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:
Nov. 15, 1994
Filed:
Oct. 08, 1993
Hirofumi Ohuchi, Himeji, JP;
Shinya Fujimoto, Himeji, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A dual-sensor type air-fuel ratio control system for an internal combustion engine. A catalytic converter disposed within an exhaust pipe is flanked by first and second upstream and downstream air-fuel ratio sensors 11, 12. An apparatus for detecting deterioration of the catalytic converter includes a deterioration decision circuit 54 for determining deterioration of the catalyst on the basis of at least the second air-fuel ratio sensor signal, a filter circuit 50 for filtering the second sensor signal, and a comparison circuit 51 for comparing the second sensor filtered and unfiltered signals. The deterioration decision circuit compares a deterioration parameter value derived from the result of the comparison with a predetermined value corresponding to a detected operation state of the engine to determine deterioration of the catalyst when the deterioration parameter value exceeds the predetermined value.