In an oil filler cap, a valve part of a valve device is arranged in a range between a lower end of a screw part that is screwed to an oil filler opening part in a cap body and a seal surface that is arranged at a higher position than the screw part, a ventilation passage part is arranged above the valve part, and a ratchet mechanism is arranged on an outer circumferential side of the ventilation passage part.

A cap assembly for a container comprises a cap and a body coupled to the cap. The body includes a peripheral wall and a valve seat. The valve seat includes a first side facing the cap and a second side facing away from the cap. A first check valve having an elastic valve body is positioned at the second side of the seat. A second check valve having an elastic valve body is positioned at the first side of the valve seat. When a pressure at the first side of the valve seat exceeds a pressure at the second side of the valve seat by a first predetermined value, the first check valve opens; and when the pressure at the second side exceeds the pressure at the first side by a second predetermined value, the second check valve opens.

The fuel tank cap with charcoal canister includes a fuel tank inner cap and a fuel tank outer cap. A filling chamber is disposed in the fuel tank inner cap. The fuel tank outer cap wraps up the upper port of the filling chamber. The fuel tank inner cap has a volume chamber having an upper vent cap. Between the side wall of the upper vent cap and the inner wall of the volume chamber, there is an air gap. The filling chamber has a lower breathing panel. Between the lower breathing panel and the bottom of the filling chamber, there is a welding ring. The upper port is on the inner side of the welding ring. The lower surface of the lower breathing panel is fixed and connected with the filling chamber via the welding ring. The bottom surface of the volume chamber has an air inlet/outlet.

A vent having a vent housing defining a mounting structure, a first opening between a first end and a second end of the vent housing, a first airflow pathway from the first opening, a second airflow pathway from a second opening, and a draining pathway from the first airflow pathway through the first end of the vent housing. The first airflow pathway has a first segment and a second segment extending in opposite axial directions. An inlet relief valve and an outlet relief valve are arranged in parallel between the first and second airflow pathways. The inlet relief valve opens upon exceeding a first threshold pressure differential of the second relative to the first airflow pathway. The outlet relief valve opens upon exceeding a second pressure differential of the first relative to the second airflow pathway. A filter assembly is disposed in the vent housing across the second airflow pathway.

A fuel cap configured to be coupled with the opening of a fuel tank defining an interior for containing a volume of fuel. An inlet opening is configured to establish fluid communication with the fuel tank interior. An exit is in communication with a surrounding atmosphere, exterior to the fuel cap. A flow path is defined from the inlet opening to the exit. Adsorption media substantially fills the flow path and is configured to reduce the emission of VOC vapors through the exit to the surrounding atmosphere. The flow path extends spirally about an axis of the fuel cap from the inlet opening to the exit.

A closure device, such as a fuel cap, for controlling evaporative emissions from a fuel tank. In one aspect, the invention comprises: a housing defining an internal chamber about a central axis; a diffuser plate positioned within the internal chamber that separates the internal chamber into an upper zone and a lower zone; a hydrocarbon adsorbing media disposed in the upper zone of the internal chamber; an inlet passageway for introducing fuel vapor from a fuel vapor inlet port to the lower zone of the internal chamber; and at least one outlet passageway extending from the upper zone of the internal chamber to an atmospheric air outlet port.

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 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.

The mechanical breather valve includes a valve body, on which is installed one-way air inlet and outlet components. A tank, for environmental protection, is fitted with the breather valve and closed so that no volatile gas will be exhausted, when the pressure within is balanced with the outside. When the pressure within is negative, the one-way air inlet hole will draw air from outside to keep the balance of pressure. When the pressure within is increased, one-way air outlet hole will exhaust the additional air. When the tank is tilted or placed upside down, the breather valve can prevent the oil from flowing out of the tank for safe usage.