Abstract:
A fuel tank filler assembly includes a filler neck configured to receive a fuel supply nozzle. The filler neck includes a one-piece seamless funnel member having a tubular body configured to swirl supplied fuel and reduce vapor escape. The tubular body includes integrally formed threads for receiving a gas cap. The funnel member defines in off-set axial relation a relatively large inlet opening adapted for attachment to a receptor for the nozzle and a relatively small necked down outlet opening adapted for attachment to the inlet of a filler tube. The filler tube is in communication with the fuel tank. A method for manufacturing the fuel tank filler neck is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 10/615,485 filed on Jul. 8, 2003; which is a continuation of U.S. patent application Ser. No. 09/998,113 filed on Nov. 30, 2001 (now U.S. Pat. No. 6,588,459); which is a continuation-in-part of U.S. patent application Ser. No. 09/454,103 filed on Dec. 3,1999 (now U.S. Pat. No. 6,330,893). The disclosures of the above applications are incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a fuel tank filler neck connected to a gas tank of an automobile and, in particular, to a seamless fuel tank filler neck with integral threads.  
         BACKGROUND OF THE INVENTION  
         [0003]    Gas tank fuel systems providing reduced gasoline vapor loss are becoming increasingly important in the automobile industry to reduce needless loss of fuel. The typical solution to this problem has been to reduce the diameter of at least a section of the fuel tank filler neck. Though this approach has been somewhat successful, it is limited because as the diameter of the filler neck is decreased, the resistance to flow of the gasoline is increased. The increased resistance causes the fill neck to release any pressure buildup, thereby causing the fuel nozzle to shut off before the fuel tank is full. Another design issue is the permeability of the materials from which the fuel tank system is made. Fuel vapors may diffuse through fuel tank system components fabricated from various types of mild steels. Further, such fuel vapor diffusion increases as the mild steel components corrode over time.  
           [0004]    Another disadvantage of current filler neck design is the method by which the inlet of the filler neck is flared in order to provide a sufficient diameter to accept the gas nozzle during refueling. Typically, current filler necks are made by a process of repeated reductions and expansions of a seamed welded tube. Thus, through this mechanical process, there is an increasing tendency for the weld to leak as the tube is structurally weakened and thinner diameter tubes are used. Further, many filler necks require a retainer to be fitted to the inlet end in order to provide a sealing surface and an engageable thread for a gas cap.  
         SUMMARY OF THE INVENTION  
         [0005]    The filler neck for receiving a fuel supply nozzle for a motor vehicle fuel tank includes a one-piece seamless funnel member having an integrally formed sealing surface and integrally formed threads for receiving a gas cap. The funnel member defines in off-set axial relation a relatively large inlet opening supply nozzle and a relatively small necked down outlet opening. The offset relationship of the inlet and outlet opening and tube configuration of the transition therebetween induces a swirling motion in the fuel flow as the fuel proceeds towards the fuel tank. The resultant swirl motion of the flowing fuel leaves an opening through which any pressure buildup in the fuel tank may be vented. The spiraling motion of the fuel continues through the outlet opening and into the filler tube attached thereto, further limiting fuel vapors from escaping during refueling because of an induced suctioning effect or liquid seal that is created by the spiraling motion of the fuel through the relatively narrow passage from the funnel member to the fuel tank.  
           [0006]    The relatively larger diameter section forming the inlet opening is axially offset and spaced apart from the relatively smaller diameter tubular section forming the outlet opening. These integrally formed tubular sections are joined through a tapered section that transitions from the large diameter section to the small diameter section in a configuration designed to promote fuel swirl. For example, the tapered section may intersect the larger diameter section at an elliptically-shaped junction that lies in a plane inclined 60-85° from the axis of the tubular sections. Further, the funnel inlet opening may have a diameter D 1  and the tubular section may have a diameter D 2  with a coaxial offset at a distance X where 0.1 D 2  is less than X which is less than 0.3D 2 , and where D 1  is at least one and a half times D 2 .  
