Fuel tank venting arrangement

Abstract

A fuel tank for small internal combustion engines, the fuel tank formed of a pair of lower and upper housing members which are molded from a plastic material and are sealed to one another via heat welding, for example, to define the interior volume of the fuel tank. The lower housing member includes an integral vent tube which extends substantially upwardly within the interior of the fuel tank and includes an open end. The upper housing member includes an integral baffle wall projecting downwardly therefrom which defines a baffle chamber in which the upper end of the vent tube is received. The lower housing member additionally includes an integral fitting to which a vent conduit is attached, the fitting in fluid communication with the vent tube. In use, fuel vapors are vented from the fuel tank by passing into the baffle chamber and thence into the open end of the vent tube and through the fitting and vent conduit to a carbon canister or other containment device.

1 . A fuel tank, comprising: 
 at least two housing members joined to one another to define an interior volume therebeween;    an elongated vent tube monolithically formed with one of said housing members and extending therefrom within said interior volume.    
   
   
       2 . The fuel tank of  claim 1 , wherein at least a portion of said vent tube is oriented substantially vertically.  
   
   
       3 . The fuel tank of  claim 1 , further comprising a fuel blocking element associated with said vent tube, said fuel blocking element substantially blocking the passage of liquid fuel therethrough into said vent tube and allowing the passage therethrough of gaseous fuel vapors when pressure in said fuel tank rises above atmospheric pressure.  
   
   
       4 . The fuel tank of  claim 3 , wherein said fuel blocking element extends within said vent tube along a substantial portion of the length of said vent tube.  
   
   
       5 . The fuel tank of  claim 1 , wherein another of said housing members includes a baffle wall disposed within said interior volume, said baffle wall defining a baffle space, an end of said vent tube disposed within said baffle space.  
   
   
       6 . The fuel tank of  claim 5 , further comprising a fuel blocking element associated with said vent tube, said fuel blocking element at least one of: 
 disposed within an open upper end of said vent tube;    disposed within said baffle space; and    disposed around said vent tube.    
   
   
       7 . The fuel tank of  claim 1 , wherein said baffle wall extends along a substantial portion of a length of said vent tube.  
   
   
       8 . The fuel tank of  claim 1 , wherein said one housing member includes a wall recessed into said interior volume to define a recessed space exteriorly of said interior volume, said vent tube extending from said wall into said interior volume.  
   
   
       9 . The fuel tank of  claim 8 , wherein said one housing member further includes a fitting monolithically formed therewith, said fitting disposed within said recessed space and in fluid communication with said vent tube.  
   
   
       10 . The fuel tank of  claim 1 , wherein said fuel tank further comprises a filler neck, said filler neck having a lower end disposed within said interior volume and defining a maximum fuel level within said fuel tank.  
   
   
       11 . The fuel tank of  claim 10 , wherein said fuel tank further comprises a vapor space defined therewithin above said lower end of said filler neck.  
   
   
       12 . The fuel tank of  claim 1 , wherein said fuel tank further comprises a fuel tank cap, said fuel tank cap including a one-way valve therein allowing passage of atmospheric air therethrough into said fuel tank and preventing the passage of air therethrough from said fuel tank to the atmosphere.  
   
   
       13 . A fuel tank, comprising: 
 at least two housing members joined to one another to define an interior volume therebeween;    an elongated vent tube connected to one of said housing members and extending therefrom within said interior volume; and    a fuel blocking element disposed within said vent tube and extending within said vent tube along a substantial portion of a length of said vent tube, wherein said fuel blocking element substantially blocks the passage of liquid fuel therethrough into said vent tube and allows the passage therethrough of gaseous fuel vapors when pressure in said fuel tank rises above atmospheric pressure.    
   
   
       14 . The fuel tank of  claim 13 , wherein said vent tube is monolithically formed with one of said housing members.  
   
   
       15 . The fuel tank of  claim 13 , wherein another of said housing members includes a baffle wall disposed within said interior volume, said baffle wall defining a baffle space, an end of said vent tube disposed within said baffle space.  
   
   
       16 . The fuel tank of  claim 15 , wherein said baffle wall extends along a substantial portion of said vent tube.  
   
   
       17 . The fuel tank of  claim 13 , wherein said one housing member includes a wall recessed into said interior volume to define a recessed space exteriorly of said interior volume, said vent tube extending from said wall into said interior volume.  
   
   
       18 . The fuel tank of  claim 17 , wherein said one housing member further includes a fitting monolithically formed therewith, said fitting disposed within said recessed space and in fluid communication with said vent tube.  
   
   
       19 . The fuel tank of  claim 13 , wherein said fuel tank further comprises a fuel tank cap, said fuel tank cap including a one-way valve therein allowing passage of atmospheric air therethrough into said fuel tank and preventing the passage of air therethrough from said fuel tank to the atmosphere.