Fuel system and fuel distributor strip for fuels, in particular for hydrogen
Patent Information
- Application Number
- EP2023792976
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-31
- Filing Date
- 2023-10-19
- Publication Date
- 2025-12-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Fuel rails for internal combustion engines, particularly those handling hydrogen, face challenges in mechanical stress due to high pressures and vibrations, leading to structural weakening and potential fuel leakage at connecting surfaces, where conventional relief notches compromise material strength and tightness.
A fuel distribution strip with multiple grooves on the connecting piece and base body optimizes the capillary effect during soldering, ensuring a consistent and strong solder joint by distributing solder material evenly, thereby enhancing the connection's strength and tightness, suitable for high-pressure hydrogen applications.
The design achieves a reliable, high-strength, and gas-tight connection capable of withstanding pressures up to 35 MPa, preventing fuel leakage and maintaining material integrity over the component's service life.
Smart Images
Figure EP2023079115_08082024_PF_FP
Abstract
Description
[0001] Description
[0002] title
[0003] Fuel system and fuel distribution manifold for fuels, especially for hydrogen
[0004] State of the art
[0005] The invention relates to a fuel system, in particular a fuel injection system or a fuel injection system, and a fuel rail. Specifically, the invention relates to the field of fuel systems for motor vehicles. Specifically, the invention relates to a fuel injection system for hydrogen.
[0006] A fuel rail for internal combustion engines is known from US Pat. No. 9,546,634 B2. Furthermore, this document discloses that fuel rails must meet stringent requirements with regard to mechanical stress caused by high internal pressures and fluctuations in these internal pressures, as well as vibrations. Particular weak points arise, for example, at brazed or welded connecting surfaces, where fractures frequently occur. The known fuel rail therefore has relief notches on the outside of its rail tube, which are spaced apart from connecting devices connected to the rail tube.
[0007] The fuel rail known from US Pat. No. 9,546,634 B2 addresses problems that arise when liquid fuels are pumped into the fuel rail under high pressure. This known measure has the disadvantage of resulting in a structural weakening of the material, significantly reducing the load-bearing capacity in relation to the overall material used and, in particular, the weight of the fuel rail.
[0008] A fuel rail must be able to withstand the loads encountered throughout its service life. A significant portion of this stress is caused by temperature and pressure loads. In the area of connecting pieces, especially cups, there is also the problem that the material connection must remain tight throughout its service life to prevent fuel from escaping at the connection point. With a soldered joint, the problem arises that a gap that is too narrow between the connecting piece and the base body of the fuel rail can prevent the filler material, particularly copper, from being distributed evenly, thus reducing the strength of the joint.On the other hand, if the gap is too wide, the strength of the joint is reduced almost to the strength of the filling material itself, and the gap may not be completely filled due to reduced capillary action, which also reduces the strength of the joint.
[0009] Disclosure of the invention
[0010] The fuel distribution rail according to the invention with the features of claim 1 and the fuel system according to the invention with the features of claim 10 have the advantage that an improved design and functioning are possible, which in particular enables the tightness and strength of a connection between a connecting piece, in particular a cup, and a base body to be ensured.
[0011] The measures set out in the subclaims enable advantageous further developments of the fuel distribution bar specified in claim 1 and the fuel system specified in claim 10.
[0012] The fuel distribution rail and the fuel system designed as a fuel injection system are particularly suitable for hydrogen injection applications. The fuel distribution rail can be used to distribute the fuel to several fuel valves. During operation, the fuel valves can inject the gaseous fuel required for the combustion process, particularly hydrogen, into the respective combustion chamber of the internal combustion engine at a suitable pressure.
[0013] The at least one fuel valve is not a component of the fuel distribution manifold according to the invention. In particular, the fuel distribution manifold according to the invention can also be manufactured and sold independently of a fuel system.
[0014] It is conceivable that only a single groove is provided, which is provided either on the connecting piece or on the base body. However, a design with multiple grooves is preferred. This makes it possible, in particular, to optimize the distribution of the material (solder, solder material, soldering agent) between the connecting piece and the base body by utilizing the capillary effect along multiple grooves. This can also enable an optimized geometry of the grooves. For example, the grooves can be designed to be at least approximately rectilinear, at least in a projection along a projection axis, in particular along a projection axis in the direction of which the connecting surface at the mouth opening of the connecting channel points at least approximately towards the base body. If the connecting channel exits perpendicularly at the mouth opening at the connecting surface, then the projection axis is the same as the exit direction of the connecting channel.This arrangement, which includes several grooves, achieves a beneficial capillary effect.
