Fuel cap with emissions protection

Abstract

A fuel tank cap for use with a fuel storage tank includes: a vapor storage receptacle; a purge path in fluid communication with the vapor storage receptacle; and a liquid discriminating membrane configured to be disposed at least in part between the vapor storage receptacle and fuel in the fuel storage tank. A fuel storage system includes: a fuel storage tank; a fill inlet connected to the fuel storage tank; and a fuel tank cap. The fuel tank cap includes: a vapor storage receptacle; a purge path in fluid communication with the vapor storage receptacle; and a liquid discriminating membrane configured to be disposed at least in part between the vapor storage receptacle and fuel in the fuel tank.

1 . A fuel tank cap for use with a fuel storage tank, comprising:
 a vapor storage receptacle;   a purge path in fluid communication with the vapor storage receptacle; and   a liquid discriminating membrane disposed at least in part between the vapor storage receptacle and liquid fuel in the fuel storage tank.   
     
     
         2 . The fuel tank cap of  claim 1 , wherein the fuel tank cap defines a cavity, and the vapor storage receptacle is disposed in the cavity. 
     
     
         3 . The fuel tank cap of  claim 1 , wherein the vapor storage receptacle is connected to the fuel tank cap. 
     
     
         4 . The fuel tank cap of  claim 1 , wherein the vapor storage receptacle comprises a canister. 
     
     
         5 . The fuel tank cap of  claim 1 , wherein the vapor storage receptacle comprises an absorbent granulated carbonaceous material. 
     
     
         6 . The fuel tank cap of  claim 1 , wherein the vapor storage receptacle comprises a carbon bed. 
     
     
         7 . The fuel tank cap of  claim 1 , wherein the purge path comprises a purge line configured for active purge. 
     
     
         8 . The fuel tank cap of  claim 1 , wherein the purge path is configured for passive purge. 
     
     
         9 . The fuel tank cap of  claim 1 , further comprising a filter disposed between the vapor storage receptacle and the purge line. 
     
     
         10 . The fuel tank cap of  claim 1 , wherein the purge path corresponds with a tether for the fuel tank cap. 
     
     
         11 . The fuel tank cap of  claim 1 , wherein the membrane is configured to impede liquid from contacting the vapor storage receptacle. 
     
     
         12 . The fuel tank cap of  claim 1 , wherein the membrane is vapor permeable. 
     
     
         13 . The fuel tank cap of  claim 1 , wherein the membrane is configured so that the vapor storage receptacle is fluidly sealed from the fuel storage tank. 
     
     
         14 . The fuel tank cap of  claim 1 , wherein the membrane is directly connected to the vapor storage receptacle. 
     
     
         15 . The fuel tank cap of  claim 1 , further comprising a support, wherein the membrane is configured for connection to the support. 
     
     
         16 . The fuel tank cap of  claim 1 , wherein the vapor storage receptacle comprises an aperture in fluid communication with atmospheric air. 
     
     
         17 . The fuel tank cap of  claim 1 , further comprising an orifice plate disposed in the purge path. 
     
     
         18 . A fuel storage system, comprising:
 a fuel storage tank;   a fill inlet connected to the fuel storage tank; and   a fuel tank cap having:
 a vapor storage receptacle; 
 a purge line in fluid communication with the vapor storage receptacle; and 
 a liquid discriminating membrane disposed at least in part between the vapor storage receptacle and fuel in the fuel storage tank. 
   
     
     
         19 . A fuel tank cap for use with a fuel storage tank, comprising:
 a carbon bed;   a purge path in fluid communication with the carbon bed;   a filter disposed between the carbon bed and the purge line; and   a vapor permeable and liquid discriminating membrane disposed between the carbon bed and fuel in the fuel storage tank to fluidly seal the carbon bed from the fuel storage tank, wherein the membrane discriminates between liquid fuel and fuel vapor and impedes liquid from contacting the carbon bed.