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

Abstract

The present invention relates to an 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. The valve (2) has an inlet-side valve end (5) that forms the inlet-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 spherical section of the valve (2), a spherical bearing in the retaining elements (7, 8) is ensured.According to the invention, a separate, but attachable to the valve (2) spherical body (9) with spherically curved contact surfaces (36, 41) is provided, wherein the spherically curved contact surfaces (36, 41) correspond on the one hand to a surface (16) of the first retaining element (7) and on the other hand to a surface (21) of the second retaining element (8) to form a spherical bearing.

Description

State of the art

[0001] 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.

[0002] From DE 10 2014 200 597 A1, a holder for a fuel injection system is known. In this holder, a holder serves 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 bears 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.

[0003] Furthermore, DE 10 2015 205 980 A1 discloses a hydraulic connection for connecting a fuel injection valve to a fuel-carrying component. This arrangement includes a mounting bracket, which in turn has a support surface. A fuel injection valve connection nozzle is provided, which can be supported on the support surface of the mounting bracket. A connection body is also provided, with a hydraulic connection formed between the fuel injection valve connection nozzle and the connection body. For this purpose, a spherically convex curved contact surface is provided on the connection body, and a conically extending support surface is formed on the fuel injection valve connection nozzle. Contact between the fuel injection valve connection nozzle and the connection body is established at the convexly curved contact surface and the support surface to form the hydraulic connection.The support surface of the connecting piece is axially symmetrical with respect to a longitudinal axis. Therefore, the mating area consists of a known metallic ball / cone seal.

[0004] 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.

[0005] 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 fuel, especially hydrogen, into a combustion chamber of an internal combustion engine is to be provided.

[0006] 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. Disclosure of the invention

[0007] 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 an independent spherical body, which can be attached to the valve, and two retaining elements enables a metal-to-metal seal that does not allow leakage even at high pressures. According to the invention, the spherical body is shaped such that it enables a ball-joint-like bearing at an opening of the first retaining element and at an opening of the second retaining element simultaneously.

[0008] Furthermore, the design of the system according to the invention allows for simple and safe assembly.

[0009] The dependent claims describe preferred embodiments of the invention.

[0010] The metal-to-metal seal or bearing is preferably a metallic ball / cone seal, wherein the ball sections are preferably provided on the spherical body and the conical surfaces on the retaining elements.

[0011] Particularly preferred are spherically convex segments of the spherical body whose radii are either constant or vary 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 segments should lie on the central axis of the spherical body.

[0012] It is particularly advantageous to provide a spherical body which, in addition to a metallic ball / cone seal or cone / cone seal or ball / ball seal, allows for a further seal by means of an additional sealing element.

[0013] While the first retaining element, the second retaining element, and the spherical body 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 preferably a PTFE sealing ring. The two bearing points are positioned as far apart as possible in the axial direction. The valve is supported by the sealing ring against the wall of the longitudinal bore in the cylinder head.

[0014] To avoid a large volume of damage 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 µm. Therefore, the outer diameter of the valve end and the inner diameter of the longitudinal bore in the cylinder head differ only very slightly.

[0015] 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.

[0016] The valve may have a curved shape due to its design, without this introducing a lateral 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 a high manufacturing tolerance with regard to coaxiality and angular errors between the medium-supplying connection, e.g., a supply line such as 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's suspension, combined with the spherical bearing and the optimized sealing package, ensures optimal sealing and lateral force-free installation of all valves along the entire length of the supply or distribution line, even with large deviations in coaxiality, position, and manufacturing-related angular errors.

