Patent Publication Number: US-6705292-B2

Title: Apparatus and method of connecting a fuel injector and a fuel rail

Description:
FIELD OF THE INVENTION 
     This disclosure relates to a fastener, a mounting arrangement, and a method for connecting a fuel injector with respect to a fuel rail, and more particularly, for orienting the fuel injector with respect to the fuel rail. 
     BACKGROUND OF THE INVENTION 
     Fuel can be supplied to an internal combustion engine by way of a fuel rail assembly that can include a fuel rail and at least one fuel injector. The fuel injectors can be coupled to the fuel rail with clips. When a clip is used to couple an injector to a cup, it is believed that there are at least two different types of forces that are required: the forces required to compress a sealing member between the cup and the injector, and the forces required to engage the clip with respect to the injector and the cup. It is believed that known clips concurrently apply both types of forces. Consequently, it is believed that these known clips suffer from a number of disadvantages including improperly compressing the sealing member and improperly securing the injector with respect to the cup. 
     It is believed that there is a need to provide a clip that overcomes the disadvantages of known clips. 
     SUMMARY OF THE INVENTION 
     The present invention provides a clip for fastening a fuel injector to a fuel injector cup of a fuel injection system. The fuel injector cup includes an end, an inner surface, and an outer surface defining a shoulder. And the fuel injector includes an exterior groove and an O-ring that is adapted to sealingly engage the inner surface of the fuel injection cup. The clip includes first and second portions. The first portion engages the exterior groove on the fuel injector. And the second portion engages the shoulder on the outer surface of the fuel injector cup so as to retain along an axis the fuel injector relative to the fuel injector cup. The first portion is axially spaced from the second portion such that a first axial measurement between the first portion and the O-ring exceeds a second axial measurement between the end of the fuel injector cup and the shoulder on the outer surface of the fuel injector cup. 
     The present invention also provides a mounting arrangement for a fuel rail. The mounting arrangement includes a fuel injector, a fuel injector cup, and a fastener. The fuel injector includes a body that defines an interior fuel passage that extends between an inlet and an outlet. The body of the fuel injector also includes first and second exterior grooves. The first exterior groove receives a compliant seal, and the second exterior groove is located between the first groove and the outlet. The fuel injector cup includes an end that defines an aperture through which passes along an axis the inlet of the fuel injector. The fuel injector cup also includes inner and outer surfaces. The inner surface contiguously engages the compliant seal, and the outer surface includes a shoulder that faces generally opposite the end of the fuel injector cup. The fastener includes first and second portions. The first portion engages the second exterior groove on the body of the fuel injector, and the second portion engages the shoulder on the outer surface of the fuel injector cup so as to axially retain the fuel injector relative to the fuel injector cup. The first portion is axially spaced from the second portion such that a first axial measurement between the first portion of the fastener and the compliant seal exceeds a second axial measurement between the end of the fuel injector cup and the shoulder on the outer surface of the fuel injector cup. 
     The present invention also provides a method of securing a fuel injector to a fuel rail. The fuel injector is displaceable along an axis with respect to the fuel rail. The method includes providing the fuel injector with a clip and an O-ring, and engaging the fuel injector with respect to the fuel rail. The clip is adapted to secure the fuel injector with respect to the fuel rail. And the O-ring provides a fuel tight seal between the fuel injector and the fuel rail. The engaging the fuel injector with respect to the fuel rail occurs such that the O-ring establishes the fuel tight seal prior to the clip being coupled to the fuel rail. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention. 
     FIG. 1 is perspective view of a fuel rail assembly. The left side shows an exploded arrangement of a rail, injector, and clip in accordance with the present invention. The right side shows an assembled arrangement of a rail, injector, and clip in accordance with the present invention. 
     FIG. 2 is a partial cross sectional view of the fuel rail assembly shown in FIG.  1 . The fuel injector, cup, and clip according to the present invention are shown in an intermediate state of assembly. 
     FIG. 3 is perspective view of the injector and clip shown in FIG.  1 . 
     FIG. 4 is an exploded view of the fuel rail assembly shown in FIG.  1 . 
