Injection system having at least one valve for metering a fluid

Abstract

The present invention relates to an injection system having at least one valve (2) for metering a fluid, in particular a fuel injection valve for injecting a gaseous fuel into a combustion chamber (3) of an internal combustion engine. The valve (2) has an inflow-side valve end (5) that forms the inflow-side inlet for the fluid. Furthermore, a first retaining element (7) and a second retaining element (8) are provided, wherein the first retaining element (7) has an opening (15) and the second retaining element (8) has an opening (20), and wherein the opening (15) and the opening (20) are configured such that, together with at least one ball portion (22) of the valve (2), spherical bearing in the retaining elements (7, 8) is ensured. According to the invention, a sealing element (45) which seals radially with respect to the first holding element (7) is arranged on a lateral surface of the inlet-side valve end (5) of the valve (2), which sealing element (45) is provided between a first metal point of contact of the valve (2) with the first holding element (7) and a second metal point of contact of the valve (2) with the second holding element (8), as viewed in the axial direction.

Description

[0001] R. 412657

[0002] - 1 -

[0003] Description

[0004] title

[0005] Injection or blow-in system with at least one valve for metering a fluid

[0006] State of the art

[0007] The present invention relates to an injection or injection system with at least one valve for metering a fluid, in particular a fuel injection valve for injecting a gaseous fuel into a combustion chamber of an internal combustion engine. Specifically, the invention relates to an injection system with which hydrogen can be injected directly into the combustion chamber of a mixture-compressing, spark-ignition internal combustion engine.

[0008] From DE 10 201 200 597 A1, a holder for a fuel injection system is known. In this holder, a fuel injection valve is used to hold a fuel injection valve at a connection point of a fuel-carrying component. A connecting piece of the fuel injection valve has a partially spherical sealing surface that rests against a conical sealing surface of the component, the connecting piece being subjected to a preload force against the conical sealing surface. The preload force is applied by a clamping screw and transmitted via guide elements.

[0009] Furthermore, a hydraulic connection for connecting a fuel injection valve to a fuel-carrying component is known from DE 10 2015 205 980 A1. This arrangement is described in R. 412657.

[0010] - 2 - a mounting bridge, which in turn has a support surface. A fuel injector connection nozzle is provided, which can be supported on the support surface of the mounting bridge. Furthermore, a connection body is provided, wherein a hydraulic connection is formed between the fuel injector connection nozzle and the connection body. For this purpose, a spherically convex curved bearing surface is provided on the connection body, and a conically extending support surface is formed on the fuel injector connection nozzle. Contact between the fuel injector connection nozzle and the connection body is established at the convexly curved bearing surface and the support surface to form the hydraulic connection. The support surface of the connection nozzle is axially symmetrical with respect to a longitudinal axis.Therefore, the mating area uses a known metallic ball / cone seal.

[0011] Fuel injectors are known in various designs according to the prior art. In high-pressure injection systems for liquid fuels, as the aforementioned prior art documents demonstrate, a metal-to-metal connection is increasingly implemented between a fuel rail and an injector in the connection area. However, these metal-to-metal connections require relatively high forces with which the sealing components must be pressed together to ensure sufficient sealing.

[0012] In the course of the search for alternative fuels to reduce or avoid harmful emissions, in particular an optimized solution for connecting or suspending a fuel injection valve for the direct injection of a gaseous R. 412657

[0013] - 3 -

[0014] Fuel, especially hydrogen, is supplied to a combustion chamber of an internal combustion engine.

[0015] Tests on engine test benches have shown that a simple transfer of the known mountings or suspensions of direct-injection fuel injectors for liquid fuels to a mounting or suspension of direct-injection fuel injectors for gaseous fuels is not readily possible. The higher the lateral force introduced by the mounting bracket, the more the service life of the fuel injector, during which full functionality is guaranteed, is reduced due to the high stress. This disadvantage is to be overcome by the invention for a "suspended" fuel injector.

