Abstract:
A fuel filler pipe having a trigger point formed between the fuel supply port and the fuel tank. The trigger point is a trough-like depression which, if there is a structural disruption of the vehicle, will facilitate a buckling mode in the pipe and consequent energy absorption. This configuration reduces or eliminates the amount of displacement of the fuel filler pipe into the fuel tank during such structural disruption of the vehicle.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to vehicle fuel systems. More specifically, the present invention relates to a fuel pipe having a trigger point which allows the fuel pipe to buckle if there is a structural disruption of the vehicle, thus reducing or entirely eliminating the amount of displacement of the fuel filler pipe into the fuel tank during the structural disruption. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the modern motor vehicle fuel is delivered to the fuel tank by a fuel filler pipe. The fuel filler pipe creates a fluid connection between the fuel supply port disposed within the fuel filler housing and the fuel tank. Fuel filler pipes are made of a metal or a synthetic resin. Those fuel filler pipes composed of metal are typically composed of stainless steel, aluminum, or steel. 
         [0003]    Fuel systems in motor vehicles, including the fuel filler pipe, must meet certain safety standards. In seeking to surpass known standards, motor vehicle manufacturers attempt to improve the integrity of their vehicle fuel system designs. One sought-after improvement has to do with the fuel filler pipe of the fuel system and how it reacts in the event of a structural disruption of the vehicle. Accordingly, as in so many areas of motor vehicle technology, there is room in the art of motor vehicle fuel systems for providing an alternative configuration to known fuel filler pipe designs. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention provides an alternative configuration for a fuel filler pipe which includes an area of reduced cross-section relative to the rest of the fuel filler pipe which defines a crumple area or a trigger point in the fuel filler pipe. The trigger point formed in an appropriate location facilitates a buckling mode in the pipe in the event that there is a structural disruption of the vehicle and consequent energy absorption. By providing the trigger point in an appropriate place in the fuel filler pipe, during such a disruption the amount of possible displacement or intrusion of the pipe into the fuel tank is reduced or eliminated. 
         [0005]    With the trigger point provided at an appropriate location on the fuel filler pipe with an appropriate geometry, an alternative construction of the current fuel filler pipe is provided. 
         [0006]    Other advantages and features of the invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    For a more complete understanding of this invention, reference should now be made to the embodiment illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention wherein: 
           [0008]      FIG. 1  shows an elevation view of a fuel filler pipe in relation to a fuel tank, partially broken away, according to the prior art; 
           [0009]      FIG. 2  shows an elevation view of a fuel filler pipe in relation to a fuel tank, partially broken away, according to the present invention; 
           [0010]      FIG. 3  shows a close-up view of the trigger point of the fuel pipe of the present invention; 
           [0011]      FIG. 4  is a cross section of the trigger point of the fuel filler pipe according to the present invention taken along lines  4 - 4  of  FIG. 3 ; and 
           [0012]      FIG. 5  shows the fuel filler pipe and fuel tank of  FIG. 2  after a structural disruption of the vehicle with the filler pipe in a buckled condition. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]    In the following figures, the same reference numerals will be used to refer to the same components. In the following description, various operating parameters and components are described for one constructed embodiment. These specific parameters and components are included as examples and are not meant to be limiting. 
         [0014]    With reference to  FIG. 1 , a fuel delivery assembly according to known technology, generally illustrated as  10 . The fuel delivery assembly  10  includes a fuel tank  12 , a fuel filler port  14 , and a fuel filler pipe  16  connected to a fuel tank inlet pipe  18 . An air vent tube  20  is provided in fluid relation to the fuel filler port  14 . As is known in the art, the fuel filler pipe  16  is of a constant diameter between the fuel filler port  14  and the fuel tank pipe  18 . 
         [0015]    With reference to  FIGS. 2 through 4 , a fuel delivery assembly according to the present invention, generally illustrated as  30 , is shown. The fuel delivery assembly  30  includes a fuel tank  32 , a fuel filler port  34 , and a fuel filler pipe  36  connected to a fuel tank inlet pipe  38 . In addition, an air vent tube  40  is provided in fluid relation to the fuel filler port  34  as is conventionally provided. 
         [0016]    The diameter of the fuel filler pipe  36  from its inlet end at the fuel filler port  34  to its outlet end at the fuel tank inlet pipe  38  is relatively constant with the exception of an area of reduced cross-section which defines a crumple area or a trigger point  42  which is located on a bend of the fuel filler pipe  36 . The trigger point  42  defines a trough-like depression and may be formed by any one of several known methods, including formation by a punch or by stamping. The thickness of the wall of the fuel filler pipe  36  at the trigger point  42  may be the same as the thickness of the other areas of the wall of the fuel filler pipe  36  or may be of reduced thickness to allow for more effective buckling if there is a structural disruption of the vehicle. 
         [0017]    The trigger point  42  is preferably formed at the bend of the fuel filler pipe  36  as illustrated to increase the tendency of this area to form a plastic hinge upon loading. 
         [0018]    Correct placement and geometry of the trigger point  42  relative to the fuel filler pipe  36  are factors that need to be carefully considered. As illustrated particularly in  FIG. 2 , the trigger point  42  is disposed at the bent area of the fuel filler pipe  36  that is formed roughly half-way between the fuel filler port  34  and the fuel tank inlet pipe  38 . According to such placement, if there is a structural disruption of the vehicle the trigger point  42  facilitates a buckling mode and consequently absorbs energy that would otherwise cause displacement or intrusion of the fuel tank inlet pipe  38  into the fuel tank  32 . 
         [0019]    While the trigger point  42  is illustrated as being at the approximate mid-point of the fuel filler pipe  36  between the fuel filler port  34  and the fuel tank inlet pipe  38 , the trigger point  42  may be formed at an alternative point on the fuel filler pipe  36  or there may be two or more trigger points fitted on the fuel filler pipe  36 . 
         [0020]    A cross-sectional view of the fuel filler pipe  36  at the trigger point  42  is illustrated in  FIG. 4 . A certain percentage of the circumference of the filler pipe  36  is encompassed by the trigger point  42 . As illustrated, about  20  percent of the circumference of the filler pipe  36  is encompassed by the trigger point  42 . However, it is to be understood that a greater or lesser percentage of the circumference of the filler pipe  36  may be encompassed by the trigger point  42  without deviating from the scope of the present invention. Preferably the trigger point  42  will encompass between about 10 and 30 percent of the circumference of the filler pipe  36 . In any event, it is preferable that the trigger point  42  not be axisymmetric to avoid the backflow of fuel which might otherwise result. 
         [0021]    The possible result of a structural disruption of the vehicle is illustrated in  FIG. 5  where the impact force has been transmitted to the trigger point  42  which has absorbed the energy from the impact force that caused the structural disruption of the vehicle and has allowed a slight angular deformation or buckling of the fuel filler pipe  36  at the trigger point  42 . Intrusion of the fuel tank inlet pipe  38  has thus been avoided and, in addition, no rupturing of the connection between the fuel tank inlet pipe  38  and the fuel tank  32  has occurred, virtually eliminating the possibility of fuel spillage. 
         [0022]    The foregoing discussion discloses and describes an exemplary embodiment of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.