[0017] 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. drawing

[0018] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 A schematic sectional 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, Fig. 2 a schematic perspective view of the injection system in the upper suspension area with several hood-like retaining elements and the connection to a distribution line in the form of a fuel rail and a schematically broken-up cylinder head, Fig. 3 a perspective view of a first spherical body as a single component for the ball joint in the upper suspension area according to a first embodiment of the present invention, Fig. 4 a top view of the first spherical body according to Fig. 3, Fig. 5 a sectional view of the spherical body according to a section along the line V - V in Fig. 4, Fig. 6 a schematic sectional view of the blowing system in the upper suspension area according to a second embodiment of the present invention, Fig. 7 a top view of the second spherical body according to Fig. 6 and Fig. 8 a sectional view of the spherical body according to a section along line VIII - VIII in Fig. 7. Preferred embodiments of the invention

[0019] The following refers to the Fig. Figures 1 to 8 describe in detail an injection system 1 according to preferred embodiments of the invention. Preferably, it is an injection system 1 for injecting a gaseous fuel, in particular hydrogen, into a combustion chamber 3 of an internal combustion engine. Alternatively, the system designed according to the invention can also be used as an injection system 1 for injecting a liquid fuel into a combustion chamber 3 of an internal combustion engine; from hereafter, it will only be referred to as an injection system 1. Alternative embodiments not shown in figures are also mentioned below.

[0020] 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.

[0021] The injection system 1 has two bearing points for the valve 2, wherein on the one hand an upper suspension area of ​​the valve 2 is provided and on the other hand a lower bearing area for the valve 2 is provided in a cylinder head 10. Fig. Figure 1 shows a schematic sectional view of such an injection system 1 with the two bearing points of the valve 2.

[0022] In the upper suspension area of ​​the valve 2, the design as a spherical bearing between an independent spherical body 9, which can be attached to the valve 2, and two retaining elements 7 and 8 enables a metal-to-metal seal that prevents leakage even at high pressures. According to the invention, the spherical body 9 is shaped such that it allows for a bearing similar to a ball joint at an opening 15 of the first retaining element 7 and at an opening 20 of the second retaining element 8 simultaneously, which will be described in more detail later.

[0023] 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, in the installed state of the valve 2, 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 dimension of approximately 50 to 100 µm.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.

[0024] 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.

[0025] As from Fig. As can be seen in Figure 1, the injection system 1 advantageously comprises, as an essential assembly according to the invention, the upper suspension area with the first retaining element 7, the second retaining element 8, and the independent spherical body 9, which form the upper bearing point in the suspension area of ​​the valve 2. The first retaining element 7 is, for example, L-shaped in section, and is characterized in particular by the fact that a through-hole (not shown) is provided in a flange area 11, through which a connecting element, such as a screw 13, can be guided, with which the valve 2 can be clamped to an attachment, here the cylinder head 10. In addition to the longitudinally extending flange area 11, the first retaining element 7 has a retaining area 14 extending largely at right angles to it, which has the opening 15 to allow for the bearing of the spherical body 9.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 completely axial or angled to allow a lateral supply connection from a distribution line 34, as will be shown later in the figure. Fig. 2 will be explained further. The opening 15 is shaped in a partial area such that an inner conically extending conical surface 16 is present.

[0026] Overall, the first retaining element 7 is hood-shaped with a rounded contour around its circumference, resembling, for example, a certain egg shape between the flat upper and lower surfaces, or the simplest form of a tumbler toy, or a teardrop shape. The wider portion of the retaining element 7 is located in the area of ​​the spherical body 9, and the narrower portion is located in the area of ​​the screw 13. However, other contours are equally conceivable, such as a rectangular shape for the first retaining element 7.

[0027] 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 fastening points with the screws 19 represent a statically secure solution; however, more or fewer fastening points are also conceivable.The 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 spherically shaped body 9 on both sides, form the upper bearing point.

[0028] 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 spherical body 9. In general, there are surfaces 16, 21 corresponding to the spherical body 9 on the two retaining elements 7, 8.

[0029] Fig. Figure 2 shows a schematic perspective view of the injection system 1 in the upper suspension area with four hood-like retaining elements 7 and the connection to the distribution line 34, which is designed in the form of a fuel rail, and a schematically broken-up cylinder head 10.

[0030] The four retaining elements 7 are provided on their outer surface facing the distribution line 34 with concave, transverse recesses that ensure a secure and reliable hold for the circular, cylindrical distribution line 34. The retaining elements 7 thus conform precisely to the contour of the distribution line 34.

