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:
Apr. 27, 2004
Filed:
Dec. 05, 2001
Applicant:
Inventors:
Yutaka Takaku, Mito, JP;
Toshio Ishii, Mito, JP;
Nobuo Kurihara, Hachinohe, JP;
Hiroshi Kimura, Hitachinaka, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01M 1/900 ;
U.S. Cl.
CPC ...
G01M 1/900 ;
Abstract
A combustion state is diagnoses by extracting specific rotation period component of a period synchronous with rotation from a combustion state parameter for at least two rotations. The combustion state is judged on the basis of the extracted specific rotation period component. The combustion state parameter may be the engine speed or the output torque of a multiple-cylinder engine which varies according to the combustion state of the engine.