Abstract:
Reducing fuel vapor within a vehicle fuel tank is accomplished by employing a flexible fuel sock attached to spud near the top surface of the fuel tank. The fuel sock resides within the fuel tank and retains liquid fuel during tank refueling so that the fuel is confined within the fuel sock until the fuel reaches the bottom of the fuel tank or the current level of fuel within the tank. The fuel conduit may be flexible and buoyant to accommodate any level of fuel in the tank and reduction of fuel refueling vapors. A check valve may be situated within the spud.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a flexible extension for a fuel tank inlet check valve proximate a fuel tank top wall.  
       BACKGROUND OF THE INVENTION  
       [0002]     Modern automotive vehicles typically have fuel tanks that are filled through a pipe at the top wall of the fuel tank. As liquid fuel passes through the top wall, the fuel may also pass through a check valve. The pipe and check valve permit liquid fuel to pass into and fill the fuel tank. However, the fuel is permitted to flow unrestrained from the check valve at the top of the fuel tank to the bottom of the fuel tank. Along this fuel path, fuel is able to atomize and generate fuel vapor. Additionally, fuel vapor is generated as the falling fuel meets the surface of the fuel already resident within the fuel tank. Fuel vapors generated during refueling of a vehicular fuel tank must be conditioned in a charcoal canister. Therefore, a reduction in fuel vapors generated during the filling of a fuel tank results in a reduction of fuel vapors that must be conditioned. Accordingly, a need exists for a device that efficiently manages liquid fuel flowing from a check valve, or top of a fuel tank, to the surface of the resident fuel within the fuel tank so that fuel vapor generation is minimized.  
       SUMMARY OF THE INVENTION  
       [0003]     An apparatus for reducing fuel vapor generated within a fuel tank during tank refueling includes a flexible fuel conduit that extends from a spud attached to the fuel tank at a fuel inlet of the fuel tank. The fuel conduit extends within the fuel tank from the spud to a location proximate a bottom of the fuel tank. The fuel conduit may be flexible and buoyant to accommodate any fuel level with the fuel tank during refueling. A check valve may be situated within the spud within the tank to permit fuel to flow only one-way.  
         [0004]     Further areas of applicability of the teachings of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0006]      FIG. 1  is a side view of a vehicle depicting a fuel system in phantom, including a fuel sock according to the present invention;  
         [0007]      FIG. 2  is a side view of a fuel tank depicting a general location of a fuel sock and various fuel system components;  
         [0008]      FIG. 3  is a side view of a fuel tank depicting a fuel sock engaging fuel within a fuel tank;  
         [0009]      FIG. 4  is a side view of a fuel tank depicting a fuel sock engaging fuel within a fuel tank;  
         [0010]      FIG. 5  is an enlarged view of the juncture of a fuel sock and a spud; and  
         [0011]      FIG. 6  is a side view of a prior art fuel tank depicting fuel vapors during refueling. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Referencing  FIGS. 1-5 , a fuel sock according to the present invention is depicted; however, before turning to the teachings of the present invention a review of a prior art fuel tank undergoing refueling will be explained with reference to  FIG. 6 .  
         [0013]      FIG. 6  is a side view of a prior art fuel tank depicting fuel vapors during fuel tank refueling. More specifically, a problem of the prior art fuel tank filling apparatus lies in delivering fuel within the tank which generally results in the generation of fuel vapors during refueling. A fuel tank  10  having a filler pipe  12  and a spud  14  permits liquid fuel to pass into the tank  10  from the top of the tank after the fuel passes through the filler pipe  12  and spud  14 . That is, after the fuel passes through the spud  14 , the fuel is permitted to fall into the fuel tank  10 .  
         [0014]     During fuel tank re-filling, fuel vapors  18  are generated as the fuel falls from the spud  14  toward the bottom of the fuel tank  10 . Additionally, as the falling fuel  16  strikes the fuel  20  resident on the bottom of the tank  10 , or strikes the bottom of the tank  10  itself, fuel vapors  22  are generated. The combination of the fuel vapors  18  generated during re-filling, results in vapors filling the area  24  of the fuel tank  10 . Because the area  24  fills with fuel vapors  18 ,  22 , the vapors must be managed by a vapor recovery system (not shown) to meet emission standards and to maintain acceptable pressure levels within the fuel tank  10 . The teachings of the present invention reduce the generation of such fuel vapors.  
