Ventilation control valve for fuel tank

A ventilation control valve for a fuel tank, the ventilation control valve being disposed in a ventilation passage communicating an inside and an outside of the fuel tank, the ventilation control valve comprising:

• a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state;
• a volume chamber in which volume changes in accordance with a vertical movement of the float;
• a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state;
• a gas reservoir which stores gas;
• and
• a through hole which penetrates from the gas reservoir to the volume chamber and supplies the gas from the gas reservoir to the volume chamber, wherein
• the float has a through hole which gradually reduces a buoyancy of the float, and
• the through hole on the float opens at a downstream side of the valve mechanism on the ventilation passage.

A ventilation control valve for a fuel tank, the ventilation control valve being disposed in a ventilation passage communicating an inside and an outside of the fuel tank, the ventilation control valve comprising:

• a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state;
• a volume chamber in which volume changes in accordance with a vertical movement of the float;
• and
• a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state, wherein
• the float has a through hole which gradually reduces a buoyancy of the float, and
• the flow rate adjusting mechanism includes
• a control gap provided between a cylindrical wall disposed on the float and a cylindrical wall disposed on a case.

A ventilation control valve for a fuel tank, the ventilation control valve being disposed in the ventilation passage communicating an inside and an outside of the fuel tank, the ventilation control valve comprising:

• a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state;
• a volume chamber in which volume changes in accordance with a vertical movement of the float;
• and
• a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state, wherein
• the float has a through hole which gradually reduced a buoyancy of the float, and
• the through hole on the float opens at a downstream side of the valve mechanism on the ventilation passage.

A ventilation control valve for a fuel tank, the ventilation control valve being disposed in the ventilation passage communicating an inside and an outside of the fuel tank, the ventilation control valve comprising:

• a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state;
• a volume chamber in which volume changes in accordance with a vertical movement of the float;
• and
• a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state, wherein
• the volume chamber includes:
• a fixed piston disposed on a case;
• and
• a moveable cylinder disposed on the float and moveably accommodating the fixed piston,
• the float has a through hole which gradually reduced a buoyancy of the float, and
• the flow rate adjusting mechanism includes
• a control gap provided between a cylindrical wall disposed on the float and a cylindrical wall disposed on a case.

A ventilation control valve for a fuel tank, the ventilation control valve being disposed in the ventilation passage communicating an inside and an outside of the fuel tank, the ventilation control valve comprising:

• a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state;
• a volume chamber in which volume changes in accordance with a vertical movement of the float;
• and
• a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state;
• a gas reservoir which stores gas;
• and
• a through hole which penetrates from the gas reservoir to the volume chamber and supplies the gas from the gas reservoir to the volume chamber, wherein
• the float has a through hole which gradually reduces a buoyancy of the float, and
• the flow rate adjusting mechanism includes
• a control gap provided between a cylindrical wall disposed on the float and a cylindrical wall disposed on a case.