Fuel Tank Filler Neck Check Valve

This invention relates to fuel tanks for storing liquid fuels and more particularly to filler neck and check valves for filling such tanks with fuel.

Environmental awareness has prompted numerous efforts to reduce the escape of gasoline fumes and liquid into the atmosphere, as from vehicle fuel tanks, particularly when filling the tank with fuel. Attention is now being given to fuel filling stations where self-service is now more common than service by gas station attendants. Customer self-service in the vehicle fuel tank filling operation aggravates the air pollution problems already associated with vehicle gasoline tank filler necks, which of course must be left open with the associated outside gas cap removed during tank filling. Excessive tank open time often results from improper customer operation of the fuel pump hose nozzle, such as leaving the same in the fill tube longer than necessary for tank filling while the gas cap is off and hence the tank is open via the filler neck to ambient atmosphere. Fuel splash back from the tank into and up out of the filler neck to ambient atmosphere as the tank approaches full level is also aggravated by amateur customer self-service.

It is an object of the present invention to provide an improved fuel tank and filler neck with a tank neck coupling construction which is adapted to use a non-return valve which opens to allow free flow for fuel entering a tank but which responds instantly to close the fuel tank filler neck when the flow of entering fuel is stopped to thereby prevent escape of liquid fuel and fuel vapors from the tank even with the gas cap open at the top of the filler neck.

Other objects are to provide an improved valve construction of the aforementioned character which can be retrofitted into existing tank necks without expensive redesign, and made of inexpensive materials with low mass which has a quick response to close the neck when fuel inflow is stopped to thereby prevent splash-back of fuel from the tank into and up out of the filler neck.

A further object is to provide an improved valve and tank/neck coupling construction of the aforementioned character that in the event the filler neck is pulled loose from the tank fill spout in a vehicle crash, will maintain the tank fill spout sealed closed to prevent crash induced fuel spillage from the tank via the fill spout.

In a filler neck installation of a fuel tank wherein the neck extends from the gas cap downwardly to the fuel tank, a fill-valve insert is telescoped around the depending tank end of the filler neck. This insert has an upper annular ring to receive and seal around the exterior of the tank end of the filler neck, and a lower annular valve seat encircling an insert through-passageway communicating with the neck tank-filling passageway. A flexible disc valve is center supported on a spider arm in the insert and cooperates with the valve seat to function as a one-way check valve at the tank outlet of the filler neck. A resiliently biased slide pin has a central button which supports the disc valve slidably on the spider for bodily travel of the valve disc in an opening direction far away from the valve seat to thereby reduce valve flow restriction, and allowing the disc valve to open rapidly and widely in response to fuel inflow, and responding to the ceasing of the flow to quickly move the valve disc back into position to close the annular valve seat. The insert valve remains closed and the insert assembly is positively retained against outward dislodgement from the tank fill spout by a lock ring collar in the event the filler neck is pulled loose from its compression seal frictional clamp retention in the collar, such as might occur in a vehicle crash.

These and other objects, features and advantages of the invention will be apparent from the following detailed description of the preferred embodiment and best mode presently contemplated for the invention, the appended claims and accompanying drawing in which:

FIG. 1 is a diagrammatic view of a fuel tank and filler neck embodying the present invention, with portions broken away to illustrate tank-interior details.

FIG. 2 is a fragmentary axis-centered sectional view of the filler valve tank connection with the details of the tank entrance valve of the invention.

FIG. 3 is a fragmentary cross-sectional view taken on line 3--3 of FIG. 2.

In FIG. 1, an automotive vehicle fuel tank 20 has a fuel pump module 22 therein with a removable cover 23 sealed to the top of the tank with an electrical connection 24 and a fuel line outlet connector 26. Within the tank the module 22 has a fuel reservoir 28 which contains an electrical pump 30 with an inlet 32. A float gage 34 is provided to indicate fuel level. A tank filler neck tube 40 has a top end 42 provided with a removable gas cap 44 and mounted in the vehicle body 46. A flex segment 48 connects the neck 40 with a tank fill connector collar assembly 50 shown in detail in FIG. 2.

The fuel tank 20 is formed of laminated polyethylene material 60 (with an embedded vapor barrier film) and has an integral upstanding threaded fill spout 62. A fill tube lock ring assembly comprises a cup-shaped collar 64 which has a threaded seal liner 66 formed with an inner ring flange 68 surrounding, sealing against and frictionally clamping the outer surface of the lower end 70 of the filler neck 40. A main ring seal 72 of flexible sealing material also surrounds, seals and frictionally clamps against tube end 70, and is received and contained in spout 62 between it and filler pipe end 70. An annular bead 74 of collar liner flange 68 bears against a U-cross sectional pressure wear ring 76 which is located above and pressed into ring seal 72 as collar 64 is threadably tightened down on spout 62 to develop fill-tube-mounting frictional clamp pressure and to simultaneously compress seal 72 into a liquid and gas tight seal between the spout and fill tube end.

The fill neck/tank coupler construction of the invention further includes a tank-entrance check valve insert assembly 80 slip-fit attached to the fill tube tank outlet end 70. Insert assembly 80 contains a check valve structure which opens widely to allow a high flow rate of fuel to enter the tank, but when fuel inflow is shut off at the service station fuel pump nozzle the check valve quickly closes the fill tube outlet to prevent fuel splash back up the open fill tube, and also escape therethrough of fuel vapor from the tank.

