FLUID DISTRIBUTOR FOR AN INJECTION SYSTEM AND INJECTION SYSTEM FOR MIXTURE-COMPRESSING, EXTERNALLY IGNITED INTERNAL COMBUSTION ENGINES

Abstract

A fluid distributor rail for an injection system for mixture-compressing, externally ignited internal combustion engines for metering a highly pressurized fluid. The fluid distributor rail includes a base body, and at least one connector configured on the base body. The base body with the at least one connector configured on the base body is formed by single stage or multistage forging. At least one interior space of the base body and a hydraulic fluid passage which leads into the interior space via the at least one connector configured on the base body are formed on the base body by machining after the forging. At least one element for connection is formed at least in part by mechanical cold-forming on at least one connector configured on the base body.

Claims

1-9. (canceled)

10. A fluid distributor for an injection system for a mixture-compressing, externally ignited internal combustion engine, which meters a fluid under high pressure, the fluid distributor comprising: a base body; at least one connector configured on the base body, wherein the base body with the at least one connector configured on the base body is formed by single stage or multistage forging, wherein at least one interior space of the base body and a hydraulic fluid passage which leads into the interior space via the at least one connector configured on the base body are formed on the base body by machining after the forging; and at least one element configured for connection is formed at least in part by mechanical cold-forming on at least one connector configured on the base body.

11. The fluid distributor according to claim 10, wherein the fluid distributor is a fuel distributor rail.

12. The fluid distributor according to claim 10, wherein, on the at least one connector configured on the base body, the element configured for connection formed at least in part by mechanical cold-forming is an external thread, and that the external thread is formed at least in part, at least substantially, by thread rolling.

13. The fluid distributor according to claim 10, wherein, on at least one connector configured on the base body, the element configured for connection which is formed at least in part by mechanical cold-forming is an internal thread, and that the internal thread is formed at least in part, at least substantially, by thread forming.

14. The fluid distributor according to claim 10, wherein, the at least one connector configured on the base body, on which the at least one element configured for connection is formed at least in part by mechanical cold-forming, is a high-pressure connector.

15. The fluid distributor according to claim 10, wherein the at least one connector configured on the base body, on which the at least one element configured for connection is formed at least in part by mechanical cold-forming, is a pressure sensor connector.

16. The fluid distributor according to claim 10, wherein, on the at least one connector configured on the base body, the element configured for connection which is formed at least in part by mechanical cold-forming is a conical sealing surface, and the sealing surface is formed, at least substantially, by roller burnishing.

17. The fluid distributor according to claim 10, wherein, on the at least one connector configured on the base body, the element configured for connection which is formed at least in part by mechanical cold-forming, is a conical sealing surface, an external thread for fastening, is provided on the at least one connector, and the sealing surface is formed by mechanical cold-forming in such a way that compressive residual stresses are introduced at the sealing surface which, with respect to loads on the sealing surface and the thread for fastening, counteract bending stresses resulting from a spreading of the conical sealing surface, to reduce a plastic spreading on the thread.

18. The fluid distributor according to claim 10, wherein at least one high-pressure connector, one pressure sensor connector, and a plurality of valve connectors are provided as the at least one connector, the high-pressure connector, the pressure sensor connector, and the plurality of valve connectors are configured on the base body, and the base body with at least the high-pressure connector, the pressure sensor connector and the plurality of valve connectors is formed by single stage or multistage forging from a single forged blank or as a single part.

19. An injection system configured for a mixture-compressing, externally ignited internal combustion engine, configured to inject a fluid that is fuel including gasoline and/or ethanol and/or a mixture comprising fuel, comprises: at least one fluid distributor which meters the fluid under high pressure, the fluid distributor, including: a base body, at least one connector configured on the base body, wherein the base body with the at least one connector configured on the base body is formed by single stage or multistage forging, wherein at least one interior space of the base body and a hydraulic fluid passage which leads into the interior space via the at least one connector configured on the base body are formed on the base body by machining after the forging, and at least one element configured for connection is formed at least in part by mechanical cold-forming on at least one connector configured on the base body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Preferred embodiment examples of the present invention are explained in more detail in the following description with reference to the figures in which corresponding elements are provided with the same reference signs.

[0022] FIG. 1 shows an injection system for a mixture-compressing, externally ignited internal combustion engine comprising a fluid distributor in a schematic sectional view according to a first embodiment example of the present invention.