           [0007]    This invention also includes a method of manufacturing the filler neck for a motor vehicle fuel tank. Generally, the filler neck is formed by deep-drawing a seamless funnel member and integrally forming threads and a sealing surface. The funnel member includes an enlarged inlet at one end, and a relatively small outlet at the opposite end, wherein a portion of the funnel member is configured to induce a sufficient swirl to create a passage for suctioning fuel vapors to prevent escape during refueling and to provide a vent passage for any pressure buildup in the fuel tank. A length of butt-seam tubing is cut to form a filler tube of desired length. An end of the filler tube is telescopically aligned with the outlet of the funnel member to securely join the funnel and filler tube together. The filler tube is bent to a desired shape. Further, the configuration may be leak tested to verify the integrity of joining the funnel member to the filler tube and the attachment of a nozzle receptor, if any, to the funnel member, and the integrity of the butt-seam joint and the filler tube subsequent to bending. The funnel member may be attached to the filler tube by braising, adhesive bonding, or welding. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]    [0008]FIG. 1 is a schematic view of a fuel tank filler neck with integral threads incorporated in an automobile fuel tank system according to the present invention;  
         [0009]    [0009]FIG. 2 is a partially sectioned side view of the fuel tank filler neck of FIG. 1 in the fuel tank system;  
         [0010]    [0010]FIG. 3 is a schematic dimensional view of the filler neck as a funnel member according to the present invention;  
         [0011]    [0011]FIG. 4 is a cross sectional view of the fuel tank filler neck according to the present invention with a gas cap engaged thereby;  
         [0012]    [0012]FIG. 5 is a cross sectional view of a fuel tank filler neck with a barbed end according to the present invention;  
         [0013]    [0013]FIG. 6 is a cross sectional view of a fuel tank filler neck with a hose bead according to the present invention;  
         [0014]    [0014]FIGS. 7 a - 7   i  are schematic illustrations of the method for making a fuel tank filler neck according to the present invention;  
         [0015]    [0015]FIG. 8 is a schematic view of a method of forming threads in the fuel tank filler neck according to the present invention; and  
         [0016]    [0016]FIG. 9 is a schematic view of another method of forming threads in the fuel tank filler neck according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Reference will now be made in detail to presently preferred compositions or embodiments and methods of the invention, which constitute the best modes of practicing the invention presently known to the inventors.  
         [0018]    With reference to the drawings, a schematic of an embodiment of a filler neck  2  incorporated into an automobile fuel tank system  4  is provided. The fuel tank system  4  generally includes a filler neck  2 , a filler tube  24 , a fuel tank  28 , and a gas cap  14 , and is supported by an automobile body  16 , which includes a movable cover  20  to conceal the gas cap  14 .  
         [0019]    The filler neck  2  generally includes a one-piece, seamless funnel member  8  having a tubular body. The filler neck  2  may receive a nozzle receptor  12 , which is an insert adapted to receive a fuel nozzle  6  during fueling. Similar filler necks are disclosed in U.S. Pat. Nos. 6,330,893 and 6,588,454, both assigned to Shelby Enterprises Inc., and expressly incorporated herein by reference.  
         [0020]    One-piece, seamless funnel member  8  may be made of a number of types of metals. Suitable materials include, but are not limited to, cold-rolled steel, zinc nickel, plated steel, zinc-galvanized plated steel,  300  series stainless steels such as 304 stainless steel, 400 series stainless steels such as 409 stainless steel, terne plated steel, tin plated steel, nickel plated steel, galvaneal, and aluminum. Funnel member  8  may also be made from injection molded plastics including, but not limited to, acetal glass composites, nylon glass composites, liquid crystal polymer glass composites, polyethylene, polyethylene glass composites, polypropylene, and polypropylene glass composites. The funnel member  8  may also include an anti-corrosive coating.  
