Method for producing a fuel rail for a pressure vessel system, fuel rail, pressure vessel system and motor vehicle

Abstract

The technology disclosed in the present invention relates to a method for manufacturing a fuel rail for a pressure vessel system, a fuel rail, a pressure vessel system, and a motor vehicle. The method comprises the following steps: providing a preferably straight fuel line; forming a plurality of rail connectors (210), wherein the rail connectors (210) have an enlarged cross-section relative to the provided fuel line, and wherein the rail connectors (210) are integrally formed with the fuel line.

Description

Background Art

[0001] Motor vehicles with pressure vessels are known from the prior art. Typically, each vehicle is equipped with up to three large pressure vessels. Due to their size, these pressure vessels are difficult to integrate into the vehicle. Furthermore, there are vehicle designs in which significantly more pressure vessels are integrated into the vehicle, each individual pressure vessel being essentially tubular. Pressure vessel systems with multiple storage tubes can be better integrated into existing installation space. However, these pressure vessel systems are relatively complex and expensive, as they must meet the same requirements for range and component safety as conventional pressure vessel systems. Furthermore, the probability of leaks increases with the relatively large number of connections. Summary of the Invention

[0002] A preferred objective of the technology disclosed in this application is to reduce or eliminate at least one disadvantage of prior art solutions or to provide an alternative solution. A particularly preferred objective of the technology disclosed in this application is to provide a relatively simple, cost-effective, reliable, lightweight, and / or space-optimized pressure vessel system. Further preferred objectives can be derived from the beneficial effects of the technology disclosed in this application. These objectives are achieved by the subject matter of the independent claims. The dependent claims constitute preferred embodiments.

[0003] The technology disclosed in this application relates to a pressure vessel system for a motor vehicle (e.g., a car, motorcycle, or commercial vehicle). The pressure vessel system includes at least one, and preferably multiple, pressure vessels for storing fuel. The pressure vessel system is used to store fuel in a gaseous state under ambient conditions. The pressure vessel system can be used, for example, in a motor vehicle operating on compressed natural gas (also known as CNG), liquefied natural gas (also known as LNG), or hydrogen. The pressure vessel system is fluidically connected to at least one energy converter configured to convert the chemical energy of the fuel into another energy form, such as a fuel cell or an internal combustion engine.

[0004] A pressure vessel may be, for example, a high-pressure gas container. A high-pressure gas container is designed to permanently store fuel at a nominal working pressure (also known as nominal working pressure, or NWP) of at least 350 bar (overpressure relative to atmospheric pressure) or at least 700 bar at ambient temperature. The pressure vessel may have a circular or oval cross-section. For example, multiple pressure vessels may be provided, their longitudinal axes extending parallel to one another in the installed position. Each pressure vessel may have a length-to-diameter ratio of 4 to 200, preferably 5 to 100, and particularly preferably 6 to 50. The length-to-diameter ratio is the quotient of the total length of the pressure vessels (e.g., the total length of the storage pipe without fluid connections) as the numerator and the maximum outer diameter of the pressure vessel as the denominator. The pressure vessels may, for example, be arranged directly adjacent to one another at a distance of less than 20 cm, less than 15 cm, less than 10 cm, or less than 5 cm. The pressure vessels may be mechanically coupled to one another at one or both ends. Furthermore, it can be advantageous to provide a common body connection element for each of the multiple pressure vessels at both ends, by means of which the pressure vessels can be secured in the motor vehicle. This system is particularly suitable for flat installation spaces, particularly in the floor area below the vehicle interior. In a preferred embodiment, the multiple pressure vessels together with the body connection element form a pressure vessel assembly. The pressure vessel assembly can advantageously be accommodated in a housing. This pressure vessel assembly (possibly with the housing) is typically integrated into the motor vehicle as a single component.

[0005] The pressure vessel includes a connecting piece. The connecting piece forms the pressure vessel opening of the pressure vessel. Typically, the connecting piece is arranged at one end of the pressure vessel. The connecting piece is preferably made of metal and is often also referred to as a "boss." The connecting piece is preferably arranged coaxially with the longitudinal axis of the pressure vessel. The connecting piece is used to form a fluid connection between the fuel storage volume of the pressure vessel and the energy converter of the motor vehicle. A portion of the connecting piece is guided out of the pressure vessel. Another portion can be integrated into the vessel wall. In other words, the connecting piece can be constructed integrally with the pressure vessel or installed therein. However, it is also conceivable that the connecting piece be installed outside the pressure vessel. For example, the connecting piece can include a section that extends into the vessel wall and is surrounded by a fiber-reinforced layer. This fiber-reinforced layer can also be referred to as a reinforcement and is generally applied by braiding and / or winding. Preferably, the connecting piece includes an end face that typically extends approximately parallel to a plane oriented perpendicular to the longitudinal axis of the pressure vessel. The connecting piece preferably does not include a separate fuel tank shut-off valve, but is instead connected to the common valve unit disclosed herein via a fuel-conducting section. In one embodiment, a line rupture safety valve can be provided in each of the fuel storage volume and in the connection piece of the at least one pressure vessel, which prevents fuel from escaping from the pressure vessel in the event of a fault. This line rupture safety valve prevents uncontrolled release of fuel in the event of a line rupture in the line system downstream of the fuel supply system and automatically resets when the fault has been resolved.

[0006] The portion of the outer surface of the connecting piece extending from the pressure vessel comprises a sealing surface and a curved fixing surface. The sealing surface can be configured as a truncated cone or funnel-shaped surface that tapers into the connecting piece. The sealing surface is configured to seal the fluid connection between the pressure vessel and a fuel-conducting section of the motor vehicle, particularly the fuel rail disclosed herein, when the pressure vessel is in the installed position. To this end, the outer surface of the fuel-conducting section can contact the sealing surface of the connecting piece directly or with an intervening sealing element. Preferably, the outer surface of the fuel-conducting section is curved, particularly preferably a spherical segment, which at least partially contacts the sealing surface. Therefore, if the spherical segment-shaped outer surface of the fuel-conical segment and the truncated cone-shaped sealing surface intersect, a good sealing seat is created. Furthermore, this allows for simple orientation of the pressure vessel. The curved fixing surface can be formed by a surface segment of a spherical segment or a cylinder. The fixing surface is provided for directly or immediately fixing the pressure vessel to at least one vehicle body connecting element.

