Patent Publication Number: US-6910642-B2

Title: Fuel injection valve

Description:
FIELD OF THE INVENTION 
   The present invention relates to a fuel injector. 
   BACKGROUND INFORMATION 
   German Published Patent Application No. 198 53 102 discloses a fuel injector for internal combustion engines that is put together from two preassembled independent assemblages. A functional part substantially encompasses an electromagnetic circuit and a sealing valve, while a connector part is constituted principally by a hydraulic connector and an electrical connector. In the completely assembled fuel injector, electrical connecting elements and hydraulic connecting elements of the two assemblages coact to ensure a reliable electrical and hydraulic connection. Mechanical joining of the two assemblages and good stability of the fuel injector, as well as sufficient sealing, are ensured by an injection-molded sheath around the join region. 
   The fuel injector known from German Published Patent Application No. 198 53 102 is disadvantageous in particular because the electrical plug contact produced integrally with the injection-molded sheath can be adapted only with great complexity (by retooling the injection-molding machines) to different plug connector systems. 
   In addition, the fact that fuel passes through the injection-molded plastic connector part is disadvantageous because the plastic is exposed to the dissolving ability of the fuel, and leaks can thereby occur due to dissolution of the plastic. The stability of the connector during operation of the internal combustion engine is also not sufficiently ensured, due to heating and subsequent deformation. 
   SUMMARY OF THE INVENTION 
   The fuel injector according to the present invention has, in contrast, the advantage that the metal hollow body which is inserted into an inflow end of the valve sleeve of the fuel injector not only stabilizes the fuel injector but also provides a generic base for the installation of different connector plugs that can easily be clipped onto the extension of the fuel injector. 
   It is also advantageous that the connector plug can be slid or clipped onto the metal hollow body by a retainer, the retainer e.g. being capable of being embodied as a spring ring that partially surrounds the metal hollow body. 
   Advantageously, the contact lugs of the magnet coil and of the connector plug are oriented parallel to one another and to the valve sleeve, which makes possible simple installation and subsequent connection. 
   It is additionally advantageous that both the fuel injector and the metal hollow body can be manufactured separately and can then be combined, with no need to modify the design of the conventional components of the fuel injectors. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic section through an exemplified embodiment of a functional part of a fuel injector. 
       FIG. 2  is a schematic section through the fuel injector depicted in  FIG. 1 , combined with the connector part configured according to the present invention. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows, in a partial and schematic sectioned depiction, a longitudinal section through a fuel injector  1  that is suitable in particular for injecting fuel into an intake manifold (not depicted in further detail) of an internal combustion engine. 
   Fuel injector  1  encompasses a magnet coil  2  that is wound onto a coil support  3 . Coil support  3  is encapsulated in a valve housing  4  and sealed by a cover  5 . Configured on coil support  3  is a contact lug  6  that, in the exemplified embodiment, is oriented parallel to a longitudinal axis  33  of fuel injector  1 . 
   Passing through coil support  3  is a valve sleeve  7  that is of tubular configuration and encompasses a support tube  8 , injection-embedded or welded therein, that serves as the internal pole of magnet coil  2 . Valve housing  4 , for example, can serve as the external pole of magnet coil  2 . Positioned on the outflow side of support tube  8  is an armature  9  which is configured integrally with a valve needle  10 . Flowthrough openings  11 , which direct the fuel flowing through fuel injector  1  to a sealing seat, are provided in valve needle  10 . 
   An annular filter  12  for filtering the fuel is positioned in the region of flowthrough openings  11 . Valve needle  10  is in working engagement, preferably by welding, with a valve closure member  13  (spherical in the exemplified embodiment) that, with a valve seat element  14 , forms a sealing seat. Configured downstream from the sealing seat in a perforated spray disk  34  is at least one spray discharge opening  15  from which fuel is injected into the intake manifold (not depicted further). 
