초록

A tank venting system includes a diaphragm valve movable to open and close a passageway leading to a fuel tank. The system also includes a fuel vapor recovery canister used to adsorb hydrocarbons associated with fuel vapor flowing through the passageway.

대표청구항 ▼

The invention claimed is: 1. A tank venting system comprising a base formed to include a tank passageway adapted to be coupled in fluid communication to a fuel tank and a canister passageway adapted to be coupled in fluid communication to a vapor recovery canister and arranged to open into the tank

The invention claimed is: 1. A tank venting system comprising a base formed to include a tank passageway adapted to be coupled in fluid communication to a fuel tank and a canister passageway adapted to be coupled in fluid communication to a vapor recovery canister and arranged to open into the tank passageway, the base also being formed to include a valve seat at a fluid-conducting interface between the tank and canister passageways, a diaphragm valve having a first side exposed to fuel vapor extant in the tank and canister passageways and an opposite second side exposed to outside air, the diaphragm valve being mounted for movement relative to the base to a closed position wherein the first side engages the valve seat to block flow of fuel vapor between the tank and canister passageways and an opened position wherein the first side disengages the valve seat to allow flow of fuel vapor between the tank and canister passageways, and hydrocarbon recovery means for receiving any diffused hydrocarbon material associated with fuel vapor extant in the tank and canister passageways that has diffused through pores extant in the diaphragm valve and exited through the pores opening on the opposite second side of the diaphragm valve and for discharging such diffused hydrocarbon material into the canister passageway for delivery to the vapor recovery canister upon exposure of the canister passageway to a purge vacuum sufficient to apply a suction force to the first side of the diaphragm valve to move the diaphragm valve to assume the closed position so that negative pressure extant in the canister passageway is not applied to the fuel tank via the tank passageway. 2. The tank venting system of claim 1, wherein the hydrocarbon recovery means includes a shell cooperating with the base to form an interior region bounded in part by the second side of the diaphragm valve and located to receive diffused hydrocarbon material exiting the diaphragm valve through the pores opening in the second side of the diaphragm valve, a vapor-conducting conduit having an inlet opening into the interior region and an outlet opening into the canister passageway, and a hydrocarbon filter located in the interior region at the inlet of the vapor-conducting conduit to adsorb diffused hydrocarbon material entrained in fuel vapor flowing from the interior region through the hydrocarbon filter and the vapor-conducting conduit into the canister passageway upon exposure of the canister passageway to the purge vacuum and application of the purge vacuum to the interior region via the canister passageway, vapor-conducting conduit, and hydrocarbon filter. 3. The tank venting system of claim 2, wherein the hydrocarbon recovery means further includes a valve seat associated with the vapor-conducting conduit and a vacuum-actuated regulator mounted for movement from a normally closed position engaging the valve seat to block flow of fuel vapor from the hydrocarbon filter into the canister passageway through the vapor-conducting conduit to an opened position disengaging the valve seat to allow flow of fuel vapor laden with diffused hydrocarbon material from the hydrocarbon filter into the canister passageway through the vapor-conducting conduit upon exposure of the canister passageway to the purge vacuum. 4. The tank venting system of claim 3, wherein the shell is formed to define the valve seat and an upper portion of the vapor-conducting conduit opening into the interior region, the base is formed to include a lower portion of the vapor-conducting conduit opening into the canister passageway, and the hydrocarbon recovery means further includes means for establishing a sealed connection between the base and the shell at a junction of the upper and lower portions of the vapor-conducting conduit so that fuel vapor laden with diffused hydrocarbon material flows from the upper portion into the lower portion without leakage. 5. The tank venting system of claim 4, wherein the lower portion of the vapor-conducting conduit has a first inner diameter and the base further includes a protuberance extending into the lower portion of the vapor-conducting conduit to provide a reduced-diameter purge orifice having a second inner diameter that is less than the first inner diameter. 