[0016] Disclosure of the invention

[0017] The injection or blowing system according to the invention, with at least one valve for metering a fluid and the features of claim 1, has the advantage that optimal valve mounting is achieved and, in addition, an optimized connection of the valve thus mounted to a supply line is enabled. In the upper suspension area of ​​the valve, the design as a spherical bearing between a partially spherical valve end of the valve and two retaining elements enables a metal-to-metal seal, which does not allow leakage even at high pressures.According to the invention, a sealing element is arranged on a lateral surface of the inlet-side valve end of the valve, sealing radially against the first retaining element, and is provided in the axial direction between a first metallic contact point of the valve with the first retaining element and a second metallic contact point of the valve with the second retaining element. R. 412657.

[0018] - 4 -

[0019] In addition to its particularly advantageous sealing and bearing functions, the sealing element also serves as an assembly aid, since the free movement of the valve is somewhat restricted due to friction when it is installed in the first retaining element. Therefore, the design of the system according to the invention allows for simple and safe assembly.

[0020] The dependent claims describe preferred embodiments of the invention.

[0021] The metal-to-metal seal or bearing is preferably a metallic ball / cone seal, wherein the ball sections are preferably located at the inlet-side valve end of the valve and the cone surfaces are located at the retaining elements.

[0022] The spherical sections at the end of the valve are particularly preferred if they are spherically convex, with either constant radii or varying radii across the entire spherical body. For example, the radii above and below an imaginary equator can differ. Ideally, the centers or pivot points of these sections should lie on the central axis of the valve.

[0023] While the first retaining element, the second retaining element, and the valve with its integrated spherical bearing form an upper suspension area for the valve, a second bearing point for the valve is formed at a lower valve end facing the combustion chamber in the area of ​​a sealing ring, which is in particular a sealing ring made of PTFE. The two bearing points are maximally far apart in the axial direction R. 412657

[0024] - 5 - apart. The valve is supported by the sealing ring against the wall of the longitudinal bore of the cylinder head.

[0025] To avoid a large volume of debris in the longitudinal bore, an annular gap is advantageously formed between the wall of the longitudinal bore and the blow-off valve end, the radial extent of which is only approximately 50 to 100 pm. Therefore, the outer diameter of the valve end and the inner diameter of the longitudinal bore in the cylinder head differ only very slightly.

[0026] The valve aligns itself with the wall of the longitudinal bore via the bearing point on the sealing ring at the valve end. The ball joint at the upper suspension point provides the necessary degree of freedom. The valve must not be pressed axially onto the cylinder head; rather, it must "hang" freely, a design that can be described as "suspended," so that the bearing is achieved solely by the lower sealing ring and the upper ball joint. After the first retaining element is firmly connected to the cylinder head or a corresponding mounting body with a screw, the screws connecting the two retaining elements can be tightened alternately. This permanently and securely connects the valve to the retaining element's lower bracket, largely free of lateral forces.

[0027] The valve may have a curved shape due to structural reasons without introducing a transverse force into the valve, as this is prevented by the retaining device according to the invention. Furthermore, the design according to the invention allows for high manufacturing tolerances with regard to coaxiality and angular errors between the medium-supplying connection, e.g., a supply line such as R. 412657.

[0028] - 6 - e.g., a fuel rail, and the longitudinal bore of the cylinder head. The inaccuracy regarding the positioning of the fuel connection above the center point of the longitudinal bore accommodating the valve is relatively high due to the long tolerance chain and is unavoidable, especially in internal combustion engines with multiple cylinders. The suspended design of the valve mounting, in combination with the spherical bearing and the optimized sealing package, ensures optimal sealing and the installation of all valves without lateral forces along the entire length of the supply or distribution line, even with large deviations in coaxiality, position, and manufacturing-related angular errors.

[0029] The present invention is preferably used in injection systems that inject hydrogen directly into a combustion chamber. In particular, the system is suitable for the direct injection of hydrogen into a combustion chamber of an internal combustion engine.

[0030] drawing

[0031] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. The drawing shows:

[0032] Figure 1 shows a schematic perspective view of an injection system with two valve bearing points in an upper suspension area and a lower bearing area in the cylinder head in a first embodiment of the connection to a distribution line in the form of a fuel rail and a schematically broken-up cylinder head, R. 412657

[0033] - 7 -

[0034] Figure 2 shows a schematic perspective view of an injection system with two bearing points of the valve in an upper suspension area and a lower bearing area in the cylinder head in a second embodiment of the connection to a distribution line in the form of a fuel rail and a schematically indicated cylinder head.

