Patent Publication Number: US-6981662-B2

Title: Coupling device assembly

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a coupling device for use with a fuel injector and, more particularly, to a coupling device (connector bridge) used to connect solenoid wires to an end cap assembly while maintaining the solenoid wires away from a control valve of the fuel injector. 
   2. Background Description 
   Many internal combustion engines are designed to use fuel injectors. In such a typical internal combustion engine, the fuel injector is mounted partly within the combustion chamber of the engine, with the control valve mechanism mounted beneath the valve covers of the engine. In this type of configuration, the control valve mechanism which, in some conventional injectors, include solenoids and end caps, are connected to an engine wire harness assembly via solenoid wires. The engine wire harness, in turn, is connected to a driver which provides or delivers a current to the solenoids for providing control to the fuel injector, itself. 
   In general, the driver delivers a current or voltage to an open side of an open coil solenoid via the solenoid wires. The magnetic force generated in the open coil solenoid will shift a spool into the open position so as to align grooves or orifices (hereinafter referred to as “grooves”) of the control valve body and the spool. The alignment of the grooves permits the working fluid (i.e., hydraulic fluid) to flow into an intensifier chamber from an inlet portion of the control valve body. The high-pressure fluid then acts on an intensifier piston which, in turn, compresses fuel located within a high-pressure plunger chamber. As the pressure in the high-pressure plunger chamber increases, the fuel pressure rises above a needle check valve opening pressure. At the prescribed fuel pressure level, the needle check valve will shift against a needle spring and open the injection holes in a nozzle tip for injection. 
   At the end of the cycle, the driver will deliver a current or voltage to the closed coil solenoid. The magnetic force generated in the closed coil solenoid will shift the spool into the closed position so as to align grooves of the spool with ejection or discharge ports of the control valve body. This alignment permits the working fluid to flow from the intensifier chamber, through the discharge ports and then be ejected from the control valve body, via the discharge ports. The discharge of the working fluid is at a high pressure. Once the working fluid is discharged, it is captured and reused by the injector. Of course, fuel injectors may vary in their functionality such as fuel injectors with needle back pressure systems and the like; however, the above description is generally descriptive of the basic functioning of the fuel injector. 
   In these types of systems, however, the solenoid wires are permanently connected to the end caps and are routed over the discharge ports and adjacent the rocker arm assemblies of the engine. The wire harness assemblies for the solenoid wires are also located adjacent the rocker arm assemblies in such a manner that the solenoid wires must bridge the gap between the open and closed coil solenoid and the wire harness assembly (which is approximately 150 mm). In such a harsh environment, the solenoid wires are subject to failure, from such causes as:
         1. vibrations caused by the rocker arm assemblies,   2. chaffing or striking from the rocker arm assemblies, or   3. vibrations caused when the working fluid is discharged from the fuel injectors.
 
These factors, over time, lead to a failure of the fuel injector. This, of course, adversely affects the efficiency of the engine and, in instances, may result in a catastrophic failure of the engine. To repair the engine, or more particularly the solenoid wires, the entire fuel injector must be replaced including the solenoid wires. This is due to the permanent connection between the solenoid wires and the end caps. Alternatively, the entire fuel injector must be removed from the engine and the solenoid wires replaced. This is a time consuming and costly process. It is also noted that the fuel injector and solenoid wire assembly (due to the one-piece assembly) may be difficult to maneuver into place, again leading to higher manufacturing and repair costs.
       

   The present invention is directed to overcoming one or more of the problems as set forth above. 
   SUMMARY OF THE INVENTION 
   In a first aspect of the present invention, a coupling device includes a body portion adapted to be mated with an end cap assembly of a fuel injector. The body portion has a connecting portion spanning between a first electrical connector and a second electrical connector at opposing ends of the body portion. A first set of conductive leads connects the first electrical connector to a first set of solenoid wires and a second set of conductive leads connects the second electrical connector to a second set of solenoid wires. The first set of conductive leads spans the connecting portion to connect the first electrical connector and the first set of solenoid wires. In embodiments, the first set of conductive leads and the second set of conductive leads are electrically isolated from each other and are molded into the body portion, including the connecting portion. 
