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.

Date of Patent:
Jul. 25, 2000

Filed:

Feb. 28, 1997
Applicant:
Inventors:

Toshio Ishii, Mito, JP;

Toshio Manaka, Hitachinaka, JP;

Yutaka Takaku, Mito, JP;

Kiyoshi Miura, Tokai-mura, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F01N / ;
U.S. Cl.
CPC ...
60277 ; 60276 ; 731181 ;
Abstract

In a diagnostic system for an exhaust gas purifying apparatus in an internal combustion engine, such as a diagnostic system suitable for evaluating the exhaust gas purifying performance of a specific component, as an exhaust gas component concentration corresponding to an operating condition of the engine or an operating condition of the catalyst is detected using an exhaust gas component system, and the evaluation and diagnosis of the exhaust gas purifying apparatus are conducted on the basis of the thus-detected value directly or after subjecting it to an integral processing. With such a diagnostic system, it is not necessary to dispose a sensor upstream of the catalyst in the exhaust gas purifying apparatus, for diagnosis of the catalyst, thus permitting the system to be less expensive, highly durable and afford a high diagnostic accuracy according to operating conditions.


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