[0007] A recess can be provided in the connector, which is recessed relative to the end face of the connector. The recess can be constructed to at least partially and preferably completely accommodate a section of the fuel line and, in particular, the rail joint. The recess is preferably constructed in a C-shaped or U-shaped manner along the longitudinal axis of the pressure vessel in cross section. Typically, the recess divides the end face of the connector into two circular or annular segments. These segments are opposite to each other. In a preferred embodiment, the connector includes a (preferably split) internal thread into which the (preferably split) external thread of the pressure plate engages in order to clamp the rail joint. In other words, the projection forming the end face segment preferably has an inner side. In the assembled state, the inner side faces the section of the fuel line or rail joint accommodated in the recess. Advantageously, an internal thread is provided on this inner side.

[0008] The at least one body connection element is used to directly or indirectly fix the pressure vessel to the body of the motor vehicle and can have any suitable shape. The connecting piece or body connection element is designed to transmit the forces and moments generated by the pressure vessel during operation of the motor vehicle to the body of the motor vehicle at the corresponding end, on which the connecting piece is arranged. The body connection element can have a curved and preferably spherical inner surface, the curvature of which is used to form the contact surface substantially corresponding to the curvature of the outer surface of the fixing surface. It is also conceivable to provide a clamping ring for the body connection. In this way, the largest possible contact surface can be achieved for the reliable transmission of mechanical loads. In one embodiment, the body connection element can be a beam, to which multiple pressure vessels are fixed. The beam itself can be connected to the body of the motor vehicle via a body connection point. For example, the body connection element can be a longitudinal beam or a cross beam.

[0009] The fastening surface and the sealing surface are advantageously arranged laterally on the portion of the connecting piece extending from the pressure vessel. The connecting piece may advantageously include an end face arranged in a plane extending substantially perpendicular to the longitudinal axis of the pressure vessel. The portion of the connecting piece extending from the pressure vessel may also include a circumferential surface on which (lateral) outer surfaces are provided, wherein the fastening surface and the sealing surface may be provided on these circumferential surfaces. In one embodiment, the circumferential surface may advantageously extend perpendicularly to the end face. The fastening surface and the sealing surface may be arranged relative to each other such that, in the installed position, they can be clamped relative to each other using the same at least one clamping means (e.g., a screw). In another embodiment, the fastening surface may be arranged laterally on the portion of the connecting piece extending from the pressure vessel, and the sealing surface may be provided on the end face of the extending portion of the connecting piece. This advantageously separates the vehicle body connection from the fluid connection. This may result in a more stable design and may be advantageous with respect to the layout and / or assembly of such a system. The design of the connecting piece disclosed herein is particularly advantageous and can be combined with conventional fuel supply sections or the fuel rail disclosed herein.

[0010] To form the support point, the fuel guide section and / or the vehicle body connection element can preferably clamp the portion of the connecting piece that extends outward. The connecting piece and, in particular, the fastening surface thus serve to support the pressure vessel in the motor vehicle. This type of support at the end of the pressure vessel is also known as a "neck mount."

[0011] The pressure vessel system or pressure vessel can be arranged such that fuel can flow in or out at the ends of the pressure vessel via fluid channels extending laterally, in particular perpendicularly, to the longitudinal axis of the pressure vessel. In an alternative embodiment, the pressure vessel system or pressure vessel can be designed such that fuel can flow in or out via fluid channels extending parallel to the longitudinal axis of the pressure vessel. It is particularly preferred that no (tank shut-off) valves are screwed into the connecting piece, which valves (together) form the fluid channels.

[0012] The fuel-conducting section is used to fill the pressure vessels with fuel and / or remove fuel from the pressure vessels. Preferably, the pressure in the fuel-conducting section substantially corresponds to the internal pressure of the pressure vessels. The pressure vessels are typically connected in parallel. Multiple pressure vessels are fluidically connected to one another or to one another without interruption. "Without interruption" in this context means that there are no valves between the pressure vessels that would interrupt the fluid connection during trouble-free operation. Therefore, the fuel pressures in the various pressure vessels typically have substantially the same value.

[0013] If the pressure vessel system includes multiple pressure vessels, at least one of the fuel-conducting sections disclosed herein can preferably be configured as a fuel rail. This fuel rail can also be referred to as a high-pressure fuel rail. It is typically located upstream of a (high-pressure) pressure reducer. In principle, this fuel rail can be configured similarly to a high-pressure injection rail of an internal combustion engine. The fuel rail advantageously includes multiple rail connections for direct connection to the pressure vessels. Advantageously, each rail connection is located directly on the rail housing and / or is spaced uniformly apart from one another. The fuel rail is advantageously configured to withstand approximately the same pressure as the pressure vessels connected to it.

[0014] The fuel rail can be designed to be substantially flexurally rigid. "Flexurally rigid" in this context means that the fuel rail is rigid with respect to bending, or that, during functional use, bending occurs only inconspicuously and insignificantly. In an alternative embodiment, the fuel rail can be designed to compensate for positional variations of the pressure vessel, and in particular, its connectors. A positional variation is a deviation between the actual position of the pressure vessel (during operation, during manufacturing, during maintenance use, or otherwise) and the assumed nominal position of the structure. Positional variations can result, for example, from expansion of components (e.g., the pressure vessel) due to changes in internal pressure and / or temperature. Furthermore, positional variations (positional deviations) can occur due to manufacturing tolerances. The fuel rail can be designed to compensate for tolerances perpendicular to the longitudinal axis of the pressure vessel system.