   In another aspect of the present invention, the coupling has a main body portion having a first and second shoulder, an end body adjacent to the second shoulder, first and second housings extending from the first and second shoulders and a connecting portion. The connecting portion connects the first shoulder and the second shoulder. A first and second set of solenoid wires partially extend within the end body portion and a first set of terminals are associated with the first housing and a second set of terminals are associated with the second housing. A first set of conductive leads electrically connect the first set of terminals to the first set of solenoid wires and spans the connecting portion. Also, a second set of conductive leads electrically connects the second set of terminals to the second set of solenoid wires. In embodiments, the conductive leads are molded in the main body portion and more specifically in the connecting portion. 
   In yet another aspect of the present invention, a device for coupling a wire harness to a fuel injector is provided. This device includes a coupling device having a body portion having a connecting portion connecting a first housing and a second housing at opposing ends thereof. The housings each house first and second terminal portions, respectively. A first set of conductive leads spans the connecting portion to connect the first terminal portion to a first set of solenoid wires and a second set of conductive leads connects the second terminal portion to a second set of solenoid wires. An end cap assembly is coupled to the coupling device and includes a first housing at a first side for housing a first end cap terminal and a second housing at a second side for housing a second end cap terminal. The first terminal portion and the first end cap terminal are electrically couplable to one another, and the second terminal portion and the second end cap terminal are electrically couplable to one another. 
   In embodiments of this and other aspects, the body portion may include a first shoulder and a second shoulder and an end body portion adjacent to the second shoulder. The first housing extends from the first shoulder and the second housing extends from the second shoulder. The connecting portion connects the first shoulder and the second shoulder. The first and second housings of the end cap include a first and second cavity that couples with the first and second housing of the coupling device, respectively. A locking device may be provided for locking the first housing and the second housing of the coupling device to the first housing and the second housing of the end cap, respectively. Additionally, the first and second set of conductive leads and the first and second set of solenoid wires may be molded into the coupling device. In further embodiments, the terminal portions of either the coupling device or the end caps may be (i) female-type electrical connectors, (ii) male-type electrical connectors, (iii) opposing spring-like electrical connectors and (iv) contact plates. The connecting portion fits about the end cap assembly. 
   In yet another embodiment of the present invention, a fuel injector assembly is provided. The fuel injector assembly includes a fuel injector having a control valve body, an intensifier housing coupled to the control valve body and a nozzle assembly coupled to the intensifier housing. The assembly further includes a coupling device having a body portion having a connecting portion spanning between a first housing and a second housing, each of which house first and second terminal portions, respectively. The coupling device further includes a first set of conductive leads spanning the connecting portion to connect the first terminal portion to a first set of solenoid wires. A second set of conductive leads connects the second terminal portion to a second set of electrical connector leads. An end cap of the assembly is coupled to the coupling device and the control valve. The end cap assembly includes a first housing extending from a first side and housing a first end cap terminal portion and a second housing extending from a second side and housing a second end cap terminal portion. The first terminal portion and the first end cap terminal portion are electrically couplable to one another, and the second terminal portion and the second end cap terminal portion are electrically couplable to one another. In embodiments, the connecting portion fits about the control valve. 
   In yet still another embodiment of the present invention, a method is provided for manufacturing a coupling device. The method includes the steps of:
         1. providing conductive leads with connector portions extending therebetween;   2. attaching (e.g., soldering) respective ends of the conductive leads to solenoid wires and first and second terminal portions to form an assembly;   3. placing the assembly in a mold having pins, the pins corresponding to locations of the connector portions;   4. overmolding the assembly within the mold to form a molded assembly;   5. removing the molded assembly from the mold; and   6. punching holes corresponding to the placement of the pins and the connector portions in order to electrically isolate each of the conductive leads.       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which: 
       FIG. 1  shows a bottom view of the coupling device of the present invention; 
       FIG. 2  shows a bottom view of the coupling device of the present invention with a cut-away portion; 
       FIG. 3  shows a top view of an end cap design of the present invention used with the coupling device of  FIG. 1 ; 
       FIG. 4   a  shows a cross sectional view of the end cap design of  FIG. 3  along line  3   a — 3   a;    
       FIG. 4   b  shows a cross sectional view of the end cap design of  FIG. 3  along line  3   b — 3   b;    
       FIG. 5  shows a partially assembled perspective view of the coupling device and the end cap of  FIGS. 1 and 3 , respectively; 
       FIG. 6  shows an assembled perspective view of the coupling device and the end cap of an embodiment of the present invention; 
       FIGS. 7   a  and  7   b  show another embodiment the coupling device and the end cap of an embodiment of the present invention; 
       FIGS. 8   a  and  8   b  show an embodiment the coupling device and the end cap of the present invention; 
       FIGS. 9   a  and  9   b  show an embodiment the coupling device and the end cap of the present invention; 
       FIGS. 10   a  and  10   b  show an embodiment the coupling device and the end cap of the present invention; 
       FIG. 11  shows a method of manufacturing the coupling device of the present invention; and 
       FIG. 12  shows connector leads prior to the molding of the coupling device of the present invention. 
