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) of the first retaining element (7) is 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, the second retaining element (8) is designed in such a way that, on one side, it receives the valve end (5) of the valve (2) in the opening (20) and engages around same in a clasp-like manner by means of two leg portions (31) and, on the other side, engages with a pin-like bearing portion (28) in a depression (30) of the first retaining element (7) in order to form a bearing point.

Description

[0001] R. 416272

[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. 416272.

[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 used 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. O-ring seals are also known, of course.

[0012] In the course of the search for alternative fuels to reduce or avoid harmful emissions, an optimized solution for connecting or suspending a fuel injection valve for the direct injection of a gaseous R. 416272 is particularly important.

[0013] - 3 -

[0014] Fuel, in particular hydrogen or CNG, 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 blow-in 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, the spherical bearing of the valve is provided in a first retaining element, while a second retaining element is designed such that it, on the one hand, clamps around the inlet-side valve end of the valve by means of two leg sections and, on the other hand, engages with a pin-like bearing section in a

[0018] - 4 -

[0019] The first retaining element is deepened to form a bearing point.

[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 section is preferably located at the inlet-side valve end of the valve and the cone surface is located at the first retaining element.

[0022] A particularly preferred design is a spherically convex section at the valve end, with a radius that is either constant or varies across the entire spherical body. However, for spherical sections with different radii at the valve end, the centers or pivot points of these sections should ideally 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 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.

[0024] 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 pm. In this respect, the outer diameter of the valve end and the R. 416272 differ.

[0025] - 5 -

[0026] The inner diameter of the longitudinal bore in the cylinder head is extremely small.

[0027] 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. A screw connecting the two retaining elements permanently and securely fastens the valve to the retaining element's lower bracket, largely free of lateral forces.

[0028] 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 mounting, 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. R. 416272.

[0029] - 6 -

[0030] Advantageously, 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. In addition to its particularly advantageous sealing and bearing function, 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 reliable assembly.

[0031] 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.

[0032] drawing

[0033] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. The drawing shows:

[0034] Figure 1 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 first embodiment of the connection to a distribution line in the form of a fuel rail and a schematically broken-up cylinder head.

[0035] Figure 2 shows a schematic sectional view of the injection system in the upper suspension area with two retaining elements and the integrated spherical bearing of the valve, R. 416272

[0036] - 7 -

[0037] Figure 3 shows a schematic sectional view of the injection system in the upper suspension area with two retaining elements and the integrated spherical bearing of the valve in a sectional view rotated by 90° compared to Figure 2.

[0038] Figure 4 shows a schematic perspective view of the blowing system in the upper suspension area with two holding elements.

[0039] Preferred embodiments of the invention

[0040] The following section describes in detail, with reference to Figures 1 to 4, 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 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, whereby from now on it will only be referred to as an injection system 1. Alternative embodiments not shown in figures are also mentioned below.

[0042] 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. R. 416272

[0043] - 8 -

[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 an 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 2 and 3.

[0046] The first retaining element 7 is designed with a trough-like receiving section 23 for the distribution line 34.

[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 such 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 compressive 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, R. 416272

[0048] - 9 -

[0049] The diameter of the valve 2 at its valve end 6 and the diameter of the longitudinal bore 35 differ only slightly. Thus, for optimal bearing, the annular gap formed between the wall of the longitudinal bore 35 and the valve end 6 can have a radial extent of only approximately 50 to 100 pm. This particularly advantageous design keeps the damaged volume very small in the longitudinal bore 35 of the cylinder head 10, so close to the combustion chamber 3.

[0050] 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 as a result of the described clamping device.

[0051] The first retaining element 7 is designed with a trough-like receiving section 23 for the distribution line 34, whereby the distribution line 34 is only indicated very schematically.