6. The tank venting system of claim 2, wherein the shell includes a lid coupled to the base and arranged to cooperate with the second side of the diaphragm valve to form an upper chamber therebetween located to receive diffused hydrocarbon material exiting the diaphragm valve through the pores opening on the second side of the diaphragm valve and a cover coupled to the lid to form a cover chamber therebetween, the cover chamber contains the hydrocarbon filter and communicates with the vapor-conducting conduit via the inlet, the lid is formed to include a port arranged to conduct fuel vapor extant in the upper chamber into the cover chamber, and at least a portion of the hydrocarbon filter is interposed between the port of the lid and the inlet of the vapor-conducting conduit to intercept and adsorb diffused hydrocarbon material entrained in fuel vapor entering the cover chamber through the port formed in the lid and flowing toward the inlet of the vapor-conducting conduit. 7. The tank venting system of claim 6, wherein the hydrocarbon recovery means further includes hydrocarbon purge means for applying a purge vacuum to the canister passageway to apply the suction force to the first side of the diaphragm valve to move the diaphragm valve to assume the closed position and for applying the purge vacuum to the cover chamber via the canister passageway and the vapor-conducting conduit to draw outside air into the cover chamber though a vent port formed in the shell and opened to outside air surrounding the shell and then into the hydrocarbon filter to purge hydrocarbon material from the hydrocarbon filter and entrain the purged hydrocarbon material in fuel vapor drawn from the cover chamber, vapor-conducting conduit, and the canister passageway for delivery to a vapor-recovery canister associated with the canister passageway. 8. The tank venting system of claim 6, wherein the hydrocarbon recovery means further includes an umbrella/duckbill valve mounted on the lid and configured to provide umbrella valve means for controlling flow of fuel vapor containing diffused hydrocarbon material from the upper chamber through the port formed in the lid into the cover chamber to reach the hydrocarbon filter so that fuel vapor is able to flow from the upper chamber into the cover chamber whenever the diaphragm valve moves from the closed position to the opened position and duckbill valve means for controlling flow of outside air entering the cover chamber through the vent port into the upper chamber to maintain pressure in the upper chamber at about atmospheric pressure. 9. The tank venting system of claim 6, wherein the hydrocarbon recovery means further includes discharge valve means normally closing the port formed in the lid for allowing flow of fuel vapor containing diffused hydrocarbon material from the upper chamber through the port formed in the lid into the cover chamber to reach the hydrocarbon filter in response to movement of the diaphragm valve from the closed position to the opened position. 10. The tank venting system of claim 6, wherein the hydrocarbon recovery means further includes intake valve means for selectively conducting outside air and fuel vapor extant in the cover chamber into the upper chamber through an aperture formed in the lid to maintain fuel vapor extant in the upper chamber at about atmospheric pressure. 11. The tank venting system of claim 10, wherein the hydrocarbon recovery means further includes discharge valve means normally closing the port formed in the lid for allowing flow of fuel vapor containing diffused hydrocarbon material from the upper chamber through the port formed in the lid into the cover chamber to reach the hydrocarbon filter in response to movement of the diaphragm valve from the closed position to the opened position and a valve unit coupled to the lid to extend through the aperture formed in the lid and the valve unit is made of a monolithic hydrocarbon permeation-resistant material and is configured to include the discharge valve means and the intake valve means. 12. The tank venting system of claim 6, wherein the lid is formed to include a port opening into the upper and cover chambers and an aperture opening into the upper and cover chambers, a flow control valve unit arranged normally to close the port and the aperture and mounted for movement relative to the lid to open one of the port and aperture to regulate fuel vapor flow between the upper and cover chambers, the diaphragm valve is made of a hydrocarbon permeable elastomeric material formed to include pores through which hydrocarbon material is able to flow, and the flow control valve unit, lid, and base are made of a hydrocarbon permeation-resistant material. 13. The tank venting system of claim 1, wherein the hydrocarbon recovery means includes a hydrocarbon filter arranged to adsorb diffused hydrocarbon material and to lie in a filter passageway having an inlet receiving the diffused hydrocarbon material and an outlet opening into the canister passageway and hydrocarbon purge means for applying a purge vacuum to the canister passageway to apply the suction force to the first side of the diaphragm valve to move the diaphragm valve to the closed position and for applying the purge vacuum to the filter passageway via the canister passageway to draw air through the hydrocarbon filter to entrain hydrocarbon material adsorbed on the hydrocarbon filter into the air drawn through the hydrocarbon filter to produce a stream of fuel vapor moving through a portion of the canister passageway toward a vapor recovery canister associated with the canister passageway. 