   

   DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
   The present invention is directed to a coupling device used with a fuel injector. The coupling device (referred to also as a connector bridge) is adapted to be coupled and decoupled to an end cap of a control valve of the fuel injector. The coupling device of the present invention is also designed to maintain the solenoid wires away from the rocker arm assemblies and fluid discharge ports of the fuel injector, itself. These features ensure that the rocker arm assemblies as well as the fluid being ejected from the fuel injector will not fray, fatigue or otherwise cause a failure of the solenoid wires. The coupling device also ensures that the solenoid wires remain substantially stationary thereby preventing any fatigue or failure of the solenoid wires caused by vibrational events. As a further advantage of the present invention, any failure of the solenoid wires, terminals to the end cap assembly or other parts may easily be replaced by simply removing and replacing the coupling device of the present invention. That is, by using the coupling device of the present invention there is no need to cut the solenoid wires, and remove and disassemble the fuel injector due a failure of a part. 
   Embodiments of the Coupling Device of the Present Invention 
   Referring now to  FIG. 1 , a bottom view of the coupling device of the present invention is shown. The coupling device is generally depicted as reference numeral  10  and includes a body portion  12 , preferably molded from any well-known materials. The body portion  12  includes an end portion  14 , shoulder portions  16   a ,  16   b  and a connecting portion  18 . In embodiments, the connecting portion  18  is a bridge or span connecting the shoulders  16   a  and  16   b . In embodiments, a plurality of holes or punches  12   a  may be dispersed throughout the end portion  14 , shoulder portions  16   a ,  16   b  and the connecting portion  18 . It should be understood by those of skill in the art that the terminology “shoulder portion” may equally be exchanged with other terminology to describe this feature of the coupling device such as a projection, support, member, platform or the like. However, for convenience and consistency, shoulder portion will be used throughout the present description. 
   Still referring to  FIG. 1 , housings  20   a  and  20   b  are molded or mounting to the respective shoulders  16   a  and  16   b , where each of the housings has an interior cavity  22   a  and  22   b . In one aspect of the present invention, the first and second shoulders, the first and second housings and the connecting portion are a single integral molded piece. Terminals  24   a  and  24   b  are respectively provided within the housings  20   a  and  20   b  and, in aspects of the invention, within the respective cavities  22   a  and  22   b . In one embodiment, the terminals  24   a  and  24   b  may be female-type connectors within the respective cavities  22   a  and  22   b . In alternative embodiments, the terminals  24   a  and  24   b , may be male-type connectors, opposing spring-like connectors, contact plates or any combination thereof or the like. The housings  20   a  and  20   b  preferably extend downward from the shoulder portions  16   a  and  16   b , and may be molded into various shapes such as round, square, rectangular, oval and the like. 
     FIG. 1  further shows clips or other fastening devices  26   a  and  26   b  provided adjacent to each of the housings  20   a  and  20   b . In embodiments, the fastening device  26   a  is located at one side of the housing  20   a  and the fastening device  26   b  is located at another side of the housing  20   b . In other words, the fastening devices  26   a  and  26   b , in embodiments, are not located on a same side of the respective housings  20   a  and  20   b , but are provided in an offset configuration. Conductive leads  28  are molded into the body portion  12  and are electrically connectable between the terminals  22   a  and  22   b  and solenoid wires  30 . In embodiments, a first set of conductive leads extends from the terminals  24   a  to the solenoid wires via the shoulder portion  16   a  to the end portion  14 . Additionally, a second set of conductive leads extends from the terminals  24   b  to the solenoid wires via the shoulder portion  16   b , the connecting portion  18  and the end portion  14 . The conductive leads  28  and portions of the solenoid wires  30  are preferably molded into the body  14  of the present invention, where each of the conductive leads are electrically isolated to prevent shorting. The solenoid wires  30  are also electrically isolated from one another, but electrically connected to each of the respective conductive leads  28 . The molding of the solenoid wires into the coupling device prevents rotation of the solenoid wires, as well as directs the solenoid wires away from the fuel injector and other components of the internal combustion engine to prevent failure thereof. 
