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A fuel system and a method of method of managing fuel vapor pressure in the fuel system. The fuel system a fuel tank having a headspace, a fuel vapor collection canister in fluid communication with the headspace, a purge valve, and a fuel vapor pressure management apparatus. The method includes perf

A fuel system and a method of method of managing fuel vapor pressure in the fuel system. The fuel system a fuel tank having a headspace, a fuel vapor collection canister in fluid communication with the headspace, a purge valve, and a fuel vapor pressure management apparatus. The method includes performing leak detection on the headspace, and preventing a flow of fluid through an elastic diaphragm during leak detection. The elastic diaphragm includes at least one opening through which passes the flow of fluid. And the preventing the flow of fluid includes a first portion of the elastic diaphragm sealingly engaging a second portion of the elastic diaphragm. The method further includes relieving excess negative pressure in the headspace and relieving excess positive pressure in the headspace by fluid flow in different directions along the same flow path that includes the opening in the diaphragm.

대표청구항 ▼

What is claimed is: 1. A fuel system for supplying fuel to an internal combustion engine, the fuel system comprising: a fuel tank having a headspace; an intake manifold of the internal combustion engine in fluid communication with the headspace; a fuel vapor collection canister in fluid communica

What is claimed is: 1. A fuel system for supplying fuel to an internal combustion engine, the fuel system comprising: a fuel tank having a headspace; an intake manifold of the internal combustion engine in fluid communication with the headspace; a fuel vapor collection canister in fluid communication with the headspace; a purge valve having a first side in fluid communication with the intake manifold and having a second side in fluid communication with fuel vapor collection canister and with the headspace; and a fuel vapor pressure management apparatus including: a housing coupled to the fuel vapor collection canister and defining an interior chamber; a pressure operable device including a diaphragm separating the interior chamber into a first portion in fluid communication with the fuel vapor collection canister and a second portion in fluid communication with a vent port, the diaphragm including a central portion movable along an axis, a peripheral portion fixed with respect to the housing, and an intermediate portion coupling the central and peripheral portions, a first arrangement of the pressure operable device occurs when there is a first negative pressure level in the fuel vapor collection canister relative to the vent port and the diaphragm is in a nearly undeformed configuration, the intermediate portion having at least one aperture and sections engaging each other to prevent fluid flow through the at least one aperture, a second arrangement of the pressure operable device permits a first fluid flow from the vent port to the fuel vapor collection canister when the diaphragm is in a first deformed configuration, and a third arrangement of the pressure operable device permits a second fluid flow from the fuel vapor collection canister to the vent port when the diaphragm is in a second deformed configuration; and a switch signaling the first arrangement of the pressure operable device. 2. The fuel system according to claim 1, wherein the intermediate portion of the diaphragm comprises: a convolute including a crest coupling first and second sidewalls; a first root section coupling the first sidewall and the central portion of the diaphragm; a second root section coupling the second sidewall and the peripheral portion of the diaphragm, the second root section sealingly engaging the first root section in the nearly undeformed configuration of the diaphragm, and the second root section disengaging the first root section in the first and second deformed configurations of the diaphragm; and a plurality of apertures penetrating at least one of the crest and the first and second sidewalls, the first and second fluid flows passing through the apertures in the first and second deformed configurations of the diaphragm. 3. The fuel system according to claim 1, wherein the pressure operable device comprises a resilient element biasing the diaphragm toward the nearly undeformed configuration. 4. The fuel system according to claim 1, further comprising: an engine control unit operatively connected to the purge valve, the engine control unit being electrically connected to the switch. 5. The fuel system according to claim 1, further comprising: a contiguous connection between the fuel vapor collection canister and the housing. 6. The fuel system according to claim 1, further comprising: a remote connection extending between the fuel vapor collection canister and the housing spaced from the fuel vapor collection canister. 7. The fuel system according to claim 6, wherein the remote connection is selected from a group consisting of a rigid pipe and a flexible pipe. 8. A method of managing pressure in a fuel system supplying fuel to an internal combustion engine, the fuel system including a fuel tank partially defining a headspace, the method comprising: connecting in fluid communication a fuel vapor collection canister to the headspace; connecting in fluid communication a fuel vapor pressure management apparatus to the fuel vapor collection canister, the fuel vapor pressure management apparatus performing leak detection on the headspace, the fuel vapor management apparatus including: a housing coupled to the fuel vapor collection canister and defining an interior chamber; a diaphragm dividing the interior chamber into a first portion in fluid communication with the fuel vapor collection canister and a second portion in fluid communication with a vent port; and establishing a fluid flow path extending between the fuel vapor collection canister and the vent port, the establishing including passing through the first portion of the interior chamber, passing through a plurality of apertures penetrating the diaphragm, and passing through the second portion of the interior chamber; relieving with the fuel vapor pressure management apparatus excess negative pressure in the fuel vapor collection canister via fluid flow in a first direction along the fluid flow path; and relieving with the fuel vapor pressure management apparatus excess positive pressure in the fuel vapor collection canister via fluid flow in a second direction along the fluid flow path, the second direction being opposite to the first direction; wherein the performing leak detection on the headspace comprises occluding the fluid flow path by having a first portion of the diaphragm sealingly engaging a second portion of the diaphragm. 9. The method according to claim 8, wherein the first and second portions of the diaphragm comprise concentric annuli. 10. A method of managing fuel vapor pressure in a fuel system supplying fuel to an internal combustion engine, the fuel system including a headspace, the method comprising: performing leak detection on the headspace of the fuel system; and preventing a flow of fluid through an elastic diaphragm during the performing leak detection, the elastic diaphragm including at least one opening through which passes the flow of fluid, and the preventing the flow of fluid including a first portion of the elastic diaphragm sealingly engaging a second portion of the elastic diaphragm. 11. The method according to claim 10, further comprising: performing excess negative pressure relief of the headspace, the performing excess negative pressure relief including the flow of fluid passing in a first direction through the at least one opening; and deforming the elastic diaphragm in a first deformed configuration during the performing excess negative pressure relief. 12. The method according to claim 11, further comprising: performing excess positive pressure relief of the headspace, the performing excess positive pressure relief including the flow of fluid passing in a second direction through the at least one opening, the second direction being opposite the first direction; and deforming the elastic diaphragm in a second deformed configuration during the performing excess positive pressure relief. 13. The method according to claim 10, further comprising: performing excess positive pressure relief of the headspace, the performing excess positive pressure relief including the flow of fluid passing through the at least one opening; and deforming the elastic diaphragm during the performing excess positive pressure relief. 14. The method according to claim 10, wherein the at least one opening comprises a plurality of apertures. 15. The method according to claim 10, wherein the first and second portions of the diaphragm comprise concentric annuli.