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:
Oct. 29, 1991
Filed:
Jun. 12, 1990
Yasunari Seki, Wako, JP;
Yosuke Tachibana, Wako, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
Failure of a valve timing changeover control system of an internal combustion engine is detected by comparing a present value of an air-fuel ratio feedback control correction coefficient which is varied in response to output from an O.sub.2 sensor with a predetermined value of the correction coefficient obtained based on values of same obtained during the feedback control of the air-fuel ratio. Alternatively, or in combination, failure of the valve timing changeover control system is detected by determining whether a present value of the correction coefficient obtained with respect to each of a plurality of cylinders of the engine in response to output from each of O.sub.2 sensors corresponding to the each cylinder is outside a predetermined range of deviation of values of the correction coefficient from a reference value, the deviation resulting from differences in characteristics between the cylinders.