opening direction. This means that a larger solenoid coil is required, which increases the energy consumption and installation space requirements.

[0011] The present invention attempts to remedy this situation, in particular to enable the use of a smaller magnetic coil.

[0012] To solve the problem, a shut-off valve with the features of claim 1 is proposed. Advantageous embodiments of the invention are described in the dependent claims. Furthermore, a hydrogen tank system with a shut-off valve according to the invention is described. Disclosure of the invention

[0013] The proposed shut-off valve for hydrogen tank systems includes a main valve with a stroke-moving main valve piston, which at one end delimits a control chamber, at the other end interacts with a main valve seat and is acted upon in the direction of the main valve seat by the spring force of a spring, a control valve for controlling the stroke movements of the main valve piston, wherein the control valve has a control valve armature which is arranged at an axial distance coaxial to the main valve piston and is acted upon by the spring force of the spring or of another spring in the direction of a control valve seat, and an annular solenoid coil for actuating the control valve and for acting upon an end section of the main valve piston designed as a plunger armature.

[0014] The indirect control of the main valve via the pilot valve allows for the use of a smaller solenoid coil, as it only needs to provide the force required to open the pilot valve. Opening the pilot valve causes a pressure drop in the control chamber, thus reducing the pneumatic forces acting on the main valve piston in the closing direction. Because the pilot chamber end section of the main valve piston also acts as a plunger, an additional magnetic force is exerted on the piston. The combination of pneumatic and magnetic forces then opens the main valve.

[0015] Opening the shut-off valve therefore requires less magnetic force, allowing the use of a smaller solenoid coil. This results in savings in both energy and installation space.

[0016] According to a preferred embodiment of the invention, the control chamber can be pressurized with gas from a storage volume via an inlet throttle, abbreviated as Z-throttle, and can be relieved via the control valve seat when the control valve is open. The control valve seat, or a bore downstream of the control valve seat, acts as an outlet throttle, abbreviated as A-throttle. When the control valve is open, the gas flows from the storage volume into the control chamber via the Z-throttle and from there into an outlet via the A-throttle. Pneumatically, the control chamber is thus located between the storage volume and the outlet. A pressure level between the storage pressure and the outlet pressure is therefore established in the control chamber. After the control valve is closed and the A-throttle is closed, pressure can be built up again in the control chamber via the inlet throttle.If the shut-off valve is used in a hydrogen tank system, the gas is preferably hydrogen. This means that the control chamber is supplied with hydrogen via the inlet throttle, preferably from a storage volume of a pressure vessel within the hydrogen tank system, so that the control chamber is pressurized to the storage pressure. High pressure then prevails in the control chamber, while on the control side, a lower pressure exists depending on the operating point, for example, in the case of a flow rate being drawn due to the seat throttling at the main valve. The pressure differential creates a pneumatic force which, together with the spring force of the at least one spring, ensures that the shut-off valve closes and remains closed when the solenoid coil is de-energized. Even at operating points without flow rate being drawn and therefore without a pressure drop at the main valve seat, the main valve is reliably closed or held closed by the spring force.

[0017] A guide gap can be used as an inlet restrictor. This gap exists between the end section of the main valve piston, designed as a plunger, and a housing-side guide section that receives the end section. In this case, no further measures are required to form the inlet restrictor. Alternatively or additionally, the end section of the main valve piston, designed as a plunger, can have at least one longitudinal groove and / or flattening to form the inlet restrictor. This allows for a larger and / or more defined restrictor cross-section. In a further advantageous embodiment, a sealing element is provided in the guide area, pneumatically separating the control chamber from the accumulator pressure. In this case, the inlet restrictor is implemented via an additional restrictive connection between the accumulator volume and the control chamber, for example, via a restrictor bore on the housing, valve, or seal side.

[0018] The control valve armature is preferably designed as a flat armature. To optimize the field line guidance, it is further proposed that the flat armature maintain a radial clearance around the entire housing of the shut-off valve. This clearance ensures that when the solenoid coil is energized, a magnetic field is generated whose field lines are predominantly guided through the axial working air gap, resulting in a high force acting on the control valve armature.

