Patent Publication Number: US-2005115636-A1

Title: Head for a fuel tank filler neck

Description:
The present invention relates to a head for a fuel tank filler tube of the kind fitted to motor vehicles driven by internal combustion engines.  
     BACKGROUND OF THE INVENTION  
      As a general rule, a head for a filler tube comprises a tubular body which defines a filler duct and which has one end for connection to the tube and an opposite end that forms a filler orifice to enable the nozzle of a fuel pump to be inserted into the filler duct.  
      During filling, it is necessary to remove fuel vapor, firstly to limit the amount that escapes into the atmosphere, and secondly to ensure that the vapor does not lead to pressure rising in the filler tube. Such an increase in pressure would run the risk of triggering the pump nozzle too soon, thereby stopping the delivery of fuel before the tank is, in fact, full.  
      A system for removing fuel vapor and delivering it to a unit for treating such vapor (known as a canister) is therefore associated with the tank. A pipe connects the tank to the canister. A first segment of the pipe extends parallel to the filler tube as far as a check valve device from which a second segment of the pipe goes to the canister. The check valve device is mounted on the head of the filler tube and the check valve is connected either to the hatch giving access to the filler orifice and for handling by the user, or else to a pivoting flap for closing the filler duct and designed to be pushed aside by the nozzle when it is inserted into the filler duct, so as to be moved from a closed position to an open position during filling.  
      Those systems present the drawback of being relatively heavy, bulky, complex with numerous parts, and expensive to manufacture.  
     BRIEF SUMMARY OF THE INVENTION  
      The invention provides a head for a fuel tank filler tube, the head comprising a tubular body having one end for connection to the tube and an opposite end forming a filler orifice enabling a fuel pump nozzle to be introduced into a first end of a filler duct which is defined by the body and which possesses an opposite, second end for opening out into the filler tube via the connection end of the body, the body incorporating a segment of fuel vapor removal duct arranged to communicate firstly with the outside of the body via a vent which is provided through a side wall of the body and which is associated with vent shutter means mounted in the body to be actuatable between a vent shutting position and a vent disengaging position and, secondly, at least during filling, with the filler tube at the connection end of the body.  
      Thus, the segment of removal duct associated with the filler tube head is incorporated in the body thereof and opens out into the filler tube which is also used as a segment of the duct for removing fuel vapor. The structure of the filler tube head is then particularly simple, compact, light in weight, and the number of parts used for removing vapor is small. Manufacturing costs and time (in particular assembly time) are relatively small.  
      In a particular embodiment, the vent shutter means comprises a shutter element connected to a bushing mounted in the body in the vicinity of the first end of the filler duct to be driven by the pump nozzle in sliding movement from a first position in which the shutter element closes the vent towards a second position in which the shutter element is disengaged from the vent.  
      The shutter means are thus actuated automatically during filling.  
      Preferably, the bushing comprises a first end portion mounted in the first end of the filler duct, and an opposite second end portion which projects from the first end of the filler duct and which is connected to the shutter element by an arm extending axially inside the body outside the filler duct.  
      The shutter means are thus simple in structure.  
      Advantageously, the first end portion of the bushing includes an end wall that is convex towards the inside of the bushing, and is provided in its side wall with at least one slot in the vicinity of said end wall for passing fuel and, preferably, the filler duct includes an enlarged segment extending facing the second end portion of the bushing when the bushing is in its second position.  
      This improves the flow of fuel.  
      According to a particular characteristic, the removal pipe is annular in shape and surrounds the filler duct.  
      The filler tube head is then particularly compact.  
      Other characteristics and advantages of the invention will appear on reading the following description of a particular, non-limiting embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Reference is made to the accompanying drawings, in which:  
       FIG. 1  is a diagrammatic exploded view in perspective of the filler tube head in accordance with the invention; and  
       FIG. 2  is a diagrammatic longitudinal section view of said filler tube head. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The invention as shown in the figures relates to a head given overall reference  1  for a filler tube  2  of a fuel tank (not shown). By way of example, the fuel tank belongs to a motor vehicle having the filler tube  2  disposed in its bodywork in such a manner that the head  1  opens to the outside of the bodywork. By way of example, the head  1  is mounted in a setback formed in the bodywork and closed by a hatch that is accessible from the outside.  
      The head  1  comprises a tubular body given overall reference  3 , being defined by a substantially cylindrical wall  4  having one end  5  bonded to the filler tube  2 , and an opposite end  6  on which there is mounted an annular sealing element  7  defining a filler orifice  8  associated with a filler cap  9 . The annular sealing element  7  is made of a flexible material and is intended to form an abutment against the fuel pump nozzle being pushed further into the body  3  through the filler orifice  8 , while nevertheless providing leaktight contact with the nozzle.  