[0015] It is advantageous if at least one groove of the connecting piece and / or at least one groove of the base body extend at least to one edge of the connecting surface of the connecting piece. In particular, grooves of the connecting piece can end at the edge. Grooves on the base body can also extend slightly beyond the edge of the connecting surface. In preparation for the soldering process, the solder material can be distributed around the edge of the connecting piece. When the workpiece is heated, the solder material melts and is drawn into the gap between the connecting surface of the connecting piece and the base body. If the gap is very narrow, then, in contrast to a conventional soldering process, a solder connection with an optimized thickness corresponding to the gap at the groove is achieved at the grooves.This results in an advantageous distribution of the solder material at least in one groove as well as a limitation of the thickness, so that the strength of the connection is optimized.
[0016] It is advantageous for the connector to have several grooves that intersect at least in pairs, and / or for the base body to have several grooves that intersect at least in pairs. This achieves an optimized capillary effect, with the intersection points ensuring complete circumferential enclosure of the outlet opening.
[0017] It is advantageous for the connecting piece to have at least three grooves that intersect in pairs and extend at least approximately like a curved or non-curved polygon between the intersection points, and / or for the base body to have at least three grooves that intersect in pairs and extend at least approximately like a curved or non-curved polygon between the intersection points. This provides an optimized design.
[0018] It is advantageous that the base body has a cylindrical outer surface, at least at the connecting surface of the connecting piece, and that the connecting surface of the connecting piece is designed in a cylindrical outer surface corresponding to the cylindrical outer surface of the base body. This allows the gap between the connecting surface of the connecting piece and the base body to be optimally adjusted to a small size.
[0019] It is advantageous for the average gap width between the outer side of the base body and the connecting surface of the connecting piece at the at least one groove of the connecting piece and / or at the at least one groove of the base body to be in a range of approximately 0.05 mm to approximately 0.20 mm, in particular in a range of approximately 0.05 mm to approximately 0.15 mm. This results in an optimized connection. In particular, this results in a good seal and a high degree of connection strength.
[0020] It is advantageous for the average gap width between the outer side of the base body and the connecting surface of the connecting piece at the at least one groove of the connecting piece and / or at the at least one groove of the base body to be at least approximately equal to 0.10 mm. This results in an optimized connection. In particular, this results in a good seal and a high degree of connection strength.
[0021] It is advantageous that the angle of contact of the connecting surface of the connector, with which the connecting surface encloses the outer surface of the base body, is not greater than 180°, and in particular less than 180°. The connection can advantageously be ensured via a solder joint, thus enabling simple assembly.
[0022] It is advantageous that the base body is designed such that a fuel under a pressure of at least 35 MPa can be stored and / or distributed within the base body. This provides a preferred area of application. For highly stressed base bodies, one or more grooves are preferably provided only on the connecting surface of the connecting piece to prevent weakening of the base body or a reduction in its strength.
[0023] Short description of the drawings
[0024] Preferred embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawings, in which corresponding elements are provided with identical reference numerals. They show: Fig. 1 shows a fuel system designed as a fuel injection system with a fuel distribution rail in a partial, schematic representation according to an embodiment of the invention;
[0025] Fig. 2 shows the section designated II in Fig. 1 with a base body and a connecting piece connected to the base body, with a fuel valve connected to the connecting piece being shown in part;
[0026] Fig. 3 is a highly simplified schematic representation of a connecting piece from the viewing direction designated III in Fig. 2 to illustrate the embodiment;
[0027] Fig. 4 is a schematic representation of a connecting surface of the connecting piece shown in Fig. 3 from the viewing direction designated IV, showing a configuration with four grooves;
[0028] Fig. 5 is a schematic representation of the base body and the connecting piece during manufacture, showing a gap between the base body and the connecting surface of the connecting piece; and
[0029] Fig. 6 shows the base body and the connecting piece shown in Fig. 5 during manufacture, showing a process for reducing and / or adjusting the gap.
