초록

A TVVA with a buoyant overfill protection float contains the float closely and axially slidably within a sleeve, and feeds a negative pressure created by the rapid flow of fill vapors over the outside of the sleeve into the sleeve to hold the float down and prevent it from corking.

대표청구항 ▼

In a vehicle fuel tank vapor recovery system of the type that has a vapor storage canister and a tank vapor vent valve assembly that routes the flow of fuel vapor displaced from the fuel tank during fuel fill to said canister, but which blocks liquid fuel from reaching said canister, the improvement

In a vehicle fuel tank vapor recovery system of the type that has a vapor storage canister and a tank vapor vent valve assembly that routes the flow of fuel vapor displaced from the fuel tank during fuel fill to said canister, but which blocks liquid fuel from reaching said canister, the improvement comprising, a lightweight and buoyant float with an elongated axis having a seal at its upper end, a float chamber through which said flow of displaced tank vapor passes, said chamber having an interior wall within which said float is slidably received so as to move up and down along its axis, said interior wall having an inner surface that forms a thin envelope of space about said float while leaving said float upper end free, said interior wall also having an outer surface that is exposed to said flow of displaced tank vapor, a pressure tube extending through said float chamber interior wall so as to open at its inner end into said space envelope and at its outer end into said flow, and, a vapor vent line running from said canister to said float chamber and opening through said float chamber above said float seal, whereby, during fuel fill, as displaced tank vapor flows through said float chamber and past said pressure tube outer end, a negative pressure is created in said envelope of space that serves to keep said float down, and should liquid fuel reach said float chamber, it will flow into said envelope of space and around said float, buoying it freely up along its axis until its seal blocks said vapor vent line.