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. 13, 1993
Filed:
Dec. 18, 1991
Keith D Armitage, Canton Township, Wayne County, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A method of detecting a misfire condition in a spark ignited internal combustion engine where the idle speed of the engine is controlled by an idle speed control means which controls engine idle speed by varying the spark timing advance for the engine ignition system. With the engine running at idle speed, the instantaneous spark timing advance being developed is repeatedly sampled for a predetermined number of consecutively occurring data samples. The absolute difference in sampled spark timing advance values between each pair of data samples is calculated for all of the predetermined number of data samples. The absolute differences in spark timing values that occur between data samples are added together to provide a sum total. If the sum total exceeds a reference value, the engine is operating in a misfire condition.