Provided is a flap valve device and a gas liquid separation device provided with a flap valve. The flap valve device includes a main body having an opening, a flap for selectively closing the opening and a torsion coil spring provided between the main body and the flap for biasing the flap in an opening direction. The flap valve device further comprises a main body side bearing; a flap side bearing; a connecting member including a hinge shaft passed through the main body side bearing, the flap side bearing and the torsion coil spring, and an extension extending from an end of the hinge shaft along an outer part of the flap; and a spring engagement portion provided on the main body for engaging an end of the torsion coil spring; another end of the torsion coil spring being engaged by the extension, which is engaged on the flap.

A fuel evaporative emission processing system suitable for a hybrid vehicle includes a shut-off valve, a first purge control valve and a second purge control valve. The shut-off valve is selectively opens and closes a fuel vapor passage between a fuel tank and a canister. The first purge control valve selectively opens and closes a purge passage between the canister and the intake passage of an internal combustion engine. The second purge control valve selectively opens and closes a tank opening passage between the canister and the fuel tank. When releasing a pressure for refueling, the second purge control valve with a small diameter opens prior to opening of the shut-off valve so that blow-by of gas associated with opening of the shutoff valve is prevented.

A fuel evaporative emission processing system suitable for a hybrid vehicle includes a shut-off valve, a first purge control valve and a second purge control valve. The shut-off valve is selectively opens and closes a fuel vapor passage between a fuel tank and a canister. The first purge control valve selectively opens and closes a purge passage between the canister and the intake passage of an internal combustion engine. The second purge control valve selectively opens and closes a tank opening passage between the canister and the fuel tank. When releasing a pressure for refueling, the second purge control valve with a small diameter opens prior to opening of the shut-off valve so that blow-by of gas associated with opening of the shutoff valve is prevented.

Provided is a flap valve device and a gas liquid separation device provided with a flap valve wherein the flap valve device is highly compact, and is easy to assemble. In a normally open flap valve device (2) comprising a main body (5) having an opening (4), a flap (6) for selectively closing the opening and a torsion coil spring (7) provided between the main body and the flap for biasing the flap in an opening direction, the flap valve device further comprises a main body side bearing (21) provided on the main body; a flap side bearing (25) provided on the flap; a connecting member (27) including a hinge shaft (27A) passed through the main body side bearing, the flap side bearing and a coil portion (7A) of the torsion coil spring so as to serve as a pivot shaft for the flap, and an extension (27B) extending from an end of the hinge shaft along an outer part (6B) of the flap; and a spring engagement portion (43) provided on the main body for engaging an end of the torsion coil spring; another end of the torsion coil spring being engaged by the extension, the extension being engaged on the outer part of the flap.