This application is a 35 USC 371 application of PCT/EP 2005/056788 filed on Dec. 14, 2005.
1. Field of the Invention
In fuel injection systems for direct-injection internal combustion engines, fuel injectors that contain one or more electrically triggerable valves are employed. For instance, an electrically triggerable magnet valve or piezoelectric valve may be provided for controlling a needle valve and thus for controlling the course of injection. Further valves may be used, for instance for a pressure boost. The electrical contacting of these valves, however, is often a challenge.
2. Prior Art
Since the electrically triggerable valve or valves are typically accommodated in the interior of an injector body, the electrical contacting of these electrically triggerable valves presents considerable technical difficulties. In many cases, on top of the injector body there is an electrical contact that can be connected to a corresponding control system and power supply system located outside the injector body. Via this contact (which may be either a multiple plug, or a plurality of individual plugs), all the electrically triggerable valves received in the interior of the injector body are as a rule triggered. In the interior of the injector body, this electrical contact must be connected to corresponding contacts of the electrically triggerable valve or valves of the injection system. This connection is typically done by means of flexible electrical cables and a simple soldering process.
This method for electrically contacting the electrically triggerable valves is associated with various disadvantages, however. For instance, the method is technically quite labor-intensive, since typically the cables must be initially soldered by hand against the corresponding electrical contacts. In practice, this method step requires great effort and is very time-consuming. Moreover, the connection between the electrically triggerable valves and the electrical contact on the injector body can be undone again only with difficulty. For removing or disassembling the injector body, the soldered connections must typically be unsoldered again. Such a labor-intensive process makes it uneconomical to repair the injectors or replace individual parts of the injector body.
According to the invention, a fuel injector for injecting fuel into a combustion chamber of an internal combustion engine and an orientation sleeve for use in a fuel injector of the invention and a method for producing a fuel injector of the invention are proposed, in which the above-described disadvantages of the prior art are avoided or reduced. The fuel injector has an injector body contact with an injector axis, at least one electrically triggerable valve let into the injector body, and at least one electrical injector body contact that is accessible from outside the injector body. At least one of the electrically triggerable valves should have at least one electrical valve body contact.
A fundamental concept of the present invention is to use a solid conductor for the electrical connection between the at least one valve contact and the at least one injector body contact, which solid conductor, in contrast to a simple cable or wire, does not become deformed under its own weight and is contactable via plug contacts, for instance, instead of a soldered connection. Slight plastic deformation of the solid conductor under its own weight and under additional exertion of force can be tolerated, if the design of the solid conductor remains substantially unchanged. The at least one solid conductor thus represents a kind of artificial lengthening of the electrical valve contacts.
However, the problem then is that the solid conductor when the fuel injector is put together must usually be guided through one or more conductor conduits, which in various regions or modules of the fuel injector can have different angles of inclination to the injector axis. Thus a solid conductor is extended out of a module at a first angle, for instance, and then on being guided into a conductor conduit of a second module, which has a different angle of inclination to the injector axis from the first angle of inclination, must be adapted to that first angle of inclination. This makes assembling the individual modules of the fuel injector more difficult. The angle adaptation can also lead to problems, particularly when the solid conductor is inserted into a plug contact that has only a slight angular tolerance. The fundamental concept of the invention to solve these problems of angle adaptation is to use at least one orientation sleeve. By means of this orientation sleeve, a predetermined inclination, such as 0L176\f“Symbol”\s12, to the injector axis is forced on the at least one solid conductor in at least one module, either entirely or in part. For instance, a solid conductor on being extended out of a conductor conduit of a module can be compelled to have the angle of inclination of the conductor conduit in an adjacent module or further module into which the solid conductor is then introduced.
The invention is described in further detail below in conjunction with the drawings.
Shown are:
In
The injector body 110 furthermore has a first magnet valve 111, disposed in the control module 132, for controlling the pressure boost in the pressure booster module 138, and a second magnet valve 112, disposed in the nozzle module 140, for controlling the actual injection event via an injection valve member (not shown).
