Abstract:
A fuel injection system includes a fuel injector socket including a first attachment feature and a fuel injector including a second attachment feature that corresponds with the first attachment feature. The first attachment feature engages with the second attachment feature connecting the fuel injector to the fuel injector socket and preventing rotational movement of the fuel injector relative to the fuel injector socket. The corresponding attachment features not only enable simple connection and disconnection of a fuel injector to a fuel injector socket of a fuel rail, but can also be integrated into existing injector to fuel rail assembly processes and are applicable in any fuel injection system. The corresponding attachment features may be used with metal fabricated fuel rail assemblies as well as for fuel rail assemblies where the manifold supply tube and the fuel injector sockets are overmolded with a plastic material.

Description:
TECHNICAL FIELD 
     The present invention relates to engine management systems and components of internal combustion engines; more particularly, to fuel injection systems; and most particularly, to apparatus and method for connecting a fuel injector to a fuel rail. 
     BACKGROUND OF THE INVENTION 
     Fuel rails that are used to deliver fuel to individual fuel injectors of internal combustion engines are well known. A fuel rail assembly, also referred to herein simply as a fuel rail, is essentially an elongated tubular fuel manifold connected at an inlet end to a fuel supply system and having a plurality of ports for mating in any of various arrangements with a plurality of fuel injectors to be supplied. In what is referred to as a return-less system, a fuel return line does not fluidly connect the fuel rail back to the fuel supply system at a rail outlet end. In a “return” system, a fuel line fluidly connects the end of the fuel rail opposite the inlet end back to the fuel supply system. Typically, a fuel rail assembly includes a plurality of fuel injector sockets in communication with a manifold supply tube, the injectors being inserted into the sockets. Fuel rails are typically used on internal combustion engines with multi-point fuel injection systems. 
     Typically, a fuel injector is connected to a fuel rail using two different methods. In a first prior art method, a clip, such as a c-clip, is used to hold the injector to the fuel injector socket of the fuel rail. The clip also prevents the injector from rotating within the socket. In a second prior art method, a lower and an upper cushion hold the injector between the fuel injector socket and the intake manifold or the cylinder head. In this case the fuel injector socket typically includes a finger that prevents rotation of the injector within the socket. Both prior art methods utilize separate parts, such as the clip or the cushions, which creates extra costs and requires cycle time for installation. Therefore, it is desirable to reduce the number of parts required in the assembly of a fuel injection system. 
     Efforts to eliminate separate parts for the injector to fuel rail installation have been undertaken in more recent prior art with limited success. Features integrated within the fuel injector socket, the injector, or both, often required relatively tight tolerances, which may result in increased machining time and higher production costs. 
     U.S. Pat. No. 5,301,647, for example, teaches a fastening clip for integral formation with a portion of the body of a fuel injector and that provides attachment and retention. Modifications to the injector are needed to integrate a cylindrical wall including a plurality of apertures and catches. 
     U.S. Patent Application No. 2006/0065244, for example, discloses an integral device that provides rotational orientation while allowing axial sliding engagement of the fuel injector relative to the socket after assembly. Retention tabs integrated within the socket engage with corresponding grooves integrated within the injector. 
     What is needed in the art is a fuel injector to fuel rail connection that does not require separate parts or expensive machining operations. 
     What is further needed in the art is a relatively simple connection of a fuel injector to a fuel injector socket of a fuel rail that enables efficient assembly as well as disassembly if needed. 
     It is a principal object of the present invention to provide a method for connecting a fuel injector to a fuel rail that reduces manufacturing cycle time and provides easier package for shipping compared to current methods. 
     SUMMARY OF THE INVENTION 
     Briefly described, a fuel injector to fuel rail connection, in accordance with the invention, includes corresponding attachment features integrated into a fuel injector socket of a fuel rail and a fuel injector. The corresponding attachment features not only connect the fuel injector securely to the fuel injector socket of a fuel rail, but also provide a force to prevent injector rotation relative to the socket that is higher than the force provided by known prior art attachment features. By introducing corresponding attachment features in accordance with the invention, separate prior art parts such as clips or cushions can be eliminated simplifying the fuel injector installation process and reducing assembly costs. Furthermore, the corresponding attachment features not only enable simple connection and disconnection of a fuel injector to a fuel injector socket of a fuel rail, but can also be integrated into existing injector to fuel rail assembly processes and are applicable in any fuel injection system. Still further, the corresponding attachment features in accordance with the invention may be used with metal fabricated fuel rail assemblies as well as for fuel rail assemblies where the manifold supply tube and the fuel injector sockets are overmolded with a plastic material. 