[0015] In a preferred embodiment, the fuel rail is not formed from a dedicated housing, but rather from a fuel line or fuel pipe, preferably a metal pipe, particularly preferably a stainless steel pipe. Advantageously, the fuel rail comprises only one fuel line, which interconnects multiple rail connections (e.g., at least three or at least five rail connections) without providing additional sealing points between the rail connections. The fuel line preferably has a wall thickness of 0.75 mm to 5 mm, or 1 mm to 3.5 mm, or 1.5 mm to 2 mm. The fuel line preferably has an outer diameter of 4 mm to 15 mm, or 5 mm to 12 mm, or 6 mm to 10 mm. The fuel line is preferably circular. It is also conceivable for the fuel line to have a polygonal cross-sectional geometry. In this case, for polygons with an even number of corners (e.g., a rectangle), the outer diameter corresponds to the maximum outer distance between opposing surfaces. For equilateral polygons with an odd number of corners (e.g., a pentagon), the outer diameter corresponds to the diameter of the circle defined by the outer corner vertices of the polygon. In the case of an elliptical cross-sectional geometry, the outer diameter corresponds to the maximum outer diameter.

[0016] The fuel rail can be produced particularly economically and in a fault-proof manner using the fuel line.

[0017] Each rail connector of the fuel rail has an enlarged cross-section relative to the fuel line region immediately adjacent to the rail connector, with the cross-section being perpendicular to the longitudinal axis of the fuel line in the rail connector region. The rail connector is advantageously constructed integrally with the fuel line or formed integrally therewith. The rail connector is preferably made of the same material as the fuel line. "Integral" in this context means that the rail connector cannot be removed from the fuel line without damage or, if necessary, is formed from the fuel line itself by coating with additional material. If other components also form the rail connector, they are materially connected to the fuel line. In other words, the rail connector is typically a thickened region of the fuel line, produced, for example, by forming, coating, and / or removing material, even though the fuel line itself is present in the thickened region. The fuel rail can, in particular, be made from a high-pressure line. At least one of the rail connectors is preferably spaced apart from an end of the fuel line. Thus, the rail connector is not located at each end of the fuel line, but rather at a location between the ends of the fuel line. The rail connectors are often spaced the same distance apart from one another. A rail connector hole is typically provided in at least one rail connector. This rail connector hole is a through-hole that establishes a fluid connection between the pressure vessel and a fluid channel within the fuel line. Advantageously, the through-hole can be a drilled hole, i.e., a hole formed by drilling. The rail connector hole usually extends at an angle, and preferably perpendicularly, to the longitudinal axis of the fuel line or a fluid channel formed therein.

[0018] The fuel rail can include curved subregions. These curved subregions can be formed, in particular, by a bend in the fuel line. Advantageously, any stress introduced into the fuel rail by the bend can be at least reduced by heat treatment. The curved subregions are advantageously disposed between two rail connections. The curved subregions are provided to compensate for possible positional changes of the pressure vessels in their installed position, for example, in a direction perpendicular to the longitudinal axes of the pressure vessels, which are arranged substantially parallel to each other, and / or for angular offsets of the pressure vessels relative to each other. Furthermore, thermal stresses due to differential thermal expansion can be compensated. To this end, the curved subregions of the fuel rail can be substantially elastically deformable. The shape or course of the fuel line in the curved subregions is precisely designed for this purpose. Preferably, the multiple rail connections lie on a common axis, while the curved subregions extend at least partially at a distance from the common axis. For example, the distance from the common axis can be at least 4 cm, at least 6 cm, or at least 8 cm. Advantageously, a fuel rail is proposed in which the length between two rail connections is greater than the direct distance between the sealing surfaces of two adjacent pressure vessels, thereby better compensating for any tolerances. The fuel rail, and in particular the curved subregion, can be at least partially zigzag-shaped or zigzag-shaped. Advantageously, at least one section extends at an angle to the common axis and particularly preferably perpendicular thereto, with the section being at least 4 cm, or at least 6 cm, or at least 8 cm long. In the installed position, the curved subregion can extend at least partially into the intermediate region between two directly adjacent pressure vessels. Such an intermediate region can occur, in particular, in the tapered dome region of the pressure vessels. This allows for a particularly space-saving arrangement of the fuel rail.

[0019] The at least one fuel rail and the at least one body connecting element can each clamp a plurality of pressure vessels. This advantageously allows for a particularly simple, space-saving, and cost-effective pressure vessel system that can be easily, reliably, and quickly assembled.

[0020] According to the technology disclosed herein, at least one thermally activatable pressure relief device can be directly connected to at least one of the fuel rails disclosed herein without requiring additional line sections. Alternatively or additionally, at least one thermally activatable pressure relief device can be provided on at least one pressure vessel, and preferably on each pressure vessel, preferably at the distal end, the proximal end, or both ends relative to the fuel-guiding section. For example, the thermally activatable pressure relief device can be provided in connectors and / or corresponding end pieces at the two facing ends of the pressure vessel. Thermally activatable pressure relief devices, also known as thermal pressure relief devices (TPRDs) or temperature fuses, are typically located near the pressure vessel. When exposed to heat (e.g., by a flame), fuel stored in the pressure vessel is discharged into the surrounding environment via the TPRD. Once the TPRD's trigger temperature is exceeded (heat activated), the pressure relief device discharges the fuel. Furthermore, a trigger line can be provided. Such a system for thermal pressure relief is described, for example, in German Patent Application No. DE 10 2015222252 A1.

[0021] At least one valve unit can be connected directly to the fuel rail without requiring any additional line sections, wherein the valve unit includes at least one valve that is closed when de-energized. Particularly preferably, during normal operation of the vehicle, the multiple pressure vessels are fluidically connected to the valve without interruption. The valve is a valve whose input pressure is (substantially) equal to the pressure of the multiple pressure vessels. In particular, the valve is an open-loop or closed-loop controllable valve. In Commission Regulation (EU) No. 406 / 2010 of 26 April 2010 implementing Regulation (EC) No. 79 / 2009 of the European Parliament and of the Council on the type-approval of motor vehicles powered by hydrogen, such a tank shut-off valve is also referred to as the first valve. Furthermore, the valve is used to shut off the fluid connection between the individual pressure vessels and downstream components of the fuel supply system during normal operation, for example, when the vehicle is stationary and / or when a fault has been detected and the fluid connection is to be shut off for safety reasons. Typically, no valve that is closed when de-energized is provided between the fuel storage volume of the pressure vessel and the rail connection.