[0052] Figure 2 shows a schematic sectional view of the injection system 1 in the upper suspension area with two retaining elements 7, 8 and the integrated spherical bearing of the valve 2. As can be seen in Figures 2 to 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. Furthermore, another bearing section is provided between the first retaining element 7 and the second retaining element 8. The first retaining element 7 has, in addition to a receiving section 22 for the distribution line 34, a block-like base body 26 from which the receiving section 22 extends laterally. R. 416272

[0053] - 10 - and a downstream extension section 29, which serves to accommodate the valve 2.

[0054] 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 in order to ultimately allow the gas to flow into the valve 2 parallel to its axis. Other angles for an oblique flow are conceivable at any time. The opening 15 then also forms the larger diameter interior of the downstream extension section 29 of the first retaining element 7.

[0055] The opening 15 is designed to allow the inlet-side valve end 5 of the valve 2 to be supported. The opening 15 is a through-opening through which the valve 2 is supplied with the medium to be discharged. A portion of the opening 15 is shaped such that it has an internal conical surface 16.

[0056] Overall, the first retaining element 7 is designed in a block-like form with a rounded overall contour, for example, in one direction perpendicular to the extension of the distribution line 34, the first retaining element 7 has a larger extension, for example, to accommodate a screw 19. However, other contours are equally conceivable, such as a rectangular design of the first retaining element 7.

[0057] The second lower retaining element 8 is disc-shaped. The second retaining element 8 has, for example, a threaded bore 18 into which a screw 19 can be screwed, which can be guided through a corresponding through-hole 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 screw 19. This fastening point is marked with R. 416272.

[0058] - 11 - the screw 19 represents a statically safe solution; however, more fastening points are also conceivable.

[0059] According to the invention, the second retaining element 8 is designed such that, on the one hand, it receives the valve end 5 of the valve 2 in its opening 20 and clamps it around by means of two leg sections 31, and on the other hand, it engages with a pin-like bearing section 28 in a recess 30 of the first retaining element 7 to form a bearing point. The recess 30 is provided on the underside of the first retaining element 7 facing the second retaining element 8. Similar to the opening 15 with the conical surface 16, the recess 30 on the first retaining element 7 is also provided with a conical surface 21. The pin-like bearing section 28 of the second retaining element 8 corresponds to this conical surface 21, and this bearing section 28 has a spherically rounded end to form the second bearing point. The bearing section 28 with its spherically convex bearing surface can also be referred to as a fixing pin.

[0060] The alignment of the leg sections 31 forming a clamp is achieved, for example, via two flattened surfaces 36 provided on the outer circumference of the valve 2. Alternative alignment options or anti-rotation devices are also conceivable.

[0061] The two conical surfaces 16 and 21 of the first retaining element 7 together with the valve end 5 of the valve 2, which is spherically shaped on one side, and the spherically rounded bearing section 28 of the second retaining element 8 form two bearing points which together characterize the upper suspension area according to the invention.

[0062] A spherical bearing is understood to be a bearing that is either a ball / taper bearing or similar to a rod end R. 416272

[0063] - 12 - or a ball joint with two spherically curved corresponding bearing surfaces.

[0064] Figure 3 shows a schematic sectional view of the injection system 1 in the upper suspension area with two retaining elements 7, 8 and the integrated spherical bearing of the valve 2, in a sectional view rotated by 90° compared to Figure 2. This makes the second bearing point between the first and second retaining elements 7, 8 particularly clear. The engagement of the screw 19 in the threaded bore 18 of the second retaining element 8 is also clearly visible. The screw 19 is supported below its screw head on the upper surface of the first retaining element 7 by one or more washers 38. In the embodiment shown in Figure 3, two washers 38, 38' are used, which, for example, have conically inclined or convex contact surfaces to allow them to interlock with each other. Washers can also be omitted entirely if the shape of the screw head or the bearing surface of the first retaining element 7 permits this.

[0065] This view is primarily intended to highlight another essential detail, which is characterized by a sealing element 45 on the outer circumference of the valve end 5.

[0066] 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 means of 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, with the sealing element 45 being located in R. 416272.

[0067] - 13 - ideally has a circular cross-section and a radial seal is achieved through this arrangement.