         [0021]    With reference to FIGS. 1 and 2, the funnel member  8  is defined at one end by an inlet opening  10  adapted to receive the gas cap  14 , which screws directly into threads  36  integrally formed in the funnel member  8 . The threads  36  may be screw, quarter-turn, eighth-turn or quick-turn configurations, or another known thread configuration.  
         [0022]    An opposite end of the funnel member  8  is defined by an outlet opening  22 , which is coupled to a first end  34  of the filler tube  24  via a brazed joint  42 . At a second end  32 , the filler tube  24  is coupled to the fuel tank  28  to provide fluid communication with the funnel member  8 . The gas cap  14 , which seats against a rolled-over sealing surface  70  formed about the inlet opening  10 , may include a seal  72  to prevent fuel or vapor loss between the gas cap  14  and the funnel member  8 .  
         [0023]    The fuel tank system  4  may also include a vent tube  26 , which connects to the funnel member  8  at funnel vent opening  30  and to the fuel tank  28  at fuel tank opening  40 . Vent opening  30  may either be pierced in the funnel member  8  after it is drawn or it may be incorporated in the sheet stock before the funnel member  8  is drawn. The vent tube  26  allows displaced vapors in the fuel tank  28  to be vented during fueling. The vent tube  26  may be replaced by a system that recirculates the fuel vapor. Such systems are known to individuals skilled in the art.  
         [0024]    During fueling, the gas cap  14  is removed and the fuel nozzle  6  is inserted through the inlet opening  10 . Fuel flows from the fuel nozzle  6  and through the funnel member  8 , the configuration of which induces a swirling motion to the fuel as the fuel flows towards the filler tube  24  and fills the fuel tank  28 . More specifically, the offset axial relationship of the inlet opening  10  and the outlet opening  22  causes supplied fuel to impinge sidewall  74  of the funnel member  8 , whereby fuel spirals as it flows toward the filler tube  24 . The swirling motion of the fuel created by the funnel member  8  causes a suctioning effect or liquid seal that prevents fuel vapors from escaping into the atmosphere during refueling. The swirling motion of the fuel also creates a central void that allows any pressure buildups created during refueling to vent, thereby preventing premature shutoff of the fuel nozzle  6 .  
         [0025]    With reference to FIG. 3, a relatively larger diameter section  46  forming the inlet opening  10  is arranged about an axis  48  and spaced-apart axially offset therefrom is a relatively smaller diameter tubular section  50  arranged about an axis  52  forming the outlet opening  22 . As shown, the axis  48  and axis  52  are parallel, but can be positioned divergently. The larger diameter section  46  and the smaller diameter tubular section  50  are connected to one another by a tapered section  54  that transitions from the larger diameter section  46  to the smaller diameter tubular section  50 . The tapered section  54  intersects the larger diameter section  46  at an elliptically shaped junction  56  that lies in a plane inclined at angle A, which is 60-85° from the axis of the tubular sections  46 ,  50 . The inlet opening  10  may have a diameter D 1  of approximately 60 mm and the tubular section may have a diameter D 2  of approximately 25 mm with a coaxial offset at a distance X of approximately 15 mm. The relationship of the inlet opening  10  and the outlet opening  22  and the configuration of the tapered section  54  cause the fuel to swirl during fuel filling.  
         [0026]    With reference to FIG. 4, a view of the filler neck  2  with the gas cap  14  screwed in is illustrated. The inlet opening  10  is defined in part by the rolled-over sealing surface  70  of the filler neck  2 , which provides a sealing surface against which the gas cap  14  seals when threaded into the threads  36 . The seal  72  may be positioned between the gas cap  14  and the sealing surface  70 , or made part of the gas cap  14 . For this arrangement, the nozzle receptor  12  includes a body  76  defining an opening  78  and seats within the filler neck  2  to receive and position the fuel nozzle  6 . As shown, the nozzle receptor  12  is held in position by crimps  60 ,  62  projecting against indentations  64 ,  68  to secure the nozzle receptor  12  in the filler neck  2 .  
