Abstract:
An apparatus for recirculating fuel vapors in a vehicle. The apparatus includes a filler head connected to a fuel vapor conduit and a tubular aspirator located within the filler head. The aspirator has at least one orifice in its side wall so that when fuel flows through the aspirator when the vehicle is refueled, a low pressure area that draws fuel vapors through the orifice and into the fuel flow within the aspirator is created.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Ser. No. 61/577,158, filed Dec. 19, 2011. 
     
    
     FIELD 
       [0002]    The present disclosure relates to an apparatus for vehicle fuel systems and, more particularly to, an apparatus that recirculates fuel vapors within the fuel system. 
       BACKGROUND 
       [0003]    Vehicle fuel systems are required to prevent fuel vapors created in the vehicle&#39;s fuel tank from releasing into the atmosphere when the vehicle is refueled. To reduce the fuel vapors in the tank, and thereby reduce the amount of fuel vapors that are released into the atmosphere, some vehicles contains carbon canisters that collect and store the fuel vapors until the vapors can be drawn into the engine and burned off during combustion. The carbon canisters need to be sized appropriately to be able to store the necessary amount of fuel vapors. Carbon canister sizing in hybrid vehicles presents a particular problem because, under some driving conditions, there will be no combustion that can burn off the vapors from the carbon canister. As a result, hybrid vehicles may have large carbon canisters. Because space is a premium in most vehicle types, reduction in the size of the carbon canister is desired. Furthermore, the reduction in the size of the carbon canister reduces costs, which is also desired. 
         [0004]    To reduce the size of the canisters, some vehicles recirculate the fuel vapors so that they mix with the incoming fuel and enter the fuel tank. However, these recirculation systems typically have large variances in the amount of fuel vapor that is recirculated. As a result, the size of the canister may only be minimally reduced. Furthermore, many of the recirculation systems may cause spit-back or fuel spray and release fuel vapors into the atmosphere during the refueling process. Thus, there is a need for a recirculation system that increases fuel vapor recirculation, reduces the variation of the amount of fuel vapor recirculated, and reduces spit-back, fuel-spray, and the release of fuel vapors during the refueling process. 
       SUMMARY 
       [0005]    The present disclosure provides an apparatus for recirculating fuel vapors. The apparatus includes a fuel vapor conduit, a filler head connected to the fuel vapor conduit, and a hallow tubular aspirator open at both ends and located within the filler head. The aspirator has at least one orifice in its side wall so that a fuel flow through the aspirator draws the fuel vapors through the at least one orifice and into the fuel flow within the aspirator. 
         [0006]    In one embodiment, the aspirator may be movably located within the filler head and may be connected to the filler head by a guide rod. The guide rod may have a corresponding guide spring that applies a force to the aspirator. The aspirator may have a lip at one end that is connected to the guide rod and the corresponding guide spring. In another embodiment, the aspirator may be connected to the filler head by three guide rods and the aspirator may have more than four orifices. 
         [0007]    In use, the aspirator may mate with a nozzle that dispenses fuel and may have an inner diameter that is larger than an inner diameter of the nozzle. Furthermore, the fuel flow from the nozzle into the aspirator may create a low pressure area in the aspirator that draws the fuel vapors through the orifice and into the fuel flow within the aspirator. 
         [0008]    The apparatus may further include an aspirator guide within the filler head with an opening aligned with the aspirator. In use, the nozzle may pass through the aspirator guide before mating with the aspirator. 
         [0009]    In another embodiment, the present disclosure provides an apparatus for recirculating fuel vapors from a fuel tank. The apparatus includes a fuel conduit connected to the fuel tank, a fuel vapor conduit connected to the fuel tank, and a filler head having a first end and a second end, the filler head being connected to the fuel conduit and the fuel vapor conduit. The filler head is designed to accept a nozzle that dispenses fuel at the first end. The apparatus further includes a hallow tubular aspirator open at both ends and located within the filler head. The aspirator has a first end proximate the first end of the filler head and one orifice passing completely through a side wall of the aspirator near the aspirator first end to connect an internal portion of the aspirator to an internal portion of the filler head. 