     FIG. 5 is a perspective view showing a detail of the cup shown in FIG. 1 
     FIG. 6 is a perspective view of the clip shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the figures, there is shown a mounting arrangement  10  according to the present invention. As used herein, like numerals indicate like elements throughout. The fuel mounting arrangement  10  includes a fuel injector  20  that is moved along an axis  12  into mating engagement with a fuel rail  40 , and secured thereto with a fastener  70 . The fastener  70  can be a clip. 
     The fuel injector  20  includes a body  22  that defines an interior fuel passage (not shown) that extends between an inlet  26  and an outlet  28 . The body  22  of the fuel injector  20  also includes a first exterior groove  30  and a second exterior groove  32 . The first exterior groove  30  receives a compliant seal  34 . The compliant seal  34  can be an O-ring, for example. The second exterior groove  32 , which may partially or completely circumscribe the body  22 , is located axially between the first exterior groove  30  and the outlet  28 . The body  22  may also be configured to angularly orient about the axis  12  the fastener  70  with respect to the fuel injector  20 . For example, a tab  36  can extend from the body  22 . Of course, different configurations, such as a recess, could also be used for achieving this angular orientation. 
     The fuel rail  40  provides fluid communication between at least one fuel injector cup  42  and a supply of fuel, e.g., a fuel tank (not shown). The fuel injector cup  42  includes an end  44  that defines an aperture  46 . The inlet  26  of the fuel injector  20  is moved along the axis  12  such that it passes through the aperture  46  and inside an inner surface  48  of the fuel injector cup  42 . The inner surface  48  contiguously engages the compliant seal  34 . An outer surface  50  of the fuel injector cup  42  includes a shoulder  52  that faces generally opposite the end  44  of the fuel injector cup  42 . According to a one embodiment, the shoulder  52  may be defined by a first surface on a protrusion  54 . Of course, the surface  52  could also be defined otherwise, e.g., by a lateral face of a groove formed on the outer surface  50 . The protrusion  54  also has opposing sides  56   a,   56   b  that may be used to angularly orient about the axis  12  the fastener  70  with respect to the fuel injector cup  42 . 
     The inner surface  48  of the fuel injector cup  42  may include a chamfer  58  that is proximate the end  44 . A range of the included angle  58   a  for the chamfer  58  with respect to the axis  12  is preferably 20° to 60°. A most preferred included angle  58   a  is approximately 40°. Such a chamfer  58  can facilitate the insertion of the fuel injector  20  into the fuel injector cup  42  by receiving and guiding the compliant seal  34  into sealing engagement with a non-chamfered portion  60  of the inner surface  48 . In particular, the chamfer  58  provides gradual compression of the compliant seal  34 . 
     The fastener  70  includes a first portion  72  that engages the second exterior groove  32  on the body  22  of the fuel injector  20 . The first portion  72  includes a plurality of projections  74   a,   74   b  (two are shown) that resiliently engage the second exterior groove  32 . Preferably, the projections  74   a,   74   b  include a pair of opposing projections, i.e., they generally oppose one another with respect to the axis  12 . 
     The fastener  70  also includes a second portion  76  that engages the shoulder  52  on the outer surface  50  of the fuel injector cup  42 . As such, the second portion  76  and the shoulder  52  cooperatively retain along an axis  12  the fuel injector  20  relative to the fuel injector cup  42 . Preferably, a pair of second portions  76   a,   76   b  respectively engage a pair of shoulders  52   a,   52   b,  which are located on opposite sides of the axis  12 . 
     The fastener  70  also includes a recess  78  that receives the protrusion  54 , which can define the shoulder  52 , when the second portion  76  engages the shoulder  52  on the outer surface  50  of the fuel injector cup  42 . Preferably, a pair of recesses  78   a,   78   b  respectively engage the pair of shoulders  52   a,   52   b,  which are located on opposite sides of the axis  12 . 
     The fastener  70  can also include a third portion  80  that engages the fuel injector  20  so as to prevent relative rotation about the axis  12  between the fastener  70  and the fuel injector  20 . 
     The fastener  70  also includes a fourth portion  82  that engages the fuel injector cup  42  so as to prevent relative rotation about the axis  12  between the fastener  70  and the fuel injector cup  42 . Preferably, the fourth portion  82  includes pairs of fingers  84   a,   84   b  that engage the opposing sides  56   a,   56   b  of the protrusion  54 . 