     In accordance with the present invention, the fuel injector socket includes a slot that receives a projection included in the fuel injector. An anti-rotation feature integrated into the slot prevents radial movement of the fuel injector relative to the socket. Fuel pressure prevents axial movement of the fuel injector relative to the socket during operation. 
     In further accordance with the present invention, the fuel injector socket includes a tab having an anti-rotation feature and securing the socket to a projection integrated in the fuel injector. The injector to socket assembly may be designed either such that the tab is flexible or that the projection includes a locking feature. 
     In still further accordance with the present invention, the fuel injector includes a groove that includes the anti-rotation feature and receives the socket that includes a tab having an inward pointing lip. During installation, the fuel injector is simply pushed axially into the socket to engage the tab of the socket with the groove of the injector. For disassembly, the fuel injector can be pushed up, rotated, and finally pulled out from the socket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is an isometric view of a fuel injector and fuel injector socket prior to installation, in accordance with the invention; 
         FIG. 2  is a plan front view of the fuel injector installed in the fuel injector socket shown in  FIG. 1 , in accordance with the invention; 
         FIG. 3  is a plan back view of the fuel injector installed in the fuel injector socket shown in  FIG. 1 , in accordance with the invention; 
         FIG. 4  is a plan front view of a fuel injector installed in another fuel injector socket, in accordance with the invention; 
         FIG. 5  is a plan back view of the fuel injector installed in the fuel injector socket shown in  FIG. 4 , in accordance with the invention; 
         FIG. 6  is a plan front view of a fuel injector installed in another fuel injector socket, in accordance with the invention; 
         FIG. 7  is a cross-sectional view of the fuel injector installed in the fuel injector socket shown in  FIG. 6 , in accordance with the invention; 
         FIG. 8  is a partial cross-sectional view of the fuel injector similar to the injectors shown in  FIGS. 6 and 7 , but with a flexible extended projection, in accordance with the invention; 
         FIG. 9  is a plan front view of a fuel injector and a fuel injector socket prior to installation, in accordance with the invention; 
         FIG. 10  is an isometric view of the fuel injector shown in  FIG. 9 , in accordance with the invention; 
         FIG. 11  is a plan front view of the fuel injector installed in the fuel injector socket shown in  FIG. 9 , in accordance with the invention; and 
         FIG. 12  is an isometric view of the fuel injector installed in the fuel injector socket as shown in  FIG. 11 , in accordance with the invention. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , a fuel injection system  10  includes fuel injector socket  20  and fuel injector  30 . Fuel injector  30  is shown prior to installation in socket  20  in  FIG. 1  and installed in socket  20  in  FIG. 2 . Fuel injector socket  20  is part of a fuel rail assembly and is in communication with a fuel supply tube (not shown). 
     Fuel injector socket  20  has a generally cylindrical elongated shape and extends longitudinally along central axis  12  from a first end  22  to a second end  24 . The first end  22  is in fluid communication with the fuel supply tube. The second end  24  is open and receives fuel injector  30 . Socket  20  includes a primary slot  26  positioned proximate to second end  24 . Slot  26  includes a first segment  262 , a second segment  264 , and a third segment  266 , all in fluid communication with each other. First segment  262  extends upwards in axial direction from second end  24  of socket  20  and, therefore is open at end  272 . First segment  262  serves as an inlet. Second segment  264  extends radially from end  274  of first segment  262  and connects first segment  262  with third segment  266 . Third segment  266  extends downwards from end  276  of second segment  264  in axial direction towards second end  24 . Third segment  266  of slot  26  does not extend all the way to second end  24  and, consequently, is closed at bottom  268 . Third segment  266  forms an orientation stopper  28  that prevents rotational movement. Fuel injector socket  20  may be manufactured by machining, forming or molding. 