14. The tank venting system of claim 13, wherein the base is formed to include a port having an inlet opening into the canister passageway and an outlet opening into the tank passageway and further comprising a vacuum-relief regulator mounted for movement relative to the base from a normally closed position blocking flow of outside air entering the canister passageway through the port into the tank passageway to an opened position allowing flow of outside air entering the canister passageway through the port into the tank passageway when pressure in the tank passageway rises above a predetermined subatmospheric level. 15. A tank venting system comprising a diaphragm valve movable to control air and fuel vapor flow between a canister passageway adapted to be coupled to a fuel vapor recovery passageway and a tank passageway adapted to be coupled to a fuel tank, a first side of the diaphragm valve being exposed to fuel vapor extant in the canister and tank passageways and being movable to engage a valve seat provided in a base formed to include the canister and tank passageways to block air and fuel vapor flow between the canister and tank passageways, a shell coupled to the base and formed to include an interior region bounded in part by an opposite second side of the diaphragm valve, the shell further including a lid coupled to the base to cause the diaphragm valve to lie in a region formed between the lid and the base and to partition the region into a lower chamber bounded in part by the first side of the diaphragm valve and defined by the canister and tank passageways and an upper chamber bounded in part by the lid and the opposite second side of the diaphragm valve and located to receive diffused hydrocarbon material exiting through pores opening on the opposite second side of the diaphragm valve, and a hydrocarbon filter located in the interior region outside of the upper chamber and configured to adsorb any diffused hydrocarbon material associated with fuel vapor in the canister and tank passageways that has diffused through pores extant in the diaphragm valve and exited through the pores opening on the opposite second side of the diaphragm valve. 16. The tank venting system of claim 15, wherein the base is formed to include a port having an inlet opening into the canister passageway and an outlet opening into the tank passageway and further comprising a vacuum-relief regulator mounted for movement relative to the base from a normally closed position blocking flow of outside air entering the canister passageway though the port into the tank passageway to an opened position allowing flow of outside air entering the canister passageway though the port into the tank passageway when pressure in the tank passageway rises above a predetermined subatmospheric level. 17. The tank venting system of claim 16, wherein the canister passageway terminates at the valve seat and the vacuum-relief regulator is arranged to underlie the first side of the diaphragm valve. 18. The tank venting system of claim 15, wherein the shell further includes a cover mounted on the lid to form a cover chamber containing the hydrocarbon filter, the lid is formed to include a port arranged to conduct fuel vapor extant in the upper chamber into the cover chamber to allow diffused hydrocarbon material entrained in the fuel vapor to reach the hydrocarbon filter, and further comprising discharge valve means normally closing the port formed in the lid for allowing flow of fuel vapor containing diffused hydrocarbon material from the upper chamber through the port formed in the lid into the cover chamber to reach the hydrocarbon filter in response to movement of the diaphragm valve from the closed position to the opened position. 19. The tank venting system of claim 18, wherein the lid is also formed to include an aperture separate from the port and further comprising intake valve means for selectively conducting outside air admitted into the cover chamber through a vent port formed in the cover into the upper chamber through the aperture to maintain fuel vapor extant in the upper chamber at about atmospheric pressure. 20. The tank venting system of claim 19, further comprising a valve unit coupled to the lid to extend through the aperture formed in the lid and the valve unit is made of a monolithic hydrocarbon permeation-resistant material and is configured to include the discharge valve means and the intake valve means. 