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:
Jul. 19, 2011
Filed:
May. 09, 2007
Tomoo Kawase, Aichi-ken, JP;
Eiichi Kurokawa, Okazaki, JP;
Satoshi Hada, Inazawa, JP;
Toshiyuki Suzuki, Handa, JP;
Katsuhide Akimoto, Nishio, JP;
Tomoo Kawase, Aichi-ken, JP;
Eiichi Kurokawa, Okazaki, JP;
Satoshi Hada, Inazawa, JP;
Toshiyuki Suzuki, Handa, JP;
Katsuhide Akimoto, Nishio, JP;
Denso Corporation, Kariya, JP;
Abstract
A gas concentration measuring apparatus for use in air-fuel ratio control of automotive engines is designed to determine the concentration of oxygen within a wide and a narrow range using a sensor current flowing through a sensor element. The apparatus includes an amplifier circuit equipped with an operational amplifier and a plurality of amplifying resistors and a switch. The switch is responsive to a request signal to switch a relation in electrical connection between an operational amplifier and the amplifying resistors to distribute the amplifying resistors into an input resistor and a feedback resistor for the operational amplifier to change an amplification factor of the amplifier circuit. This results in a change in resolution of measurement of the concentration of oxygen, thereby ensuring enhanced accuracy in determining the concentration of oxygen in a selected one of the narrow and wide ranges.