[0022] The technology disclosed herein also relates to a motor vehicle having the disclosed pressure vessel system or pressure vessel. The underbody area of the motor vehicle can be divided into different underbody mounting areas by at least one beam. This beam can be provided to transfer loads applied to the vehicle during a side impact to the opposing side sills. Fuel rails can be provided on or in several or all of the underbody mounting areas, to which the pressure vessels arranged in the respective underbody mounting areas are connected. In one embodiment, it can be provided that each underbody mounting area is equipped with a high-voltage battery or pressure vessel system, depending on customer requirements.

[0023] The technology disclosed herein also includes a method for manufacturing a fuel rail for use in a pressure vessel system having multiple pressure vessels for storing fuel, particularly for manufacturing the fuel rail disclosed herein and / or for use in the pressure vessel system disclosed herein. The method includes the following steps:

[0024] - provide (preferably straight) fuel lines;

[0025] A plurality of rail connections are formed, wherein the rail connections have an enlarged cross section perpendicular to the axis AA of the fuel line relative to the provided fuel line and are formed integrally with the fuel line and cannot be detached non-destructively.

[0026] The method may include providing a rail joint connection hole in the formed rail joint. This step may be performed before or after forming the curved partial area. The rail joint connection hole may be, for example, a drilled hole, which is advantageously inserted before or after the step of forming the curved partial area.

[0027] The method may comprise the step of providing a curved local area in the fuel line, in particular a curved local area as disclosed herein.

[0028] The method may include forming multiple rail joints using a forming process, particularly rotary forging. Rotary forging, or net shape forming, is a stepwise pressure forming method in which a forming tool is arranged concentrically around the workpiece. The tool is vibrated at a high frequency with a short stroke. This results in a relative rotational motion between the tool and the workpiece.

[0029] Alternatively or additionally, material coating methods such as overlay welding, recasting, and overmolding can be used. The rail joint geometry can also be formed by applying a semi-finished product. The semi-finished product can then be compressed, glued, plastically deformed, brazed, or welded. For example, a sleeve with the rail joint geometry can be used, which is materially connected to the fuel line.

[0030] Alternatively or in addition, an etching process or a cutting process can be used to form the rail joint. Methods composed of combinations of the above methods are also conceivable. The geometric shape of the rail joint does not have to be spherical and can also be set to other geometric shapes. Usually, the front end of the rail joint is basically constructed in the shape of a spherical segment in order to form a sealed fluid connection. For example, it can be stipulated that only the front end of the rail joint is basically in the shape of a spherical segment in accordance with the purpose. For example, the rail joint can be constructed in a cylindrical shape, in particular with a dome as a front end. It is also conceivable to provide at least one sealing element, such as an O-ring, in the assembled state on the wall of the fluid channel provided in the connector. The sealing element can, for example, be supported on a cylindrical outer wall section of the rail joint and pressed against the inner wall of the fluid channel of the connecting element.

[0031] In other words, the method disclosed herein for manufacturing a fuel rail may include the following steps:

[0032] 1. Provide a straight fuel line; then

[0033] 2. Producing a thickening with the appropriate geometry (e.g. by rotary forging); then

[0034] 3. forming a plurality of connection holes in the thickened portion / geometry; and thereafter

[0035] 4. Bend the fuel line into the desired shape.

[0036] The pressure vessel can also be connected via a partially spherical fuel line. This sphere can be radially opened at one location, creating a one-piece "mini-T." The sphere with the hole can be fixed to the appropriate part of the vessel using suitable clamping devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The technology disclosed herein will now be explained with reference to the accompanying drawings. In the drawings:

[0038] Figure 1 A schematic cross-sectional view showing a first embodiment of the technology disclosed herein;

[0039] Figure 2 A schematic diagram illustrating another embodiment of the technology disclosed herein;

[0040] Figure 3 shows a schematic diagram of a fuel rail 200 according to the techniques disclosed herein;

[0041] Figure 4 Show the basis Figure 3 A schematic diagram of the positioning of the fuel rail 200;

[0042] Figure 5 Show the basis Figure 3 A schematic diagram of the assembled fuel rail 200 together with the vehicle body connection device;

[0043] Figure 6 Shown in accordance with Figure 5 A schematic cross-sectional view of an embodiment of the invention;

[0044] Figure 7 A schematic cross-sectional view illustrating another embodiment of the technology disclosed herein;

[0045] Figure 8 A schematic cross-sectional view illustrating another embodiment of the technology disclosed herein;

[0046] Figure 9 A schematic cross-sectional view illustrating another embodiment of the technology disclosed herein;

[0047] Figure 10 A schematic diagram showing an underbody area of a motor vehicle according to another embodiment;

[0048] Figure 11 A schematic diagram showing an underbody area of a motor vehicle according to another embodiment;

[0049] Figure 12 A schematic diagram illustrating another embodiment of the technology disclosed herein;

[0050] Figure 13 Show the basis Figure 12 a cross-sectional perspective view of an embodiment of ; and

[0051] Figure 14 A cross-section of the connecting piece along the longitudinal axis of the pressure vessel is shown. DETAILED DESCRIPTION

[0052] Figure 1A schematic cross-sectional view of a first embodiment of the technology disclosed herein is shown. Three pressure vessels 100 are shown, each having a connector 130. It is also conceivable that additional pressure vessels 100 may form a pressure vessel system. The connectors 130 are integrally integrated into the pressure vessel wall. The pressure vessel walls of the pressure vessels 100 are each formed by a liner 110 and a fiber-reinforced layer 120. The connectors 130 comprise coaxially extending fuel channels that open into a truncated-cone or funnel-shaped region at the end of the connector 130. A sealing surface 132 of the connector 130 is located in this region. In this funnel-shaped region, the pipeline system leading to the fuel consumer contacts the respective pressure vessel 100. To this end, the pipeline system comprises pipeline connectors, each including a union nut and a pipe end that tapers toward the end. The pipeline system forms a fuel-conducting section. The pipeline system comprises a plurality of individual pipeline elements, such as pipes, T-connectors, and union nuts. Furthermore, body connection elements 300 are shown, each forming a receptacle for the curved fixing surfaces 134 of the connecting piece. The body connection elements 300 are designed separately. Similarly, a common body connection element 300 can be provided for all three pressure vessels 100. The fixing surfaces 134 have a curvature on their contact surfaces that is substantially identical to the inner surface of the (corresponding) body connection element 300. The fixing surfaces 134, laterally formed on the outer surfaces of the outwardly directed portions of the connecting piece, press against the body connection elements 300, thereby securing them. This embodiment allows each pressure vessel 100 to be rotated into the correct position during assembly before being secured. Advantageously, the fluid connection achieved via the sealing surface 132 is functionally separated from the body connection achieved via the fixing surface 134, so that the forces and moments required to secure the pressure vessels are not transmitted via the pipe system.

