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:
Jul. 11, 1995
Filed:
Dec. 14, 1993
Mark V Casarella, Fenton, MI (US);
James R Yurgil, Livonia, MI (US);
David R Wade, Waterford, MI (US);
Gary A Kleinfelder, Mercer, PA (US);
Kurt A Wellenkotter, Rochester Hills, MI (US);
John F Vangilder, Webberville, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A diagnostic for an internal combustion engine exhaust gas treatment means includes a series of enabling conditions for modelling temperature and operational stability of the treatment means and includes first and second stage tests alternately applied on an engine air/fuel ratio cycle-by-cycle basis in accord with the diagnosed performance of the treatment means using post-converter oxygen sensor information. When the treatment means performance is diagnosed as being degraded close to a failed condition, the first stage is disabled and the more statistically rigorous second stage is activated to closely scrutinize converter performance using a two phase approach for false alarm protection.