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:
Jun. 27, 1995
Filed:
Sep. 21, 1994
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 is disposed within an exhaust pipe for purifying an exhaust gas. A first air-fuel ratio sensor 11 is disposed upstream of the catalyst for detecting concentration of a particular component of the exhaust gas to output a first air-fuel ratio signal V1 indicating the concentration. A second air-fuel ratio sensor 12 is disposed downstream of the catalyst for detecting concentration of the particular exhaust gas component to output a second air-fuel ratio signal V2 indicating the concentration. An apparatus for detecting deterioration of the catalytic converter includes a deterioration decision means 54 for determining deterioration of the catalyst on the basis of at least the second air-fuel ratio signal, a filtering means 50 for filtering the second air-fuel ratio signal to thereby derive a filtered air-fuel ratio signal, and comparison means 51 for comparing the second air-fuel ratio signal with the filtered air-fuel ratio signal. The deterioration decision means 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.