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:
Mar. 19, 2002
Filed:
Jun. 12, 2000
Shigeru Kawamoto, Hitachi, JP;
Yutaka Takaku, Mito, JP;
Toshio Ishii, Mito, JP;
Yoshihisa Fujii, Hitachinaka, JP;
Shinji Nakagawa, Hitachinaka, JP;
Minoru Oosuga, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The invention provides a method of controlling an air-fuel ratio and for diagnosing a deterioration of a catalyst having an NOx trapping agent in an internal combustion engine. An exhaust gas purifying apparatus having an NOx trapping agent arranged within an exhaust gas passage, an air-fuel ratio changing means temporarily changing the air-fuel ratio of the exhaust gas from the lean to the stoichiometric or rich air-fuel ratio at a predetermined cycle, a particular component detecting means detecting a particular component in the exhaust gas downstream the NOx trapping agent, a NOx discharge or reduction completion judging means, and NOx discharge or reduction completion time detecting means detecting a time required for purifying the NOx.