Vehicle refueling valve

摘要

A refueling valve (22) for a motor vehicle includes an integrated control valve (66) therein having a vent tube (64) that has a first valve seat (62) on one end thereof and a second valve seat (100) on the other end thereof that cooperate respectively with a float valve (60) and with a diaphragm controlled pressure responsive cut-off valve (124) that is operative in accordance with a sensed pressure condition in a fuel filler pipe (14) to control fuel venting to a charcoal canister (28) and to prevent the escape of fuel vapors from a filler neck (12). The diaphragm (98) is communicated with a pressure sensing port (50) in the filler neck (12) below a trap door (40) therein that opens during refueling and is closed once the fuel nozzle is removed. The pressure sensing port (50) is located upstream of a venturi (45) that produces negative pressure at the pressure sensing port (50) and on the diaphragm (98). A spring (120) biases the cut-off valve (124) normally closed. The diaphragm member (98) is responsive to a reduced pressure condition in the filler neck (12) to open the cut-off valve (124) to allow vapors to be vented from the fuel tank (18) to the charcoal canister (28) during refueling.