         [0027]    With reference to FIG. 5, the filler neck  2  includes barbs  76 ,  78 ,  80  formed in smaller diameter tubular section  50 , thereby facilitating connection to the filler tube  24 . With reference to FIG. 6, the filler neck  2  includes a hose bead  58  formed in smaller diameter tubular section  50 , similarly facilitating connection to the filler tube  24 , particularly one made of plastic or rubber.  
         [0028]    The fuel tank filler neck of this invention may be made by a number of processes which include eyelet/progressive stamping, eyelet stamping, progressive die stamping, transfer die stamping, and hydroforming. If the fuel tank filler neck is made of plastics, injection molding and compression molding are suitable methods for manufacturing the fuel tank filler neck.  
         [0029]    The method of manufacturing the filler neck  2  will now be described with reference to the drawings. The filler neck  2  for motor vehicle fuel tank system  4  is formed by deep-drawing a seamless funnel member  8  having a relatively larger inlet opening  10  at one end and a relatively smaller outlet opening  22  at an opposite end. A portion of the filler neck  2  is configured to induce a sufficient swirl to create a hollow passage for suctioning fuel vapors into the fuel tank  28  and to allow venting of any pressure buildup in the fuel tank  28  during fueling. A length of butt-seam tubing is cut to form the filler tube  24  of desired length. An end of the filler tube  24  is aligned with the outlet opening  22  of the funnel member  8  and joins the funnel member  8  and the filler tube  24  together. The filler tube  24  is bent to a desired shape and the nozzle receptor  12  is attached to the funnel member  8  adjacent funnel inlet opening  10 . The configuration may be leak tested to verify the integrity of joining the funnel member  8  to tubular member  24  and the attachment of nozzle receptor  12  to the funnel member  8 , and the integrity of the butt-seam joint  42  and the tubular member  24 . The funnel member  8  is attached to the tubular member  24  by braising, adhesive bonding, or welding.  
         [0030]    With reference to FIGS. 7 a - 7   i , schematic illustrations of the method for making the filler neck  2  and attaching the filler tube  24  are provided. In FIG. 7 a,  sheet stock is formed into a circular blank that is drawn into a funnel shape in FIG. 7 b . The drawing method may include several dies in which the funnel is progressively formed into the desired funnel shaped. The ends of the funnel shape are trimmed in FIG. 7 c  to remove excess stock and thereby form the funnel member  8 . In FIG. 7 d,  pipe stock is cut to desired length to form the filler tube  24 , which is then at the ends in FIG. 7 e  in order to provide an attachment mechanism to the funnel member  8 . The filler tube  24  and the funnel member  8  are aligned in FIG. 7 f  and brazed or welded together in FIG. 7 g . The funnel member  8  and the filler tube  24  assembly is bent in FIG. 7 h . The threads  36  are formed into the funnel member in FIG. 7 i.    
         [0031]    With reference to FIG. 8, a method of forming the threads  36  in the funnel member  8  is provided. The threads  36  are made by a forming tool  90  including wheels  92 ,  94 , which in combination are of appropriate shape to form the threads  36  in the sidewall  38  of the funnel member  8 . The wheels  92 ,  94 , which are mounted on shafts  96 ,  98 , spin in directions A, B as they press on the sidewall  38  to form the threads  36 . This spinning allows forming tool  90  to form the periphery of the funnel member  8  about the inlet opening  10 .  
         [0032]    With reference to FIG. 9, another method of forming threads in the funnel member  8  is provided. The threads  36  are made by a crimping tool  100 , which includes crimping halves  102 ,  104 . The sidewall  38  is placed between crimping halves  102 ,  104 , which are pressed together in directions A, B to form the threads  36 . This process is repeated along the sidewall  38  until the threads  36  are completely formed in the funnel member  8  about the inlet opening  10 .  
         [0033]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.