     FIG. 2  shows a bottom view of the coupling device of the present invention with a cut-away portion. In this view, it is shown that the conductive leads  28  and portions of the solenoid wires  30  are molded into the body  14  of the coupling device of the present invention. This view further shows the first set of conductive leads extending from the terminals  24   a  to the solenoid wires and the second set of conductive leads extending from the terminals  24   b  to the solenoid wires. In one aspect, the first set of conductive leads extends via the connecting portion  18 . 
     FIG. 3  shows a top view of an end cap design of the present invention used with the coupling device  10  of  FIG. 1 . In this embodiment, the control valve of the fuel injector is generally depicted as reference numeral  31 . End caps  32   a  and  32   b  are coupled to respective sides of the control valve  31  for providing control to the fuel injector in a manner well known in the art. In the embodiment of  FIG. 3 , the end caps  32   a  and  32   b  include respective housings  34   a  and  34   b , each formed with a cavity  36   a  and  36   b . Male-type terminals  38   a  and  38   b  extend within each of the respective cavities  36   a  and  36   b . It should be well recognized that the terminals of the end caps may also be female-type connectors, opposing spring-like connectors, contact plates, a combination thereof or the like, depending on the configuration of the terminals of the coupling device  10 . 
   In embodiments, in the coupled state, the housings  20   a  and  20   b  of the coupling device  10  are sized and shaped to fit within the respective cavities  36   a  and  36   b  of the end caps. In this manner, the respective terminals of the end caps and coupling device, in the coupled state, are in electrical contact. A projection  40   a  and  40   b  extends from an exterior part of the respective housing  34   a  and  34   b , corresponding to and aligning with the clips or other fastening devices  26   a  and  26   b . In an alternative embodiment, the housings  34   a  and  34   b  of the end caps may be sized and shaped to fit within the respective cavities  22   a  and  22   b  of the coupling device. The projections  40   a  and  40   b  extend from an exterior part of the respective housings of the coupling device, corresponding to and aligning with the clips or other fastening devices extending from the end caps. The combination of the clips and projections provide for a locking mechanism, as shown in  FIG. 6 . 
     FIG. 4   a  shows a cross sectional view of the end cap design of  FIG. 3  along line  3   a — 3   a  and  FIG. 4   b  shows a cross sectional view of the end cap design of  FIG. 3  along line  3   b — 3   b . In the embodiments of  FIGS. 4   a  and  4   b , the terminals of the end caps are shown as male-type terminals  38   a  and  38   b.    
     FIG. 5  shows a partially assembled perspective view of the coupling device and the end cap of any embodiment of the present invention. In this embodiment, the housings  20   a  and  20   b  are fitted within the respective cavities  36   a  and  36   b  of the end caps. The projections  40   a  and  40   b  are aligned with the clips  26   a  and  26   b  in order to securely mount the coupling device to the end caps of the present invention. In embodiments, the fastening device  26   a  is located at one side of the housing  20   a  and aligned with the projection  40   a  placed on a same side of the housing  34   a . Likewise, the fastening device  26   b  is located at another side of the housing  20   b  and aligned with the same side of the housing  34   b . In other words, the fastening devices  26   a  and  26   b  and projections  40   a  and  40   b  are, in embodiments, in an offset configuration. It is further seen that the connecting portion  18  extends around the control valve  31  thus ensuring the elimination of:
         1. vibrations of the solenoid wires caused by the rocker arm assemblies,   2. chaffing or striking of the solenoid wires from the rocker arm assemblies, or   3. vibrations of the solenoid wires caused when working fluid is discharged from the fuel injector.       
   It should be understood that the coupling device  10  of the present invention is designed, basically, to the shape of the control valve  31  and more particularly to align with the placement of the end caps. Accordingly, the coupling device  10  of the present invention, and more particularly the connecting portion  18  and the housings may have other configurations or sizes depending on the size and shape of the fuel injector. Thus, the coupling device is not limited to the shape and size shown in  FIGS. 1–5 . 
     FIG. 6  shows an assembled perspective view of the coupling device and the end cap of an embodiment of the present invention. In this view, the solenoid wires  30  are shown connected to a wire harness  50 . The end caps are connected to the control valve  31  which, in turn, is coupled to a fuel injector  60  having an intensifier body  60   a  and a nozzle  60   b . The fastening devices  26   a  and  26   b  are fully coupled to the projections  40   a  and  40   b  in order to securely mount the coupling device  10  to the respective end caps of the control valve  31 . This prevents decoupling and elimination of vibration problems. The solenoid wires  30  are remote from the discharge port  31   a  of the fuel injector. 