[0035] Figure 3 shows a schematic sectional view of the blowing system in the upper suspension area with a holding element for connection to a distribution line according to the embodiment of Figure 1.

[0036] Figure 4 shows a schematic sectional view of the blowing system in the upper suspension area with a holding element for connection to a distribution line according to the design of Figure 2 and

[0037] Figure 5 shows a detailed view of the bearing area between the retaining element and the valve in the form of an injector for injecting a gaseous fuel according to the embodiments of the previous figures.

[0038] Preferred embodiments of the invention

[0039] The following describes in detail, with reference to Figures 1 to 5, an injection system 1 according to preferred embodiments of the invention. Preferably, this is an injection system 1 for injecting a gaseous fuel, in particular...

[0040] Hydrogen, into a combustion chamber 3 of an internal combustion engine.

[0041] In principle, the system designed according to the invention can alternatively also be used as an injection system 1 for injecting a liquid fuel into a combustion chamber 3 of an internal combustion engine, wherein R. 412657

[0042] - 8 - From now on, only one blowing system 1 will be referred to. Alternative embodiments not shown in figures will also be mentioned below.

[0043] The injection system 1 comprises at least one valve 2 for metering a fluid, in particular a gaseous fuel such as hydrogen, but also CNG, methane, ammonia, etc. The valve 2 is designed as an injection valve 2 that injects directly into the combustion chamber 3. The gas to be injected flows through the valve 2. The gas enters the valve 2, which can also be referred to as an injector, via an inlet-side valve end 5, while the metering, jet shaping, and conditioning of the gaseous medium take place at an outlet-side valve end 6 facing the combustion chamber 3.

[0044] The injection system 1 has two bearing points for the valve 2, wherein an upper suspension area for the valve 2 is provided on the one hand and a lower bearing area for the valve 2 is provided in a cylinder head 10 on the other. Figure 1 shows a schematic perspective view of such an injection system 1 with the two bearing points of the valve 2 in a first embodiment of the connection to a distribution line 34 in the form of a fuel rail.

[0045] In the upper suspension area of ​​the valve 2, the design as a spherical bearing between the inlet-side valve end 5 of the valve 2 and a first retaining element 7 enables a metal-to-metal seal, which prevents leakage even at high pressures. According to the invention, the inlet-side valve end 5 of the valve 2, together with the first retaining element 7, is shaped such that a ball-joint-like bearing is enabled at an opening of the first retaining element 7, which will be described in more detail later with reference to Figures 3 and 4. R. 412657

[0046] - 9 -

[0047] The valve 2 has a circumferential sealing ring 33 on its outer circumference at its valve end 6 facing the combustion chamber 3. This sealing ring forms the second bearing point of the valve 2. Ideally, this is a PTFE sealing ring, dimensioned or inserted into an annular groove on the valve 2 in such a way that a spherical bearing is preferably achieved. This is because, when the valve 2 is installed, the sealing ring 33 bulges slightly radially outwards, so that under pressure, the sealing ring 33 bears only an approximately linear bearing against the wall of a longitudinal bore 35 in the cylinder head 10 for receiving the valve 2. Advantageously, the diameter of the valve 2 at its valve end 6 and the diameter of the longitudinal bore 35 differ only slightly. For optimal bearing, the annular gap formed between the wall of the longitudinal bore 35 and the valve end 6 can only have a radial extent of approximately 50 to 100 pm.In a particularly advantageous way, the damaged volume is kept very small so close to the combustion chamber 3 in the longitudinal bore 35 of the cylinder head 10.

[0048] In this previously described mounting of valve 2, the two bearing points are located as far apart as possible. Due to structural constraints, valve 2 can even have a certain "curved shape" without this introducing a lateral force into valve 2 due to the described clamping device.

[0049] Figure 2 shows in a schematic perspective view an alternative injection system 1 with the two bearing points of the valve 2 in a second embodiment of the connection to a distribution line 34 in the form of a fuel rail.

[0050] While according to the first embodiment shown in Figure 1, the first

[0051] Retaining element 7 a clamp- or claw-like receiving section 22 R. 412657

[0052] - 10 - the first retaining element 7 according to the second embodiment according to Figure 2 is designed with a trough-like receiving section 23 for the distribution line 34.