[0019] The at least one spring of the shut-off valve is preferably housed in the control chamber, which thus also serves as the spring chamber. If there is only one spring, it can be supported on one side by the main valve piston and on the other by the control valve armature. Using only one spring reduces the number of components. However, the spring force must be matched to the force required to close the main valve, so it may be oversized for closing the control valve. This force must then be provided by the solenoid coil to open the control valve. Therefore, to allow for an even smaller solenoid coil, it is advantageous to include a second spring, which is smaller and matched to the control valve. To accommodate the two springs, the control chamber is preferably divided by a partition with a flow-through opening, creating two spring chambers connected via the flow-through opening.The partition also serves to support the two springs on the housing side.

[0020] Furthermore, it is proposed that the main valve piston has or forms an annular collar with a stop surface, preferably in which at least one radially extending flow channel is formed. The annular collar, together with a stop surface on the housing side, forms a stroke stop. In contact with the stroke stop, the at least one radially extending flow channel ensures that the inlet throttle remains pneumatically connected to the storage volume. The annular collar can be formed, for example, by a local thickening of the main valve piston. Alternatively, the main valve piston can have a separate ring- or sleeve-shaped part that is arranged on the outer circumference of the main valve piston and connected to it by force-fit, form-fit, and / or material-fit.

[0021] In a further development of the invention, it is proposed that the main valve piston has a section designed as a flat armature, in which at least one flow opening and / or a radially extending flow channel is / are formed. Due to its larger diameter, the section of the main valve piston designed as a flat armature has a larger magnetic interface than the section designed as a plunger armature, resulting in a higher force acting on the main valve piston. The design of the main valve piston as a plunger and flat armature thus enables further optimization of the magnetic field line guidance, in which the field lines of the magnetic circuit are predominantly guided through axial working air gaps. The opening of the main valve piston is then achieved by the applied pneumatic pressure conditions and by the magnetic forces acting on the two armature sections.

[0022] Furthermore, it is proposed that the solenoid coil exhibits increased magnetic resistance in a region interacting with the flat armature section of the main valve piston. This increased magnetic resistance further amplifies the field lines as they pass through the flat armature section of the main valve piston, resulting in a greater force on the armature. In extreme cases, this region can even reach saturation.

[0023] The section of the main valve piston designed as a flat armature can simultaneously form a stop surface, which interacts with a stop surface on the housing side to form a stroke stop. In this case, the flat armature replaces an annular collar. The at least one flow opening and / or the at least one radially extending flow channel formed in the flat armature then ensures the pneumatic connection of the inlet throttle to the storage volume.

[0024] Preferably, the control valve armature has at least one flow-through opening to relieve pressure in the control chamber. This at least one flow-through opening ensures that the control chamber can be relieved via the open control valve when the control valve armature is at full stroke. The at least one flow-through opening can, for example, be designed as an angled bore through which the control chamber remains connected to the control valve seat.

[0025] A preferred application area for a shut-off valve according to the invention is hydrogen tank systems, and a hydrogen tank system is further proposed that comprises at least one pressurized gas container and a shut-off valve according to the invention for shutting off the pressurized gas container. The hydrogen tank system can be used, in particular, in a fuel cell vehicle or in a vehicle with hydrogen combustion.

[0026] Preferred embodiments of the invention and their advantages are explained in more detail below with reference to the accompanying drawings. These show: Figur 1 a)-e) each a schematic longitudinal section through a first shut-off valve according to the invention in different switching positions, Figur 2 a)-e) each a schematic longitudinal section through a second shut-off valve according to the invention in different switching positions, Figur 3 a)-e) each a schematic longitudinal section through a third shut-off valve according to the invention in different switching positions and Figur 4 a)-e) each a schematic longitudinal section through a fourth shut-off valve according to the invention in different switching positions. Detailed description of the drawings

[0027] The in the Figure 1 (a)-e)The illustrated shut-off valve 1 has a main valve 2 with a movable main valve piston 3, which interacts with a main valve seat 4 and is acted upon in the direction of the main valve seat 4 by the spring force of a spring 5. At its end opposite the main valve seat 4, the main valve piston 3 defines a control chamber 6, which is connected via an inlet restrictor 13 to gas from a storage volume of a pressurized gas container (not shown). The gas flows from the storage volume of the pressurized gas container via a gas line 26 into a valve chamber 27 and from there via the inlet restrictor 13 into the control chamber 6. In this case, the inlet restrictor 13 is formed by the guide clearance of a housing-side guide section for guiding the main valve piston 3. Thus, storage pressure or high pressure prevails in the control chamber 6 and in the valve chamber 27.On the control side, i.e., in a gas line 25, a pressure level is typically lower than the storage pressure. The applied pneumatic pressure conditions and the spring force of the spring 5 therefore push the main valve piston 3 into the main valve seat 4, so that the main valve 2 is closed.