     FIGS. 7   a  and  7   b  show another embodiment of the coupling device and the end cap of the present invention. In the embodiments of  7   a  through  9   b , each of the end cap housings is generally depicted as reference numeral  34  and each of the coupling device housings is generally depicted as reference numeral  20 . In  FIGS. 7   a – 7   b , the end cap housing  34  has female-type connector terminals  72  and the coupling device housing  20  has male-type connector terminals  70 . In the coupled state, the male-type connector terminals  70  are designed to couple to the respective female-type connector terminals  72 .  FIGS. 1–3  depict the remaining features of the coupling device and the end caps. 
     FIGS. 8   a  and  8   b  show another embodiment the coupling device and the end cap of the present invention. In this embodiment, the coupling device housing  20  has male-type connector terminals  70  and the end cap housing  34  has two sets of opposing spring-like connectors  74 . In the coupled state, the male-type connector terminals  70  are sandwiched between and are in electrical communication with each respective set of opposing spring-like connectors  74 . A groove  76  is provided in each housing  20 , between each connector terminal  70 . Additionally, a projection or separator portion  78  is provided in each housing  34  of the end caps  32 , between inner ones  74   a  of the opposing spring-like connectors  74 . This features helps in the alignment of the housings of the end caps and the coupling device (i.e., terminals thereof) and further prevents electrical shorting or communication between the non-respective terminals.  FIGS. 1–3  depict the remaining features of the coupling device and the end caps. 
     FIGS. 9   a  and  9   b  show another embodiment the coupling device and the end cap of the present invention. In this embodiment, the housing  20  includes opposing spring-like connectors  80  and the end cap housing  34  includes male-type connector terminals  82 . In the coupled state, each of the male-type connector terminals  82  is sandwiched between and in electrical communication with each respective opposing spring-like connector  80 . Much like that shown in  FIGS. 8   a  and  8   b , the embodiment of  FIGS. 9   a  and  9   b  is also provided with a groove  76  and separator portion  78 .  FIGS. 1–3  depict the remaining features of the coupling device and the end caps. 
     FIGS. 10   a  and  10   b  show another embodiment the coupling device and the end cap of the present invention. In this embodiment, the coupling device housing  20  has plate-like connector terminals  84  and the end cap housing  34  has two sets of opposing spring-like connectors  74 . This type of configuration is referred to as a knife-blade connection. In the coupled state, the plate-type connector terminals  84  are in electrical communication with each respective set of opposing spring-like connectors  74 . Again, a groove  76  and separator portion  78  is provided in this embodiment.  FIGS. 1–3  depict the remaining features of the coupling device and the end caps. 
   Method of Manufacturing Coupling Device of the Present Invention 
     FIG. 11  shows a method of manufacturing the coupling device of the present invention. In the method of manufacturing, several copper leads are first provided (step  1100 ). As seen in  FIG. 12 , in a preferred embodiment, four copper leads  28  are each connected to adjacent copper leads via a bridging portion  28   a , which correspond to the placement of the punches or holes  12   a . The bridging portions  28   a  provide for a robust and stable platform for future molding. Each end of the copper lead is electrically attached (i.e., soldered) to a terminal a respective solenoid wires  30 . The assembly shown in  FIG. 12  is then placed into a mold (step  1120 ) which corresponds to a shape of the final product. (Steps  1110  and  1120  may be interchangeable.) In the embodiments, the mold may include the same shape as the coupling device shown in  FIG. 1 , with housing features, terminals and the like. Accordingly and for discussion purposes, it may be assumed that the coupling device shown in  FIG. 1  is substantially identical to the mold used to form the coupling device. The mold includes placement pins, which correspond to the punches or holes  12   a  and the bridge or connector portions  28   a . The pins are utilized to maintain the conductive leads in a stationary position during the molding process, and are also used to form the holes  12   a  in the coupling device of the present invention. The coupling device  10  is then over-molded in step  1130 . Once the mold has set, the coupling device  10  is then taken out of the mold and the holes  12   a  are punched at the bridging portions  28   a  (i.e., at the previous placement of the pins). The punching of the holes eliminates electrical connection between the copper leads  28  thus preventing electrical shorts and the like. 
   While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims.