PLASTIC FUEL RAIL HAVING INTEGRATED ELECTRICAL WIRING

Abstract: A fuel rail (12) including an electrical strip (20) is utilized to electrically couple fuel injectors to an external electrical connector (26) situated on an outside surface of the fuel rail. The fuel rail is preferably made from plastic and includes injector cups situated in fuel injector attachments for mechanically receiving the fuel injectors. The fuel injectors are electrically and mechanically coupled to the fuel rail by an upward mechanical motion. The fuel injectors include clip-like electrical connectors which receive connector fingers of the electrical strip which are disposed in the injector cups. The fuel rail was preferably blow molded in a manifold.

Description: PLASTIC FUEL RAIL HAVING INTEGRATED ELECTRICAL WIRING Cross Reference to Related Application The present application is related to commonly assigned United States Patent Application Serial No. 08/398, 1 96 filed on 02 March 1 995, entitled "Connector Injector with Tension and Electrical Connection to a Fuel Rail." Field of the Invention The present invention relates generally to a fuel injection system for an engine. More particularly, the present invention relates to a fuel rail having an electrical strip for electrically connecting an external connector to a fuel injector interface. The fuel injector interface is configured to mechanically and electrically couple the fuel injector to the fuel rail. Background of the Invention Fuel systems often include one or more fuel injectors coupled to a metal fuel rail. The fuel injector receives fuel from the fuel rail at a fuel input and provides the fuel at a fuel output for use by an engine in response to an electrical signal. The fuel injector typically includes an external male electrical connector for receiving the electrical signal. The electrical signal is produced by an electronic ignition control system or other electrical control system and is provided across an external conductor (e.g., control wiring) to an external female connector which can be joined to the external male connector on the fuel injector. Typically, fuel injectors have been physically (e.g., mechanically) coupled to the fuel rail by a metal clip. The metal clip mechanically secures the fuel input of the fuel injector to an injector cup of the fuel rail and ensures that the fuel injector is maintained in the injector cup when the fuel is pressurized. The fuel injectors are generally electrically coupled to the electrical ignition control system via external connectors and conductors which are separate from the mechanical interface. The control wiring (e.g., external electrical conductors) generally must be fixed or harnessed to particular locations on the fuel rail or other engine components to prevent the control wiring from interfering with engine operation and to ensure the integrity of the electrical connections. Heretofore, fuel injection systems have required electrical connection systems including external electrical conductors and external electrical connectors for electrically coupling the fuel injector to the control wiring. Such systems are disadvantageous because the electrical connectors and the fuel rail must be joined to the fuel injector in separate assembly steps. Also, electrical connection systems utilizing external connectors and conductors often require additional fastening hardware and bulky electrical connectors to provide a secure electrical connection. Further, the external connectors and conductors are generally expensive. Thus, there is a need for an integrated wiring system for a fuel injection system which allows the fuel injector to be simultaneously mechanically mated to the full injector cup and electrically coupled to the electronic ignition control system. There is also a need for a conductive strip integral the fuel rail which eliminates the need for external electrical connectors and conductors coupled to the fuel injectors. Summary of the Invention The present invention relates to a fuel supply system including fuel injectors. The fuel supply system includes a fuel rail having an interior surface and an exterior surface, fuel injector attachments or interfaces coupled to the fuel rail, an electrical connector disposed on the exterior surface of the fuel rail, and an electrical connector strip having connector fingers. The injector attachments mechanically receive the fuel injectors. The electrical connector strip is adjacent the interior surface and electrically coupled to the electrical connector. The connector fingers are disposed in the fuel injection attachment for electric coupling to the fuel injectors. The present invention further relates to a fuel injector system for use in an engine. The fuel injector system includes fuel injector means for providing fuel to the engine in response to a control signal, fuel rail means for providing the fuel, fuel injector attachment means for mechanically receiving the fuel injectors and providing the fuel from the fuel rail to the fuel injectors, input means for receiving the control signal, and electrical strip means for electrically coupling the input means to internal electrical connectors of the fuel injector means. The electrical strip means is coupled to the input means and at least partially disposed in the fuel injector attachment means. The electrical strip means provides the control signal from the input means to the fuel injector means and is at least partially disposed in the fuel rail means. The present invention even further relates to a method of manufacturing a fuel rail having an integrated electrical strip. The fuel rail is for use in a fuel injection system, including fuel injectors, fuel injector interfaces, an external electrical connector disposed on the fuel rail, and an initially generally planar electrical strip having connector fingers. The fuel injector interfaces are adapted to be coupled to the fuel injectors. The method includes steps of inserting the electrical strip within the fuel rail, electrically coupling the electrical strip to the external electrical connector, and arranging the connector fingers to be disposed within the fuel injector interfaces. The fuel injectors are electrically coupled to the external connector via the electrical strip. In one implementation of the present invention, a plastic fuel rail includes an integrated electrical strip for coupling an external electrical connector mounted on the fuel rail to fuel injectors mechanically coupled to fuel injector cups. The electrical strip is preferably comprised of a generally planar, non-conductive plastic member having at least one conductive line on a top surface and a bottom surface. The electrical strip is generally flexible so that it may be easily installed within the fuel rail. In another implementation of the present invention, connector fingers on the electrical strip are disposed within the injector cups to receive clip-like internal electrical connectors on the fuel injectors. The clip-like electrical connectors pinch the connector fingers. The fuel injectors are mechanically held to the fuel rail by a radial flange/snap engagement at the fuel injector interface. The present invention advantageously integrates within the plastic fuel rail. The fuel rail may be situated within a manifold of the engine control wiring, e.g., the electrical coupling between an external electrical connector and the individual fuel injectors. The fuel injector may be both mechanically coupled to the fuel rail and electrically coupled to the electronic injection control system by a single upward mechanical motion. Brief Description of the Drawings The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: Figure 1 is a cross sectional side view schematic drawing of a fuel supply system including a fuel rail mechanically and electrically engaged with fuel injectors in accordance with an exemplary embodiment of the present invention; Figure 2 is a top view schematic drawing of the fuel rail illustrated in Figure 1 showing fuel injector interfaces and an external electrical connector; Figure 3 is a detailed cross sectional view of the fuel rail illustrated in Figure 2 a long line 3-3; and Figure 4 is a top view schematic drawing of an electrical strip for use in the fuel rail illustrated in Figure 2 in accordance with an exemplary embodiment of the present invention. Detailed Description of the Preferred Embodiment Referring generally to the schematic cross sectional side view drawing of Figure 1 , an engine (not shown) includes a manifold 8 housing a fuel supply system 10. Fuel supply system 10 generally includes a fuel rail 1 2 and a fuel injector 14. Fuel rail 1 2 can be fabricated from plastic and includes an electrical strip 20 serving as integrated wiring which is coupled to a clip-like electrical connector 22 of injector 14. Electrical strip 20 is coupled to an external electrical connector 26 (Figure 2) which is coupled to an electronic ignition control system (not shown). Fuel rail 1 2 is preferably overmolded into manifold 8 to simplify the overall installation of fuel supply system 1 0. Fuel rail 1 2 can be completely buried in manifold 8 only requiring external interfaces such as a fuel input 35 for connection to a fuel line attachment and external electrical connector 26. Connector 26 and input 35 are preferably sealed with respect to manifold 8. The orientation of fuel supply system 1 0 within manifold 8 inherently provides a double wall around fuel passages, thereby allowing each wall to be thinner. Preferably, fuel rail 1 2 is made from a material such as . Electrical strip 20 includes connector fingers such as connector finger 30 having a trapezoidal termination 24 (see Figure 4). Electrical strip 20 is coupled to external electrical connector 26 (Figure 2) and connector finger 30. Connector finger 30 are disposed within an injector cup 31 which is disposed within an injector attachment 56 (see Figure 2). Fuel rail 1 2 mechanically receives fuel injector 14 at injector cup 31 . Fuel rail 1 2 receives fuel from a fuel line other fuel source (not shown) at fuel input 35 and provides fuel to injector 14 at injector cup 31 . Fuel injector 14 preferably protrudes into an air stream 41 of manifold 8 and includes a fuel input 29 which receives fuel from injector cup 31 of fuel rail 1 2. Injector 14 provides the fuel from fuel input 29 to a nozzle or fuel output 32 for use by manifold 8 in response to one or more electrical signals received at connector 22. Injector 14 is slidably attached to fuel injector attachment 56 at fuel input 29, thereby permitting insertion, removal and replacement of injector 14 relative to rail 12. Injector 14 also includes a radial flange 38 mechanically configured to slide into and engage a snap interface 21 on fuel injector attachment 56. Snap interface 21 locks injector 14 to rail 1 2 and ensures a sealed mechanical connection about injector cup 31 . Injector cup 31 preferably includes an O-ring 37 for preventing fuel from leaking at the interface of injector 14 and rail 1 2. Fuel supply system 10 is shown with fuel rail 12 mated with fuel injector 14. In accordance with this exemplary embodiment, injector 14 is mechanically coupled to fuel rail 12 by an upward physical motion joining interface 21 with radial flange 38. Snap interface 21 and radial flange 38 resist downward forces due to the pressurized fuel in rail 12. Preferably, manifold 8 is manufactured in a lost core molding process to maintain appropriate tolerances so that manifold 8 can seal snap interface 21 . Alternatively, a separate sleeve (not shown) may be utilized to cover snap interface 21 . Electrical connector 22 is simultaneously electrically coupled to or connected to connector finger 30 of electrical strip 20 by the same motion that mechanically couples injector 14 to rail 12. When connector finger 30 engages (e.g., is coupled to) connector 22, injector 14 is electrically coupled to receive one or more electrical signals from the electrical ignition control system (not shown) via external connector 26 and electrical strip 20. Connector 22 preferably slides up connector finger 30 at trapezoidal termination 24. Connectors 22 are preferably held in place by mechanical forces due to the clip-like construction of connectors 22 which squeeze connector finger 30. Therefore, the orientation of rail 12 and injector 14 advantageously allows fuel rail 12 to be electrically and mechanically mated to fuel injector 14 simultaneously when snap interface 21 engages radial flange 38. With reference to Figure 2, fuel rail 1 2 is preferably comprised of a unitary plastic molded piece 50 and a unitary plastic molded piece 52. Pieces 50 and 52 are preferably joined at a juncture 53 including an O-ring seal (not shown). Rail 1 2 also includes connector 26 integrally electrically coupled to each fuel injector attachment 56 via electrical strip 20. Each fuel injector or attachment 56 includes its own injector cup 31 (Figure 1 ). External connector 26 is preferably an integrally formed connector on an outside surface 62 of rail 12 configured for connection to a male connector (not shown) coupled to the electronic ignition control system (not shown). Connector 26 is situated on surface 62 of rail 1 2 for access to the male connector (not shown). Preferably, connector 26 includes five pins such as pins 81 (e.g., one more pin than the number of injectors such as fuel injector 1 4). Additionally, rail 1 2 is coupled to fuel input 35 which is configured for