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:
Mar. 18, 1980
Filed:
Jul. 27, 1978
David W Rogers, Rochester, NY (US);
General Motors Corporation, Detroit, MI (US);
Abstract
In an evaporative control system for reducing emission of fuel vapors from an engine fuel system there is provided a vacuum operated valve arrangement having a two-position valve which is spring biased to open to permit venting of fuel vapor from a carburetor fuel bowl to a carbon canister when the engine is not running and is responsive to engine vacuum only above a predetermined negative pressure to close to prevent such venting when the engine is running, and a check valve and bleed valve arrangement which is operable to trap engine vacuum at the two-position valve at a vacuum at or above the predetermined negative pressure whenever the engine vacuum drops below such pressure to thereby maintain the two-position valve in its closed position preventing fuel vapor venting during engine running at low engine vacuum and operating to release the trapped engine vacuum at the two-position valve to thereby permit the valve to open to permit fuel vapor venting when the engine is not running.