[0023] FIG. 2 shows a high-pressure connector of a fluid distributor according to a second embodiment example of the present invention in a schematic illustration.

[0024] FIG. 3 shows a pressure sensor connector of a fluid distributor according to a third embodiment example of the present invention in a schematic illustration.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0025] FIG. 1 shows an injection system 1 comprising a fluid distributor 2 in a schematic sectional view according to one possible configuration. In this embodiment, the fluid distributor 2 of the fuel injection system 1 a fuel distributor rail 3 configured according to the present invention. A high-pressure pump 4 is provided as well. The high-pressure pump 4 is connected to the fluid distributor 2 via a fuel line 5 configured as high-pressure line 5. During operation, a fuel, in particular gasoline and/or ethanol, or a mixture comprising fuel, is supplied as a fluid at an inlet 6 of the high-pressure pump 4.

[0026] The fluid distributor 2 serves to store and distribute the fluid to injection valves 7 to 10 configured as fuel injection valves 7 to 10 and reduces pressure fluctuations and pulsations. The fluid distributor 2 can also serve to dampen pressure pulsations that can occur when fuel injection valves 7 to 10 are switched. During operation, high pressures p can occur at least temporarily in an interior space 11 of the fuel distributor rail 3.

[0027] The fluid distributor 2 configured as the fuel distributor rail 3 comprises a tubular base body 14, which is formed by single stage or multistage forging and is subsequently mechanically worked. The fuel distributor rail 3 further comprises a high-pressure connector 15 which serves as a high-pressure inlet 15, and a plurality of valve connectors 16 to 19 which are provided on the tubular base body 14 and serve as high-pressure outlets 16 to 19. A pressure sensor connector 20 is provided on the tubular base body 14 as well.

[0028] In this embodiment example, according to a preferred embodiment of the present invention, the base body 14 with at least the high-pressure connector 15, the pressure sensor connector 20 and the plurality of valve connectors 16 to 19 is formed by single stage or multistage forging from a single forged blank 14′. As a result, the tubular base body 14, the high-pressure connector 15, the pressure sensor connector 20 and the valve connectors 16 to 19 are then formed from a forged single part 14′. The high-pressure connector 15, the pressure sensor connector 20 and the valve connectors 16 to 19 are thus forged to the base body 14. The production of the base body 14 can thus be based on a single material. There is also no need for material-locking production processes to assemble a base body from multiple single parts.

[0029] In a modified embodiment, the base body 14, the high-pressure connector 15 and the pressure sensor connector 20 are configured in this way as a single part 14′. In a further modified embodiment, the base body 14 and the high-pressure connector 15 are configured in this way as a single part 14′. In a further modified embodiment, the base body 14 and the pressure sensor connector 20 are configured in this way as a single part 14′. In one of these modified embodiments, the valve connectors 16 to 19 can in particular not be forged or only partially forged to the base body 14.

[0030] The valve connectors 16 to 19 are preferably implemented without threads, wherein connections to the injection valves 7 to 10 can be sealed via sealing rings. The connectors 16 to 19 can be configured here as cups 16 to 19, on which the injection valves 7 to 10 are suspended.

[0031] In this embodiment example, a pressure sensor 21 is provided which is connected to the pressure sensor connector 20 and measures the pressure p in the interior space 11 during operation. The tubular base body 14 is closed at one end 22 by a closure 23, which is configured in this embodiment example as a closure screw 23. In this case, an internal thread 24 can be formed at the end 22 of the tubular base body 14.

[0032] After forging, the tubular base body 14 or the forged single part 14′ is worked by at least one machining process. In this embodiment, a bore 25 is furthermore formed in the tubular base body 14 after forging to create the interior space 11. During operation, the fluid supplied at the high-pressure inlet 15 can be distributed to the injection valves 7 to 10 connected at the high-pressure outlets 16 to 19 via the interior space 11. In this embodiment example, the injection system 1 is fastened in a suitable manner to an internal combustion engine 12, in particular to a cylinder head 13.

[0033] In addition, bores 26 to 31 are introduced into the forged single part 14′ by a machining process. The bores 27 to 30 here serve as connecting bores 27 to 30 for the high-pressure outlets 16′ to 19′. The bore 26 is used for the high-pressure inlet 15. The bore 31 is used for the pressure sensor connector 20. In this embodiment example, the bores 26 to 31 are components of hydraulic fluid passages 26′ to 31′.

