Abstract:
The present invention is directed to an electrical connector that attaches a fuel injector assembly to a vehicle control assembly. The electrical connector comprises a plastic molded body having two integrally formed portions, a base portion and a stem portion, and an electrical contact extending through the body from the stem portion to the base portion. The base is inserted into the fuel injector assembly with the electrical contact engaging a corresponding contact within the fuel injector assembly. Similarly, the electrical contact in the stem portion of the connector is attached to a corresponding contact of a control assembly, which provides the electrical signals to operate the fuel injector. The base portion includes a metallic sleeve that extends between its sidewalls and cooperates with a locking pin that is inserted through openings in the fuel injector assembly to lock the two components together. The sleeve openings are slightly offset from the fuel injector assembly openings so that when the locking pin is inserted, it aligns the two components and urges the electrical connector further into the fuel injector assembly. Additionally, the sides of the connector include deformable “crush pads” that when inserted into the fuel injector assembly are reshaped to provide a “snug” fit between the electrical connector and the fuel injector assembly.

Description:
FIELD OF INVENTION 
   The present invention is directed to an electrical connector that attaches a fuel injector assembly to a control assembly. The control assembly sends electrical signals that control the timing of the fuel injectors to the fuel injector assembly via the electrical connector, which is provided with several features that improve the attachment between the electrical connector and the fuel injector assembly. 
   BACKGROUND OF THE INVENTION 
   Internal combustion vehicle engines have typically used carburetors to control their fuel-air mixture. A carburetor performs this task by drawing in liquid fuel from a fuel reservoir, vaporizing the liquid fuel, and then mixing it with a stream of air. More recently, carburetors have been replaced with more efficient electronic fuel injectors that pump vaporized fuel into an air stream in a timed or metered fashion. Because of their increased efficiency and performance, electronic fuel injectors have largely replaced carburetors in most vehicles today. 
   The timing of the operation of the fuel injector is regulated by a control assembly that sends electrical signals via an electrical connector. However, due to the electrical connector&#39;s close proximity to the engine pistons, it is subjected to particularly severe vibrations and is prone to becoming disconnected from the fuel injector assembly. The vibrations cause the electrical connector to suffer degraded performance by allowing contact phenomena, such as fretting or jitter, to establish themselves between the contacts of the electrical connector and the fuel injector. When the connection between the electrical connector and the fuel injector is not sufficiently secure, these problem are often exaggerated because any movement or “wiggle” between the two components worsen over time until the two components become disconnected. 
   Therefore, it would be advantageous to provide a electrical connector that is securely attached to a fuel injector assembly to provide a stable electrical connection between the control assembly and the fuel injector assembly. It would also be advantageous to provide an electrical connector that is resistant to shaking and vibration so as not to interfere with the electrical connection between the control assembly and fuel injector assembly. 
   SUMMARY OF INVENTION 
   The present invention is directed to an electrical connector that is attached to a fuel injector assembly and dampens vibrations between the electrical connector add fuel injector assembly. The electrical connector is comprised of a plastic molded body having two integrally formed portions, a base portion and a stem portion, and one or more electrical contacts extending through the body from the base portion to the stem portion. The base is inserted into the fuel injector and electrically connected thereto, while the stem portion of the connector is electrically attached to a control assembly. 
   The base portion of the electrical connector includes several features that improve the attachment between the electrical connector and the fuel injector assembly. The base portion includes a metallic sleeve with openings on both ends that partially align with corresponding openings in the fuel injector, and is secured by inserting a locking pin through the sleeve and fuel injector openings. The sleeve openings are slightly offset from the fuel injector assembly openings so that when the locking pin is inserted, the electrical connector is forced into the fuel injector assembly. 
   As a result of the locking pin forcing the electrical connector into the fuel injector assembly, the locking pin becomes slightly curved. This has the favorable effect of converting some of the shear forces, which act perpendicular to the locking pin, into less damaging tensile forces which act along its longitudinal axis. 
   The sleeve also has enlarged tapered ends that move the contact point between the sleeve and the locking pin into the interior of the base portion, where the shear forces acting on the locking pin and sleeve are less likely to fail. The tapered ends also have the added advantage of making it easier to insert the locking pin into the sleeve. 
