Vapor-liquid control fuel cap

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

• closure means for closing the filler neck,
• pressure relief means for venting pressurized fuel vapor in the filler neck through the closure means, and
• 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, the closure means including an inner surface defining a venting aperture and providing a first valve seat surrounding the venting aperture, the pressure relief means including a pressure relief valve and spring means for yieldably biasing the pressure relief valve against the first valve seat normally to close the venting aperture, and the roll-over control means including passageway means for establishing fluid communication of liquid fuel and fuel vapor in the filler neck with the pressure relief valve so that said liquid fuel and fuel vapor cooperate with the spring means to exert a closure-inducing force on the pressure relief valve.

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

• closure means for closing the filler neck,
• pressure relief means for venting pressurized fuel vapor in the filler neck through the closure means, the pressure relief means including a pressure relief valve movable between filler neck-venting and non-venting positions, and
• roll-over control means for selectively using liquid fuel and fuel vapor in the filler neck to exert a closing force on the pressure relief valve so that the pressure relief valve is moved to its non-venting position, thereby blocking discharge of liquid fuel in the filler neck to the atmosphere through the pressure relief means during vehicle rollover or the like.

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

• closure means for closing the filler neck,
• pressure relief means for venting pressurized fuel vapor in the filler neck through the closure means, the pressure relief means including a pressure relief valve exposed to liquid fuel and fuel vapor in the filler neck and movable between filler neck-venting and non-venting positions, and
• roll-over control means for selectively maintaining the pressure relief valve in its non-venting position to prevent discharge of liquid fuel in the filler neck to the atmosphere through the pressure relief means, the roll-over control means including sensing means movably coupled to the closure means for sensing inversion of the filler neck during vehicle rollover and equalization means responsive to the sensing means for creating a valve movement-controlling force during vehicle rollover, the equalization means being configured to apply the valve movement-controlling force to the pressure relief valve to position the pressure relief valve in its non-venting position

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

• closure means for closing the filler neck,
• pressure relief means for venting pressurized fuel vapor in the filler neck through the closure means, and
• roll-over control means for creating a region within the closure means in communication with the pressure relief means to receive liquid fuel and fuel vapor from the filler neck during vehicle rollover or the like to disable the pressure relief means so that discharge of liquid fuel in the filler neck through the pressure relief means to the atmosphere is blocked.

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

• closure means for closing the fill neck,
• pressure relief means for venting pressurized fuel vapor in the filler neck through the closure means, the pressure relief means including a valve seat and a companion pressure relief valve movable to mate with the valve seat, the pressure relief valve cooperating with the closure means to define a suction chamber and being formed to include at least one fluid-conducting passageway interconnecting the vacuum chamber and the filler neck, and
• vacuum relief means on the pressure relief valve for unblocking the at least one fluid-conducting passageway in response to suction caused by sub-atmospheric pressure in the filler neck to draw air extant in the suction chamber into the filler neck via the at least one fluid-conducting passageway, thereby lowering the pressure in the suction chamber to decrease any closure-inducing force exerted on the pressure relief valve by pressure in the suction chamber so that atmospheric forces exerted on the pressure relief valve operate to move the pressure relief valve away from its valve seat to permit atmospheric air to be drawn into the filler neck by sub-atmospheric pressure in the filler neck.

A vacuum valve for regulating introduction of atmospheric air into tank means, the vacuum valve comprising

• chamber means for containing air,
• primary valve means responsive to suction caused by sub-atmospheric pressure in the tank means for communicating air extant in the chamber means with the tank means to lower pressure in the chamber means, and
• auxiliary valve means responsive to a predetermined decrease in pressure in the chamber means for communicating atmospheric air with the tank means.