The invention is directed to a gas cap with built-in funnel for small engines. The gas cap provides a compact funnel of sufficient size to speed the refueling process and prevent spills, and may further provide a valve to prevent the escape of gasoline fumes from the fuel tank.

A fuel cap capable of preventing a reduction in breathability in a housing due to a moistened adsorbent and appropriately discharging fuel vapor includes a housing including an inner space through which vapor generated in a fuel tank flows upward from below. A granular adsorbent is disposed in the inner space of the housing. A lower air-permeable layer is disposed below the adsorbent, and an upper air-permeable layer is disposed above the adsorbent. A lower porous member is disposed between the adsorbent and the lower air-permeable layer. The lower air-permeable layer, the lower porous member, and the upper air-permeable layer respectively have a porous structure. A density of the lower porous member is lower than a density of the lower air-permeable layer and a density of the upper air-permeable layer.

A system for cleaning a fuel cap valve of a vehicle, may include a fuel cap having an air breather passage and a negative-pressure valve body configured for opening or closing the air breather passage; a canister for collecting evaporated gas inside a fuel tank to supply the evaporated gas into an engine intake system; and a negative-pressure control mechanism for controlling an engine negative pressure, which is applied from the engine intake system to the negative-pressure valve body of the fuel cap through the canister and the fuel tank, to reach a predetermined level or more, or for controlling the engine negative pressure at a repetition interval, in a fuel cap cleaning mode for cleaning the negative-pressure valve body of the fuel cap.

A tank cap structure of an embodiment includes a cap body, a grip portion, a valve device, and a ratchet mechanism. The valve device includes a valve case which has a cylindrical shape about a screw axis and accommodates a float, and a valve body which has a tapered shape thinner than the valve case and extends toward an opening.

The cap body includes a cylindrical receiving portion which has a cylindrical shape about the screw axis. A seal-receiving portion receiving a seal member held between the cap body and an oil filler port portion is provided on an outer circumferential surface of the cylindrical receiving portion. A valve-receiving portion receiving the valve device inserted into an inner circumference of the cylindrical receiving portion is provided on an inner circumferential surface of the cylindrical receiving portion.

An evaporated fuel processing device may be provided with: a canister configured to adsorb fuel evaporated in a fuel tank; a purge passage connected between the canister and an intake passage of an engine; a pump provided on the purge passage; a concentration sensor configured to detect a concentration of purge gas; a branch passage connected to the purge passage; and a switching device configured to switch between a state in which the purge gas passes through the purge passage between both ends of the branch passage and a state in which the purge gas does not pass through the purge passage between the both ends of the branch passage. The concentration sensor is provided on the branch passage.

A fuel tank cap for two-way gas intake and exhaustion contains: a body including a first lid and a second lid. The first lid has a coupling orifice configured to connect with a pressure adjustment module, the pressure adjustment module has a rotatable knob and a limiting unit, and the first lid has a locking rib. A first spring is defined between the first lid and the second lid, and the second lid includes an accommodation groove and a connection portion. The accommodation groove accommodates a flexible adjustment valve and a second spring, and the flexible adjustment valve has a main part and a flexible stop unit which has a movement travel in which the flexible stop unit expends or retracts. The main part has at least one seal loop and a defining rib. The second spring abuts against the defining rib and the limiting unit.

A fuel cap is constituted to close an upper portion of a tubular member constituting a filler opening of a fuel tank, and wherein the breather mechanism is constituted to discharge vaporized fuel separated by gas-liquid separation in a labyrinth path within the fuel cap through a breather drain hose supported at a side of the fuel tank, the fuel tank further comprising: a plate member fixed to a support member to support the fuel cap to the fuel tank; and a seal member to airtightly communicate an exit of the labyrinth path and an end portion of the breather drain hose when the fuel cap is closed. The breather drain hose connected to a lower side of the seal member is supported by the plate member.

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.

For transmission of rotative operation on a lid body to a cap body, a transmission mechanism for mechanically coupling the lid body and the cap body transmits the rotative operation on the lid body to the cap body. If a pressure difference determined across a seal plate between a pressure in an inlet and a pressure outside the inlet becomes a predetermined pressure or more, the seal plate makes irreversible shape change. The irreversible shape change of the seal plate releases the transmission mechanism from the mechanical coupling to at least one of the lid body and the cap body, thereby cutting transmission of the rotative operation on the lid body to the cap body. Thus, a fuel cap to be provided is capable of notifying the occurrence of abnormality in a fuel system as physical feeling during operation on the fuel cap.

The cap assembly for a carbon canister fuel tank includes an outer cap and an inner cap. There is a cavity with an opening at the inner cap, and the outer cap is above the inner cap covering the opening. There is a lower vent cap in the cavity which divides the cavity into a filling cavity and a volume cavity. There is a through hole in the center of the lower vent cap with a breathing valve which would open automatically when there is air pressure imbalance in the filling cavity and volume cavity. The first vent hole is at the bottom of the volume cavity, while the second vent hole is at the bottom of the filling cavity. The first vent hole, breathing valve and the second vent hole are arranged in sequence to constitute the exhaust channel for the vaporizing oil gas in the fuel tank.