[0053] Figure 3 shows a schematic sectional view of the blowing system 1 in the upper suspension area with a first retaining element 7 for connection to the distribution line 34 according to the embodiment of Figure 1, while Figure 4 shows a schematic sectional view of the blowing system 1 in the upper suspension area with a first retaining element 7 for connection to the distribution line 34 according to the embodiment of Figure 2.

[0054] As can be seen in Figures 3 and 4, the injection system 1 advantageously comprises, as an essential assembly according to the invention, the upper suspension area with the first retaining element 7, a second retaining element 8, and a bearing section at the inlet-side valve end 5 of the valve 2, which form the upper bearing point in the suspension area of ​​the valve 2. The first retaining element 7 has, in addition to the receiving section 22, a block-like base body 26 from which the receiving section 22 extends laterally, and a downstream-oriented extension section 29, which serves to receive the valve 2.

[0055] The first retaining element 7 is also characterized by the fact that a through-hole (not shown) is provided, through which a connecting element, such as a screw 13, can be inserted to clamp the valve 2 to an attachment, in this case the cylinder head 10. The base body 26 of the first retaining element 7 has an opening 15, which serves for the flow of the medium and which, for example, can extend at a right angle from the distribution line 34 to allow the gas to flow into the valve 2 parallel to its axis. The opening 15 also forms the larger diameter R. 412657

[0056] - 11 -

[0057] Interior of the downstream extension section 29 of the first retaining element 7.

[0058] The opening 15 is designed to allow for the mounting of the inlet-side valve end of the valve 2. The opening 15 is a through-opening through which the valve 2 is supplied with the medium to be discharged. The through-opening can be fully axial (Figure 4) or angled to allow a lateral supply connection from the distribution line 34 (Figure 3). A portion of the opening 15 is shaped such that it has an internal conical surface 16.

[0059] Overall, the first retaining element 7 is block-shaped with a rounded contour around its circumference. In a direction parallel to the extension of the distribution line 34, the first retaining element 7 has a greater extension to accommodate the screw 13. To accommodate two screws 13, as shown in the second embodiment according to Figure 2, a largely symmetrical design of the first retaining element 7 on both sides of the distribution line 34 may also be advisable. However, other contours are equally conceivable, such as a rectangular shape for the first retaining element 7.

[0060] The second lower retaining element 8 is disc-shaped. The second retaining element 8 has, for example, two threaded bores 18 opposite each other at 180°, into which screws 19 can be screwed. These screws can be guided through corresponding through-holes 17 in the first retaining element 7. In this way, the first and second retaining elements 7, 8 can be clamped to each other via the screws 19. In addition to the fastening of the first retaining element 7 to the cylinder head 10 with the screw 13, the two R. 412657

[0061] - 12 -

[0062] The fastening points with the screws 19 represent a statically secure solution; however, more or fewer fastening points are also conceivable. A continuous opening 20 of the second retaining element 8, like the opening 15 of the first retaining element 7, is shaped in a partial area such that an inner conically extending conical surface 21 is present, with the two conicities running in opposite directions, conically widening in the first retaining element 7 when viewed in the direction of flow and conically tapering in the second retaining element 8. Both conical surfaces 16 and 21, together with the valve end 5 of the valve 2, which is spherically shaped on two sides, form the upper bearing point.

[0063] A spherical bearing is understood to be a bearing that is either a ball / taper bearing or similar to a rod end or a ball joint with two spherically curved corresponding bearing surfaces, whereby the spherical bulge on the retaining elements 7, 8 has a larger radius than the radii of the corresponding valve end 5 of the valve 2. In general, there are therefore surfaces 16, 21 corresponding to the valve 2 on the two retaining elements 7, 8.

[0064] The first retaining elements 7 are shaped on their outer sides facing the distribution line 34 in such a way as to enable secure and reliable retention of the circular and cylindrical distribution line 34. The retaining elements 7 thus conform precisely to the contour of the distribution line 34.

[0065] For a fluid connection, the distributor line 34 has transversely extending outlet bores which, in the example according to Figures 1 and 3, open directly into transversely extending sections of the openings 15 in the retaining elements 7. The retaining elements 7 are fastened to the distributor line 34 such that a plumb line, R. 412657

[0066] - 13 - in particular copper solder, into which recesses on the outside are inserted and subsequently brazed at temperatures between 450°C and 900°C, e.g., but also in a vacuum HTL process at up to approx. 1100°C. As an alternative to the aforementioned stainless steel tubes as solder rails, forged rails can also be used as distribution lines 34.