receiving the fuel line of the engine (not shown). With reference to Figure 3, a cross sectional view of rail 1 2 includes connector 26 and electrical strip 20. Electrical strip 20 is disposed in fuel rail 1 2 adjacent an inside surface 68 so that the flow of fuel in rail 1 2 is not significantly affected. Strip 20 is secured to rail 1 2 through an aperture 90 by a head 92 of pin 81 . Pin 81 which is disposed through a washer 98 and O-ring seals 95 is electrically connected to strip 20 via head 92. Alternatively, pin 81 may be brazed to strip 20. Aperture 90 is preferably aligned with aperture 99 in rail 1 2. With reference to Figure 4, a top view of strip 20 shows a generally rectangular, initially planar plastic member having a conductive pattern on a top surface 102. The conductive pattern includes conductive lines 104, 106, 108 and 1 10, each separately extending from one of connector fingers 30 to one of apertures 90. Additionally, strip 20 includes a conductive line on a back surface (not shown) extending from the middle hole of apertures 90 to each connector finger 30. Lines 1 04, 1 06, 108 and 1 1 0 provide individual control signals for each injector 14 in fuel supply system 10. Each conductive line is coupled to a respective pin 81 via head 92 at one of apertures 90. Also, the conductive line on the back surface of electrical strip 20 is coupled to the middle aperture of apertures 90 and provides a ground signal to each connector finger 30. Clip-like connectors 22 engage lines 1 04, 1 06, 108 and 1 1 0 and the conductive line on the back surface of strip 20 to provide a secure electrical connection between strip 20 and injector 1 4. Trapezoidal terminations 24 provide a larger surface area for clip-like connectors 22 to engage connector fingers 30 and prevent connector fingers 30 from being pushed out of injector cup 31 . The manufacturing of rail 1 2 including integrated electrical strip 20 is discussed below as follows with reference to Figures 1 -4. Rail 12 is separated into a piece 50 and a piece 52. Electrical strip 20 is coiled and inserted into piece 52 and manipulated so that apertures 90 in strip 20 are aligned with similarly situated apertures 99 in rail 12 proximate electrical connector 26. Pin 81 is riveted through each of apertures 90 and 99. Strip is held to inside surface 68 of rail 1 2 by head 92 of pin 81 and washer 93. Alternatively, pin 81 may be brazed to strip 20. After electrical strip 20 is inserted into piece 50, and strip 20 is uncoiled and manipulated so that connector fingers 30 extend into injector cup 31 of fuel injector attachment 56. Next, injector strip 20 is coiled and inserted into piece 52. Electrical strip is then uncoiled and manipulated so that connector fingers 30 extend in injector cups 31 of injector attachment 56 on piece 52. Pieces 50 and 52 are joined at juncture 53 and sealed so that fuel does not leak as fuel flows from fuel input 35 to injector cups 31 and injector attachments 56 on both pieces 52 and 62. Trapezoidal termination 24 are preferably configured to prevent connector fingers 30 from being pushed back into injector cups 31 once connector fingers 30 are uncoiled into injector cups 31 . Other injectors 14, rails 1 2, and strips 20 may be utilized in fuel supply system 10 depending on upon the requirements of the particular application. For example, a fuel rail 1 2 for an eight-cylinder engine may include eight separate fuel injectors 14 and eight separate injector cups 31 . Alternatively, strip 20 may be manufactured from various materials suitable for use in fuel rail 1 2. Additionally, rail 12 and injector 14 may include fittings, grooves, keys, key seats, or channels for providing a stable interconnecting or coupling scheme in fuel supply system 1 0. It is understood that, while the detailed description and drawing shows specific examples of the present invention, they are for the purposes of illustration only. The present invention is not limited to the precise details and conditions disclosed. For example, clip-like electrical connector 22 is shown on injector 1 4 and a female electrical connector is shown on rail 1 2, other types of electrical interface between injectors 14 and rail 1 2 may be utilized. Further still, although rail 1 2 and strip 20 and preferably made of plastics, other materials may be suitable for use in fuel supply system 1 0. Various changes can be made to the details disclosed without departing from the spirit of the invention which is defined by the following claims.