The separation between the control module 132 and the rest of the injector body 110 along the first parting line 124 is of considerable practical significance. This separability or disconnectability has the effect that the (“dry”) control module 132 and the (“wet”) part of the injector body 110 located below the first parting line 124 can be designed, produced and tested separately, and then put together. Moreover, because of this separability, individual components of the injector body 110 can easily be replaced for maintenance purposes, for instance.
The magnet valve 112 in the nozzle module 140 is electrically triggerable via two electrical valve contacts 114. The injector body 110, on its upper end, has an electrical injector body contact 116 that is accessible from above. In the modular construction of the injector body 110 as shown, the capability of breaking down the injector body 110 and of simple modular assembly is achieved by providing that the valve contacts 114 be connected electrically to the injector body contact 116 in such a way that simple assembly and capability of breaking down the injector body continue to be assured.
In this exemplary embodiment, for connecting the two electrical valve contacts 114 to the injector body contact 116, two conductor conduits 120 are provided, which extend through the modules 138, 136 and 134. The conductor conduits 120 are formed by bores in the pressure booster module 138, in the line connection module 136, and in the sealing plate 134. Once the injector body 110 has been put together, these bores are each aligned at the parting lines 128 and 126, so that the result is a single, continuous conductor conduit 120.
The individual bores of the conductor conduit 120, in this exemplary embodiment, in the various modules 138, 136, 134 each have a rectilinear course. With the provisions of the invention, a curved course of the bores can also be achieved. However, the bores in the individual modules 138, 136, 134 do have a different inclination relative to an injector axis 142. While the conductor conduit 120 in the pressure booster module 138 has an inclination of 1° to the injector axis 142, the inclination in the line connection module 136, in this exemplary embodiment, is 2.2°. These different angles of inclination relative to the injector axis 142 are due to the fact that the injector body 110 tapers in its cross section toward the bottom, that is, from the control module 132 to the nozzle module 140.
The connection between the two electrical valve contacts 114 of the magnet valve 112 and the injector body contact 116 is effected, in this exemplary embodiment, in part via two solid conductors 118. The solid conductors 118 extend through the two conductor conduits 120 and connect the valve contacts 114 to electric plug contacts 122, which in turn are connected to the injector body contact 116 via an electrical connection 144 (for instance, two cables each soldered at one end to an electric plug contact 122 and at another end to the injector body contact 116). The solid conductors 118 are thus fixedly or detachably connected electrically to the valve contacts 114, for instance via a welded connection or a plug-in connection.
The connection of the solid conductors 118 to the plug contacts 122 is done reversibly, so that this connection can be made upon assembly of the injector body 110 by simply pressing the solid conductors 118 into the plug contacts 122. Conversely, in the event of maintenance, the solid conductors 118 can be easily removed from the plug contacts 122 again, and thus the injector body 110 can be broken down again without having to unsolder electrical connections. The solid conductors 118 are selected to be rigid enough that on the one hand they do not substantially change their shape under their own weight, and can thus be easily threaded through the conductor conduits 120 with their different inclinations to the injector axis 142 and plugged into the plug contacts 122. The solid conductors should have a certain plasticity, so that no mechanical stresses arise either at the transition between portions of the conductor conduits 120 that have different angles of inclination. The term “solid conductor” does not necessarily narrow the choice of materials to solid materials; on the contrary, hollow conductors (tubes) may for instance also be used as solid conductors 118, as long as they have sufficient mechanical rigidity.
Particularly on insertion of the solid conductors 118 into the plug contacts 122, or upon putting together the individual modules 132, 134, 136, 138, 140, however, the varying inclination of the conductor conduit 120 in the various modules presents problems. Typically, the individual modules 132, 134, 136, 138, 140 are put together by means of a motion and an exertion of force parallel to the injector axis 142. Thus the inclination of 2.2° of the solid conductors 118 in the line connection module 136, for instance, upon insertion of the solid conductors 118 into the plug contacts 122, which are disposed in portions of the conductor conduits 120 in the control module 132 that extend at an angle of 0° to the injector axis 142, presents difficulties. For optimized insertion of the solid conductors 118 into the plug contacts 122, the solid conductors 118 would have to extend parallel to the injector axis 142. This problem is overcome according to the invention, in this exemplary embodiment, by providing that the two solid conductors 118 are compelled to have a parallel course to the injector axis 142 by means of a respective orientation sleeve 146 (described in further detail below). Instead of two orientation sleeves 146, a single orientation sleeve 146 may also be used, which orients the two solid conductors 118 simultaneously.
