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:
Jan. 22, 1991
Filed:
Apr. 26, 1989
Junichi Kobayashi, Ushiku, JP;
Takashi Mizumori, Ibaraki, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An internal combustion engine has an intake air flowmeter which includes a first air flow rate computing means for computing the flow rate of intake air from an output of a hot-wire type air flowmeter in accordance with a first flow rate conversion function, a second air flow rate computing means for computing the intake air flow rate from data concerning a given opening degree of the throttle valve and measured engine speed in accordance with a second flow rate conversion function, and a calibration device for calibrating the first conversion function in accordance with the air flow rate computed by the second air flow rate computing means. When the extent of secular change due to contamination of the hot wire of the air flowmeter has exceeded a predetermined limit, the calibration device is put into effect to calibrate the first flow rate conversion function, so that the intake air flow rate can be measured with a high degree of accuracy without being influenced substantially by the secular change of the hot-wire type air flowmeter.