[0053] Figure 2A schematic cross-sectional view of an embodiment with multiple pressure vessels 100 is shown. Here, the pressure vessels 100 are arranged axially parallel in a plane in the underbody area of the motor vehicle. The fuel-conducting section 200 is designed as a fuel rail 200. The fuel rail 200 is made of a tube (=fuel line) with thickened, essentially spherical rail nipples 210. These rail nipples 210 each establish a fluid connection with an individual connecting piece 130 of the pressure vessel 100. The rail nipples 210 are integrally formed with the pipes and are made of the same material as the pipes, such as stainless steel. The essentially spherical outer surface of the rail nipples 210 rests sealingly against the conically shaped sealing surface 132 of each connecting piece 130. To form a sealing seat, the spherical outer surface of the rail nipples 210 is pressed against the sealing surface 132. For this purpose, a pressure plate 330 is provided opposite the sealing seat. It is braced against the corresponding connection piece 130 of the corresponding pressure vessel 100 by means of two clamping means 400 (e.g., screws). During assembly, the individual pressure vessels 100 are aligned by the contact of the sealing surface 132 and the rail connection 210 before they are mechanically fastened to the body connection element 300. Furthermore, the body connection element 300 includes two rubber bearings 320, which can be designed like the known bearings of internal combustion engines in the engine compartment.

[0054] In this embodiment, fuel rail 200 is essentially straight and does not include any curved sections for tolerance compensation. The attachment of connector 130 to common body connection element 300 and the further integration of pressure vessel 100 into the motor vehicle are not shown in detail. For this purpose, in the installed position, a base plate and underframe, which may be part of a common housing for the pressure vessel system, may be provided below the pressure vessel. Furthermore, other components, such as a line rupture safety device or a heat-activated pressure relief valve, are not shown.

[0055] Figure 3A schematic diagram of a fuel rail 200 is shown. Rail joints 210 with their rail joint connection holes 212 form a common axis AA. The region of the fuel rail 200 lying on the common axis AA extends substantially straight. A curved subregion 211 is provided between each of the two rail joints 210. The curved subregions 211 of the fuel rail 200 are regions where the fuel lines used to manufacture the fuel rail 200 are bent. The curved subregions 211 do not lie on the common axis AA, but rather extend spaced apart from the axis AA. The curved subregions 211 can be configured in various ways. In the embodiment shown here, the curved subregions 211 are configured so that the fuel rail 200 has an overall meandering course or shape. However, the curved subregions can also be configured in other patterns, such as a zigzag shape. The curved subregions are configured so that the fuel rail 200 can better compensate for positional variations or tolerances along the axis AA. To this end, the curved subregions have sections that extend at an angle, preferably perpendicularly, to the axis AA. This allows the sections used for tolerance compensation to be subjected to greater bending loads than tensile loads. The fuel rail 200 shown here with its curved subregion 211 can also be used in the embodiments according to the other figures, in which fuel rails 200 without curved subregions are shown.

[0056] Figure 4 Show that there is a basis Figure 3 Schematic diagram of an embodiment of a fuel rail 200. The fuel rail 200 is inserted into the connector 130. The spherical outer surface of the rail connector 210 rests on the sealing area 132 of the connector 130. A recess with a U-shaped cross section is provided in the end face of the connector 130, in which the respective rail connector 210 is completely accommodated. The recess is designed to be large enough so that there is sufficient space on both sides of the fuel rail 200 in the recess to allow a certain angular offset for rotation about the longitudinal axis LL of the pressure vessel. Here, two clamping means 400 (see FIG. 4 ) are provided in the end face. Figure 5 ) thread. Here, the recess is designed as a channel that extends straight in a top view and is arranged in the circular end face of the connecting piece 130. The recess thus divides the end face into two arched or circular arc segments, in which holes for the clamping means 400 (not shown) are arranged. The curved partial area 211 is arranged between the connecting pieces 130 or slightly above them and directly adjacent to the pole cap of the pressure vessel 100. This allows for a particularly space-saving design. The fixing surface 134 is arranged on the circumference of the outer circumference of the corresponding connecting piece 130. In a preferred embodiment, this circumference is surrounded and clamped for the vehicle body connection.

[0057] Figure 5 Shown in the installed position according to Figure 4Schematic diagram of an embodiment. The body connection element 300 is a beam here, which can have a substantially U-shaped cross-section. The beam can be, for example, a transverse beam or a longitudinal beam of a motor vehicle. Here, a plurality of pressure vessels 100 are fixed to the body connection element 300 by means of corresponding connecting pieces 130. A clamping band 340 surrounds the fixing surface 134 of the connecting piece 130. The clamping band 340 is essentially Ω-shaped here and is fixed to the body connection element 300 by means of screws. Preferably, body connection elements 300 are provided at both ends of the pressure vessel 100, which can be constructed in different ways. Mechanical loads occurring during operation can be transferred from the pressure vessel to the vehicle body via these body connection elements 300. The fuel rail 200 is pressed against the sealing surface 132 in the area of the rail joint 210 by means of a pressure plate 330. For this purpose, the pressure plate 330 is clamped by a clamping device 400 in the direction of the longitudinal axis LL of the pressure vessel (see Figure 1 ) axial preload. This advantageously allows for both mechanical and fluid connections to be realized within a small installation space. Assembly is simple and time-saving. Furthermore, any rotational orientation tolerances of the pressure vessel 100 are less critical.