[0068] The sealing element 45, which is arranged on the outer surface of the valve end 5 of the valve 2, is thus, viewed in the axial flow direction, downstream of the metallic contact point of the valve 2 with the first retaining element 7.

[0069] 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.

[0070] 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.

[0071] The insertion of a sealing element 45 on the outer surface of the valve end 5 allows the formation of two closely spaced sealing points, which increase the safety and sealing performance in the connection area of ​​the valve 2. Furthermore, the clamping forces can be reduced compared to a purely metallic seal. R. 416272

[0072] - 14 -

[0073] In this design, the metallic sealing line at the contact surface with the conical surface 16 is located radially inside the annular sealing element 45. The internal sealing line 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 -0°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.

[0074] 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.

[0075] For a fluid connection, the distributor line 34 has outlet bores (not shown) that open directly into sections of the openings 15 running 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, followed by brazing at temperatures between 450°C and 900°C, or, for example, in a vacuum brazing process up to approximately 1100°C. Alternatively, forged rails can also be used as distributor lines 34 instead of the aforementioned stainless steel tubes as brazing rails. R. 416272

[0076] - 15 -

[0077] The upper suspension area of ​​the valve 2 is characterized by a metallic bearing arrangement between the valve end of the valve 2 and the two conical surfaces 16 and 21 of the first retaining element 7, forming a ball-and-cone connection. The valve end 5 of the valve 2, in its partial sections, represents a semi-spherical body, which can generally be understood as a partially spherically convex body whose radii need not be constant over the entire spherical section. Ideally, the centers (pivot points) of the spherical sections should lie on the central axis of the valve 2.

[0078] The assembly is carried out by inserting the valve 2, with the sealing element 45 already mounted, from below into the opening 15 of the first retaining element 7. As already mentioned, the sealing element 45 already provides a certain degree of fixation.

[0079] 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 interacting valve end 5 and its radius at the upper contact surface. This angle will be in the range of 30° to 60°, particularly between 40° and 55°, and preferably between 45° and 50°.

[0080] The contour at the valve end 5 of the valve 2 is designed such that the valve 2 can move freely through a considerable angular range below the center point of the respective retaining element 7 without coming into radial contact with the retaining element 7 or an R. 416272

[0081] - 16 - unintentional clamping of the components against each other can occur. This "free movement" of the valve 2 in the area of ​​the extension section 29 of the retaining element 7 is of considerable advantage for the radial movement of the valve 2 during installation to compensate for tolerances.

[0082] The second lower retaining element 8 can then be slid onto the valve 2 at its inlet-side valve end 5, whereby the opening 20 of the second retaining element 8, formed between the two leg sections 31, is penetrated by the valve end 5. The contour on the outer circumference of the valve 2 ensures a defined alignment of the retaining element 8 with respect to the valve 2.

[0083] The base body 26 of the retaining element 7, for example, has a through-hole 17 for the insertion of the screw 19. This screw engages with the corresponding threaded hole 18 in the second retaining element 8, allowing 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 then connected to each other by means of the screw 19.

[0084] Screw 19 should initially be tightened only very lightly. Tightening the screws creates a ball joint, which provides defined support for valve 2 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 (e.g., by brazing), a complete Fuel Charge Assembly (FCA) is already present after the screw connections with 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 hold-down units, the device consisting of valves 2, distribution line 34, and the respective retaining elements 7 and 8 can be placed in R. 416272.

[0085] - 17 -

[0086] Cylinder head 10 of the internal combustion engine, but also on a spray test stand etc. or on a different type of attachment.

[0087] The valves 2 are now 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; 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. Finally, the screws 19 can be tightened. This permanently and securely connects the valves 2 to the retaining bracket of the respective holding element 7. The number of screws 19 can vary depending on space requirements and design.

[0088] The two conical surfaces 16 and 21 of the retaining element 7, together with the spherically shaped valve end 5 and the spherical bearing section 28 of the retaining element 8, 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.