   Additionally, the sides of the electrical connector include deformable “crush pads” that when inserted into the fuel injector assembly are reshaped to provide a “snug” fit between the electrical connector and the fuel injector assembly. 
   In addition to the above features, the stem portion of the electrical connector includes a flat top portion that serves as a identification platform, allowing manufacturing identification to be placed onto the electrical connector and easily viewed. Also, the base portion of the electrical connector includes an O-ring seal around the electrical terminals, providing a seal to prevent any fuel from entering the electrical connector. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a perspective view of an electrical connector prior to its insertion into a fuel injector assembly; 
       FIG. 2  shows a perspective view of the electrical connector after its insertion into the fuel injector assembly; 
       FIGS. 3 and 4  show side perspective views of the electrical connector; 
       FIG. 5  shows a cut-away view of a base portion of the electrical connector; 
       FIGS. 5A and 5B  show a detailed side view of a locking pin and sleeve; 
       FIGS. 5C and 5D  shows a detailed side view of the locking pin without a sleeve; 
       FIG. 6  shows perspective view of the front and bottom of the base of the electrical connector; 
       FIG. 7  shows a cross-sectional view of the side of the electrical connector; 
       FIG. 8  shows a cross-sectional view of the electrical connector and fuel injector assembly; 
       FIG. 9  shows the electrical connector prior to the attachment of an identification plate; and 
       FIGS. 10–12  show a second embodiment of the electrical connector. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A detailed description of the invention is now given with reference to  FIGS. 1–9 .  FIGS. 1 and 2  show an electrical connector  100  just prior to and after insertion into “a fuel injector assembly  102 , respectively. The electrical connector  100  is made from a high strength, corrosion resistant polymer body comprised of two integral portions, a base portion  104  and a stem portion  106 . 
   The base portion  104  is a generally cube-shaped structure that is inserted into a connector cavity  103  in the fuel injector assembly  102 . The connector cavity  103  is shaped to generally match the shape and size of the base portion  104  to provide a relatively tight or “snug” fit. The stem portion  106  extends out from the base portion  104  and includes a barrel  107  and an identification platform  108 . 
     FIGS. 3–5  show the electrical connector  100  in greater detail, with  FIG. 5  showing a cut-away view of the base portion  104 . These figures illustrate several features incorporated into the base  104  that ensure a tight and stable attachment between the electrical connector  100  and the fuel injector assembly  102 . With reference to  FIG. 5 , the base  104  includes an insert molded metallic sleeve  110  located in a generally cylindrical cavity  101  in the interior body of the base  104 , the sleeve  110  extending between the base&#39;s sidewalls  105 . The ends of the sleeve  110  have tapered openings  116  that lie flush with the sidewalls  105 , as shown in  FIGS. 3 and 4 . The sleeve  110  is preferably made from a high strength metal material, such as steel, but it is contemplated that any material may be used for the sleeve. 
   To secure the electrical connector  100  to the fuel injector assembly  102 , the electrical connector  100  is inserted into the connector cavity  103  and secured by a locking pin  112  which is inserted through openings  114  in the fuel injector assembly and into the sleeve  110 . 
   The sleeve  110  disperses the forces applied by the locking pin  112  over a broader area within the base  104 , to reduce material creepage. This effect can be seen in  FIGS. 5A–5D .  FIG. 5A  shows a side view of the base  104  and the sleeve  110  therein. The locking pin  112  abuts against the sleeve  110  which disperses the shear forces F on the base  104  around a large portion of its circumference. Over time, the shear forces F deform the base  104  as shown in  FIG. 5B  by an amount ΔX 1  (i.e. creep).  FIGS. 5C and 5D  show the effect of the locking pin  112  on a base  104  not having a sleeve  110 .  FIG. 5C  shows that the shear forces F are concentrated in a much smaller area, and  FIG. 5D  shows the amount of deformation ΔX 2  in the base  104  is much larger and more exaggerated. Using the sleeve  110  of the present invention decreases the amount of deformation such that ΔX 1  will always be less than ΔX 2 . 