      A sleeve  10  is mounted in the body  3  and defines a filler duct  11 . The sleeve  10  possesses an end  12  facing the filler orifice  8  to enable the pump nozzle to be inserted through the orifice into the filler duct  11 , and an opposite end  13  that opens out into the filler tube  2  at the end  5  of the body  3 .  
      The portion of the sleeve  10  that is adjacent to the end  13  co-operates with the wall  4  of the body  3  to define a segment of removal duct  14  for removing fuel vapor. The removal duct segment  14  is annular in shape and possesses a bottom portion  15  in communication with the filler tube  2  via the end  5  of the wall  4 , and a top portion  16  in communication with the outside of the body  3  via a vent  17  which is formed through the wall  4  thereof.  
      The end  13  of the sleeve  10  is provided on the outside with fins  18  projecting into the removal duct segment  14  to form means for condensing fuel vapor.  
      The body  3  has an overflow orifice  19  formed in the wall  4  near the end  5  thereof. The overflow orifice  19  is for connection to the tank via a pipe (not shown) returning to the tank.  
      The body  3  includes means given overall reference  20  for shutting the vent  17 , said means being mounted in the body  3  to be actuatable between a position for closing the vent  17  and a position for disengaging the vent  17 .  
      The shutter means  20  comprise a shutter element  21  connected to a bushing  22  which has an end portion  23  slidably mounted in the end  12  of the sleeve  10  opposite from an end portion  24  that projects from the end  12  of the sleeve  10 .  
      The end portion  23  of the bushing  22  includes an end wall  25  that is convex towards the inside of the bushing (in this case the end wall is conical in shape) and that is provided in its side wall with slots  26  in the vicinity of the end wall  25  to allow fuel to flow through.  
      The end portion  24  is connected to the shutter element  21  by an arm  27  extending axially in the body  3  between the wall  4  and the sleeve  10 . In this case, the shutter element  21  is formed by an outwardly-projecting stud at the free end of the arm  27  extending towards the wall  4 . The annular sealing element  7  is connected to the end portion  24  via the edge of the filler orifice  8 .  
      The bushing  22  is movable between a first position shown in  FIG. 2  in which the shutter element  21  closes the vent  17  and the slots  26  face a segment  28  of the sleeve  10  of inside diameter substantially equal to the outside diameter of the end portion  23 , and a second position in which the bushing is pushed in, and in which the shutter element  21  is disengaged from the vent  17  and the slots  26  look into an enlarged segment  29  of the sleeve  10 .  
      Resilient return means  30  urge the bushing  22  towards its first position, said means being interposed between a collar on the end portion  24  of the bushing  22  and the end  12  of the sleeve  10 . In this case, the means  30  are constituted by a helical compression spring.  
      In the normal position, while filling is not taking place, the bushing  22  is in its first position. Fuel vapor rising from the tank via the filler tube  2  condenses on making contact with the fins  18  and drops back in the form of droplets into the tank.  
      During filling, the fuel pump nozzle is inserted through the filler orifice  8  into the end portion  23  of the bushing  22  until a portion of the nozzle comes into abutment against the annular sealing element  7  and deforms it. The bushing  22  is then driven by the leading end of the nozzle to slide from its first position in which the shutter element  21  closes off the vent  17  towards its second position in which the shutter element  21  is disengaged from the vent  17 .  
      The fuel which flows from the pump nozzle is directed by the end wall  25  towards the slots  26  so as to spread out in the enlarged segment  29  prior to flowing into the tube  2 . It should be observed that the flow section for the fuel at the end  13  of the sleeve  10  is smaller than the section of the tube  2 .  
      Fuel vapor rises via the tube  2  towards the removal duct segment  14  and escapes via the vent  17  towards a canister (not shown). In order to improve the passage of vapor into the vent  17 , an opening  31  is provided in the arm  27 , which opening is designed to be level with the vent  17  when the bushing is in its second position.  
      If too much fuel is delivered before the nozzle triggers automatically, the excess fuel overflows towards the return pipe to the tank via the overflow orifice  19 .  
      After the pump nozzle has been withdrawn, the bushing  22  returns to its first position under drive from the resilient return means  30 . It should be observed that in this position the slots  26  are closed by the wall of the segment  28 .  
      Naturally, the invention is not limited to the embodiment described but also covers any embodiment and variant that reproduces the subject matter of the claims.  
      In particular, the wall  4  and the sleeve  10  may be made as a single piece; the means for actuating the shutter element to the cap  9 , to a pivoting shutter flap or to the access hatch to the filler head; the sleeve may have other forms.