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:
May. 18, 1999
Filed:
May. 08, 1997
Arthur G Poehlman, West Bend, WI (US);
Gary J Gracyalny, Milwaukee, WI (US);
Robert K Mitchell, Brookfield, WI (US);
Briggs & Stratton Corporation, Wauwatosa, WI (US);
Abstract
The automatic enrichment mechanism for an internal combustion engine is thermally-responsive and may also be centrifugally-responsive. The invention increases engine startability and minimizes stumbling and stalling of the engine during engine warmup. The thermally-responsive mechanism allows an additional reverse gas flow through the intake manifold to thereby increase the fuel discharged by the carburetor fuel nozzle. In several embodiments, the thermally-responsive mechanism, at low engine temperatures, causes a blocking or retaining member to keep an auxiliary cam member engaged with the cam follower of the valve assembly. As a result, the intake valve is partially unseated at low engine temperatures and a portion of the air/fuel mixture is fed back to the intake manifold. In these embodiments, when the engine temperature reaches a predetermined level, the thermally-responsive mechanism allows the auxiliary cam member to disengage from the cam follower in response to centrifugal force on the flyweights. In other embodiments, the thermally-responsive device allows crankcase gases to be fed to the intake manifold downstream of the fuel nozzle, causing a reverse flow of gas through the carburetor. The thermally-responsive member may be made from a thermal actuating polymer, commercial wax, bimetallic material, or from a nickel-titanium alloy which contracts at a predetermined engine temperature.