         [0015]     Turning to  FIGS. 1-5 , the teachings of the present invention will be explained.  FIG. 1  depicts a vehicle  30  having an engine  31  that is supplied by a fuel line  32 . The fuel line  32  originates from the fuel tank  34 , which is supplied fuel from filler pipe  40 , an end of which resides in the fuel receptacle  36 . After fuel passes through the fuel filler pipe  40 , it passes into the fuel sock  48 , which may be a flexible, bag-like structure. Additionally, the fuel sock  48  may be semi-flexible, or rigid. The fuel sock  48  may reach to the bottom of the fuel tank  34 , or any position above the bottom of the fuel tank  34 . At any position above the bottom, or at the bottom, the fuel sock  48  will reduce fuel splattering, and thus fuel vapors generated, during refueling of the fuel tank  34 .  
         [0016]      FIG. 2  depicts the fuel tank  34  having a fuel filler pipe  40  with a fuel inlet  38 . The fuel inlet is normally resident in the fuel receptacle  36  ( FIG. 1 ). The fuel filler pipe  40  leads from the fuel receptacle  36  to the neck  42 . The neck  42  leads to a spud  44 , which has a narrow fuel inlet portion  45  that fits within a fuel tank inlet hole at the top of the fuel tank  34 . The narrow fuel inlet portion  45  may contain an inlet check valve  46 , which may be spring-biased to a normally closed position; however, in  FIG. 2  the inlet check valve  46  is shown in a partially open position. The inlet check valve  46  permits fuel to only flow into the fuel tank  34 . Connected to the narrow fuel inlet portion  45  of the spud  44  is a first end of a fuel sock  48 . The other, second end of the fuel sock, known as the free end  52 , is shown in a horizontal position in  FIG. 2 . The parts depicted from the fuel receptacle  36  to the free end  50  of the fuel sock  48  are involved in delivering fuel into the fuel tank  34 .  
         [0017]      FIG. 2  also depicts additional fuel vapor management equipment, which will now be explained in more detail in conjunction with the above teachings. When a user desires to refuel the fuel tank  34 , he or she places the refueling nozzle (not shown) into the fuel inlet  38 . When fuel is dispensed, it travels through the fuel filler pipe  40  and the neck  42  of the spud  44 . The liquid fuel then passes through an inlet check valve  46 , also known as an ICV, which is situated in a narrow portion of the spud  44 . After passing through the ICV  46 , the fuel continues to pass through a fuel sock  48 , which passes through the interior of the fuel tank  34 . Upon passing through the main portion of the fuel sock  48  in accordance with arrow  50 , the liquid fuel reaches the fuel sock aft end  52 , which is also the free end of the fuel sock  48 .  
         [0018]     In the arrangement depicted in  FIG. 2 , the liquid fuel will strike the interior bottom surface  56  of the fuel tank  34 . This will generally cause the generation of some fuel vapors; however, because the fuel sock  48  has its aft end  52  close to the interior bottom  56  of the fuel tank  34 , the fuel vapors are minimized. Although not depicted, to further minimize vapors, the fuel sock aft end  52 , may actually contact the interior bottom  56  of the fuel tank  34  as refueling commences. By arranging the fuel sock aft end  52  as close as possible to the interior bottom  56  of the fuel tank  34 , the fuel has as short of a distance as possible to drop to the fuel tank bottom  56 , thereby generating as few fuel vapors as possible. If the fuel sock aft end  52  is contacting the fuel tank interior bottom  56 , the fuel outlet  54  will permit the fuel to smoothly exit the fuel sock  48 . Generating as few fuel vapors as possible is advantageous because interior tank pressure is minimized and fewer fuel vapors must be processed by vehicular on-board vapor processing equipment.  
         [0019]     Since fuel vapors are generated regardless of whether fuel drops to the fuel tank bottom  56 , fuel vapor processing equipment  60  resides with the fuel tank  34  to manage any vapors. For instance, with continued reference to  FIG. 2 , fuel vapor processing system  60  may entail a multi-functional control valve  58 , a grade vent valve  61 , a charcoal canister  62 , and a fresh air canister  64 . In one configuration, the multi-functional control valve  58  and grade vent valve  61  are linked with a grade vent line  66 . An inlet vent line  69  returns gaseous vapor from the multi-functional control valve  58  to the vapor inlet  70  at the fuel filler pipe  40  fuel inlet  38 . Additionally, a vapor fuel line  32  delivers fuel vapor to an engine purge valve (not shown).  
