Fluid sprinkling – spraying – and diffusing – Rigid fluid confining distributor – Assembly or disassembly feature
Reexamination Certificate
2000-05-12
2001-10-09
Miller, Carl S. (Department: 3747)
Fluid sprinkling, spraying, and diffusing
Rigid fluid confining distributor
Assembly or disassembly feature
C123S472000, C251S129150
Reexamination Certificate
active
06299079
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a fuel injector for fuel injection systems of internal combustion engines.
BACKGROUND INFORMATION
A fuel injector that may be actuated electromagnetically is discussed, for example, in U.S. Pat. No. No. 5,156,124. The fuel injector includes an electromagnetic circuit, such as a magnetic coil, an internal pole and an external pole. This injector is a “side-feed injector” in which the fuel is supplied substantially below the magnetic circuit. Starting from the magnetic coil, contact pins project from the fuel injector, are extrusion-coated over a certain length with plastic and are embedded in the plastic. The plastic extrusion coat is applied at one end of the fuel injector, and does not represent an independent component of the injector.
German Published Patent Application No. 34 39 672 concerns a fuel injector, in which, starting from its magnetic coil, contact pins project to an electric attachment, plug which is formed of plastic and partially surrounds the contact pins behind the magnetic coil. In this case, the plastic extrusion coat forming the attachment plug is sprayed onto the metallic valve housing.
German Published Patent Application No. 197 12 591 concerns a fuel injector that may be assembled from two preassembled assemblies, which include a functional part and a connection part, that are separately produced, brought into position and then permanently joined to one another. The joining of the two assemblies also produces an electrical and a hydraulic connection. The two assemblies are joined by ultrasonic welding, bonding or crimping.
SUMMARY OF THE INVENTION
It is believed that the fuel injector of an exemplary embodiment of the present invention has and reliably mounted. It is believed that this should provide relatively great mechanical stability of the fuel injector. In addition, it is believed that this should better ensure that the electrical connecting elements are safe and protected within the valve.
In addition, it is possible to vary the designs of the fuel injector very easily. This is achieved in that two assemblies of the fuel injector—a functional part and a connection part—are preassembled and brought into position separately from one another. The functional part essentially includes an electromagnetic circuit and a sealing valve composed of a valve-seat member and valve-closure member. On the other hand, the electrical and the hydraulic connections of the injection valve are provided in the connection part. All the described exemplary embodiments of the fuel injectors have the advantage that they can be produced cost-effectively with a great number of design variants. Functional parts, produced in large quantity with a substantially identical design (differences, for example, in the size of the valve-needle lift or the number of turns of the magnetic coil) can be joined to a very large number of different connection parts which differ, for example, in size and shaping, in the design of the electrical attachment plug, in the formation of the lower end face of the connection part, or even with respect to their color, marking, inscription or a different identification. Thus, in general, the logistics are simplified when producing fuel injectors.
The separation into two assemblies yields the advantage that all the negative influences when producing the connection part, made substantially of plastic, (high extrusion-coating pressures, heat generation) are kept away from the components of the functional part performing the important valve functions. The relatively dirty extrusion-coating process can advantageously be carried out outside of the functional-part assembly line.
For the extrusion coating to produce a firm joining of the two assemblies. It is believed that it is particularly advantageous to select a plastic which has its melting point at a higher temperature than the plastic used for the connection part. This ensures that the two plastics enter into polymer combination. It is believed that it is advantageous to design a labyrinth seal at the outer periphery of the connection part. This permits heat distribution during the extrusion coating, allowing good fusing. In addition, high mechanical stability in this region, and thus of the entire fuel injector, as well as good imperviousness are ensured.
It is believed that it is advantageous to provide the functional part, performing all the important valve functions, with a very short design. This expediently yields simplified access to the injector components to be adjusted, including shortened paths for the mounting of measuring arrangements such as probes for measuring the lift of the valve needle or tools for adjusting the dynamic spray quantity at the adjustment element.
Advantageously, provision can be made on the connection part at its downstream end for a plurality of axially projecting segments which extend into the extrusion coat after the extrusion-coating process. The dissipation of heat during the extrusion-coating process is improved by these segments projecting into the extrusion coat. At the same time, the hot volume in the extrusion-coating process is kept quite small. In this manner the cycle time of the extrusion coating can be markedly reduced. Moreover, the mass agglomeration within the extrusion coat is advantageously reduced. The shrinkage cavitation can thus be effectively diminished. In addition, due to the segments, turbulence develops in the flowing plastic. This results in increased stability of the entire extrusion coat.
It is expedient to arrange a fuel filter in the functional part. A possibility is to use a metal filtration fabric as a screen netting. This guarantees that, until the final assembly of the valve, no dirt particles can get into the interior of the functional part.
Advantageously, the electrical connecting elements on the functional part and connection part can be varied greatly. Thus, it is possible at anytime to design the electrical connecting elements both on the functional part and on the connection part either in a manner similar to a plug or in a manner similar to a socket, or as a combination of both possibilities.
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patent: 5156124 (1992-10-01), Sugimoto et al.
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patent: 6131829 (2000-10-01), Ricco
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patent: 34 39 672 A1 (1986-04-01), None
patent: 38 34 444 A (1990-04-01), None
patent: 197 12 591 A (1998-10-01), None
patent: WO 95 33134 A (1995-12-01), None
Dantes Guenter
Hanft Werner
Maier Dieter
Noller Klaus
Nowak Detlef
Kenyon & Kenyon
Miller Carl S.
Robert & Bosch GmbH
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