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. 30, 1987
Filed:
Sep. 26, 1986
Takayuki Itsuji, Katsuta, JP;
Sadayasu Ueno, Katsuta, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Automotive Engineering Co., Ltd., Katsuta, JP;
Abstract
An air-fuel ratio control apparatus is disclosed in which an air-fuel ratio sensor disposed in the exhaust system of an internal combustion engine produces a voltage signal correlated with the excess air ratio of the ambient gas surrounding it and has such an output characteristic as to produce a maximum output only when the ambient gas is filled with air, the air-fuel ratio of the internal combustion engine being controlled to a proper value on the basis of the detection signal of the air-fuel ratio sensor. The air-fuel ratio control apparatus further comprises a sampling device for sampling the maximum output (V.sub.x) when it is decided that the output of the air-fuel ratio sensor is maintained for a predetermined length of time or longer at a predetermined value or higher, a memory for storing the sample value of the maximum output (V.sub.x) produced by the sampling device and updating the preceding sample value (V.sub.x-1) to the present sample value (V.sub.x) when a new maximum output is sampled each time of the decision, and a calibrator for calibrating the output characteristic of the air-fuel ratio sensor on the basis of the latest updated sample value (V.sub.x).