   When the base  104  is inserted into the fuel injector assembly  102 , the sleeve openings  116  are at first offset from the fuel injector openings  114 . Upon insertion of the locking pin  112 , the openings  114  and  116  are forced to align which causes the base portion  104  to move toward the bottom and back of the connector cavity  103 . This produces a tight and secure attachment between the electrical connector  100  and the fuel injector assembly  102  by maintaining the base portion  104  under a force applied by the locking pin  112 , thereby eliminating any “wiggle” between the two. It should be noted that although the locking pin  112  moves to align the openings  114  and  116  of the electrical connector  100  and the fuel injector assembly  102 , the two sets of openings  114  and  116  never completely align. This is to maintain a continual force acting on the locking pin  112  and prevent a relaxed state where the electrical connector  100  may “rock” within the fuel injector assembly  102 . 
   Furthermore, the sleeve openings  116  are tapered, having an outer face with a diameter larger than that of the locking pin  112  and tapering inwardly to an inner face having a diameter that closely matches the locking pin  112 . The tapering produces an inner face that lies within the body of the base portion  104 . This tapered feature provides several advantages, one of which is that the large diameter of the sleeve&#39;s outer face makes insertion of the locking pin  112  into the sleeve  110  much easier, especially considering that the sleeve openings  116  are offset from the fuel injector assembly openings  114 . 
   Also, the principal forces acting at the connection between the sleeve  110  and locking pin  112  are shear forces. By using the tapered openings, the shear forces acting on the outer face of the sleeve openings  116  are moved into the interior of the body of the base  104  to the inner face of the sleeve opening  116 , this being the contact point between the locking pin  112  and the sleeve  110 . This is advantageous because the sidewalls  105  of the base portion are the locations that are most susceptible to cracking or failure due to shear forces. By moving the contact point between the locking pin  112  and the sleeve  110  inward, those shear forces are moved inside of the base  104  where failure is less likely to occur. 
   Additionally, because the sleeve openings  116  are offset from the fuel injector openings  114 , the insertion of the locking pin  112  into the sleeve  110  causes the locking pin  112  to curve slightly, as best shown in  FIG. 5 . The curve is produced by the reactive forces generated in the locking pin  112  by the offset openings  114  and  116 , and the force necessary to align the openings  114  and  116  (although the holes are never completely aligned). The slight curve has the desired effect of further reducing the shear forces acting on the locking pin  112 . This is because the locking pin  112  is placed in the entry/exit direction of the fuel injector cavity  103 , and the forces acting on the locking pin  112  are perpendicular to the entry/exit direction. Therefore, with a perfectly straight locking pin  112 , all the forces acting on the locking pin  112  are shear forces perpendicular to the entry/exit direction. However, by providing a curved locking pin  112 , some of the perpendicular shear forces are transferred to act along the length of the locking pin  112  in tension. Therefore, some of the shear forces are converted to tensile forces, and because the locking pin  112  is stronger in tension than in shear, the curved locking pin  112  is less likely to fail. 
   The base portion  104  also has an inwardly curved front wall  118 , as best shown in  FIGS. 5 and 6 . The curved front wall  118  provides a gap between the base  104  and an opposing wall  119  of the fuel injector assembly  102  when the electrical connector  100  is inserted therein.  FIG. 8  shows the electrical connector  100  inserted into the fuel injector assembly  102 . In a typical fuel injector assembly, a high pressure cavity  117  is located adjacent to the electrical connector cavity  103  and separated by the wall  119 . As the fuel pressure is built up and released in the high pressure cavity  117 , the wall  119  separating the two cavities flexes outward into the electrical connector cavity  103 . The gap created by the curved front wall  118  compensates for the wall flexure and minimizes or eliminates the electrical connector&#39;s  100  movement caused by the expansion and contraction of the separating wall  119 . 
     FIGS. 3–5  show the side walls  105  of the base  104  having crush pads  120  that extend outwardly from the base  104 . The crush pads  120  are integrally formed with the base and are preferably made from the same material. The electrical connector cavity  103  is generally the same shape and size as the base  104  of the electrical connector, so that as the base  104  is inserted into the electrical connector cavity  103 , the crush pads  120  are deformed to fit within the electrical connector cavity  103 . The deformed crush pads  120  then provide a “snug” or interference fit within the electrical connector cavity  103 , preventing movement or wiggle between the electrical connector  100  and the fuel injector assembly  102 . It should be understood that the crush pads may be any shape and made from any material that is able to resiliently deform and provide the frictional engagement between the base  104  and the connector cavity  103 . 
