An embodiment fuel cap system includes a filler neck connected to a fuel pipe, a fuel cap having a cylindrical shape and able to be coupled to the filler neck by rotation, a sliding rod extending from an upper surface of the fuel cap in a shaft direction at an inside of the fuel cap and rotatable together with the fuel cap, a plunger including an upper end slidably coupled to the sliding rod in the shaft direction and a lower end including a coupling rod, and an inner ring on the filler neck and including a catching groove having an interior circumference on which the coupling rod is selectively engaged, wherein a rotation of the fuel cap is prevented when the coupling rod is engaged on the catching groove and the rotation of the fuel cap is possible when the coupling rod is disengaged from the catching groove.

A fuel cap for a vehicle has a locking structure configured to generate a sound interval, including a head portion having a handle formed at a first side and one or more striking portions installed at a second side, and a body portion integrally assembled with the head portion and having a plurality of sound generators installed at the body portion and disposed in a state of being struck by the one or more striking portions installed at the second side of the head portion according to a rotation of the head portion by a locking torque.

An in-tank fuel pump assembly and mounting system is disclosed which may be configured for mounting inside a fuel tank. The assembly includes a pump housing, pump mounted to the housing, and pressure relief valve. The housing may comprise upper and lower pump housing units coupled together. The upper housing unit is configured for mounting to a tank opening, which in one implementation may be the fuel fill opening. The lower housing unit extends into the tank to approximately the bottom of the tank. A fuel fill fluid pathway is created through the housing for adding fuel to the tank while the pump assembly remains in situ. The upper housing unit may include a removable fuel cap. The pump housing may include an integral vapor trap.

A multiple fuel tank purge system and method includes providing a pair of fuel tanks, including a main fuel tank for containing impure fuel and a separate, auxiliary fuel tank that contains commercial canned fuel. The engine runs on the impure fuel from the main fuel tank while the engine is in normal use, and then employs a shutdown cycle that switches to the commercial canned fuel from the auxiliary fuel tank for some pre-set time period. This arrangement allows the engine to be purged of the impure fuel (by burning the impure fuel during the shutdown cycle) and replaced by the commercial pre-mixed fuel before the engine is finally shut down. The system may further include a novel fuel cap with a fuel line, a tank within a tank fuel container, and/or an electronically actuated shutdown cycle mechanism.

A valve member provides for the flow of vapors from a fuel tank of an internal combustion engine to escape the fuel tank. The valve member may include a valve and a boss or spacer. The valve is configured to selectively control the flow of vapor from the fuel tank. The boss or spacer is positioned in a predetermined relationship to the valve, and the boss or spacer prevents a deformation of the valve from disrupting the selectively controlled flow of vapor from the fuel tank.

A fuel cap for a vehicle has a locking structure configured to generate a sound interval, including a head portion having a handle formed at a first side and one or more striking portions installed at a second side, and a body portion integrally assembled with the head portion and having a plurality of sound generators installed at the body portion and disposed in a state of being struck by the one or more striking portions installed at the second side of the head portion according to a rotation of the head portion by a locking torque.

A four-wheel vehicle includes an engine at least a portion of which is located farther forward than a seat, a fuel tank located above the engine and forwardly of the seat, a fuel filler including a fuel filler neck and a filler cap, a breather channel connected to the fuel filler, and an outflow prevention valve in the breather channel to prevent outflow of liquid fuel. The outflow prevention valve is located higher in a side view of the vehicle body than both of a lower end of the fuel tank and an upper end of the engine.

An in-tank fuel pump assembly and mounting system is disclosed which may be configured for mounting inside a fuel tank. The assembly includes a pump housing, pump mounted to the housing, and pressure relief valve. The housing may comprise upper and lower pump housing units coupled together. The upper housing unit is configured for mounting to a tank opening, which in one implementation may be the fuel fill opening. The lower housing unit extends into the tank to approximately the bottom of the tank. A fuel fill fluid pathway is created through the housing for adding fuel to the tank while the pump assembly remains in situ. The upper housing unit may include a removable fuel cap. The pump housing may include an integral vapor trap.

A fuel tank cap includes a casing; a main chamber disposed in the casing; a vapor vent channel disposed in the casing and communicating with the main chamber; annular partition walls disposed in the main chamber and configured to divide the main chamber into troughs surrounding a central tunnel, each partition wall including a cut so that the troughs and the tunnel are capable of communicating with each other via the cut; activated carbon filled in the troughs; and a permeable plug disposed in the tunnel, which is made by wrapping rust-resistant flexible wires so that a plurality of intercommunicated air gaps are formed among the flexible wires. The vapor vent channel includes the cuts, the troughs and the air gaps. The activated carbon captures fuel vapors and absorbs VOCs in the fuel vapors when the fuel vapors pass through the vapor vent channel.

A fuel tank includes a tank main body and a fuel filler neck. A breather hole is provided in an inner surface of the fuel filler neck. A connecting pipe opens to the inside of the fuel filler neck though the breather hole and extends from the fuel filler neck in the radial direction. The inside of the fuel filler neck includes a first vapor-liquid separation chamber therein that is partitioned from the tank main body and connected to the breather hole. Liquid fuel entering the breather channel is reduced.