21. The tank venting system of claim 15, wherein the shell further includes a cover mounted on the lid to form a cover chamber containing the hydrocarbon filter, the lid is formed to include an aperture to conduct outside air admitted in the cover chamber through a vent port formed in the cover into the upper chamber, and further comprising intake valve means for selectively conducting outside air and fuel vapor extant in the cover chamber into the upper chamber through the aperture formed in the lid to maintain fuel vapor extant in the upper chamber at about atmospheric pressure. 22. The tank venting system of claim 21, wherein the intake valve means is a duckbill valve having a mount portion coupled to the lid and arranged to extend though the aperture and a duckbill portion comprising mating first and second flaps that can be separated to open a passageway located between the flaps to couple the upper chamber and the cover chamber in fluid communication. 23. The tank venting system of claim 15, wherein the shell further includes a cover mounted on the lid to form a cover chamber containing the hydrocarbon filter, the lid is formed to include a port arranged to conduct fuel vapor extant in the upper chamber into the cover chamber to allow diffused hydrocarbon material entrained in the fuel vapor to reach the hydrocarbon filter, and further comprising hydrocarbon purge means for applying a purge vacuum to the cover chamber to draw air through the hydrocarbon filter to entrain hydrocarbon material adsorbed on the hydrocarbon filter into air drawn though the hydrocarbon filter to produce a stream of fuel vapor containing such hydrocarbon material and moving through a portion of the canister passageway toward a vapor recovery canister associated with the canister passageway. 24. The tank venting system of claim 23, wherein the purge vacuum is also applied to the canister passageway to apply a suction force to the first side of the diaphragm valve to move the diaphragm valve to the closed position so that negative pressure extant in the canister passageway is not applied to the fuel tank via the tank passageway. 25. The tank venting system of claim 15 further comprising means for transferring diffused hydrocarbon material adsorbed on the hydrocarbon filter through a portion of the canister passageway to a fuel vapor recovery canister associated with the canister passageway. 26. A tank venting system comprising a vent apparatus including a housing and a cover mounted on the housing, the housing including a base formed to include a tank passageway adapted to be coupled to a fuel tank and a canister passageway adapted to be coupled to a vapor recovery canister and configured to terminate at a valve seat, the housing further including a lid coupled to the base to form a region therebetween, the vent apparatus further including a diaphragm valve mounted in the housing to partition the region formed by the lid and the base into a lower chamber communicating with the tank and canister passageways and an upper chamber bounded in part by the lid, the diaphragm valve being mounted for movement relative to the base to a closed position engaging the valve seat to block flow of air and fuel vapor between the canister and tank passageways and an opened position disengaging the valve seat to allow flow of air and fuel vapor between the canister and tank passageways, the cover being coupled to the lid to form a cover chamber therebetween, the vent apparatus further including a hydrocarbon filter located in the cover chamber, an umbrella valve mounted on the lid and configured to control discharge of fuel vapor laden with diffused hydrocarbon material that is associated with fuel vapor in the canister and tank passageways and has diffused through pores extant in the diaphragm valve and entered the upper chamber, a duckbill valve mounted on the lid and configured to admit outside air admitted into the cover chamber through a vent port formed in cover into the upper chamber to maintain the upper chamber at about an atmospheric pressure, a vapor-conducting conduit having an inlet opening into the canister passageway and an outlet opening into the cover chamber, and a check valve located in the vapor-conducting conduit and yieldably biased by a spring normally to assume a closed position blocking flow of fuel vapor from the cover chamber to the canister passageway through the vapor-conducting conduit, and hydrocarbon purge means for applying a purge vacuum to the canister passageway to apply a suction force to the diaphragm valve to move the diaphragm valve to the closed position and to apply a suction force to the check valve to move the check valve against the spring to an opened position so that a vacuum is applied to the hydrocarbon filter to draw air through the hydrocarbon filter to entrain hydrocarbon material adsorbed on the hydrocarbon filter into air drawn through the hydrocarbon filter to produce a stream of fuel vapor containing such hydrocarbon material and moving through the vapor-conducting conduit and a portion of the canister passageway toward a vapor recovery canister associated with the canister passageway.