[0031] For a fluid connection, the distributor line 34 has transverse outlet bores that open directly into transverse sections of the openings 15 in the retaining elements 7. The retaining elements 7 are fastened to the distributor line 34 by inserting a solder, in particular copper solder, into the recesses on the outside and subsequently brazing at temperatures between 450°C and 900°C, or, for example, in a vacuum brazing process up to approximately 1100°C.

[0032] In the Fig. 3 to 5 shows an independent spherical body 9 as a single component in a first embodiment, wherein Fig. 3 is a perspective view of the first spherical body 9, Fig. 4 a top view of the first spherical body 9 according to Fig. 3 shows and Fig. 5 a sectional view of the spherical body 9 according to a section along the line V - V in Fig. 4 shows.

[0033] In the illustrated embodiment, the spherical body 9 is advantageously designed as a separate spherical component according to the invention. The spherical body 9 has a flow-through inner longitudinal opening 25. At its downstream end, the longitudinal opening 25 has, for example, an internal thread 28 with which the spherical body 9 can be screwed onto the inlet-side valve end 5 of the valve 2. Besides the screw connection shown, other joining methods for attaching the spherical body 9, such as welding, are also conceivable. The downstream end of the spherical body 9 thus generally forms a mounting area for connection with the valve 2.

[0034] The spherical body 9 is designed such that it has spherically curved contact surfaces 36 and 41 facing the two conical surfaces 16 and 21 of the first and second retaining elements 7 and 8. In an axially central region, spherically convex sections 37 and flattened sections 38 alternate around the circumference. In the illustrated embodiment, six spherically convex sections 37 and six flattened sections 38 are provided. Alternatively, more or fewer sections 37 and 38 can be formed. The flattened sections 38 enable a very compact design, for example, to easily integrate the screws 19. Furthermore, this shape of the spherical body 9 facilitates the engagement of a screw tool (not shown).The spherical bodies 9 can be transformed into the desired contour either from previously manufactured, highly reproducible spheres or from bar stock.

[0035] The term "spherical body 9" refers to a component that approximately resembles a sphere, but does not have to be a perfect sphere, but could, for example, be one that is based on the Fig. The spherical body 9 can possess the design features described in sections 3 to 5, including one or more internal bores and machined sections on the outer circumference. Particularly in the case of spherical bodies 9 manufactured from bar stock, cylindrical, nozzle-like extensions can also remain on the downstream side of the spherical body 9 towards the valve 2. Such an axial extension would then extend radially from the lower spherically curved contact surface 41 within the contact surface 41 as a single axial extension of the spherical body 9. Such an axial nozzle-like extension of the spherical body 9 could then, for example, have the internal thread 28 for a screw connection or form another type of fastening area, e.g., for welding.

[0036] The upper suspension area of ​​the valve 2 features a metallic bearing arrangement between the spherical body 9 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 spherical body 9 is expressly to be understood generally as a spherically convex body whose radii need not be constant over the entire spherical body 9. In fact, it is conceivable that different radii are provided above and below an imaginary spherical equator for the individual spherically convex contact surfaces 36 and 41, so that these spherical areas 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 contact surface 36 towards the upper conical surface 16 should have a smaller radius than the radius of the spherical area with contact surface 41 towards the lower conical surface 21. Ideally, the centers (pivot points) of the spherical areas should lie on the central axis of the spherical body 9.

[0037] 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.

[0038] 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. Before the spherical body 9 is attached to the valve 2, a sealing element should advantageously be inserted into the gap to seal the spherical body 9 against the valve 2. Ideally, the sealing element is a sealing disc 40 that seals against the valve 2. The sealing disc 40 can be made of metal (e.g., copper) or an elastomeric plastic. An alternative to a sealing disc 40 can also be a disc-shaped or a sleeve-shaped sealing element.

[0039] The spherical body 9 is then attached to the valve end 5 of the valve 2, either, as shown, via a screw connection with the internal thread of the spherical body 9 corresponding to an external thread on the valve 2, or by welding or a similar joining method.

