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:
May. 29, 2012
Filed:
May. 21, 2009
Eisaku Fukuchi, Mito, JP;
Akihito Numata, Hitachiomiya, JP;
Heikichi Kamoshita, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Disclosed is a diagnostic control apparatus for internal combustion engines capable of accurately diagnosing the presence and extent of air/fuel ratio variations in engine cylinders, even when the system has no part for detecting the air/fuel ratio in each cylinder. The diagnostic control apparatus measures the time required for the crankshaft to rotate to a specified angle for each cylinder; and based on this measured, required time, derives the 0.5 order component as the rotation fluctuation component for each two rotations of the crankshaft per each cylinder or the 1.0 order component as the rotation fluctuation component for each single rotation of the crankshaft; and also counts the number of times the 0.5 order component or 1.0 order component deviates from the preset range in the period set for each cylinder, and diagnoses an error in the output or in the air/fuel ratio for a particular cylinder when that count value exceeds a specified value.