     Fuel injector  30  includes a primary projection  34  that corresponds with primary slot  26 . Projection  34  may have, but is not limited to, a rectangular shape and extends outwards from the outer surface  32  of injector  30 . Projection  34  is positioned axially below and at a distance from an o-ring  36  of injector  30  such that projection  34  does not interfere with the sealing process during installation of injector  30  in socket  20 . The dimensions of projection  34  are chosen such that projection  34  is able to travel easily within slot  26  of socket  20 . The depth of projection  34  is chosen such that projection  34  preferably extends outward beyond the outer surface  202  of socket  20 . The width of projection  34  is chosen such that projection  34  fits into third section  266  of slot  26 . The height of projection  34  is chosen such that projection  34  can be moved up and down in axial direction within second segment  264  of slot  26 . 
     During installation of injector  30  in socket  20 , injector  30  is moved in an axial direction towards the second end  24  of socket  20 . The projection  34  of injector  30  is in line with the first section  262  of slot  26  of socket  20 . During upward movement of injector  30 , the projection  34  enters and travels within first segment  262  of slot  26 . By turning injector  30  clockwise (looking upward along central axis  12  in  FIG. 1 ), the projection  34  travels in a radial direction within second segment  264  of slot  26 . If the end of second segment  264  is reached, injector  30  is pulled down in an axial direction away from socket  20  and projection  34  travels downwards within third section  266  of slot  26  to a locking position. In the locking position, projection  34  rests at the bottom  268  of third segment  266  of slot  26 . 
     Optionally, as a second method of installation of injector  30  in socket  20 , projection  34  may be aligned with third section  266 . Then, during upward movement of injector  30 , the projection  34  contacts second end  24  and flexes closed bottom  268  away from central axis  12  allowing projection  34  to snap into segment  266 . In this position, projection  34  rests at the bottom  268  of third segment  266  of slot  26 . 
     During operation, fuel pressure of fuel supplied by the fuel supply tube (not shown) will press injector  30  down in an axial direction away from socket  20 . As a result, projection  34  is held down at the bottom  268  of third segment  266  of slot  26  in a locked position. In this locked position, radial movement of injector  30  relative to socket  20  is prevented clockwise and counter-clockwise by orientation stopper  28  and the wall  270  of third segment  266  of slot  26  opposite from orientation stopper  28 , respectively. 
     During dis-assembly of injector  30  from socket  20 , injector  30  is pushed up in an axial direction towards first end  22  of socket  20 , is turned counter-clockwise in radial direction (looking upward along central axis  12  in  FIG. 1 ), and finally pulled down in axial direction out of socket  20 . During the removal of injector  30  from socket  20 , projection  34  travels within slot  26  in an opposite direction as during the first installation method described above. 
     While socket  20  is shown in  FIGS. 1 and 2  to include one slot  26 , more than one slot  26  may be included in socket  20 . While injector  30  is shown in  FIGS. 1 and 2  to include one projection  34 , injector  30  may be manufactured with additional projections if socket  20  includes additional slots  26 . While second segment  264  of slot  26  is shown in  FIGS. 1 and 2  to extend to the right from first segment  262 , slot  26  may be designed such that second segment  264  extends to the left from first segment  262 . In this case, injector  30  may be rotated counter-clockwise during the first installation method in socket  20  and clockwise during dis-assembly. 
     Referring to  FIG. 3 , fuel injector socket  20  is shown to include an optional secondary slot  16  and fuel injector  30  is shown to include an optional secondary projection  18  that corresponds with secondary slot  16 . Slot  16  is preferably positioned at the back of socket  20  opposite from slot  26 . Projection  18  is preferably positioned at the back of injector  30  opposite from projection  34 . Slot  16  receives projection  18 . Projection  18  travels within slot  16  to a supporting position during installation of injector  30  in socket  20 . 
     Slot  16  only includes a first section  162  and a second section  164  that are comparable to first section  262  and second section  264  of slot  26 , respectively. By omitting a third segment comparable to segment  266  of slot  26 , no orientation stopper  28  is formed. Thus, slot  16  simplifies correct installation of injector  30  in socket  20  and provides additional support for injector  30  in axial direction when installed, but does not provide an anti-rotation structure, such as orientation stopper  28 . Slot  16  has generally the same dimensions as slot  26  to ensure effortless installation of injector  30  in socket  20 . More than one slot  16  may be included in socket  20  and more than one corresponding projection  18  may be included in injector  30 . 