[0040] Subsequently, the first upper retaining element 7 is placed onto the spherical body 9 to form the upper suspension area. In the Fig. Figure 1 clearly shows the L-shaped contour of the first retaining element 7, in which the flange area 11 with at least one through-hole for the screw 13 and the retaining area 14 are situated at largely right angles to each other. The retaining area 14 has the opening 15 required for the ball joint or spherical bearing, which comes into contact with the spherical body 9. 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 spherical body 9 with which it interacts and its radius at the contact surface 36. This angle will be on the order of 30° to 60°, particularly between 40° and 55°, and preferably between 45° and 50°.The same applies to the angle of the conical surface 21 of the opening 20 in the lower retaining element 8.

[0041] In the holding area 14 of the holding element 7, for example, two through holes 17 are provided, which serve to guide two screws 19 through them in order to enable clamping of the two holding elements 7 and 8 with corresponding threaded holes 18 in the second holding element 8. The two through holes 17 are, for example, arranged largely opposite each other in the holding area 14 around the opening 15.

[0042] After the upper retaining element 7 is placed on the spherical body 9, a line contact is established between the retaining element 7 and the spherical body 9. 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 securely and firmly attached to the distribution line 34, as described above, for example by brazing, a complete Fuel Charge Assembly (FCA) is already present after the screw connections with the screws 19 are made. This assembly includes the distribution line 34, the necessary number of valves 2, and the respective hold-down units.Following the assembly of these holding units, the device consisting of valves 2, distributor line 34 and the respective holding elements 7 and 8 can be installed in the cylinder head 10 of the internal combustion engine, but also on a spray test stand etc. or on a different type of attachment.

[0043] The valves 2 align themselves 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; rather, they must "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 alternately tightened. This permanently and securely connects the valve 2 to the lower support of the retaining element 7. The number of screws 13, 19 can vary depending on space requirements and design.

[0044] In the Fig. Figure 6 shows a schematic sectional view of the injection system 1 in the upper suspension area according to a second embodiment of the present invention. This embodiment differs from the previously described embodiment in particular in that an additional seal is provided in the area of ​​contact between the spherical body 9 and its upper contact surface 36 with the conical surface 16 of the first retaining element 7. The seal is implemented by means of a circumferential groove 44 on the outer surface of the spherical body 9 in the area of ​​its upper contact surface 36. An annular sealing element 45 can be inserted into this groove 44. The groove 44 has a width of 2 to 3 mm and a depth of 1 to 2 mm.

[0045] While Fig. 7 a top view of the second spherical body 9 according to Fig. 6 represents shows Fig. 8 a sectional view of the spherical body 9 according to a section along line VIII - VIII in Fig. 7. The arrangement of the groove 44 on the spherical body 9 in the area of ​​its upper contact surface 36 becomes particularly clear. The circumferential groove 44 interrupts the spherically curved contact surface 36 approximately in a central position, so that sufficiently large spherical sections of the contact surface 36 remain both below and above the groove 44 for the function of the ball joint.

[0046] Suitable materials for the ring-shaped sealing element 45 include plastics such as EPDM, VMQ, FKM or VI or comparable plastics that enable a reliable sealing effect in the temperature range of -60°C to +150°C, which is particularly desirable for media such as hydrogen.

[0047] In this embodiment as well, both conical surfaces 16 and 21 of the retaining elements 7 and 8, together with the spherically shaped spherical body 9, form the upper spherical bearing point. The alignment of the conical surfaces 16 and 21 with the spherical body 9 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.

[0048] Background of the in the Fig.The solution shown in Figures 6 to 8 is based on the fact that the issue of tightness and leakage is of particular importance, especially in hydrogen engines. 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 onto the spherically curved contact surface 36 of the spherical body 9 allows for the formation of two adjacent 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.