   When fuel injector  1  is in the inactive state, armature  9  is impinged upon by a return spring  16  in such a way that fuel injector  1  is held closed by the pressure of valve closure member  13  on valve seat element  14 . Return spring  16  is positioned in a recess  17  of armature  9  and of support tube  8 , and is preloaded by an adjusting sleeve  18 . On the inflow side of adjusting sleeve  18 , a cup-shaped filter element  19  is preferably pressed into valve sleeve  7 . The fuel that is introduced through a central fuel inlet  20  flows through fuel injector  1  through recess  17  and flowthrough openings  11  to the sealing seat and to spray discharge opening  15 . 
   When an electric current is conveyed to magnet coil  2  via an electrical line (not depicted in further detail) and contact lug  6 , a magnetic field is established that, when sufficiently strong, pulls armature  9  against the force of return spring  16  into magnet coil  2 , opposite to the flow direction of the fuel. A working gap  21  configured between armature  9  and support tube  8  is thereby closed. As a result of the motion of armature  9 , valve needle  10  configured integrally with armature is also carried along in the linear stroke direction, so that valve closure member  13  lifts off from valve seat element  14  and fuel is directed to spray discharge opening  15 . 
   Fuel injector  1  is closed as soon as the current energizing magnet coil  2  is shut off and the magnetic field has decayed sufficiently that return spring  16  pushes armature  9  away from support tube  8 , so that valve needle  10  moves in the outflow direction and valve closure member  13  settles onto valve scat element  14 . 
     FIG. 2  shows, in a partial sectioned depiction, fuel injector  1  that is depicted in FIG.  1  and is assembled and equipped with the features according to the present invention. Identical components arc labeled with matching reference characters. Repetition of the description of previously known components can be dispensed with. 
   Fuel injector  1  is depicted in  FIG. 2  in a completely manufactured state. A collar  22  is placed or injection-molded onto valve housing  4  at its lower end, thereby forming an annular groove into which a first seal  23  is introduced. 
   An annular metal hollow body  25  is inserted into an inflow end  24  of valve sleeve  7  and is welded to valve sleeve  7  e.g. in the region of filter clement  19 . A customer-specific retainer  26  is slipped onto metal hollow body  25  by a retainer  27 , preferably made of plastic, which is embodied e.g. as a spring ring and at least partially surrounds metal hollow body  25 . Connector plug  26  has a contact lug  28  that is directed toward contact lug  6  of magnet coil  2  and is joined thereto after assembly by suitable techniques such as e.g. welding, soldering, or adhesive bonding, or by way of a crimped or plug connection. 
   In order to protect contact lug  28  during further processing of fuel injector  1 , connector plug  26  has a plastic sleeve  29  that surrounds contact lug  28  and projects beyond it. Plastic sleeve  29  is also referred to as a “clip connector,” and possesses a circumferential groove  30  that, during further processing, serves as a mount for an injection-embedding mold. 
   After the assembly of connector plug  26 , fuel injector  1  and metal hollow body  25  joined thereto are equipped with an injection-molded plastic sheath  31  and equipped, for mounting on a fuel distribution line, with a second seal  32 . For that purpose, the respective customer-specific electrical connector plugs  26  are, for example, introduced into a customer&#39;s own injection-embedding molds. 
   Sealing between connector plug  26  and injection-molded plastic sheath  31  is accomplished by melting connector plug  26  in the region of specifically shaped, annularly circumferential ridges  35  in central region  36  of connector plug  26 , for which reason the plastic of injection-molded plastic sheath  31  must have a higher melting point than that of connector plug  26 . 
   Ideally, connector plug  26  is used in a specific desired color of plastic, so that connector plugs  26 , serving for color identification, clearly characterize fuel injector  1  without additional instructions. With a color identification system of this kind, different valve types can be classified very easily. 
   With the features described above, it is possible to manufacture a fuel injector  1  having a generic magnet coil  2  and a generic contact lug  6  that can each be equipped with any desired electrical connector plug  26 , with no need to have a test stand and fabrication device available at the factory for each of the different connector plugs  26 . 
   The invention is not limited to the exemplified embodiment presented and is also applicable e.g. to fuel injectors  1  of any design.