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. 29, 2002
Filed:
Mar. 20, 2001
Shinji Nakagawa, Hitachinaka, JP;
Minoru Ohsuga, Hitachinaka, JP;
Yutaka Takaku, Mito, JP;
Kouzou Katogi, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
There is disclosed an apparatus in which changes of linear A/F sensor or engine response characteristics can be detected with high precision in a broad range during operation of an engine. The apparatus includes a controller for controlling an air/fuel ratio of each cylinder of a multiple cylinder engine, and a linear A/F sensor for emitting an output which is proportional to the air/fuel ratio of an exhaust tube assembly. The air/fuel ratio of a specific cylinder is changed by a predetermined amount, a vibration component amplitude or a frequency component based on an engine rotation number is extracted from a signal obtained from the linear A/F sensor , and the response characteristics of an air/fuel ratio detector or the engine are detected from the amplitude or a power of the frequency component.