     The first portion  72  of the fastener  70  is spaced from the second portion  76  such that a first axial measurement  86  (taken parallel to the axis  12 ) between the first portion  72  and the compliant seal  34  exceeds a second axial measurement  88  (also taken parallel to the axis  12 ) between the end  44  of the fuel injector cup  42  and the shoulder  52  on the outer surface  50  of the fuel injector cup  42 . 
     According to a preferred embodiment, the first axial measurement  86  exceeds the second axial measurement  88  such that the compliant seal  34  initiates contiguously engagement with the inner surface  48  of the fuel injector cup  42  before the second portion  76  engages the shoulder  52  on the outer surface  50  of the fuel injector cup  42 . And according to a more preferred embodiment, the first axial measurement  86  exceeds the second axial measurement  88  such that the compliant seal  34  is sealingly engaged with the inner surface  48  of the fuel injector cup  42  before the second portion  76  engages the shoulder  52  on the outer surface  50  of the fuel injector cup  42 . 
     A method of securing the fuel injector  20  with respect to a fuel rail  40  in accordance with the present invention will now be described. The compliant seal  34 , e.g., an O-ring, is installed in the first exterior groove  30  on the body  22  of the fuel injector  20 . And the fastener  70 , e.g., a clip, is coupled with respect to the fuel injector  20 , e.g., the first portion  72  of the fastener  70  is inserted into the second exterior groove  32  on the body  22  of the fuel injector  20 . 
     Next, the fuel injector  20  is displaced along the axis  12  such that the compliant seal  34  establishes a fuel tight seal between the body  22  of the fuel injector  20  and the inner surface  48  of the fuel injector cup  42 . Moreover, this fuel tight seal is achieved prior to the fastener  70  being coupled to the fuel rail  40 , i.e., before the second portion  76  of the fastener  70  engages the shoulder  52  on the outer surface  50  of the fuel injector cup  42 . 
     According to a preferred embodiment, there are three stages of displacing along the axis  12  of the fuel injector  20  with respect to the fuel injector cup  42 . First, the fuel injector  20  with the compliant seal  34  and the fastener  70  are displaced along the axis  12  to a first position relative to the fuel rail  40 . The initial contact of the compliant seal  34  with both the body  22  of the fuel injector  20  and the inner surface  48  of the fuel injector cup  42  occurs in the first position. Second, the fuel injector  20  with the compliant seal  34  and the fastener  70  are further displaced along the axis  12  to a second position that is between the first position and the fuel rail  40 . Compression of the compliant seal  34  between the body  22  of the fuel injector  20  and the inner surface  48  of the fuel injector cup  42  begins at the second position. And third, the fuel injector  20  with the compliant seal  34  and the fastener  70  are further displaced along the axis  12  to a third position that is between the second position and the fuel rail  40 . The fastener  70  is coupled to the fuel injector cup  42 , i.e., the second portion  76  engages the shoulder  52 , at the third position. 
     Accordingly, this separates the forces associated with compressing the compliant seal  34  from the forces associated with fastening the fuel injector  20  to the fuel rail  40 . Preferably, the compliant seal  34  is compressed past the chamfer  48  of the inner surface  48  of the fuel injector cup  42  before the second portion  76  of the fastener  70  makes contact with the protrusion  54  on the outer surface  50  of the fuel injector cup  42 . Thus, the present invention ensures that the compliant seal provides a fuel tight seal between the fuel injector  20  and the fuel rail  40 , and ensures the proper connection between the fuel injector  20  and the fuel rail  40 . 
     According to the present invention it is also possible to establish a particular angularly orient about the axis  12  of the fuel injector  20  with respect to the fuel rail  40 . In particular, the third portion  80  of the fastener  70  can cooperatively engage the tab  36  that extends from the body  22  of the fuel injector  20  so as to prevent relative rotation about the axis  12  between the fastener  70  and the fuel injector  20 . Similarly, the pairs of fingers  84   a,   84   b  of the fourth portion  82  of the fastener  70  can cooperatively engage the opposing sides  56   a,   56   b  of the protrusion  54  so as to prevent relative rotation about the axis  12  between the fastener  70  and the fuel injector cup  42 . Thus, the present invention can also ensure the relative orientation of the fuel injector  20  with respect to the fuel rail  40 . 
     While the present invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.