         [0010]    In one embodiment, the aspirator may be movably connected to the filler head. In another embodiment, the aspirator may be connected to the filler head by at least one guide rod with a corresponding guide spring. In use, the aspirator may contact a nozzle that dispenses fuel. Furthermore, in use, the aspirator may move between the first and second ends of the filler head to maintain contact with the nozzle. 
         [0011]    In another embodiment, fuel dispensed into the first end of the filler head may pass through the aspirator. The fuel passing through the aspirator may create a low pressure area near the first end of the aspirator that may draw the fuel vapors from the fuel tank through the at least one orifice and into the fuel passing through the aspirator. 
         [0012]    Further areas of applicability of the present disclosure will become apparent from the detailed description, drawings, and claims provided hereinafter. It should be understood that the detailed description, including disclosed embodiments and drawings, are merely exemplary in nature, intended for purposes of illustration only, and are not intended to limit the scope of the invention, its application, or use. Thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  illustrates a diagram of a fuel system according to an exemplary embodiment. 
           [0014]      FIG. 2  illustrates a portion of the fuel system of  FIG. 1  according to an exemplary embodiment. 
           [0015]      FIG. 3   a  illustrates a cross-section of a filler head according to an exemplary embodiment. 
           [0016]      FIG. 3   b  illustrates another cross-section of a filler head according to an exemplary embodiment. 
           [0017]      FIG. 4  illustrates another cross-section of a filler head according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  illustrates a diagram of a vehicle&#39;s fuel system  100  according to an exemplary embodiment. The fuel system  100  includes a fuel tank  110 , fuel conduit  120 , fuel vapor conduit  130 , and filler head  140 . The fuel tank  110  stores fuel for the vehicle and is connected to filler head  140  by way of the fuel conduit  120  and the fuel vapor conduit  130 . The filler head  140  provides access to the fuel system  100  and interacts with a fuel pump nozzle  102 . In use, the filler head  140  mates with the fuel pump nozzle  102  and fuel flows from the nozzle  102  into the filler head  140  through the fuel conduit  120  and into the fuel tank  110 . Fuel vapors from the fuel tank  110  pass through the fuel vapor conduit  130  into the filler head  140  and are introduced into and become a part of the incoming liquid fuel flow and are sent back into the fuel tank  110  as liquid fuel. In this manner, the fuel system  100  recirculates fuel vapor from the fuel tank  110 . 
         [0019]      FIG. 2  illustrates details of the filler head  140  according to an exemplary embodiment. The filler head  140  includes a fuel cap retainer  242 ; an aspirator guide  244 ; aspirator  250 ; guide rods  290 ,  292 ,  294 ; guide springs  291 ,  293 ,  295 ; and a fuel tube  298 . The filler head  140  has a hallow cylindrical body  245 , fuel introduction end  241 , and fuel exit end  243 . The fuel introduction end  241  accepts the fuel pump nozzle  102 . The fuel exit end  243  has a frusto-conical shape and connects to the fuel conduit  120 . The fuel vapor conduit  130  connects to the body  245 . 
         [0020]    The fuel cap retainer  242  sits a top the fuel introduction end  241  of the filler head  140  and extends partially into the body  245 . The aspirator  250  resides within the body  245  of the filler head  140  and is movably connected to the filler head  140  by way of the guide rods  290 ,  292 ,  294  and corresponding guide springs  291 ,  293 ,  295 . The fuel tube  298  is connected to the aspirator  250  and extends through the body  245  and into the fuel exit end  243  of the filler head  140 . The aspirator guide  244  resides within the filler head  140  between the aspirator  250  and the fuel cap retainer  242 . In use, the nozzle  102  extends through the fuel cap retainer  242  and aspirator guide  244  and mates with the aspirator  250 . Fuel dispensed from the nozzle  102  flows through the aspirator  250  into the fuel tube  298  and then into the fuel conduit  120 . In another embodiment, the filler head  140  may include a doughnut shaped nozzle seal that rests on the aspirator guide  244  within the fuel cap retainer  242 . The nozzle seal may help to increase the efficiency of the fuel system  100  as it recirculates fuel vapor from the fuel tank  110 . 