The orientation sleeves 146 are thrust partway into the conductor conduits 120 in the line connection module 136, in such a way that the ends of the solid conductors 118 are thrust through the orientation sleeves 146. A parallel course to the injector axis 142 imposed on the ends of the solid conductors 118, which without orientation sleeves 146 would emerge from the conductor conduits 120 at an angle of inclination of 2.2° to the injector axis 142. After the modules 134 and 136 have been put together, the orientation sleeves 146 protrude partway into the conductor conduits 120 (extending parallel to the injector axis 142) in the sealing plate 134.
In the exemplary embodiment shown in
In
The solid conductors 118 in this exemplary embodiment are also relatively sheathed with shrink-fit hoses 212. The shrink-fit hoses 212 insulate the solid conductors 118 electrically from the walls of the conductor conduits 120 of the injector body 110. To economize on costs, the shrink-fit hoses 212 are not shrunk onto the solid conductors 118 in their entirety, but rather only in some portions. The shrink-fit hoses 212 extend upward from the electrically insulating thermoplastic 210. Alternatively to a shrink-fit hose 212, rigid or elastic electrically insulating plastic sleeves, for instance, can also be used as electric insulators for the solid conductors 118. The electrical insulation, particularly of the shrink-fit hose 212, however, ends in each case below the upper ends 214 of the solid conductors 118, so that the upper ends 214 of the solid conductors 118 are not sheathed in an electrically insulating way and can be plugged in an electrically connecting way into the plug contacts 122. In this way, without a complicated soldering or welding process, by simply putting the segments of the injector body 110 together, an electrically conductive connection between the valve contacts 114 and the injector body contact 116 can be made. On the other hand, the injector body 110 can easily be dismantled again for maintenance purposes, with the plug connection 122 disconnected from the solid conductors 118 again simply by the exertion of force. Unsoldering or disconnecting the connection in some other way is not necessary, since the connection is reversible.
In
The line connection module 136 has a substantially cylindrical conductor conduit 120, with a diameter D of 2 mm. This conductor conduit 120 is inclined by an angle α of 2.2° relative to the injector axis 142. The line connection module 136 has a height h of 40.8 mm, and on its upper end 310, oriented toward the sealing plate 134, it has an annular shoulder 312. The conductor conduit 120, at a length of x=15 mm from the upper end 310 oriented toward the sealing plate 134, is widened at 314 to a diameter d of 3 mm. In the region of this widened portion 314 to a diameter of d=3 mm, the angle of inclination of the conductor conduit 120 also changes relative to the injector axis 142, since in this widened region 314, the conductor conduit 120 extends parallel to the injector axis 142.
A solid conductor 118 extends through the conductor conduit 120. The solid conductor 118 is electrically insulated from the line connection module 136 by means of a shrink-fit hose 212 (see
In
The method shown in
In
As already explained above in conjunction with
In
A bore that is rotationally symmetrical to a sleeve axis 714 is located in the interior of the orientation sleeve 146. The bore is subdivided into two outer catch regions 716 and one inner orientation region 718. In the area of the orientation region 718, the bore has a cylindrical course that is parallel to the sleeve axis 714. The catch regions 716 initially have a first conical region 720 with an opening angle of 30°, in this exemplary embodiment (that is, an inclination of the wall by 15° to the sleeve axis 714). This is adjoined by a cylindrical region 722 with a larger diameter than the bore of the orientation region 718. In cylindrical region 722, with the solid conductor 118 inserted, the end of the shrink-fit hose 212 can for instance be received, so that the solid conductor 118 is insulated electrically continuously relative to the fuel injector. The cylindrical region 722 is finally adjoined by a second conical region 724, which opens directly into the orientation region 718. In this second conical region 724, the tube wall in this exemplary embodiment again has an opening angle of 30° (that is, again an angle of 15° to the sleeve axis 714). As described above, the orientation sleeve 146 may also be designed as a double orientation sleeve 146; two orientation sleeves, for instance, from the exemplary embodiment shown in
In
