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:
Oct. 15, 2002
Filed:
Aug. 10, 2001
Shujiro Morinaga, Takahama, JP;
Masaaki Nakayama, Toyoake, JP;
Naoki Yoshiume, Kariya, JP;
Masahiko Yamaguchi, Obu, JP;
Denso Corporation, Kariya, JP;
Abstract
An engine has an upstream-side catalyst and a downstream-side catalyst. First and second air-fuel ratio sensors are provided on the upstream and downstream sides of the upstream-side catalyst, respectively. A third air-fuel ratio sensor is provided on the downstream side of the downstream-side catalyst. The deteriorating state of the upstream-side catalyst is diagnosed during a period of time in which the third sensor is outputting a voltage in a predetermined range, and the air-fuel ratio is controlled to maintain the voltage output of the third sensor in the predetermined range during the period of time to diagnose the deteriorating state of the upstream-side catalyst.