This is a continuation-in-part of co-pending patent application Ser. No. 07/198,384 filed 1/25/88, now U.S. Pat. No. 4,883,103, issued Nov. 28, 1989, which is a continuation-in-part of application Ser. No. 106,632, filed 10/8/87, now U.S. Pat. No. 4,816,045, issued Mar. 28, 1989, which is a continuation-in-part of application Ser. No. 896,081 filed 3/31/86, now U.S. Pat. No. 4,770,677, issued Sept. 13, 1988.
The present invention relates to a sealing assembly in a filler neck, and particularly to means for establishing a seal between the filler neck and a liquid-dispensing nozzle in the filler neck. More particularly, the present invention relates to a sealing assembly in a vehicle fuel system filler neck for sealingly admitting a fuel-dispensing nozzle into the filler neck without permitting substantial exhaustion of fuel vapors in the filler neck to the atmosphere or admission of atmospheric pressure into the fuel system through the filler neck.
Polluting emissions are released into the atmosphere during each and every motor vehicle refueling activity through the mouth of the filler neck. In view of the frequency of vehicle refueling activities, it will be appreciated that a significant quantity of otherwise combustible fuel is lost to the atmosphere each time a vehicle is refueled.
New fuel vapors are generated during refueling due to splash and agitation of the dispensed fuel, as well as from potential temperature differences between the fuel tank and the dispensed fuel. In addition, as the liquid fuel dispensed at the pump fills the vehicle fuel tank, fuel vapors that are present in the tank and generated during refueling are displaced by liquid fuel. These displaced fuel vapors are moved out of the fuel tank vapor space by the displacing action of the liquid fuel. In conventional vehicle fuel systems, these displaced vapors are released directly into the atmosphere via the fuel tank filler neck and are a contributing factor to air pollution.
Many conventional filler necks and fuel tank assemblies on vehicles are not configured to control this escape of fuel vapor effectively during the refilling process. Generally, the filler neck of a vehicle has a diameter greater than the diameter of the fuel-dispensing nozzle. Because of the relatively large diameter of the filler neck with respect to the fuel-dispensing nozzle, the fuel vapor created by fuel dispensed into the fuel tank through the filler neck escapes out through the filler neck and to the atmosphere substantially continuously during the filling operation. This creation of fuel vapor during the refueling process has recently been recognized as a major contributor to pollution of the atmosphere, especially with newer, more volatile blends of vehicle fuel.
Attempts have been made to control this escape of fuel vapor during the filling process by adapting the service station fuel-dispensing nozzle to include a vapor recovery portion which captures the escaping fuel vapor and prevents the fuel vapor from escaping into the atmosphere. Such conventional methods of capturing the escaping fuel vapor have generally proven unsatisfactory because of the complexity of the system and because of relatively poor vapor-capturing characteristics of the system. It is generally recognized that for satisfactory fuel vapor control during refilling, a system must be provided which is on-board the vehicle for capturing and controlling such fuel vapor generated during refilling. Ideally, such a system would work automatically without any operator supervision.
Another problem with many conventional filler neck and fuel tank assemblies is that it is sometimes extremely difficult to achieve accurate filling levels because of poorly designed filler neck seals which leak, resulting in an inability to maintain any vacuum that might develop in the filler neck itself during introduction of fuel into the filler neck. Conventional fuel nozzles are often equipped with vacuum-actuated systems that shut off flow of fuel through the nozzle upon exposure of a sensor in the nozzle to a predetermined negative pressure. Typically, the splashed back fuel enters and blocks a conduit formed in the nozzle to lie in communication with the sensor to generate the negative pressure, thereby shutting off fuel flow.
Relying upon fuel splash-back provides generally unsatisfactory fill level consistency because such fuel splash back is dependent upon a number of factors. Such factors include the flow rate of the nozzle, the configuration and routing of the filler neck, and the general orientation of the filler neck with the fuel tank, as well as fuel-dispensing nozzle sensitivity. Because of such inconsistency in achieving accurate fill levels, it would be advantageous to provide a nozzle shutoff control system having an improved means for providing a negative pressure signal to a vacuum-actuated shutoff sensor which would ideally permit the fuel tank to be filled to accurate, consistent fill levels during each refueling operation.
One object of the present invention is to provide a sealing assembly for partitioning a fuel-conducting passageway in a filler neck to limit flow of vapors and gases through the passageway during dispensing of fuel into the filler neck and past the sealing assembly.
Another object of the present invention is to provide a sealing assembly for preventing fuel vapor loss to the atmosphere through the filler neck during refueling in cooperation with a fuel vapor recovery system.
Yet another object of the present invention is to provide a sealing assembly for blocking communication of an inner chamber of the filler neck with the atmosphere during refueling to maintain a negative pressure condition in the inner chamber in cooperation with a vapor-handling system to enhance operation of a vacuum-actuated nozzle shutoff system communicating with the inner chamber.