[0058] Also shown is a base plate 700. Securing elements 710 extend from the base plate 700. These securing elements 710 simultaneously serve to stabilize the base plate 700. Other elements of the pressure vessel system, such as pipe rupture safety devices, thermal pressure relief devices, etc., are not shown.

[0059] Figure 6 A schematic cross-sectional view of the pressure vessel 100 and the fuel rail 200 is shown. The connecting piece 130 is again integrally formed with the pressure vessel 100 and is partially surrounded by the fiber-reinforced layer 120 of the pressure vessel wall. A recess with a U-shaped cross-sectional geometry is provided in the end face. A central hole opens into this recess, connecting the fuel storage volume V to the conical opening in the recess. The outer circumference of the connecting piece 130 has a circumferential surface forming a fastening surface 134. In the assembled state, this fastening surface 134 is surrounded by a clamping band 340. A pressure plate 330 extends into the recess of the connecting piece 130 and contacts the rail connector 210. In the contact region, the pressure plate 330 has a surface shape corresponding to the outer surface of the rail connector 210.

[0060] Figure 7A schematic cross-sectional view of another embodiment is shown. Here, the fuel rail 200 includes three rail connectors 210, via which the three pressure vessels 100 are fluidically connected to one another in an uninterrupted manner. Possible additional components, such as line rupture safety devices or heat-activated pressure relief valves, are not shown. The sealing surface 132 of the connector 130 is oriented by the rail connectors 210 and simultaneously pressed downward. The body connection element 300, particularly its inner surface, exerts a counterforce, thereby holding the connector 130 in place. Fastening elements 710 extend from the base plate 700. These fastening elements 710 also serve to stabilize the base plate 700. Laterally to the fuel rail 200, the valve unit 220 is directly fastened to the fuel rail 200. A valve, closed when de-energized, is provided in the valve unit 220. This valve prevents fuel from being supplied to downstream components of the fuel supply system (e.g., components of the anode subsystem of the fuel cell system). Typically, a pressure reducer is provided adjacent to or within valve unit 220 , reducing the pressure to a medium pressure range (typically to a value between 5 and 50 bar). From valve unit 220 , an extraction connection 202 emerges, which can be connected, for example, to an extraction line (not shown). A filler connection 204 is provided at the other end of the fuel rail, which can be connected to a filler line. Instead of lines to other components, another fuel rail or other element can also be directly coupled thereto.

[0061] Figure 8A schematic cross-sectional view of another embodiment is shown. Only the most important differences from the previous embodiment are explained in detail below. For other details, reference is made to the description of the other figures. In addition to the rail connector 210 for the pressure vessel 100 and the connectors or pipe connectors 202 , 204 for the valve unit 220 , the fuel rail 200 also includes a further pressure relief connector for connecting a heat-activated pressure relief device 240 . If a thermal event occurs, the pressure relief device 240 is triggered and all three pressure vessels 100 are depressurized. Preferably, provision may be made for line rupture safety devices to be provided at the ends of the fuel rail 200 , particularly at or in the pipe connectors 202 , 204 and / or in the valve unit 220 . These line rupture safety devices cut off the fluid connection to adjacent components of the vehicle's fuel supply system if (i) damage to the pressure vessel 100 and / or the fuel rail 200 is to occur and / or (ii) activation of the pressure relief device 240 is to occur. In a preferred embodiment, a heat-activated pressure relief device 240 is also provided at the end facing away from the connector 130 . Here, a schematic diagram shows beams 500 that demarcate the various floor installation spaces. Here, the left-hand beam 500 extends downward from the vehicle floor 600. To facilitate this, the fuel line connection 204 is oriented downward. This allows the fuel line to be laid beneath the beam 500. At the right edge, the beam 500 is assumed to extend upward and away from the floor 700. At this edge, the fuel line can be laid over the beam 500. The specific layout of the line can be adapted to the installation situation.

[0062] Figure 9 A schematic cross-sectional view of another embodiment is shown. Only the most important differences from the previous embodiment are explained in detail below, and for other purposes, reference is made to the description of the other figures. Fuel rail 200 also includes a valve unit 230, which can be located at the other end of fuel rail 200. For example, a check valve can be provided in valve unit 230, which prevents fuel from flowing back into the upstream region of the refueling path. A heat-activated pressure relief device 240 (not shown) can also be provided on this unit.

[0063] Figure 10A top view of the underbody area of a motor vehicle is shown. Beams 500 divide the underbody area into various underbody installation areas. These underbody installation areas are essentially equal in size. Each beam 500 extends from one side sill to the other in the transverse direction of the vehicle and significantly contributes to the rigidity of the vehicle body structure. A pressure vessel system is located in the right underbody installation area. The pressure vessel system comprises three pressure vessels 100, which are arranged between two beams 500. The pressure vessels 100 are arranged parallel to each other and to the beams 500. One end of each pressure vessel 100 is connected to a fuel rail 200 via a connecting piece 130. Heat-activatable pressure relief devices 240 are located at the opposing ends of each pressure vessel 100. The fuel rail 200 forms a fuel-conducting section. Connected to one end of the fuel rail 200 is a fuel line 270, which serves as a filler pipe and is connected to the vehicle's fuel tank connector (not shown). A valve unit 220 with a valve that closes when de-energized is located at the other end of the fuel rail 200. The valve, which is closed when de-energized, is open-loop or closed-loop controlled by the vehicle's controller. Fuel is removed from the pressure vessel by actuating the valve. Valve unit 220 is fluidically connected to pressure reducer 290 via fuel line 270. Downstream of pressure reducer 290, another fuel line 270 is provided, which leads to the vehicle's energy converter (not shown). Depending on the vehicle design, additional pressure vessels and additional fuel rails 200 may be provided in other underbody installation areas, fluidically connected in series or parallel with the illustrated pressure vessels. It is also conceivable to install high-voltage batteries in one or more underbody installation areas. It is also conceivable to use the same vehicle architecture for purely battery-powered vehicles without a pressure vessel system.