Valve insert assembly 80 has a tubular mounting portion 82 which terminates at the top end, as viewed in FIG. 2, in a shouldered ring 84. Tubular portion 82 is installed by inserting it tank-end first into the exterior end of tank spout 62 until shouldered ring 84 abuts an internal shoulder 86 provided on the inside of spout 62. Preferably the tubular portion 82 also has an annular detent ring 87 which snaps into a complimentary retainer groove in the fill spout 62. Installation is also facilitated by a cam ring 89 on the tubular portion which also "loosely" retains it in the fill spout 62. Seal ring 72 as installed abuts the top of ring 84 and cooperates with lock ring collar 64 to positively prevent removal of insert 80 from the spout once so installed.

Insert assembly 80 also has an inner depending re-entrant tubular portion 88, spaced inwardly of and concentric with portion 82 and terminating in a generally open, tri-legged spider base having three radial legs 90 integral therewith. The legs mount an integral central valve support disc 92 and a guide sleeve 94 that protrudes upstream therefrom into tube end 70. A preferably stainless steel T-shaped valve carrier 100 having a hollow slide pin shank 101 terminates at its bottom end integrally in a button head 102 having an annular sealing rib 104 facing upstream. A coil spring 108 is abutted between the central valve support 90/92 and a lock cap 106 fixed on the top of pin 101 that urges carrier 100 and associated button head 102 upwardly (upstream).

A movable valve seat sealing member of valve insert assembly 80 is loosely disposed between button head 102 and the support disc 92 and comprises a flexible resilient silicone rubber flapper disc 110 having a central hole through which passes carrier shank 101. Disc 110 has a outside diameter such that its periphery overlies and extends beyond an annular valve seat 112 integrally formed on the downstream end of depending tubular portion 88. Valve disc 110 has sufficient resilience to allow it to flex downstream to partially wrap around head 102 during and in response to rapid fuel inflow down tube 70, but a resilient memory which causes it to return to the generally planar or frusto-conical closure position and shape shown in FIG. 1 to sealably engage valve seat 112 when no fuel is present upstream of the valve disc. When the valve is closed the resilient disc and the annular rib 104 of the valve carrier provide a seal between them.

To assemble the parts, valve insert assembly 80 is positioned in threaded spout 62 with shouldered ring 84 bottomed against spout shoulder 86. Main sealing ring 72 is next inserted in spout 62 and secondary ring 76 placed against its upper end. The cup-shaped lock ring collar 64 containing the threaded liner 66 is then loosely threaded down onto spout 62. Next the lower end of the fill pipe 70 is slidably inserted through ring flange 68, main seal 72 and into tubular portion 88 of valve insert 80 to thereby preferably position tube end 70 on the bottom shoulder of the tubular portion 88 and preferably protruding slightly into tank 20 as shown in FIG. 2. After the fill pipe is inserted, the threaded lock ring collar 64 can then be threadably tightened down to cause the annular bead 74 to axially compress the seals 72 and 76 and radially expand seals 72 the main seal 72 for liquid and vapor sealing between tube 70 and spout 62 and to thereby frictionally clamp the filler neck 40 to the tank.

In operation when liquid fuel is introduced into the open top of the fill pipe 40 from the hose pump nozzle at the station pump, with gas cap 44 open or removed, the rapid fuel flow in the direction of the arrows in FIG. 2 will force open the flexible perimeter of the rubber disc 110 (bend it in the downstream direction) and also force it to move bodily along with button head 102 downstream against the biasing force of spring 108. This fuel inflow must not be unduly restricted because to do so would cause premature shut-off of the pump nozzle by its automatic shut-off mechanism. Hence the calibration of spring 108, the flexing of the disc 110 and the downstream bodily travel of valve disc 110 on carrier 100 away from valve seat 112 must be such that a flow of fuel at the rate of twelve to fifteen gallons per minute will pass freely into the fuel tank.

When the fuel inflow from the pump nozzle is cut off, spring 108 will force carrier 100 to move slidably and quickly in the upstream direction back to its position shown in FIG. 2. This motion in conjunction with the yieldably resilient recovery of the rubber disc 110, will rapidly and almost immediately close disc 110 sealably against seat 112 to thereby prevent liquid splash back and/or the escape of fuel vapor from the tank to the atmosphere via tube 70. Of course, excess vapor pressure in the tank headspace acting on disc 110 and/or liquid fuel splashed from the tank interior toward the fill pipe outlet against disc 110 will accelerate such spring-biased and flap recovery valve closing action.

In accordance with another feature of the invention, filler neck end 70 could be yanked loose from collar assembly 50 by extreme pull-out forces generated in some vehicle crashes due to its frictional slip fit and clamping in the collar without damaging or rupturing the integrity of the tank 20. However, in such event valve insert assembly 80 remains securely fastened in and to tank spout 62 by the positive retention of collar structure 64/66/68 acting on seal 72 to hold insert shoulder 84 against spout shoulder 86 and detent ring 87. Hence the flow opening defined by valve seat 112 in the inner end of the insert will remain sealed by valve 110, and seal 72 will retain sufficient sealing capability to prevent fuel leakage between insert 80 and spout 62.