[0089] Figure 4 shows a schematic perspective view of the blowing system 1 in the upper suspension area with two retaining elements 7, 8, which illustrates the aforementioned features of the invention from an additional perspective. R. 416272

[0090] - 18 -

[0091] A further embodiment, not explicitly shown, will be mentioned as part of the invention. In this embodiment, the bearing point with the recess 30 and the pin-like bearing section 28 is configured exactly the opposite of the solutions described previously. According to the invention, the second retaining element 8 is thus designed such that, on the one hand, it receives the valve end 5 of the valve 2 in its opening 20 and clamps it around by means of two leg sections 31, and on the other hand, it has a recess 30 into which a pin-like bearing section 28 of the first retaining element 7 engages to form a bearing point. The recess 30 is provided on the upper surface of the second retaining element 8 facing the first retaining element 7. Similar to the opening 15 with the conical surface 16, the recess 30 on the second retaining element 8 is also provided with a conical surface 21.The conical surface 21 corresponds to the pin-like bearing section 28 of the first retaining element 7, with this bearing section 28 having a spherically rounded end to form the second bearing point. The bearing section 28 with its spherically convex bearing surface can also be referred to as a fixation pin.

[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. 416272 - 19 - 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) that 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) is designed such that, together with at least one spherical section of the valve (2), a spherical bearing in the first retaining element (7) is ensured, characterized in that the second retaining element (8) is designed such thatthat, on the one hand, it receives the valve end (5) of the valve (2) in the opening (20) and clamps it around by means of two leg sections (31) and, on the other hand, engages with a pin-like bearing section (28) in a recess (30) of the first retaining element (7) to form a bearing point, or, on the other hand, a pin-like bearing section (28) of the first retaining element (7) engages in a recess (30) of the second retaining element (8) to form a bearing point.

2. System according to claim 1, characterized in that a metallic contact point of the valve (2) is formed by a contact area at least partially spherically shaped at the valve end (5). R. 416272 - 20 - 3. System according to claim 2, characterized in that the spherically shaped contact area at the valve end (5) interacts with a conically extending conical surface (16) of the opening (15) of the first retaining element (7).

4. System according to one of the preceding claims, characterized in that the second lower retaining element (8) is designed in a disc shape.

5. System according to one of the preceding claims, characterized in that the recess (30) is provided on an underside of the first retaining element (7) facing the second retaining element (8) and, similar to the opening (15), the recess (30) on the first retaining element (7) is also provided with a conical surface (21), or that the recess (30) is provided on an upper side of the second retaining element (8) facing the first retaining element (7) and, similar to the opening (15), the recess (30) on the second retaining element (8) is also provided with a conical surface (21).

6. System according to claim 5, characterized in that the conical surface (21) of the first retaining element (7) corresponds to the pin-like bearing section (28) of the second retaining element (8) or that the conical surface (21) of the second retaining element (8) corresponds to the pin-like bearing section (28) of the first retaining element (7), wherein this bearing section (28) has a spherically rounded end in each case to form the second bearing point.

7. System according to claim 6, characterized in that the second spherically formed contact area on the first or second retaining element (7, 8) cooperates with the conically extending conical surface (21 ) of the recess (30) of the first or second retaining element (7, 8) to form a metallic bearing. R. 416272 - 21 - 8. System according to one of claims 4 to 7, characterized in that the second retaining element (8) has a threaded bore (18) into which a screw (19) can be screwed, which can be guided through a corresponding through bore (17) in the first retaining element (7) in order to clamp the two first and second retaining elements (7, 8) to each other.

9. System according to one of the preceding claims, characterized in that the valve (2) has flattenings (36) on the outer circumference of the inlet-side valve end (5) which serve to align the leg sections (31) forming a clamp.

10. System according to one of the preceding claims, characterized in that a sealing element (45) is arranged on a lateral surface of the inlet-side valve end (5) of the valve (2) which seals radially against the first retaining element (7).

11. System according to claim 10, characterized in that 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) at the first retaining element (7).

12. 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. R. 416272 - 22 - 13. System according to claim 12, 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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