[0030] Embodiments of the invention
[0031] Fig. 1 shows a fuel system 1 with a fuel distribution rail 2 and an internal combustion engine 3 with a cylinder head 4 in a partial, schematic representation according to an exemplary embodiment of the invention. Depending on its design, the fuel distribution rail 2 can serve to store and / or distribute at least one gaseous or liquid fuel. In this exemplary embodiment, the fuel distribution rail 2 and the fuel system 1 designed as a fuel injection system 1 serve to inject gaseous fuel, in particular hydrogen, into combustion chambers of the internal combustion engine 3.
[0032] The combustible gas is fed into the fuel distribution rail 3 via a conveyor device 5. This can also reduce the gas pressure. From the fuel distribution rail 2, the gas can be injected into the combustion chambers via fuel valves 6, 7, and 8. The fuel distribution rail 2 can be connected to the cylinder head 4 via brackets 10, 11, 12, and 13.
[0033] The fuel distribution rail 2 comprises a base body 15, which serves to store and / or distribute fuel. In particular, hydrogen can be stored in the base body and distributed among the fuel valves 6, 7, 8. The fuel distribution rail 2 also comprises connecting pieces 16, 17, 18, to each of which a fuel valve 6, 7, 8 is connected. The base body 15 is preferably designed such that a fuel under a pressure of at least 35 MPa can be stored and / or distributed in the base body 15. Accordingly, the connection between the base body 15 and each of the connecting pieces 16, 17, 18 is designed to meet the requirements for such a pressure.
[0034] Fig. 2 shows the section designated II in Fig. 1 with the base body 15 and, as an example, the connecting piece 16 connected to the base body 15, wherein the fuel valve 6 connected to the connecting piece 16 is also shown in part. The design of the connecting pieces 17, 18 and the connections to the base body 15 are similar.
[0035] Fig. 3 shows a highly simplified schematic representation of the connecting piece 16 from the viewing direction designated III in Fig. 2 to illustrate the exemplary embodiment. The connecting piece 16 has a connecting surface 20 facing an outer side 21 of the base body 15.
[0036] Fig. 4 shows a schematic representation of the connecting surface 20 of the connecting piece 16 shown in Fig. 3 from the viewing direction designated IV. An opening 23 of a connecting channel 22 of the connecting piece 16 is arranged in the connecting surface 20. The connecting piece 16 is connected to the base body 15 at least by a soldered connection at the connecting surface 20.
[0037] In one possible embodiment, the connecting pieces 16, 17, 18 can be attached to the base body 15 by welding. Subsequently, the gas-tight connections, in particular, can be realized by a soldering process.
[0038] In this embodiment, four grooves 25, 26, 27, 28 are formed on the connecting surface 20 of the connecting piece 16. The grooves 25, 26, 27, 28 in the connecting surface 20 of the connecting piece 16, 17, 18 are designed and arranged relative to one another such that they enclose the outlet opening 23 of the connecting channel 22 of the connecting piece 16.
[0039] In a modified embodiment, the base body 15 can have at least one groove on the connecting surface 20 of the connecting piece 16, 17, 18. This groove or these grooves of the base body 15 are then designed in the region of the connecting surface 20 of the respective connecting piece 16, 17, 18 and, if appropriate, arranged relative to one another in such a way that they enclose the mouth opening 21 of the connecting channel 22 of the connecting piece 16, 17, 18. Furthermore, grooves 25, 26, 27, 28 on the connecting piece 16 and grooves on the base body 15 can also be combined. Furthermore, in modified embodiments, more or fewer grooves can be provided depending on the application. The statements regarding the grooves 25, 26, 27, 28 apply accordingly to the grooves of the base body 15.
[0040] The grooves 25, 26, 27, 28 of the connecting piece 16, 17, 18 or the grooves of the base body 15 extend at least to an edge 35 of the connecting surface 20 of the connecting piece 16. Especially in the case of grooves formed on the base body 15, these can also extend beyond the edge 35 in order to improve the entry of the liquid solder by means of the capillary action.
[0041] The grooves 25, 26, 27, 28 intersect in pairs. In this exemplary embodiment, the grooves intersect in a quadrilateral shape when viewed from a projection along the axis 29, which extends perpendicular to the connecting surface 20, at least in the region of the mouth opening 23. An arrangement of grooves on the base body 15 can also be realized in a corresponding manner.
[0042] The connecting piece 16, 17, 18 has at least three grooves 25, 26, 27, 28 which cross each other in pairs, and between the crossing points 36, 37, 38, 39 these grooves run at least approximately according to a curved or non-curved polygon.