[0067] The upper suspension area of ​​valve 2 is characterized by a metallic bearing arrangement between the valve end of valve 2 and the two conical surfaces 16 and 21 of the first and second retaining elements 7 and 8, forming a ball-and-cone connection. The valve end 5 of valve 2, in its partial sections, represents a partially spherical body, which can generally be understood as a partially spherically convex body whose radii need not be constant over the entire spherical section. In fact, it is conceivable that different radii are provided for the individual spherically curved contact surfaces above and below an imaginary spherical equator, so that these spherical sections can interact with the conical surfaces 16 and 21, ideally aligned with their inclination or conicity, to achieve an optimized, lateral force-reduced bearing arrangement. For example,The spherical area with the contact surface towards the upper conical surface 16 should have a smaller radius than the radius of the spherical area with the contact surface towards the lower conical surface 21. Ideally, the centers (pivot points) of the spherical areas should lie on the central axis of the valve 2.

[0068] The upper end of valve 2 can, for example, be provided with a plastic overmolding that protects an electrical connection 32 for an actuator of valve 2 (not shown). R. 412657

[0069] - 14 -

[0070] The assembly is carried out by first sliding the second lower retaining element 8 onto the valve 2 at its inlet-side valve end 5, with the opening 20 of the second retaining element 8 protruding through the valve end 5. In practice, the assembly can be performed by inserting the valve 2 from below through the opening 20 of the second retaining element 8 at a 90° angle or a smaller angle relative to its final position. A subsequent rotation of the valve 2 by approximately 90° prevents it from falling out. This assembly step is similar to the twisting action required for a bayonet fitting.

[0071] The contour at the valve end 5 of the valve 2 is designed (see Figure 5) such that the valve 2 can move freely through a considerable angular range below the center point of the respective retaining element 7 without radial contact with the retaining element 7 or unintentional binding of the components to each other. This "freedom of movement" of the valve 2 in the area of ​​the extension section 29 of the retaining element 7 is a considerable advantage for the radial mobility of the valve 2 during installation to compensate for tolerances.

[0072] The first upper retaining element 7 is then placed onto the valve end 5 to form the upper suspension area. The base body 26 has the opening 15 required for the ball joint or spherical bearing, which comes into contact with the valve end 5. A portion of the opening 15 is shaped such that the inner conical surface 16 is present. The angle enclosed within the conical surface 16 can be individually adjusted depending on the radius of the valve end 5 with which it interacts and its radius at the upper contact surface. The angle is typically in the range of 30° to 60°, particularly between 40° and 55°, preferably between 45° and 50°. R. 412657

[0073] - 15 - lie. The same applies to the angle of the conical surface 21 of the opening 20 in the lower retaining element 8.

[0074] The base body 26 of the retaining element 7, for example, has two through-holes 17 for the insertion of two screws 19. These screws, in conjunction with corresponding threaded holes 18 in the second retaining element 8, allow the two retaining elements 7 and 8 to be clamped together. After the upper retaining element 7 is placed on the valve, a line contact is established between the retaining element 7 and the partially spherical valve end 5. The first retaining element 7 and the second retaining element 8 are connected to each other using the two screws 19. The screws 19 should initially be tightened only very lightly. Tightening the screws creates a ball joint, which provides the valve 2 with a defined bearing even if it is misaligned. Since the first retaining elements 7 are already secured, as described above, by, for example,After brazing, to which the distributor line 34 is securely and firmly attached, and after the screw connections with the screws 19 have been made, a complete Fuel Charge Assembly (FCA) is already present, which includes the distributor line 34, the necessary number of valves 2, and the respective hold-down units. Following the assembly of these hold-down units, the device consisting of valves 2, distributor line 34, and the respective retaining elements 7 and 8 can be installed in the cylinder head 10 of the internal combustion engine, or on a spray test stand, etc., or on another type of attachment.