[0064] Figure 11 Another top view of the floor area of a motor vehicle is shown. In this embodiment, four fuel rails 200 are provided, each with three pressure vessels 100 arranged in the floor area. The fuel rails 200 are connected in series and are each connected to one another by means of a fuel line 270 . The fuel line 270 is routed around a beam 500 . A valve unit 220 is located between the pressure reducer 290 and the fuel rails 200 . This valve unit also contains a valve that is closed when de-energized and blocks all pressure vessels 100 located in the floor area from the rest of the fuel supply system. Only one of the four fuel rails 200 is connected to a fuel line 270 serving as a filler pipe. The two center fuel rails 200 are connected only to adjacent fuel rails 200 .

[0065] Figure 12 An alternative embodiment of a pressure vessel system is shown with a compression plate 330 and a clamping device 400, in combination with Figure 13This alternative embodiment is explained in detail. Otherwise, the pressure vessel system is expediently designed as explained in conjunction with the preceding figures.

[0066] Figure 13 Shown in accordance with Figure 12 sectional perspective view of a pressure vessel system. Here, the fuel rail 200 extends in a broken line. The sections of the fuel line provided with rail connectors 210 extend parallel to one another. The rail connectors 210 each have a rail connector connecting hole 212. The rail connector connecting hole 212 enables a fluid connection between the fuel storage volume V of the pressure vessel 100 and the fluid channel of the fuel line, which is constructed as a tube here. The front end 214, which rests on the sealing surface 132 of the connector 130, is curved here and is preferably constructed in a substantially spherical manner. In the assembled state, the front end 214 forms a sealing element together with the sealing surface 132. However, other sealing systems are also conceivable. For example, in accordance with Figure 4 As in the embodiment of FIG, a recess U is provided in which the fuel line, including the rail connector 210, is arranged. Recess U extends from the end face of the connector 130 in the direction of the longitudinal axis of the pressure vessel, inward toward the fuel storage volume V. Therefore, recess U is designed to be recessed relative to the end face. Here, recess U divides the end face into two end sections, each of which is designed as an opposing annular segment. In other words, these annular segments are essentially C-shaped projections that extend outward from the bottom of recess U in the direction of the longitudinal axis of the pressure vessel. Recess U has a central region that widens in a top view of the end face and is circular in this case. In this central region, an internal thread is provided on the recess or on the projection formed by recess U. Here, a pressure plate 330 is inserted into this central region. The pressure plate 330 has an external thread on its edge that engages with the internal thread of the recess, which is now divided. Furthermore, the pressure plate 330 comprises a screw head driver (e.g. an Allen key, an Allen key, an internal multi-tooth wrench, etc.), which is provided for screwing the pressure plate 330 into the central region of the connecting piece 130 in order to thereby press the rail connecting piece 210 against the sealing surface 132 .

[0067] Figure 14 A cross-sectional view of the connecting piece 130 along the longitudinal axis of the pressure vessel is shown. A fluid channel is provided in the connecting piece 130, extending coaxially with the longitudinal axis of the pressure vessel. The fluid channel is enlarged in diameter near the end by drilling. In this area, a portion of the rail connector 210 is accommodated in the connecting piece 130. Because a different sealing concept is implemented here, the front end of the rail connector 210 is not substantially spherical in shape, but rather flat. Instead, an O-ring is provided between the wall of the fluid channel and the cylindrical outer wall section of the rail connector 210. For better securing, a groove is provided in the outer wall section.

[0068] In other words, the pressure plate 330 is a central pressure screw which is designed so that after the pipe and the ball joint are connected to the groove-shaped milled hole in the boss, it is pressed onto the sealing point via a separate thread. This advantageously reduces the space requirement, weight and / or screw connection expenditure.

[0069] Attachments with flexible fuel rails with integrated rail connectors (i.e., "mini-T-pieces") (i.e., using relatively flexible high-pressure lines) can be connected very compactly in relatively small bosses given the small diameter of the pressure vessel. Compared to other fastening methods for the pressure plate, the central threaded connection offers many advantages, such as a simpler threading process and less material consumption, resulting in weight and cost advantages. Furthermore, the threaded connection in this example effectively prevents mechanical damage in the event of a collision. Arranging the branch piece asymmetrically with respect to the line axis by means of a material-locking weld is particularly cost-effective. Advantageously, the weld serves as a seal rather than as a tensile force transmission mechanism. The pressure of the fixing screws can be effectively directed around the line via the branch piece. Under the action of pressure, the line rests against the branch piece from the inside, and the weld seam is essentially pressed against the cup-shaped component.

[0070] The concept “substantially” (e.g. “substantially bending-resistant”) in the context of the technology disclosed herein comprises a precise property or a precise value (e.g. “bending-resistant”) as well as various insignificant deviations from the function of this property / value (e.g. “tolerable deviations from bending-resistant”).

[0071] The above description of the present invention is for illustrative purposes only and is not intended to limit the present invention. Within the scope of the present invention, various changes and modifications are possible without departing from the scope of the present invention and its equivalents. For example, instead of the three pressure vessels (see Figure 12 ), any number of pressure vessels 100 can be connected to the fuel rail 200. Instead of one or four fuel rails 200, another number of fuel rails 200 can be provided. In one embodiment, the fuel rail 200 can extend over the entire base area. Advantageously, a separate fuel line 270 can also be formed by the fuel rail 200, for example by routing the fuel rail 200 around the beam 500. The pressure vessel system disclosed herein can be equipped with the fuel rail 200 disclosed herein or other fuel rails.