         [0020]     Although some fuel vapor is delivered to an engine purge valve, the multi-functional control valve  58  also delivers fuel vapor to the charcoal canister  62  via a charcoal canister line  68 . To assist in cleansing the fuel vapor in the charcoal canister  62 , a fresh air filter  64  is linked to the charcoal canister  62  via a fresh air line  66 .  
         [0021]     When fuel vapor is generated in the fuel tank  34 , the fuel vapor enters either the grade vent valve  61  or multi-function control valve  58 . In the case of fuel vapor entering via the grade vent valve  61 , such vapor is forced by pressure through the grade vent line  66  toward the multi-functional control valve  58 . From the multi-functional control valve  58 , fuel vapors may be directed through the inlet vent line  69  and returned to the fuel filler pipe  40  via a vapor inlet  70 . Alternatively, or additionally, fuel vapors may be directed from the multi-functional control valve  58  with vapor line  72  which supplies fuel vapor to the engine purge valve or the charcoal canister  62 . Fuel vapors directed to the charcoal canister  62  are directed through the charcoal canister line  68  while fresh air is directed to the charcoal canister  62  via a fresh air line  66  from a fresh air filter  64 .  
         [0022]      FIGS. 3 and 4  depict fuel tank  34  having different levels of liquid fuel. For ease of illustration, the additional fuel vapor processing equipment depicted in  FIG. 2 , has been omitted from  FIGS. 3 and 4 . FIGS.  3  and  4  emphasize the advantages of employing a fuel sock  48  to reduce fuel vapors generated during refueling according to teachings of the present invention. More specifically,  FIG. 3  depicts the aft end  52  of the fuel sock  48  delivering fuel in the direction of arrow  50 . As depicted in  FIG. 3 , the fuel level  74  is such that the fuel outlet  54  of the fuel sock aft end  52  is partially submerged in liquid fuel. By partially submerging the fuel outlet  54  in liquid fuel, turbulent flow, and thus, fuel vapors are reduced in the fuel tank  34 .  
         [0023]     Similarly to  FIG. 3 ,  FIG. 4  depicts a refueling scenario in which the fuel outlet  54  of the aft end  52  of the fuel sock  48  lies completely submerged under the level of the fuel within the fuel tank  34 . In this depiction, fuel vapors generated by the refueling fuel flow  50  are minimized. Fuel vapors within the fuel tank  34  may escape from the top surface of the fuel in the tank, but generally not from turbulent flow upon the fuel flow  50  striking the top surface  74  of the existing fuel in the tank. As a result of the refueling scenarios depicted in  FIGS. 3 and 4 , fuel is delivered to the interior of the fuel tank  34  via the fuel sock  48 , with minimal or no sloshing upon the fuel flow  50  entering the fuel tank  34 , thereby reducing or minimizing fuel vapors generated within the tank  34 . The fuel sock  48 , also known as a fuel conduit, may be flexible and buoyant to accommodate, or move up and down in accordance with any fuel level with the fuel tank  34  during refueling.  
         [0024]      FIG. 5  is an enlarged view of the junction of the spud  44  and fuel sock  48 . Furthermore, the fuel sock  48  may be connected to the narrow fuel inlet portion  45  of the spud  44  that is inside the confines of the fuel tank  34 . More specifically, the material of the fuel sock  48  may be one that can be welded onto the narrow fuel inlet portion  45  of the spud  44 . More specifically, the fuel sock  48  material may be a plastic that can tolerate the liquid and vapor fuel within the fuel tank  34  and that can be welded to the spud  44 . Alternatively, the fuel sock  48  material may be a flexible, semi-rigid, or rigid rubber, or rubber-like material that is tolerable of fuel tank environments. Additionally, within the spud  44  the ICV  46  may reside, the ICV  46  permitting fuel to pass in one direction only, that is, into the fuel tank  34 .  
         [0025]     The description of the invention is merely exemplary in nature and thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.