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. 20, 1990
Filed:
Sep. 06, 1988
Hitachi, Ltd., Tokyo, JP;
Hitachi Automotive Engineering Co., Ltd., Katsuda, JP;
Abstract
In an apparatus of the type in which the air-fuel ratio of an engine is detected by an air-fuel ratio sensor and the air-fuel ratio is feedback-controlled in accordance with the detection result to operate the engine at a desired air-fuel ratio, a change of the output characteristic of the air-fuel ratio sensor is always corrected for. The apparatus includes means for detecting the air-fuel ratio of the engine from its exhaust gas composition, means for determining whether the engine is in a given constant operating condition, means for determining a desired air-fuel ratio for the constant operating condition, means for supplying the quantity of fuel corresponding to the desired air-fuel ratio to each cylinder of the engine, means for causing some of all the cylinders of the engine not greater in number than N-1 (N represents the total number of cylinders) to misfire when the engine comes into the constant operating condition, and means for correcting the output characteristic of the air-fuel ratio detecting means in accordance with the amount of change of the output of the air-fuel ratio detecting means before and after the misfiring.