[0072] Reference Signs List

[0073] 100 pressure vessels

[0074] 110 lining

[0075] 120 fiber reinforcement layer

[0076] 130 connector

[0077] 132 sealing surface

[0078] 134 fixed surface

[0079] 200 Fuel guide section

[0080] 202 extraction pipe joint

[0081] 204 fuel pipe connector

[0082] 210 rail joint

[0083] 211 Curved local area 211

[0084] 212 Rail joint connection hole

[0085] 214 front end

[0086] 220, 230 valve units

[0087] 240 Heat-activated pressure relief device

[0088] 250 Pipeline Rupture Safety Valve

[0089] 270 fuel line

[0090] 290 Pressure Reducer

[0091] 300 Body connection elements

[0092] 320 rubber support

[0093] 330 pressure plate

[0094] 340 clamp

[0095] 400 Clamping Devices

[0096] 410 Clamping element

[0097] 500 beams

[0098] 600 Floor

[0099] 700 base plate

[0100] 710 fixing element

[0101] LL longitudinal axis of the pressure vessel

[0102] AA axis

[0103] U concavity

[0104] V Fuel storage volume

[0105] Z middle area

Claims

1. A fuel rail (200) for a pressure vessel system for storing fuel having a plurality of pressure vessels (100), the fuel rail comprising a fuel line, a bent partial region (211) and a plurality of rail connectors (210); each rail connector (210) having a cross-section that is enlarged relative to the fuel line; the rail connectors (210) being integrally formed with the fuel line, at least one of the rail connectors (210) being spaced apart from an end of the fuel line, the bent partial region (211) being arranged between two rail connectors (210); and the bent partial region (211) being arranged to compensate for positional changes of the pressure vessel (100) in its installed position, the front end (214) of the rail connector (210) being substantially spherical in shape so as to form a sealed fluid connection with a connector piece (130) of the pressure vessel for forming a fluid connection between a fuel storage volume (V) of the pressure vessel (100) and an energy converter of a motor vehicle.

2. The fuel rail (200) according to claim 1, wherein A plurality of rail joints (210) are arranged on a common axis (AA) and form the axis; and the curved partial region (211) extends at least partially spaced apart from the axis (AA).

3. The fuel rail (200) according to claim 2, wherein: The curved partial region (211) is provided for compensating, by elastic deformation, possible positional changes of the pressure vessel in its installed position.

4. The fuel rail (200) according to any one of claims 1 to 3, wherein The fuel rail (200) is at least partially configured in a zigzag or zigzag shape.

5. The fuel rail (200) according to any one of claims 1 to 3, wherein The curved partial region (211) is at least partially configured in a broken line or sawtooth shape.

6. The fuel rail (200) according to any one of claims 1 to 3, wherein A rail joint connecting hole (212) is provided in the rail joint (210), which opens into the fuel line at an angle relative to the longitudinal axis of the fuel line.

7. A pressure vessel (100) for storing fuel, the pressure vessel having a connection piece (130) for establishing a fluid connection between a fuel storage volume (V) of the pressure vessel (100) and an energy converter of a motor vehicle; - the connecting piece (130) is at least partially guided out of the pressure vessel (100); - the outer surface of the joint piece (130) has a sealing surface (132) and a curved fixing surface (134); - the sealing surface (132) is provided for sealing a fluid connection between the pressure vessel (100) and a fuel rail (200) according to any one of claims 1 to 6; and The fastening surface (134) is provided for fastening the pressure vessel (100) to at least one vehicle body connecting element (300).

8. The pressure vessel (100) according to claim 7, - the fixing surface (134) and the sealing surface (132) are arranged laterally on the part of the connecting piece (130) that is guided out of the pressure vessel (100); and The fixing surface (134) and the sealing surface (132) are arranged opposite each other.

9. The pressure vessel (100) according to claim 7, wherein: The fixing surface (134) is arranged laterally on the portion of the connecting piece (130) that is guided out of the pressure vessel (100); and the sealing surface (132) is arranged on the end face of the guided-out portion of the connecting piece (130).

10. The pressure vessel (100) according to any one of claims 7 to 9, wherein the sealing surface (132) is configured as a truncated cone surface tapering toward the connecting piece (130); and / or the fixing surface (134) is formed by a surface section of a spherical truncated body or a cylinder.

11. The pressure vessel (100) according to any one of claims 7 to 9, wherein: A recess (U) is provided in the connecting piece (130), which is recessed relative to the end face of the connecting piece (130) and is provided for at least partially accommodating a fuel rail (200).

12. The pressure vessel (100) according to any one of claims 7 to 9, wherein: The joint member (130) has an internal thread, and the external thread of the clamping plate (330) is embedded in the internal thread so as to clamp the rail joint (210).

13. A pressure vessel system comprising at least one pressure vessel (100) according to any one of claims 7 to 12, wherein: A body connection element (300) for fastening the at least one pressure vessel (100) to a body of a motor vehicle has a curved inner surface (302), the curvature of the inner surface for forming a contact surface substantially corresponding to the curvature of the outer surface of the fastening surface (134).

14. The pressure vessel system according to claim 13, wherein: At least one valve unit (220, 230) is connected to the fuel rail (200), the valve unit including a valve that closes when power is not supplied; and no valve that closes when power is not supplied is provided between the fuel storage volume (V) of the pressure vessel (100) and the rail connector (210).

15. A motor vehicle, comprising: - a fuel rail (200) according to any one of claims 1 to 6; or - at least one pressure vessel (100) according to any one of claims 7 to 12; or - At least one pressure vessel system according to claim 13 or 14.

16. A method for producing a fuel rail (200) according to any one of claims 1 to 6, the fuel rail being used in a pressure vessel system for storing fuel having a plurality of pressure vessels (100), the method comprising the following steps: - providing at least one fuel line; - forming a plurality of rail connectors (210), each of which has an enlarged cross-section relative to a provided fuel line, the rail connectors (210) being formed integrally with the fuel line, and at least one of the rail connectors (210) being spaced apart from an end of the fuel line; A curved partial region (211) is formed in the fuel line, wherein the curved partial region (211) is arranged between two rail joints (210).

17. The method according to claim 16, further comprising the steps of: A rail joint connection hole (212) is formed in the formed rail joint (210).

18. The method according to claim 16 or 17, wherein The plurality of rail joints (210) are formed by: a. by forming methods; and / or b. by the method of applying the material; and / or c. Install the semi-finished product on the fuel line by material bonding.

19. The method according to claim 16 or 17, wherein: The plurality of rail joints (210) are formed by: a. by rotary forging; and / or b. By surfacing, recasting or injection molding.

20. The method according to claim 18, wherein The semi-finished product is a semi-finished product that completely surrounds the fuel line.

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