[0028] To open the main valve 2, an annular solenoid coil 11 is used to act on a control valve armature 8 of a control valve 7, which is designed as a flat armature. The energizing of the solenoid coil 11 leads to the formation of a magnetic field, the magnetic force of which lifts the control valve armature 8 out of the control valve seat 10, so that the control valve 7 opens (see Fig. 1bBecause the control valve armature 8 is designed as a flat armature, a high magnetic force acts upon it. Furthermore, the field line guidance of the magnetic circuit is optimized by maintaining a radial distance a between the flat armature and a housing 14, so that the field lines are predominantly guided through the axial working air gap.

[0029] When the control valve 7 is open, gas flows from the control chamber 6 into the gas line 25, causing the pressure in the control chamber 6 to drop. Flow openings 24 formed in the control valve armature 8 ensure that gas can flow out of the control chamber 6 even when the control valve armature 8 is at its full stroke.

[0030] The pressure drop in the control chamber 6 leads to a reduction in pressure on the main valve piston 3, while the pressure increases on the control side, i.e., in the gas line 25. Since a control chamber-side end section 12 of the main valve piston 3 is designed as a plunger, the magnetic force of the solenoid coil 11 also acts on it, so that ultimately a combination of pneumatic and magnetic force leads to the opening of the main valve 2 (see Fig. 1c )). An annular collar 17 formed on the main valve piston 3 with a stop surface 18 limits the opening stroke of the main valve piston 3. At full opening stroke of the main valve piston 3, radially extending flow channels 19 formed in the annular collar 17 ensure that the inlet throttle 13 remains connected to the valve chamber 27 and thus to the storage volume of the pressure gas container.

[0031] To close the main valve 2, the current to the solenoid coil 11 is terminated, so that the spring 5 returns the control valve armature 8 to the control valve seat 10 and closes the control valve 7 (see Fig. 1d Since no more gas flows out of the control chamber 6, it fills with gas via the inlet throttle 13, causing the pressure in the control chamber 6 to rise again. The pneumatic pressure conditions result in a pneumatic force which, together with the spring force of the spring 5, returns the main valve piston 3 to the main valve seat 4, thus closing the main valve 2 (see Fig. 1e )).

[0032] The Figure 2a )-e) shows a further preferred embodiment of a shut-off valve 1 according to the invention. This differs from that of the Figure 1a)-e) in particular by the fact that the main valve piston 3 has not only an end section 12 designed as a plunger, but also a section 20 designed as a flat armature. In a region 23 interacting with the flat armature, the solenoid coil 11 also has an increased magnetic resistance, so that these measures ensure that the field lines are guided more strongly through the section designed as a flat armature. This results in an increased magnetic force acting on the main valve piston 3. The section 20 designed as a flat armature also replaces the annular collar 17, so that the stroke stop is formed by the section 20. At full opening stroke of the main valve piston 3, the pneumatic connection of the inlet throttle 13 to the valve chamber 27 is ensured by at least one flow opening 21 formed in the flat armature section and a flow channel 22.

[0033] The operating principle of shut-off valve 1 of the Figure 2a)-e) corresponds to that of shut-off valve 1 of the Figure 1a )-e). The Figur 2a Figure 1 shows the shut-off valve 1 with the solenoid coil 11 de-energized, i.e., in the closed state. To open the valve, the solenoid coil 11 is energized, creating a magnetic field whose magnetic force lifts the control valve armature 8 of the control valve 7 out of the control valve seat 10 (see Figure 1). Figur 2b With the control valve 7 open, gas flows from the control chamber 6 into the gas line 25, causing the pressure in the control chamber 6 to drop. This pressure drop relieves the main valve piston 3, so that the forces acting on the main valve piston 3 in the opening direction become dominant and the main valve 2 opens (see Figur 2c )). To close, the current to the solenoid coil 11 is cut off, so that spring 5 returns the control valve armature 8 to the control valve seat 10 (see 2D FigureWith the control valve 7 closed, the pressure in the control chamber 6 rises again, as it is pneumatically connected to the valve chamber 27 via the inlet throttle 13. Similarly, the pressure in the pressure chamber 6 also rises, so that the forces acting on the main valve piston 3 in the closing direction predominate and the main valve piston 3 is returned to the main valve seat 4 (see Figur 2e )).