   Above and below the crush pad  120  are a core-outs  121 , which are simply hollowed out portions of the base  104 . The core-outs  121  reduce the amount of material necessary to form the base  104 , and consequently, lowers the manufacturing cost of the electrical connector  100 . 
     FIGS. 7 and 8  show cut-away views of the electrical connector  100 , alone and connected to the fuel injector assembly  102 , respectively. As shown in the figures, a pair of electrical contacts  122  are provided within the electrical connector  100  and are run from a bottom surface  124  of the base  104  to a barrel portion  126  of the stem  106 . Each contact  122  is preferably made from a single nickel-silver alloy that does not require additional finishing and whose oxides are less electrically restrictive. Although a nickel-silver alloy is preferred, any other material that can carry an electrical signal may be used with the invention. 
   The portion of the electrical contacts  122  in the base  104  are formed as female sockets  128  into which corresponding male pins of the fuel injector assembly  102  are inserted. The portion of the electrical contacts  122  in the barrel  126  are formed as male pins  130 , so that a mating electrical harness (not shown) of a control assembly may be inserted into the barrel  126  and attached thereto. Although the electrical contact  122  has been described as having male  130  and female  128  ends, it should be understood that the type of connections used with the electrical contact  122  may be altered without departing from the scope of the invention. 
   Seals  132  are attached to the bottom surface  124  of the base  104  around the female socket  128  to prevent fuel from entering the electrical connector  100 , as” best shown in  FIG. 6 . The bottom surface of the base  124  includes two cavities  134  shaped like a figure eight (“8”). A first socket portion  136  of the cavity  134  contains the female socket  128  for the electrical connector  122 . A second socket portion  138  of the cavity  134  includes a pin  140  to help retain the seal  132 . The seal  132  is resiliently placed into the cavity  134  and is held in place due to the frictional engagement of the seal  132  with the wall of the cavity  134 , with the pin  140  providing further frictional engagement. When in place, a portion of the seal  132  protrudes out of the cavity  134  and contacts an opposing surface of the fuel injector assembly to provide the seal between the two components. Although the figures show a figure eight (8) seal  132 , the seal  132  may be made from a single O-shaped seal in the first socket portion  136  of the cavity or any other suitable configuration. 
     FIG. 9  shows additional features of the present invention. The stem  106  of the electrical connector includes a flat top platform  142 . Product identification can be placed onto the platform  142  either directly, by laser etching or ink marking, or by using an identification plate  144  which is placed onto the platform  142 . This allows important information to be placed onto the electrical connector  100  in a location that is easily viewed. Also, a support bracket  146  is provided between the base  104  and the stem  106 , providing added rigidity and strength to the electrical connector  100 . 
     FIGS. 10–12  show a second embodiment of the electrical connector  100 . Here, the shape of the base  104  has been changed, with its top portion having a rounded contour, so that the base  104  now has an “igloo” shape. This shape reduces the amount of time required to machine the electrical connector, thus reducing its manufacturing cost. 
   Additionally, the sleeve  110  is recessed within the cavity  101 , so that its ends are no longer flush with the base&#39;s sidewalls  105 . This reduces the stress on the outer surface of the base, particularly along the top contoured portion, where cracking or other failure is more likely to occur. The potential for failure at the surface is reduced by moving the contact point of the sleeve  110  with the base portion  104  into the interior of the body of the base portion  104 , where its ability to support stress is greater. This phenomenon is explained above with respect to the first embodiment of the electrical connector having a sleeve  110  with tapered ends. It should be understood that the second embodiment of the sleeve  110  also includes tapered ends, but that because the sleeve  110  is already recessed into the interior the base portion body  104 , the tapered ends are not required. 
     FIG. 12  shows the bottom surface of the base portion  104  which seals the base portion  104  of the electrical connector  100 . Here, the cavities  134  are round or “O”-shaped, rather than the figure “8” shape of the first embodiment, and hold similarly shaped round seals (not shown). A vent  150  is provided with each cavity  134  to relieve excessive pressure. 
   Lastly, it should be understood that except for the specific features mentioned above, the second embodiment of the invention is substantially similar or identical to the first embodiment of the invention. 
   Although certain presently preferred embodiments of the present invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.