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:
Aug. 06, 1996
Filed:
Nov. 10, 1994
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
There is provided an air-fuel ratio control system for controlling the air-fuel ratio of a mixture supplied to an internal combustion engine having an exhaust passage. The system includes upstream and downstream exhaust gas component concentration sensors arranged in the exhaust passage at respective locations upstream and downstream of a catalytic converter, for detecting concentration of a component contained in exhaust gases. Feedback control of the air-fuel ratio of the mixture is carried out based on a value of a control parameter set based on an output from the downstream exhaust gas component concentration sensor and an output from the upstream exhaust gas component concentration sensor. An inversion period is detected with which the output from the upstream exhaust gas component concentration sensor is inverted from one side to another side with respect to a predetermined level during the feedback control of the air-fuel ratio. It is determined whether or not one of the output from the downstream exhaust gas component concentration sensor and the value of the control parameter falls within a predetermined range. It is determined whether or not the inversion period is within a predetermined time period. Then, deterioration of the upstream exhaust gas component concentration sensor is determined based on results of these determinations.