[0075] The valves 2 are aligned with the walls of the longitudinal bores 35 via the bearing points on the sealing rings 33 at the respective valve ends 6 of the valves 2. The ball joints on the upper suspension areas provide the necessary degree of freedom. The valves 2 must not be pressed axially onto the cylinder head 10. R. 412657

[0076] - 16 - they must instead "hang" freely, which can be described as a "suspended design," so that the bearing is achieved solely by the lower sealing ring 33 and the upper ball joint. After the first retaining element 7 is firmly connected to the cylinder head 10 or a corresponding (mounting) body by means of the screw 13, the screws 19 connecting the two retaining elements 7 and 8 can be tightened alternately. This permanently and securely connects the valve 2 to the lower bracket of the retaining element 7. The number of screws 13, 19 can vary depending on space requirements and design.

[0077] Figure 5 shows a detailed view of the bearing area between the first retaining element 7 and the valve end 5 of the valve 2 in the form of an injector for injecting a gaseous fuel according to the embodiments of the preceding figures. This view is primarily intended to illustrate a further detail of the invention, characterized by a sealing element 45 on the outer circumference of the valve end 5.

[0078] The elastic seal of the valve end 5 of the valve 2, and the associated bearing relative to the first retaining element 7, ensures perfect protection of the metallic bearing on the conical surface 16 and optimized bearing of the valve 2. The seal is implemented by a circumferential groove 44 on the outer surface of the valve end 5 near the metallic contact area between the valve 2 and the first retaining element 7. The annular sealing element 45 can be inserted into this groove 44, ideally having a circular cross-section, thus providing a radial seal. R. 412657

[0079] - 17 -

[0080] The sealing element 45, arranged on the outer surface of the valve end 5 of the valve 2, is thus provided in the axial direction between the first metallic contact point of the valve 2 with the first retaining element 7 and the second metallic contact point of the valve 2 with the second retaining element 8.

[0081] Alternatively, the elastic seal of the valve end 5 of the valve 2 and the associated bearing can be provided on the corresponding side of the component assembly relative to the first retaining element 7. The seal is then implemented such that a circumferential groove 44 is provided on the wall of the inner opening 15 of the first retaining element 7 near the metallic contact area between the valve 2 and the first retaining element 7, while the outer surface of the valve end 5 of the valve 2 is, for example, smooth and cylindrical. The annular sealing element 45 can then be inserted into this groove 44, ideally having a circular cross-section, thus providing a radial seal.

[0082] The sealing element 45 arranged on the outer surface of the valve end 5 of the valve 2 is thus also provided here in the axial direction between the first metallic contact point of the valve 2 with the first retaining element 7 and the second metallic contact point of the valve 2 with the second retaining element 8.

[0083] In addition to its sealing and bearing function, the sealing element 45 also serves as an assembly aid, since the free movement of the valve 2 is somewhat restricted due to friction when the valve 2 is installed in the holding element 7.

[0084] Suitable materials for the ring-shaped sealing element 45 include plastics such as EPDM, VMQ, FKM or VI or comparable materials. R. 412657

[0085] - 18 -

[0086] Plastics that provide a reliable sealing effect in the temperature range of -60°C to +150°C, which is particularly desirable for media such as hydrogen.

[0087] The two conical surfaces 16 and 21 of the retaining elements 7 and 8, together with the spherically shaped valve end 5, form the upper spherical bearing point. The alignment of the conical surfaces 16 and 21 with the partially spherically shaped valve end 5 of the valve 2 should be such that, ideally, there is extensive line contact in the contact area of ​​the bearing point, with the line contact occurring approximately in the center of the respective conical surfaces 16 and 21.

[0088] Especially in hydrogen engines, the issue of tightness and leakage is of paramount importance. While sealing concepts using ball / cone screw connections, cone / cone screw connections, and radially sealing O-rings are already known in conventional combustion engines, combining both sealing concepts with the addition of a suspended design represents a particularly advantageous and previously unknown solution. The integration of a sealing element 45 on the outer surface of the valve end 5 allows for the formation of two closely spaced sealing points, which increase the reliability and sealing performance in the connection area of ​​the valve 2. Furthermore, the clamping forces can be reduced compared to a purely metallic seal.