     Referring to  FIG. 4 , socket  40  includes a primary tab  42  in accordance with an alternate embodiment of the invention. Tab  42  extends socket  40  in an axial direction beyond open end  402  of second end  24  of socket  40 . Tab  42  includes an opening  46  and a groove  44  that is in fluid communication with opening  46 . Groove  44  extends below opening  46  and forms an orientation stopper  48  that prevents movement in radial direction. Injector  30  includes a primary projection  34  as described above with regard to  FIGS. 1-3 . Projection  34  is designed to fit through opening  46  and into groove  44 . Socket  40  may include more than one tab  42  and injector  30  may include more than one corresponding projection  34 . Opening  46  may be positioned on either side of tab  42 . 
     During installation of injector  30  in socket  40 , injector  30  is moved in axial direction towards the second end  24  of socket  40 . The projection  34  of injector  30  is not in line with tab  42 . Once injector  30  is pushed into socket  40 , injector  30  is turned counter-clockwise (looking upward along central axis  12  in  FIG. 4 ) to move projection towards and through opening  46 . Injector  30  is then pulled down in axial direction away from socket  40 . This movement causes projection  34  to move into groove  44 . In this position, orientation stopper  48  prevents radial movement of injector  30  relative to socket  40 . 
     Optionally, as a second method of installation of injector  30  in socket  40 , projection  34  may be aligned with groove  44 . Then, during upward movement of injector  30 , the projection  34  contacts the bottom of tab  42  and flexes tab  42  away from central axis  12  allowing projection  34  to snap into opening  46  above groove  44 . In this position, projection  34  rests in groove  44 . 
     During operation, fuel pressure of fuel supplied by the fuel supply tube (not shown) will press injector  30  down in axial direction away from socket  40 . As a result, projection  34  is held in groove  44  in a locking position. 
     During dis-assembly of injector  30  from socket  40 , injector  30  is pushed up in axial direction towards first end  22  of socket  40 , moving projection  34  out of the locked position, is turned clockwise in radial direction (looking upward along central axis  12  in  FIG. 4 ) to let projection  34  exit through opening  46  of tab  42 , and finally pulled down in an axial direction out of socket  40 . 
     Referring to  FIG. 5 , socket  40  is shown to include an optional secondary tab  52  and fuel injector  30  is shown to include a corresponding secondary projection  54 . Tab  52  is preferably positioned at the back of socket  40  opposite from tab  42 . Projection  54  is preferably positioned at the back of injector  30  opposite from projection  34 . Tab  52  includes a secondary opening  56 , but no groove comparable to groove  44 . Opening  56  receives projection  54  during installation of injector  30  in socket  40 . Secondary projection  54  moves through opening  56  to a supporting position. The height  562  of opening  56  may be larger than the height  462  of opening  46 . Tab  52  simplifies correct installation of injector  30  in socket  40  and provides axial support for installed injector  30 , but does not provide anti-rotation support in both radial directions as does tab  42 . More than one tab  52  may be included in socket  40  combined with corresponding projections  54  of injector  30 . Opening  56  may be positioned on either side of tab  52 . 
     Referring to  FIGS. 6 and 7 , socket  60  includes multiple tabs  62  in accordance with an alternate embodiment of the invention. Injector  30  includes two projections  34  that correspond with the two tabs  62 . In the example shown, tabs  62  and projections  34  are positioned opposite from each other in the cross-sectional view of  FIG. 7 . More than two tabs  62  may be included in socket  60 . Each tab  62  extends socket  60  beyond second end  24  in axial direction. Each tab  62  includes a void  64 . Void  64  has a shape corresponding the shape of projection  34 . The size of void  64  is selected such that void  64  can receive and enclose projection  34 . Tabs  62  may be designed to be flexible. Tabs  62  may be able to flex away from axis  12 . Tabs  62  include a ramp  622  that extends axially below the void  64  and that is slightly bent outward away from axis  12  (as shown in  FIG. 7 ). Ramps  622  aid the installation process of injector  30  in socket  60 . 
     During installation, the fuel injector  30  is moved in an axial direction towards the second end  24  of socket  60 . The projections  34  of injector  30  are preferably in line with corresponding tabs  62 . During the axial upward movement, projections  34  will slide underneath ramps  622  of corresponding tabs  62  flexing tabs  62  at end  624  outward and away from axis  12  until the voids  64  are reached. When projections  34  enter corresponding voids  64 , tabs  62  will flex back towards axis  12  into resting position thereby locking projections  34  in place. Tabs  62  including voids  64  limit axial movement and prevent radial movement of injector  30  relative to socket  60  when installed during operation. For dis-assembly, tabs  62  are flexed outwards away from axis  12  and injector  30  is pulled downward in axial direction out of socket  60 . 
