Fuel interrupt/pressure release valve arrangement for fuel tank

摘要

A fuel interrupt/pressure release valve arrangement includes a casing mounted at an upper portion of an interior space of a fuel tank. The casing has openings for communicating the interior of the casing with an atmosphere the interior of the fuel tank. A valve housing is formed in the casing having a discharge opening at an upper end. The opening is closed by a stopper biased in a valve closing direction by a spring. A float is provided in the casing having an indentation for loosely receiving the valve housing and a through hole is formed through the float at an apex of the indentation corresponding to the position of the discharge opening of the valve housing. A protrusion formed on the float in the vicinity of the through hole so as to project in an opening direction of the valve so as to be normally in touching contact with the stopper. The buoyancy of the float is determined as to be urged in a valve closing direction by the presence of liquid state fuel in the casing and to be urged in a valve opening direction proportionally according to presence of fluid pressure of evaporated fuel in the casing. The buoyancy determined for the presence of liquid state fuel is less than the spring force of the spring by a predetermined degree.