The upper ends 214 of the solid conductors 118, which are now oriented parallel to the injector axis 142, can be inserted, after this orientation by the orientation sleeve 146, in the insertion direction 610, parallel to the injector axis, through the sealing plate 134 into the plug contacts 122. These plug contacts are in turn electrically conductively connected via the electrical connections 144 to the injector contact 116 on the top end of the fuel injector. When the line connection module 136, sealing plate 134 and control module 132 are put together, the end of the orientation sleeve 146 that protrudes from the line connection module 136 is thrust through the conductor conduit 120 in the sealing plate 134 into the conductor conduit 120 of the control module 132. The upper end 214 of the solid conductor 118 is also inserted into the plug contact 122. Before the assembly one O-ring 812 each is also inserted, upstream of the plug contacts 122, into the conductor conduits 120 of the control module 132. This O-ring 812 prevents fuel, particularly diesel oil, from being able to penetrate into the control module 132. Thus the “wet region” of the modules 134, 136, 138 and 140 is partitioned off from the “dry” control module 132 by the O-rings 812. After the modules 132, 134 and 136 are joined together, these modules are screwed together by means of a union nut 1110. For maintenance purposes, this screw connection and the electrical plug-in connection of the solid conductor 118 and the plug contact 122 can easily be undone again, so that individual modules can for instance be replaced or checked in a simple way and without requiring unsoldering.
In
First, in a first method step 1010, a first module, such as the control module 132, of the fuel injector is produced. The first module 132 should have at least one injector body contact 116. Next, in method step 1012, a second module is produced, which may for instance be the nozzle module 140. This second module 140 should have at least one electrically triggerable valve 112 with at least one electrical valve contact 114. Next, in method step 1014, the at least one electrical valve contact 114 is joined to at least one electrical solid conductor 118 that is essentially dimensionally stable under its own weight. Then in method step 1016, by means of at least one orientation sleeve 146, a predetermined inclination to the injector axis 142 is imposed on the at least one solid conductor 118, entirely or in part. Next, the two modules 132, 140 are joined directly or indirectly (see for example
The described arrangement in one of its embodiments and the described method of the invention for producing the fuel injectors represent a considerable improvement over conventional methods and arrangements, in which electrical cables are used for connection between the valve contacts 114 and the injector body contacts 116. Complicated soldering processes and tedious passing of cables through the individual modules of the injector body 110 are thus dispensed with. The processes of assembling the fuel injectors and corresponding maintenance of the fuel injectors are thus greatly simplified.
In
Unlike the exemplary embodiment of
For the assembly of the fuel injector in
Regardless of this, the control module 132 is prepared for a connection to the line connection module 136. To that end, the O-rings 812, as can be seen particularly in
Next, the control module 132 with the sealing plate 134 placed on it and the inserted orientation sleeve 146 is mounted on the line connection module 136. In this operation, as described above, the solid conductors 118 that emerge from the line connection module 136 at an angle of 1.795° each (still other angular positions are understood to be possible) are engaged by the catch regions 716 of the double orientation sleeves 146 and oriented by the orientation regions 718 of the double orientation sleeve 146 to an angle of 0° to the injector axis 142, so that the solid conductors 118 can pass through the O-rings 812 to enter the plug contacts 122, where they can enter into an electrical connection, for instance by nonpositive engagement, with the plug contacts 122, thereby creating an electrical connection between the valve contacts 114 and the injector body contact 116. The placement of the unit comprising the control module 132 and the pressure booster 134 on the unit comprising the line connection module 136, the pressure booster module 138, and the nozzle module 140 is done by blind joining, since because of the use of the double orientation sleeve 146, adjustment of the solid conductors 118 is no longer required.
The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
Number | Date | Country | Kind |
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10 2005 004 320 | Jan 2005 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2005/056788 | 12/14/2005 | WO | 00 | 6/22/2007 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2006/081895 | 8/10/2006 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
6027049 | Stier | Feb 2000 | A |
20030168532 | Maier | Sep 2003 | A1 |
20030224664 | Brock et al. | Dec 2003 | A1 |
Number | Date | Country |
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100 39 218 | Feb 2002 | DE |
Number | Date | Country | |
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20080110442 A1 | May 2008 | US |