Another object of the present invention is to provide a filler neck sealing assembly having an elastic seal configured to maintain unbroken sealing engagement with the nozzle during insertion of the nozzle into and withdrawal of the nozzle from the filler neck, even though the nozzle may have been deformed to assume an out-of-round shape.
Yet another object of the present invention is to provide a filler neck sealing assembly having an elastic seal that is configured to be stretched or distended easily to conform to the contours of an out-of-round fuel-dispensing nozzle.
According to the present invention, a filler neck seal assembly is provided for use in a filler neck sized to receive a fuel-dispensing nozzle. The seal assembly includes an elastic seal member and a seal retainer. The seal member has an annular fuel nozzle-sealing portion and an annular filler neck-mounting portion which surrounds the annular fuel nozzle-sealing portion. The seal retainer includes means for engaging a filler neck containing the seal member and means for unyieldingly clamping the annular filler neck mounting portion of the seal member to the filler neck to establish a fixed circumferentially extending liquid fuel and fuel vapor seal between the seal member and the filler neck. The filler neck-mounting portion of the seal member is clamped to cantilever the annular fuel nozzle-sealing portion in the filler neck for movement relative to the clamped filler neck-mounting portion in response to engagement with a fuel nozzle during movement of the fuel nozzle in the filler neck.
In preferred embodiments, the annular fuel nozzle-sealing portion includes an annular, radially inwardly facing, perimeter end wall defining a nozzle-receiving aperture and inclined annular outer and inner sealing faces. The outer sealing face is presented in an axially outwardly direction toward the filler neck mouth to engage the nozzle in sealing relation during insertion of the nozzle into the nozzle-receiving aperture. The inner sealing face is presented in an axially inwardly facing direction away from the filler neck mouth to engage the nozzle in sealing relation during withdrawal of the nozzle from the nozzle-receiving aperture. The outer and inner sealing faces are interconnected by the annular, radially inwardly facing, perimeter end wall and diverge in a radially outwardly extending direction away from the perimeter end wall and toward the filler neck-mounting portion.
The elastic annular seal member is formed to include an axially outwardly facing first annular groove and an axially extending second annular groove between the fuel nozzle-sealing and filler neck-mounting portions. A radially extending, axially outwardly facing surface defines a bottom wall of the first annular groove and a radially extending, axially inwardly facing surface defines a bottom wall of the second annular groove. The filler neck includes positioning means extending into the second annular groove formed in the seal member for positioning the filler neck-mounting portion in sealing engagement with the filler neck.
The seal retainer includes retaining means extending into the first annular groove formed in the seal member for retaining the filler neck-mounting portion in sealing engagement with the filler neck to establish fixed circumferentially extending liquid fuel and fuel vapor seal between the seal member and the filler neck. The seal retainer includes means for rotatably engaging the filler neck to place the retaining means in the first annular groove formed in the seal member.
One feature of the present invention is the provision in a filler neck of seal-establishing means for admitting a fuel-dispensing nozzle into an inner chamber in the filler neck without coupling the inner chamber to the atmosphere through the filler neck mouth. One advantage of such a sealing system is that it helps to prevent fuel vapor loss through the filler neck during operation of an on-board vehicle fuel vapor recovery system by blocking flow of pressurized fuel vapor in the filler neck to the atmosphere during refueling. Another advantage of this sealing system is that it cooperates with a vapor-handling system in a vehicle fuel system to maintain any negative pressure condition that develops in the inner chamber during refueling to enhance the operation of a vacuum-actuated nozzle shutoff system having its shutoff sensor communicating with the inner chamber.
Another feature of the present invention is that the seal member includes a radially outer portion that is securely clamped in place in the filler neck to establish a fixed circumferentially extending liquid fuel and fuel vapor seal in the filler neck between the seal member and the filler neck. Advantageously, such a fixed seal is less likely to be broken as a result of wear and tear on the seal member caused by repeated insertion and removal of the fuel-dispensing nozzle during refueling.
Still another feature of the present invention is that the seal member includes a radially inner portion that is configured to stretch and move relative to the clamped radially outer portion when engaged by the fuel-dispensing nozzle so that the seal member is stretched or distended to conform to the contour of a conventional or out-of-round nozzle during insertion of the nozzle into the filler neck and withdrawal of the nozzle from the filler neck. In a preferred embodiment, the seal member includes a thin annular web that is configured to interconnect the relatively thicker unclamped nozzle-sealing portion and clamped seal-mounting portions of the seal member. Provision of a thinner annular web allows the movable nozzle-sealing portion to stretch more easily to follow a regular or irregular contour of the fuel-dispensing nozzle as it is moved within the filler neck during refueling.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.