[0043] In this exemplary embodiment, the connecting surface 20 is curved. The base body 15 has a cylindrical outer side 30. The connecting surface 20 of the connecting piece 16 is designed in the shape of a cylinder jacket, corresponding to the cylindrical outer side 30 of the base body 15. At least approximately the same radii of curvature can be selected for the cylindrical outer side 30 and the connecting surface 20. Fig. 5 shows a schematic representation of the base body 15 and the connecting piece 16, 17, 18 during production, wherein a gap 44 is shown between the base body 15 and the connecting surface 20 of the connecting piece 16. Furthermore, Fig. 6 shows the base body 15 shown in Fig. 5 and the connecting piece 16 during production, wherein a process for reducing and / or adjusting the gap 44 is shown. This allows an optimized gap width of 45 to be achieved in the area of the grooves 25, 26, 27, 28.A wrap angle 46 can be 180° and preferably less than 180°.
[0044] In this exemplary embodiment, the cylindrical shell-shaped configurations of the base body 15 and the connecting piece 16 on the connecting surface 20 are realized in such a way that the manufacturing tolerances with respect to the manufacturing process, such as pressing or machining, are preferably minimized there.
[0045] As shown in Fig. 6, fixation for the welding process can be achieved via a fixing device 50. The fixation is implemented in such a way that a minimal gap 44 is achieved. In this exemplary embodiment, the connecting piece 16 is positioned offset by 180° with respect to a longitudinal axis 51 (Fig. 2) from the fixation on the base body 15. A fixing force F for fixation for welding is preferably applied in only one direction, in particular perpendicular to the longitudinal axis 51 and corresponding to the angle of 180° in the direction of fixation by the fixing device 50. With ideal tolerances, a gap 44 that disappears apart from the grooves 25, 26, 27, 28 can be realized. The tolerances are preferably specified in such a way that, apart from the grooves 25, 26, 27, 28, an at least substantially disappearing gap 44 is realized.
[0046] In a conventional design, if the gap is negligible or too small during the soldering process, sufficient filling with the solder material would no longer be guaranteed. In the invention and a possibly further developed design of the invention, the at least one groove 25, 26, 27, 28 can still create a gap width at the grooves even when components are in contact with one another, i.e., for example, the connecting piece 16 on the one hand and the base body 15 on the other, which ensures filling with the solder material via capillary action. Depending on the design, however, it is not necessarily the case that an otherwise negligible gap 44 is created. Preferably, a certain optimal gap width 45 is created at the grooves 25, 26, 27, 28.An average gap width 45 between the outer side 21 of the base body 15 and the connecting surface 20 of the connecting piece 16, 17, 18 at the grooves 25, 26, 27, 28 of the connecting piece 16, 17, 18 is preferably in a range from approximately 0.05 mm to approximately 0.20 mm, in particular in a range from approximately 0.05 mm to approximately 0.15 mm. It is particularly preferred that an average gap width 45 between the outer side 21 of the base body 15 and the connecting surface 20 of the connecting piece 16, 17, 18 at the grooves 25, 26, 27, 28 of the connecting piece 16, 17, 18 is at least approximately equal to 0.10 mm.
[0047] Accordingly, in a modified embodiment, the average gap width 45 at the at least one groove of the base body 15 is in a range from approximately 0.05 mm to approximately 0.20 mm, in particular in a range from approximately 0.05 mm to approximately 0.15 mm. Accordingly, in this modified embodiment, the average gap width 45 at the at least one groove of the base body 15 is preferably at least approximately equal to 0.10 mm.
[0048] During the soldering process, the grooves 25, 26, 27, 28 fill. This prevents a disappearing gap 44 at least at the grooves 25, 26, 27, 28. And in a case where too little solder paste, in particular copper paste, is applied, at least the grooves 25, 26, 27, 28 fill due to capillary action. This ensures a reliable seal, since a connection exists along at least one closed line corresponding to the enclosure of the mouth opening 23. In particular, the line can have the shape of a closed and possibly curved square. The quality of the soldered connection and thus the tightness can be tested easily, in particular by visual inspection. If the solder material is not specified in the process, this can be reliably identified by a quality test via the detection of a leak.Test holes for quality control, which contribute to material weakening and / or are not feasible in a cup, are not required.