[0089] In this embodiment according to the invention, the metallic sealing line lies radially inside the annular sealing element 45 at the contact surface with the conical surface 16. The internal sealing line has the advantage that the sealing element 45 is not directly exposed to hydrogen at full system pressure and temperature. (R. 412657)

[0090] - 19 -

[0091] Due to rapid expansion, the hydrogen temperature can theoretically drop below -40°C. The metallic seal radially in front of the sealing element 45 acts as a kind of "throttle." This causes the hydrogen to heat up to almost the temperature of components valve 2 and retaining elements 7 and 8. With appropriate connection to the internal combustion engine, the temperatures of these components are significantly higher than the ambient temperature.

[0092] In principle, the inventive concept can also be implemented in solutions without distribution line 34, where pipe or hose connections are used instead.

Claims

R. 412657 - 20 - Claims 1. Injection or injection system with at least one valve (2) for metering a fluid, in particular a fuel injection valve for injecting a gaseous fuel into a combustion chamber (3) of an internal combustion engine, wherein the valve (2) has an inlet-side valve end (5) which forms the inlet-side inlet for the fluid, and with a first retaining element (7) and a second retaining element (8), wherein the first retaining element (7) has an opening (15) and the second retaining element (8) has an opening (20), wherein the opening (15) of the first retaining element (7) and the opening (20) of the second retaining element (8) are designed such that, together with at least one spherical section of the valve (2), a spherical bearing in the retaining elements (7, 8) is ensured, characterized in that a sealing element (45) is arranged on a cylindrical surface of the inlet-side valve end (5) of the valve (2) which seals radially against the first retaining element (7).which is provided in the axial direction between a first metallic contact point of the valve (2) with the first retaining element (7) and a second metallic contact point of the valve (2) with the second retaining element (8).

2. System according to claim 1, characterized in that the first metallic contact point of the valve (2) is formed by an at least partially spherically formed contact area at the valve end (5) and the second metallic contact point of the valve (2) is formed by an at least partially spherically formed contact area at the valve end (5). R. 412657 - 21 - 3. System according to claim 2, characterized in that the first spherically shaped contact area at the valve end (5) with a conically extending conical surface (16) of the opening (15) of the first retaining element (7) and the second spherically shaped contact area at the valve end (5) with a conically extending conical surface (21) of the opening (20) of the second retaining element (8) each cooperate to form a metallic bearing.

4. System according to claim 3, characterized in that the inner conically extending conical surface (16) of the opening (15) of the first retaining element (7) and the inner conically extending conical surface (21) of the opening (20) of the second retaining element (8) have opposite orientations of the two conicities, viewed in the direction of flow, conically widening in the first retaining element (7) and conically narrowing in the second retaining element (8).

5. System according to one of the preceding claims, characterized in that a circumferential groove (44) is provided on the outer surface of the inlet-side valve end (5) of the valve (2), into which the sealing element (45) can be inserted.

6. System according to claim 5, characterized in that the groove (44) with the sealing element (45) is positioned such that the metallic seal at the first metallic contact point of the valve (2) with the first retaining element (7) is provided further radially inward than the seal of the sealing element (45) on the first retaining element (7).

7. System according to one of the preceding claims, characterized in that plastics such as EPDM, VMQ, FKM or VI are used as materials for the annular sealing element (45). R. 412657 - 22 - 8. System according to one of the preceding claims, characterized in that the first retaining element (7) and the second retaining element (8) can be clamped against each other, in particular by means of screws (19), preferably two screws (19) which are arranged opposite each other circumferentially.

9. System according to one of the preceding claims, characterized in that at least two first retaining elements (7) are provided which can be firmly attached to a distribution line (34) before assembly with the corresponding second retaining elements (8), in particular by means of brazing.

10. System according to one of the preceding claims, characterized in that the first retaining element (7), the second retaining element (8) and the valve (2) with the integrated spherical bearing form an upper suspension area for the valve (2), while a second bearing point of the valve (2) is formed at a lower valve end (6) in the area of ​​a sealing ring (33), in particular a sealing ring (33) made of PTFE.

11. System according to claim 10, characterized in that the valve (2) can be inserted into a longitudinal bore (35) of a cylinder head (10), wherein the sealing ring (33) is supported on the wall of the longitudinal bore (35) and wherein the annular gap formed between the wall of the longitudinal bore (35) and the valve end (6) has a radial extent of only about 50 to 100 pm.

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