[0049] With optimal design, the metallic sealing line at the contact surface 36 of the spherical body 9 is located radially inside the annular sealing element 45. The internal sealing line also has the advantage that the sealing element 45 is not directly exposed to hydrogen at full system pressure and temperature. In the event of extreme cooling of the hydrogen due to rapid expansion, the hydrogen temperature can theoretically drop below -40°C. Due to the metallic seal radially in front of the sealing element 45, a kind of "throttle" is created. This causes the hydrogen to heat up to almost the temperature of the components valve 2 and retaining elements 7, 8. With appropriate connection to the internal combustion engine, the temperatures of these components are significantly higher than the ambient temperature. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 200 597 A1

[0002] DE 10 2015 205 980 A1

[0003]

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 holding element (7) and a second holding element (8), wherein the first holding element (7) has an opening (15) and the second holding element (8) has an opening (20), wherein the opening (15) of the first holding element (7) and the opening (20) of the second holding element (8) are designed such that, together with at least one spherical section of the valve (2), a spherical bearing in the holding elements (7, 8) is ensured, characterized bythat an independent spherical body (9) which can be fastened to the valve (2) and has spherically curved contact surfaces (36, 41) is provided, wherein the spherically curved contact surfaces (36, 41) correspond on the one hand to a surface (16) of the first holding element (7) and on the other hand to a surface (21) of the second holding element (8) to form a spherical bearing. [2] Plant according to claim 1, characterized by that the spherical body (9) can either be produced from a prefabricated sphere or can be converted into the desired spherical contour from rod material. [3] Plant according to claim 1 or 2, characterized by that the spherical body (9) has a flow-through inner longitudinal opening (25). [4] Plant according to claim 3, characterized by that a fastening area for connection to the valve (2) is provided at the downstream end of the spherical body (9). [5] Plant according to claim 3 or 4, characterized by that the longitudinal opening (25) of the spherical body (9) has an internal thread (28) with which the spherical body (9) can be screwed onto the inlet-side valve end (5) of the valve (2). [6] Installation according to one of the preceding claims, characterized by that the spherical body (9) is designed in such a way that, in an axially central region, spherically convex curved sections (37) and flattened sections (38) alternate over the circumference. [7] Installation according to one of the preceding claims, characterized by that an additional sealing element (45) is integrated on the upper spherically curved contact surface (36) of the spherical body (9) facing the first holding element (7). [8] Plant according to claim 7, characterized bythat a circumferential groove (44) is provided on the spherical body (9) in the region of its upper contact surface (36), into which groove the sealing element (45) can be inserted and which is positioned such that a metallic seal on the upper spherically curved contact surface (36) is additionally made possible radially within the groove (44). [9] Installation according to claim 7 or 8, characterized by that plastics such as EPDM, VMQ, FKM or VI are used as materials for the annular sealing element (45). [10] Installation according to one of the preceding claims, characterized bythat the opening (15) of the first holding element (7) is shaped in a partial area such that an inner conical conical surface (16) is present and the opening (20) of the second holding element (8) is shaped in a partial area such that an inner conical conical surface (21) is present, wherein the two conicities run in opposite directions, widening conically in the first holding element (7) and tapering conically in the second holding element (8) as seen in the direction of flow. [11] Installation according to one of the preceding claims, characterized by that the first holding element (7) and the second holding element (8) can be clamped against one another, in particular by means of screws (19), preferably two screws (19), which are arranged circumferentially opposite one another. [12] Installation according to one of the preceding claims, characterized bythat at least two first holding elements (7) are provided which, before assembly with the corresponding second holding elements (8), can be firmly attached to a distribution line (34), in particular by means of brazing. [13] Installation according to one of the preceding claims, characterized by that the first holding element (7), the second holding element (8) and the spherical body (9) with the spherical bearing integrated there form an upper suspension region for the valve (2), while a second bearing point of the valve (2) is formed at a lower valve end (6) in the region of a sealing ring (33), in particular a sealing ring (33) made of PTFE. [14] Plant according to claim 13, characterized bythat the valve (2) can be introduced into a longitudinal bore (35) of a cylinder head (10), wherein the sealing ring (33) is mounted 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) is only approximately 50 to 100 µm in its radial extent.

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