     Referring to  FIG. 8 , injector  30  includes a flexible projection  66  in accordance with an alternate embodiment of the invention. Injector  30  may be installed in socket  60  as illustrated in  FIGS. 6 and 7 . Replacing projections  34  shown in  FIGS. 6 and 7  with flexible projection  66  shown in  FIG. 8  may provide a higher force to prevent rotation of injector  30  within socket  60  and may also position injector  30  more securely and reliably in socket  60 . Projection  66  may be designed to be flexible, including a hook portion extending downward in an axial direction. Projection includes tip  68 . 
     During installation of injector  30  in socket  60  (shown in  FIGS. 6 and 7 ), tabs  62  slide over corresponding projections  66  during upward movement of injector  30  into socket  60  flexing tip  68  of projection  66  inwards. Once projection  66 , including tip  68 , aligns with void  64 , upward movement of injector  30  is stopped. At that point, tip  68  flexes back outward and away from axis  12 , thereby locking the injector in place. For dis-assembly, tip  68  of projection  66  is flexed inward toward axis  12  to enable pulling injector  30  out of socket  60 . 
     Referring to  FIGS. 9-12 , fuel injection system  10  includes fuel injector socket  70  and fuel injector  80  according to an alternative embodiment of the invention. Fuel injector  80  is shown prior to installation in socket  70  in  FIG. 9  and installed in socket  70  in  FIGS. 11 and 12 . Socket  70  includes a tab  72  integrated into the body of socket  70 . 
     Tab  72  does not extend beyond second end  24  of socket  70 . Tab  72  is designed to be flexible allowing tab  72  to be flexed outward away from axis  12 . Tab  72  includes an inward oriented lip  74  positioned proximate to the second end  24 . In a preferred embodiment, socket  70  includes at least two tabs  72  that are positioned radially equal-spaced from each other. 
     Injector  80  includes a notch  82 . Notch  82  may be integrated in the body of injector  80  and may be located within a section  84  below o-ring  36 . Notch  82  is designed to receive lip  74  of socket  70 . Section  84  of injector  80  includes a flat sidewall  86  that is, in the example shown having two tabs, at a 90-degree angle to notch  82 . In a preferred embodiment, injector  80  includes at least two notches  82  that are positioned opposite from each other and at least two flat sidewalls  86 . One sidewall  86  is always positioned between two notches  82 . Injector  80  further includes an annular groove  88  positioned just below notches  82 . 
     During installation of injector  80  in socket  70 , notches  82  are lined up with corresponding tabs  72 . Injector  80  is pushed upward in axial direction towards socket  70 . During the upward movement, tabs  74  are flexed outward. When lips  74  meet corresponding notches  82 , lips  74  engage with notches  82 . 
     To dis-assemble injector  80  from the socket, injector  80  is pushed upward such that lips  74  of tabs  72  disengage from notches  82  and slide into annular groove  88 . Injector  80  is then rotated, either clock-wise or counter-clockwise, until lips  74  are lined up with flat sidewalls  86 . Now, injector  80  is pulled out from socket  70  by moving injector  80  downward in axial direction away from socket  70 . During this movement, lips  74  slide over flat sidewalls  86  releasing injector  80 . 
     As compared to the prior art, fuel injection system  10 , in accordance with the invention, beneficially provides corresponding attachment features integrated in fuel injector sockets  20 ,  40 ,  60  and  70  and integrated in fuel injectors  30  and  80  that not only connect the fuel injector  30  securely to the fuel injector sockets  20 ,  40 , and  60  and the injector  80  to socket  70 , but also provide a higher force to prevent injector rotation relative to the socket. Stronger anti-rotation structures, for example orientation stopper  28  and  48 , tab  62  and void  64 , or tab  72  and notch  82 , are provided, while the connection of injector to socket is simplified. Hence, lower manufacturing and assembly costs, reduced manufacturing and assembly cycle times, and easier packaging conditions are obtained. 
     While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.