Claims: CLAIMS What is Claimed is: 1 . A fuel supply system for use with a plurality of fuel injectors, the fuel supply system comprising: a fuel rail having an interior surface and an exterior surface; a plurality of fuel injector attachments coupled to the fuel rail, the fuel injector attachments mechanically receiving the fuel injectors; an electrical connector disposed on the exterior surface; and an electrical connector strip having a plurality of connector fingers, the electrical connector strip adjacent the interior surface and electrically coupled to the electrical connector, the connector fingers disposed in the fuel injector attachments for electrical coupling with the fuel injectors. 2. The fuel supply system of claim 1 wherein connector strip is comprised of a flat non-conductive strip having conductive surfaces. 3. The fuel supply system of claim 2 wherein the electrical connector is coupled to the electrical connector via a rivet disposed through an O-ring, the 0- ring being disposed between the interior and exterior surface. 4. The fuel supply system of claim 2 wherein the connector strip has a first side, a second side, a first conductive line disposed on the first side and a second conductive line disposed on the second side. 5. The fuel supply system of claim 4 wherein the second conductive line is electrically coupled to each fuel injector. 6. The fuel supply system of claim 5 wherein the second conductive line includes a plurality of separate control lines, wherein each of the separate control lines is coupled to one of the fuel injectors. 7. A fuel injector system for use in an engine, the fuel injector system comprising: a plurality of fuel injectors mean, having internal electrical connectors, for providing fuel to the engine in response to a control signal; a fuel rail means for providing the fuel; a plurality of fuel injector attachment means, coupled to the fuel rail, for mechanically receiving the fuel injector means and providing the fuel from the fuel rail to the fuel injector; input means for receiving the control signal; and an electrical strip means, coupled to the input means and at least partially disposed in the fuel injector attachment means, for electrically coupling the input means to the internal electrical connectors of the fuel injector means, whereby the electrical strip means provides the control signal from the input means to the fuel injector means, the electrical strip means being at least partially disposed in the fuel rail means. 8. The fuel injector system of claim 7 wherein the internal injector connectors are comprised of a plurality of conductive terminals arranged as a clip. 9. The fuel injector system of claim 8 wherein the clip is configured to engage the electrical strip means disposed in the fuel injector attachment means. 1 0. The fuel injector system of claim 9 wherein the electrical strip means includes conductive fingers disposed in the fuel injector attachment means. 1 1 . The fuel injector system of claim 9 wherein the electrical strip means is initially generally planar. 1 2. The fuel injector system of claim 1 1 wherein electrical strip means is comprised of a flat non-conductive strip having metallic surfaces. 1 3. The fuel injector system of claim 7 wherein each fuel injector attachment means includes a retaining snap and each injector means includes a top flange, the fuel injector means being mechanically coupled to the fuel injector attachments means via the engagement of the top flange and retaining snap. 1 4. The fuel injector system of claim 1 2 wherein the electrical strip means has a first side, a second side, a first conductive line disposed on the first side and a second conductive line disposed on the second side. 1 5. The fuel injector system of claim 14 wherein the second conductive line is electrically coupled to each fuel injector means. 1 6. The fuel injector system of claim 1 5 wherein the second conductive line includes a plurality of separate control lines, wherein each of the separate control lines is coupled to one of the fuel injector means. 1 7. A method of manufacturing a fuel rail having an integral electrical strip, the fuel rail for use in a fuel injector system, the fuel injector system including a plurality of fuel injectors, a plurality of fuel injector interfaces coupled to the fuel rail the fuel injector interfaces adapted to be coupled to the fuel injectors and to provide fuel from the fuel rail to the fuel injector, an external electrical connector disposed on the fuel rail, and an initially generally planar electrical strip having connector fingers, the method comprising steps of: inserting the electrical strip within the fuel rail; electrically coupling the electrical strip to the external electrical connector; and arranging the connector fingers to be disposed within the fuel injector interfaces, whereby the fuel injectors are electrically coupled to the external electrical connector via the electrical strip. 18. The method of claim 1 7 further comprising: forming the fuel rail in a plurality pieces to allow the insertion of the electrical strip; and joining the pieces to form the fuel rail. 1 9. The method of claim 1 8 wherein the joining step includes placing an O-ring between the pieces. 20. The method of claim 1 7 wherein the electrically coupling step includes aligning an aperture in the electrical strip with an aperture in the fuel rail and driving a conductive rivet through the apertures.

Inventors: LORRAINE JACK R, LORRAINE, JACK, R.
Applicants: SIEMENS AUTOMOTIVE CORP LP, SIEMENS AUTOMOTIVE CORPORATION
Application year: 1996
Main classification: F02M51
IPC codes: F02M51, F02M55, F02M69