[0049] The grooves 25, 26, 27, 28 can be produced by machining, embossing, or the like. The welding process can utilize laser welding or tungsten inert gas welding. The brazing process can be a high-temperature brazing process. The brazing material can comprise copper. The brazing material can connect all components involved and ensure tightness. Particular attention is paid to the parameters of cleanliness, the gap width 45 at the grooves 25, 26, 27, 28, the capillary action of the grooves 25, 26, 27, 28, and the amount of brazing material. The invention is not limited to the described embodiments.
Claims
Claims 1. A fuel distribution bar (2) for a fuel system (1), in particular for a fuel injection system or a fuel injection system, comprising a base body (15) for storing and / or distributing fuel, in particular hydrogen, and at least one connecting piece (16, 17, 18) to which a fuel valve (6, 7, 8) can be connected, wherein the connecting piece (16, 17, 18) has a connecting surface (20) facing an outer side (21) of the base body (15), wherein an opening (23) of a connecting channel (22) of the connecting piece (16, 17, 18) is arranged in the connecting surface (20), and wherein the connecting piece (16, 17, 18) is connected to the base body (15) at least by a soldered connection at the connecting surface (20), characterized in that a) the connecting piece (16, 17, 18) in its connecting surface (20) at least one groove (25, 26, 27,28) and / or that the base body (15) has at least one groove on the connecting surface (20) of the connecting piece (16, 17, 18) and b) that the at least one groove (25, 26, 27, 28) in the connecting surface (20) of the connecting piece (16, 17, 18) and / or the at least one groove of the base body (15) on the connecting surface (20) of the connecting piece (16, 17, 18) at least substantially enclose the mouth opening (21) of the connecting channel (22) of the connecting piece (16, 17, 18).
2. Fuel distribution rail according to claim 1, characterized in that at least one groove (25, 26, 27, 28) of the connecting piece (16, 17, 18) and / or at least one groove of the base body (15) extend at least to an edge (35) of the connecting surface (20) of the connecting piece (16, 17, 18).
3. Fuel distribution rail according to claim 1 or 2, characterized in that the connecting piece (16, 17, 18) has a plurality of grooves (25, 26, 27, 28) which cross at least in pairs, and / or that the base body (15) has a plurality of grooves which cross at least in pairs.
4. Fuel distribution rail according to one of claims 1 to 3, characterized in that the connecting piece (16, 17, 18) has at least three grooves (25, 26, 27, 28) which cross in pairs and run between the crossing points (36, 37, 38, 39) at least approximately corresponding to a curved or non-curved polygon, and / or that the base body has at least three grooves which cross in pairs and run between the crossing points at least approximately corresponding to a curved or non-curved polygon.
5. Fuel distribution rail according to one of claims 1 to 4, characterized in that the base body (15) has a cylinder jacket-shaped outer side (30) at least on the connecting surface (20) of the connecting piece (16, 17, 18) and that the connecting surface (20) of the connecting piece (16, 17, 18) is designed in the shape of a cylinder jacket corresponding to the cylinder jacket-shaped outer side (30) of the base body (15).
6. Fuel distribution rail according to one of claims 1 to 5, characterized in that an average gap width (45) between the outer side (21) of the base body (15) and the connecting surface (20) of the connecting piece (16, 17, 18) at the at least one groove (25, 26, 27, 28) of the connecting piece (16, 17, 18) and / or at the at least one groove of the base body (15) is in a range from approximately 0.05 mm to approximately 0.20 mm, in particular in a range from approximately 0.05 mm to approximately 0.15 mm.
7. Fuel distribution rail according to one of claims 1 to 6, characterized in that an average gap width (45) between the outer side (21) of the base body (15) and the connecting surface (20) of the connecting piece (16, 17, 18) at the at least one groove (25, 26, 27, 28) of the connecting piece (16, 17, 18) and / or at the at least one groove of the base body (15) is at least approximately equal to 0.10 mm.
8. Fuel distribution rail according to one of claims 1 to 7, characterized in that a wrap angle (46) of the connecting surface (20) of the connecting piece (16, 17, 18), with which the connecting piece (16, 17, 18) encompasses the outer side (21) of the base body (15) at its connecting surface (20), is not greater than 180°.
9. Fuel distribution rail according to one of claims 1 to 8, characterized in that the base body (15) is designed such that a fuel under a pressure of at least 35 MPa can be stored and / or distributed in the base body (15).
10. Fuel system (1), in particular fuel injection system or Fuel injection system, with at least one fuel distributor rail (1) according to one of claims 1 to 9.