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:
Jun. 19, 1990
Filed:
Feb. 14, 1989
Junichi Ishii, Katsuta, JP;
Matsuo Amano, Hitachi, JP;
Nobuo Sato, Iwaki, JP;
Nobuo Kurihara, Hitachioota, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A method for feedback controlling air-fuel ratio of the mixture supplied to an internal combustion engine having a plurality of cylinders comprises the steps of, detecting respective air-fuel ratios of the exhaust gas from the respective cylinders with an air-fuel ratio sensor having a substantially linear output characteristic; calculating an average air-fuel ratio by using the latest detected air-fuel ratios of the respective cylinders; determining a fundamental feedback correction coefficient .beta..sub.0 for a cylinder of which air fuel ratio is feedback controlled next; retrieving a learning correction coefficient .beta..sub.1 for the cylinder of which air-fuel ratio is feedback controlled next from a learning map prepared by learning for the corresponding cylinder; and determining new learning correction coefficients .beta..sub.1 for the respective cylinders using respective deviations of the respective detected current air-fuel ratios from the latest average air-fuel ratio calculated in the previous step, whereby air-fuel ratio control at any desired air-fuel ratio is carried out with a high accuracy and with a uniform air-fuel ratio throughout the whole cylinders.