         [0021]      FIGS. 3   a  and  3   b  illustrate cross-sections of the filler head  140  according to an exemplary embodiment. As illustrated in  FIG. 3   a , the fuel cap retainer  242  is attached to a top portion of the body  245  of the filler head  110 . The aspirator guide  244  mates with the fuel cap retainer  242  and creates a seal along the body  245 . The aspirator guide  244  has an opening  348  that extends through the aspirator guide  244 . A central axis of the opening  348  is offset from the central axis of the filler head  140 . In another embodiment, the central axis of the opening  348  may be aligned with the central axis of the filler head  140 . 
         [0022]    The aspirator  250  includes a hallow shaft  362  with a lip  352  at a first end  360  of the shaft  362  near the aspirator guide  244  that extends away from the shaft  362  out to the body  245  of the filler head  140 . A central axis of the hallow shaft  362  aligns with the central axis of the opening  348 . The lip  352  is offset from the aspirator guide  244  by guide pieces  346  that contact a top surface  354  of the lip  352 . The guide pieces  346  slope from an outer portion  347  of the opening  348  toward the shaft  362  but do not extend to the edge  363  of the shaft  362 , thereby creating a ledge  364  between the edge  363  and the guide pieces  346 . 
         [0023]    The guide rod  290  connects to the aspirator guide  244  and the body  245  and extends through an opening in the lip  352  of the aspirator  250 . The guide spring  291  extends between the bottom of the guide rod  290  and a bottom surface  353  of the lip  352  and applies a force to the aspirator  250  in the direction of arrow  389 . Guide rods  292 ,  294  ( FIG. 2 ) and guide springs  293 ,  295  ( FIG. 2 ) connect to the aspirator guide  244 , body  245 , and aspirator  250  in a similar manner. The guide rods  290 ,  292 ,  294  are evenly spaced around the inner periphery of the filler head  140  and operate to allow aspirator  250  to move along the guide rods  290 ,  292 ,  294  within the filler head  140 . When no outside force is applied to the aspirator  250 , the guide springs  291 ,  293 ,  295  position the aspirator  250  next to the aspirator guide  244 . 
         [0024]    In another embodiment, four guide rods  290  may be used to movably connect the aspirator  250  within the filler head  140  and may be unevenly spaced around the periphery of the filler head  140 . In yet another embodiment, two guide rods  290  may be used to movably connect the aspirator  250  within the filler head  140  and may be evenly spaced around the periphery of the filler head  140 . In yet another embodiment, hydraulics may be used to movably connect the aspirator  250  within the filler head  140 . It should be understood that any means of movably connecting the aspirator  250  to and within the filler head  140  may be implemented without departing from the scope of the invention. 
         [0025]    As illustrated in  FIG. 3   b , the shaft  362  of the aspirator  250  extends away from the lip  352  and the aspirator guide  244 . The second end  361  of the shaft  362  is connected to the fuel tube  298 . The first end  360  of the shaft  362  has six orifices  356  with inner openings in the inner portion of the shaft  362  just below the edge  363 . The orifices  356  extend through the wall  365  of the shaft  362  at an angle and have outer openings on the outer portion of the shaft  362  below the lip  352  of the aspirator  250 . The orifices  356  connect the internal space  349  of the filler head  140  with the inside portion of the shaft  362 . The orifices  356  are cylindrical, have a diameter between about 1 and about 5 mm, and are evenly spaced around the periphery of the shaft  362 . In another embodiment, the orifices  356  may be rectangular, oval, hexagonal, or any other shape and may be unevenly spaced around the periphery of the shaft  362 . In yet another embodiment, the aspirator  250  may have more or less than six orifices  356 , and each orifice  356  may have a varying shape and diameter. 
         [0026]    Referring to  FIGS. 1-3   b , in use, the fuel pump nozzle  102  extends through the guide opening  348  and contacts the ledge  364  of the aspirator  250 . If the nozzle  102  is not in contact with the ledge  364  during the fueling process (when the nozzle  102  is dispensing fuel into the filler head  140 ) spit-back, fuel spray, and the release of fuel vapors into the atmosphere may occur. To avoid these negatives events, the guide rods  290 ,  292 ,  294  and corresponding guide springs  291 ,  293 ,  295  operate to ensure that fuel pump nozzles  102  of varying lengths contact the ledge  364  of the aspirator  250  when inserted into the filler head  140 . The guide rods  290 ,  292 ,  294  and corresponding guide springs  291 ,  293 ,  295  also operate to ensure that the fuel pump nozzle  102  inserted at varying depths within the filler head  140  contacts the ledge  364  of the aspirator  250 . 
