Patent ID: 7011077

Claim:
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.