Liquid splash control fuel cap

A fuel cap for use in a vehicle fuel system filler neck having a mouth, the cap comprising

• closure means for closing the mouth of the filler neck,
• pressure-relief means for venting pressurized fuel vapor in the filler neck through the closure means,
• roll-over control means for controllably disabling the pressure-relief means during vehicle rollover or the like to block discharge of liquid fuel in the filler neck to the atmosphere through the pressure-relief means,
• a hollow support fixture depending from the closure means to extend into the filler neck upon engagement of the closure means and the filler neck, and
• means disposed in the hollow support fixture for actuating the roll-over control means to disable the pressure-relief means during normal upright vehicle operation in response to introduction of liquid fuel into the hollow support fixture so that liquid fuel in the filler neck due to agitation of the vehicle during normal operation is not discharged to the atmosphere through the pressure-relief means.

A fuel cap for use in a vehicle fuel system filler neck having a mouth, the cap comprising

• a closure member engageable with the filler neck to close the mouth of the filler neck, the closure member being formed to include an internal region therein, a vent passageway communicating with the internal region and having an inlet aperture opening into the filler neck and an outlet aperture opening into the atmosphere, and a control passageway having an inlet aperture opening into the filler neck and an outlet aperture opening into the internal region,
• partition means for dividing the internal region into a vent chamber providing a portion of the vent passageway and a separate venting control chamber providing a portion of the vent passageway and a separate second internal region providing a space for receiving liquid fuel and fuel vapor communicated through the control passageway without introducing said liquid fuel and fuel vapor into the vent passageway, the closure member including an inner surface in the first internal region defining a venting aperture of the vent passageway to discharge fuel vapor conducted from the filler neck via the vent passageway into the vent chamber and providing a first valve seat surrounding the venting aperture, the partition means including a pressure-relief valve movable in the internal region between a vent passageway-closing position against the first valve seat and a vent passageway-opening position away from the first valve seat,
• first spring means in the venting control chamber for yieldably biasing the pressure-relief valve against the first valve seat normally to close the venting aperture so that liquid fuel and fuel vapor are unable to escape from the filler neck to the atmosphere through the vent passageway,
• means coupled to the closure member for providing a second seat surrounding the inlet aperture of the control passageway,
• a vent control valve disposed in the control passageway for movement between a control passageway-closing position against the second valve seat and a control passageway-opening position away from the second valve seat,
• second spring means in the control passageway for yieldably biasing the vent control valve against the second valve seat to block flow of liquid fuel and fuel vapor through the inlet aperture from the filler neck into the control passageway, and
• means supported by the closure member for moving the vent control valve away from the second valve seat in response to the presence of liquid fuel splash in the filler neck in excess of a selected threshold amount so that superatmospheric fuel vapor in the filler neck is admitted into the second venting control chamber via the control passageway to exert a closure-inducing force on the pressure-relief valve which cooperates with the first spring means to move the pressure-relief valve to its vent passageway-closing position.