[0034] The in the Figuren 3a )-e) The shut-off valve 1 according to the invention is a further development of the shut-off valve 1 of the Figure 1a)-e). Instead of a common spring 5, two springs 5, 9 are accommodated in the control chamber 6. The control chamber 6 is divided into two spring chambers by an intermediate wall 15 with a central flow opening 16, so that both springs 5, 9 can be supported against the intermediate wall 15. The additional spring 9 can be designed to be smaller than the spring 5, since it only needs to close the control valve 7. Accordingly, the magnetic force required to open the control valve 7 is reduced, so that a smaller solenoid coil 11 can be used. The operating principle of the shut-off valve 1 of the Figuren 3a )-e) corresponds, incidentally, to that of shut-off valve 1 of the Figure 1a )-e), so that, to avoid repetition, reference is made to the corresponding description.

[0035] The in the Figure 4a )-e) The shut-off valve 1 according to the invention is a further development of the shut-off valve 1 of the Figure 2a)-e). Instead of a common spring 5, two springs 5, 9 are also accommodated in the control chamber 6. The control chamber 6 is divided into two spring chambers by an intermediate wall 15 with a central flow opening 16, so that both springs 5, 9 can be supported against the intermediate wall 15. The additional spring 9 can be designed to be smaller than the spring 5, since it only needs to close the control valve 7. Accordingly, the magnetic force required to open the control valve 7 is reduced, so that a smaller solenoid coil 11 can be used. Since the operation of the shut-off valve 1 of the Figure 4a )-e) in addition, the shut-off valve 1 of the Figure 2a )-e) corresponds to the relevant description to avoid repetition.

Claims

1. Shut-off valve (1) for hydrogen tank systems, comprising a main valve (2) with a main valve piston (3) which is able to perform stroke movements, delimits a control chamber (6) at one end, interacts with a main valve seat (4) at the other end and is subjected to the spring force of a spring (5) in the direction of the main valve seat (4), and comprising an annular magnet coil (11) for acting on an end portion (12), in the form of a plunger-type armature, of the main valve piston (3), characterized in that the shut-off valve (1) comprises a control valve (7) for controlling the stroke movements of the main valve piston (3), wherein the control valve (7) has a control valve armature (8) which is arranged coaxially with and at an axial distance from the main valve piston (3) and which is subjected to the spring force of the spring (5) or of a further spring (9) in the direction of a control valve seat (10), wherein the magnet coil (11) actuates the control valve.

2. Shut-off valve (1) according to Claim 1, characterized in that the movements of the main valve piston (3) and the control valve armature (8) are in opposite directions.

3. Shut-off valve (1) according to Claim 1 or 2, characterized in that the control chamber (6) is able to be charged with a gas, preferably with hydrogen, from a storage volume via an inflow throttle (13) and, with the control valve (7) open, is able to be relieved of pressure via the control valve seat (10).

4. Shut-off valve (1) according to Claim 3, characterized in that the end portion (12) of the main valve piston (3) in the form of a plunger-type armature has at least one longitudinal groove and / or flattening for forming the inflow throttle (13).

5. Shut-off valve (1) according to one of the preceding claims, characterized in that the control valve armature (8) is in the form of a flat armature, which preferably maintains a distance (a) from a housing (14) circumferentially in a radial direction.

6. Shut-off valve (1) according to one of the preceding claims, characterized in that the at least one spring (5, 9) is accommodated in the control chamber (6), which is preferably subdivided by an intermediate wall (15) with a throughflow opening (16).

7. Shut-off valve (1) according to one of the preceding claims, characterized in that the main valve piston (3) has or forms a ring-like collar (17) with a stop surface (18), in which there is preferably formed at least one radially extending flow channel (19).

8. Shut-off valve (1) according to one of the preceding claims, characterized in that the main valve piston (3) has a portion (20) in the form of a flat armature, in which at least one throughflow opening (21) and / or one radially extending flow channel (22) are / is formed.

9. Shut-off valve (1) according to Claim 8, characterized in that the magnet coil (11) has an increased magnetic resistance in a region (23) which interacts with that portion (20) of the main valve piston (3) which is in the form of a flat armature.

10. Shut-off valve (1) according to one of the preceding claims, characterized in that the control valve armature (8) has at least one throughflow opening (24) for relieving the control chamber (6) of pressure.

11. Hydrogen tank system comprising at least one compressed gas container and one shut-off valve (1) according to one of the preceding claims for shutting off the compressed gas container.