Vapor Emission Control Fuel Cap

Abstract

A fuel tank assembly with a fuel cap sub-assembly that includes active (that is, automatic) pressure equalization hardware and a passive (that is, manually operated) vent. The fuel cap assembly further includes radially oriented ratchet teeth. The fuel cap assembly further includes single piece fuel cap tether that is anchored in the interior space of the fuel tank.

1 . A fuel tank assembly comprising:
 a fuel tank defining an interior space;   a passive vent that is movable between: (i) an open position that opens a first air communication path between the interior space of the fuel tank and the external atmosphere, and (ii) a closed position that closes the first air communication path; and   an active pressure equalization hardware that automatically and selectively opens at least a second air communication paths in response to a pressure difference between the interior space of the fuel tank and the eternal atmosphere.   
     
     
         2 . The assembly of  claim 1  wherein the passive vent comprises biasing hardware shaped, located and/or connected to bias the passive vent sub-assembly to its closed position. 
     
     
         3 . The assembly of  claim 1  wherein the active pressure equalization hardware comprises an air intake valve shaped, structured and located to automatically and selectively open the second air communication path between the interior space of the fuel tank and the external atmosphere when the negative relative pressure in the interior space of the fuel tank increases in magnitude above a threshold negative pressure. 
     
     
         4 . The assembly of  claim 1  wherein the active pressure equalization hardware comprises a vapor exhaust valve shaped, structured and located to automatically and selectively open the second air communication path between the interior space of the fuel tank and the external atmosphere when the positive relative pressure in the interior space of the fuel tank increases in magnitude above a threshold positive pressure. 
     
     
         5 . The assembly of  claim 1  wherein the active pressure equalization hardware comprises:
 an air intake valve shaped, structured and located to automatically and selectively open the second air communication path between the interior space of the fuel tank and the external atmosphere when the negative relative pressure in the interior space of the fuel tank increases in magnitude above a threshold negative pressure; and 
 a vapor exhaust valve shaped, structured and located to automatically and selectively open a third air communication path between the interior space of the fuel tank and the external atmosphere when the positive relative pressure in the interior space of the fuel tank increases in magnitude above a threshold positive pressure. 
 
     
     
         6 . The assembly of  claim 5  further comprising a fuel cap sub-assembly comprising a removable fuel cap, wherein the passive vent, the air intake valve and the vapor exhaust valve are all built into the fuel cap. 
     
     
         7 . The assembly of  claim 1  further comprising a fuel cap sub-assembly comprising a removable fuel cap, wherein the passive vent and the active pressure equalization hardware are built into the fuel cap. 
     
     
         8 . A fuel cap assembly comprising:
 a removable fuel cap comprising a first cap member and a second cap member; and   fuel cap receiving hardware connected, shaped and/or located to removably engage the removable fuel cap;   wherein:   the removable fuel cap defines a central axis, an axial direction, an angular direction and a radial direction;   the removable fuel cap and fuel cap receiving hardware are connected, shaped and/or located so that the removable fuel cap is removed by turning it in the angular direction and translating it in the axial direction;   the first cap member comprises a plurality of ratchet teeth;   the second cap member comprises at least one ratchet tooth engaging member; and   the plurality of ratchet teeth face and engage with the at least one ratchet tooth engaging member in the radial direction.   
     
     
         9 . The assembly of  claim 8  wherein:
 the first cap member is an inner shell member; and 
 the second cap member is an outer shell member that fits around the inner shell member at least substantially around the angular direction. 
 
     
     
         10 . A fuel cap assembly for use with a fuel tank, the fuel cap assembly comprising:
 a fuel cap; and   a tether member made of a single piece of a single material;   wherein:   the tether member comprises a cap-securement portion that is shaped, sized and/or located to be mechanically secured to the fuel cap;   the tether member further comprises a tethering portion that is shaped, sized and/or located to: (i) be accommodated within an interior space of the fuel tank when the fuel cap is engaged to seal the fuel tank, and (ii) to tether the fuel cap at location(s) spaced apart from a fueling opening in the fuel tank when the fuel cap is removed from the fuel tank for fueling; and   the tether member further comprises an anchor portion sized, shaped and/or located to be held within the interior space of the fuel tank, and prevented by physical interference from exiting the interior space of the fuel tank through the fueling opening.