         [0027]    For example, in one embodiment, a four inch long nozzle  102  inserted into the filler head  140  contacts the ledge  364  of the aspirator  250  and moves the aspirator  250  one-half of an inch along the guide rods  290 ,  292 ,  294  toward the fuel exit end  243  of the filler head  140 . In the same embodiment, a five inch long nozzle  102  inserted into the filler head  140  contacts the ledge  364  of the aspirator  250  and moves the aspirator  250  one and one-half inches along the guide rods  290 ,  292 ,  294  toward the fuel exit end  243  of the filler head  140 . If the aspirator  250  was not movably connected to the filler head  140 , the nozzle  102  would not have been in contact with the ledge  364  of the aspirator  250  in one or both of these instances. As a result, fuel spray, spit-back, and release of fuel vapors into the atmosphere would occur during the fueling process. Because the aspirator  250  is movably connected within the filler head  140 , however, nozzles  102  of varying length will contact the aspirator  250  when inserted into the filler head  140  and fuel spray, spit-back, and fuel vapor release is avoided during the fueling process. 
         [0028]      FIG. 4  illustrates a cross-sectional top view of the nozzle  102  mating with the aspirator  250  in accordance with an exemplary embodiment. The nozzle  102  is circular shaft that has an inner surface  404 , outer surface  405 , and thickness  408  between the inner and outer surfaces  404 ,  405 . The nozzle  102  has an inner diameter  406  smaller than an inner diameter  466  of the shaft  362  and an outer diameter  407  larger than the inner diameter  466  of the shaft  362 . As a result, an outer portion  410  of the end of the nozzle  102  contacts the ledge  364  of the aspirator  250  and an inner portion  409  extends past the edge  363  and partially covers the shaft  362 . The guide opening  348  and the guide pieces  346  position the nozzle  102  so that it mates with the ledge  364  as illustrate in  FIG. 4 . 
         [0029]    It is understood that nozzles that dispense fuel are designed so that the thickness and diameter of the nozzles have the same specifications with minimal variance. As a result, the aspirator  250  mates with most nozzles in the manner described above. It is further understood that nozzles for different types of fuel may have different specifications. For example, diesel fuel nozzles may have a different diameter than gasoline nozzles. The aspirator  250  may be sized for different vehicle types to account for any difference in nozzle diameter or thickness. It is further understood that the length of a nozzle is not controlled and varies from nozzle to nozzle. 
         [0030]    In use, the nozzle  102  dispenses fuel into the shaft  362 . As the fuel flows from the smaller diameter nozzle  102  to the larger diameter shaft  362 , a vacuum or low-pressure area is created at the junction of the nozzle  102  and the shaft  362  due to the Venturi effect. Specifically, the low-pressure area is created in the shaft  362  near the shaft&#39;s  362  edge  363  below the inner portion  409  of the nozzle  102  and near the inner openings of the orifices  356 . The low-pressure area inside the shaft  362  causes air to flow from the internal space  349  within the filler head  140  into the shaft  362  of the aspirator  250  through the orifices  356 . Because the fuel vapor conduit  130  is connected to the internal space  349  within the filler head  140 , the low pressure area inside the shaft  362  draws fuel vapor from the fuel tank  110  through the fuel vapor conduit  130  into the internal space  349  within the filler head  140  and through the orifices  356  into the shaft  362 . Once within the shaft  362 , the fuel vapors interact with the fuel flowing from the nozzle  102 , recondense, and are introduced back into the fuel tank  110 . 
         [0031]    Besides reducing spit-back, fuel spray, and fuel vapor release, the guide rods  290 ,  292 ,  294  and corresponding guide springs  291 ,  293 ,  295  also operate to ensure that the fuel pump nozzle  102  contacts the ledge  364  of the aspirator  250  when nozzles  102  of varying lengths are inserted into the filler head  140  so that a constant low pressure area is maintained within the aspirator  250 . Maintaining a constant low pressure area reduces the variation in the amount of fuel vapor recirculation. Furthermore, large amounts of fuel vapor may be recirculated using the fuel system  100  because the fuel vapor is continually drawn into the fuel flow by the low pressure area created within the aspirator  250 . As a result, the size of a vehicle&#39;s carbon canister may be reduced.