The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 09, 1997
Filed:
Sep. 11, 1996
Edward George Rychlick, Canton, MI (US);
Ford Global Technologies, Inc., Dearborn, MI (US);
Abstract
A fuel canister (18) and fuel tank (14) are purged of any fuel vapors formed therein through a purge valve (22). A method (32) is used to purge the fuel canister (18) and fuel tank (14) in a manner which maintains the stoichiometric balance of fuel and air to be combusted by an internal combustion engine (12). Fuzzy logic is used to correlate the ratio of fuel to air (in mass per unit volume) to a duty cycle in which the purge valve (22) is opened. The fuzzy logic correlation includes the use of triangle functions having substantially similar period which are offset or skewed from each other by fifty percent. This allows each ratio value to be generated by two membership values which provides for a more accurate reading in a less complex manner.