Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
2011-07-19
2011-07-19
Olsen, Kaj K (Department: 1724)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S406000
Reexamination Certificate
active
07981265
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.
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Akimoto Katsuhide
Hada Satoshi
Kawase Tomoo
Kurokawa Eiichi
Suzuki Toshiyuki
Denso Corporation
Nixon & Vanderhye P.C.
Olsen Kaj K
Thai Susan
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