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:
Dec. 02, 1997
Filed:
Oct. 04, 1996
Kojiro Tsutsumi, Wako, JP;
Yuji Fujiki, Wako, JP;
Toshitaka Hachiro, Wako, JP;
Shigeto Kashiwabara, Wako, JP;
Fumio Hara, Wako, JP;
Sachito Fujimoto, Wako, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An air-fuel ratio sensor deterioration-detecting system is provided for an internal combustion engine having first and second air-fuel ratio sensors arranged in the exhaust system upstream and downstream of a catalytic converter therein. An ECU calculates a control parameter, based on an output from the second air-fuel ratio sensor, calculates an air-fuel ratio correction amount, based on an output from the first air-fuel ratio sensor and the calculated control parameter, and executes air-fuel ratio feedback control, based on the calculated air-fuel ratio correction amount. The ECU also determines deterioration of the second air-fuel ratio sensor, based on the output from the same in such a manner that the air-fuel ratio correction amount is increased or decreased by a predetermined amount, based on the output from the second air-fuel ratio when a variation in the second air-fuel ratio sensor output falls within a predetermined small variation range during execution of the air-fuel ratio feedback control, and the second air-fuel ratio sensor is determined to be deteriorated when the output variation falls within the predetermined small variation range even after the increase or decrease of the air-fuel ratio correction amount.