Abstract: A fuel tank has a filler pipe to which a vent pipe is attached on one end and which divides into two openings on the other end within the fuel tank. One opening is positioned below the other opening relative to the top of the fuel tank and has means for preventing expulsion of fuel through the vent pipe when fuel tank pressure exceeds atmospheric. The other opening is positioned to be in vapor even when the tank is filled to maximum capacity. Fuel vapor vents through the openings during refueling until fuel entering the vent pipe through the lower opening blocks the flow of vapor, thereby limiting the fuel level within the tank.

Abstract: An automotive type fuel tank has a fuel fill pipe with automatic pressure responsive fuel shutoff means, and a vapor vent assembly. The assembly has a small tube extending down through the top of the tank to below the normal fuel level of a full tank. The lower end is upturned and extends upwardly to a point near the top of the tank with a large orifice opening to vent vapors freely therethrough through the tube. A small orifice is drilled in the bottom of the tube at the bend to slowly bleed fuel into the tube as the tank fills until the fuel level blocks the vent of fuel vapors, resulting in a shutoff of the fill fuel. During operations other than filling, the small orifice prevents/minimizes expulsion of liquid fuel out the vent tube. A weighted ball further seals against fuel leakage upon vehicle or tank rollover.

Abstract: A fuel tank and filler system for an internal combustion engine includes a fuel tank, a filler pipe extending into the fuel tank, and a check valve comprising a collapsible, normally open tube secured around the outlet of the fuel filler pipe within the tank. Fuel entering the tank passes through the filler pipe and collapsible tube unimpeded. The collapsible tube has sufficient flexibility, however, to collapse upon itself in the event that fuel begins to flow outwardly through the filler pipe, thereby preventing fuel from leaving the tank through the filler pipe.