[0034] A bore 35, a conical sealing surface 36 and an external thread 37 are formed on the high-pressure connector 15. A bore 45, a conical sealing surface 46 and an internal thread 47 are formed on the pressure sensor connector 20. The bore 25 for the interior space 11 is oriented axially with respect to a longitudinal axis 50. In this embodiment example, the bores 35 and 37 are oriented radially with respect to the longitudinal axis 50.

[0035] The connectors 15 to 20 can be configured such that they are suitable for the respective application. Preferred configurations of the high-pressure connector 15 and the pressure sensor connector 20 are described with reference to FIGS. 2 and 3. The high-pressure connector 15, in particular, can also be disposed in the region labeled with II in accordance with a modified embodiment of the end 22. Instead of supplying the fuel under high pressure radially, as illustrated in FIG. 1, the fuel can then be supplied axially. An axial orientation of the pressure sensor connector 20 can additionally or alternatively be implemented as well in a corresponding manner, for example at the other end 51.

[0036] FIG. 2 shows the high-pressure connector 15 of the fluid distributor 2 according to a second embodiment example in a schematic illustration. In this case, a hydraulic fluid passage 26′ which enables fuel to be supplied to the interior space 11 is implemented at the high-pressure connector 15 (see FIG. 1). In this embodiment example, the high-pressure connector 15 comprises a cylindrical recess 53 which adjoins the conical sealing surface 36. In this embodiment example, a throttle bore 54 is provided between the cylindrical recess 53 and the bore 26 that opens into the interior space 11. The external thread 37 is formed on an outer side 55 of the high-pressure connector 15 by mechanical cold-forming. The high-pressure line 5 (FIG. 1) can thus be connected to the fluid distributor, wherein the connection at the conical sealing surface 36 is preferably implemented as a ball-cone connection.

[0037] The conical sealing surface 36 is preferably strain hardened by roller burnishing. This makes it possible to achieve very good surface qualities; at least in a relevant region, the conical sealing surface 46 can in particular be made to be nearly specular. This has a particularly favorable effect on the sealing point of a ball-cone connection. Compressive residual stresses furthermore develop underneath the worked conical sealing surface 36, which increase local strength and can in particular contribute to at least partially compensating tensile stresses that occur as a result of a bending load.

[0038] Local roller burnishing or strength rolling of the high-pressure connector 15, in particular at the conical sealing surface 36, can thus achieve a significant increase in the material hardness as well as an improvement in the surface properties without the need for additional joining processes or more expensive materials.

[0039] Roller burnishing or strength rolling processes or the like can be integrated into the machining of the forged blank 14′ as appropriate. This can depend on whether the high-pressure connector 15 or correspondingly the pressure sensor connector 20 is disposed radially, axially or possibly in some other way, in particular radially eccentrically, on the tubular base body 14 of the fluid distributor 2. If appropriate, a roller burnishing or strength rolling process or the like can also be carried out as a final processing operation (finishing) after machining, which can optionally be carried out at a dedicated processing station.

[0040] FIG. 3 shows the pressure sensor connector 20 of the fluid distributor 2 according to a third embodiment example in a schematic illustration, wherein a hydraulic fluid passage 31 to the interior space 11 is implemented (see FIG. 1), so that, when the pressure sensor 21 is installed, the pressure p in the interior space 11 can be measured by the pressure sensor 21. In this embodiment example, the thread 47 is formed as an internal thread 47 by mechanical cold-forming. It is preferable to use thread forming here. In this process, the material of the forged blank 14′ is displaced and deformed or reshaped in such a way that not only a shaping but also a certain compression of the material is achieved.

[0041] The external thread 37 of the high-pressure connector 15 and the internal thread 47 of the pressure sensor connector 20 can optionally be formed on the forged blank 14′ without thread cutting. In a modified embodiment, however, it is possible for the threads 37, 47 to be partially precut by machining if this is practical in the particular application. Even so, especially in the case of high-strength materials, it makes sense not to precut the threads, because this is an additional processing step and, particularly in the case of high-strength materials, the tool life for thread cutter or the like is reduced.

[0042] Depending on the design of the mechanical cold-forming process, specific material and/or surface properties can result, in particular on the threads 37, 47 and the conical sealing surfaces 36, 46, which differ significantly from those that result from a machining process. For example, a nearly specular surface can be achieved. A depth profile of the residual stresses and a shape and height of surface roughnesses as well as the achieved strengthening and the local microstructure of the structure can moreover be characteristically pronounced.

[0043] The present invention is not limited to the described possible configurations and embodiment examples.