Control method for gas concentration sensor

An A/F signal proportional to an oxygen concentration in the exhaust gas from an internal combustion engine is output upon application of a voltage based on an instruction from a microcomputer. At the time an element resistance is detected, a bias instruction signal Vr from the microcomputer is conv...

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Bibliographic Details
Main Authors Hada, Satoshi, Kurokawa, Eiichi, Suzuki, Toshiyuki, Kawase, Tomoo, Haseda, Satoshi
Format Patent
LanguageEnglish
Published 22.03.2005
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Summary:An A/F signal proportional to an oxygen concentration in the exhaust gas from an internal combustion engine is output upon application of a voltage based on an instruction from a microcomputer. At the time an element resistance is detected, a bias instruction signal Vr from the microcomputer is converted by a D/A converter to an analog signal Vb. An output voltage Vc obtained by removing high frequency components from the analog signal Vb through an LPF is input to a bias control circuit . During this time period in which the element resistance is detected, an accurate A/F signal is not output. Therefore, the A/F signal that has theretofore prevailed is held by a Sample/Hold circuit to thereby prevent the use of an erroneous A/F signal. Namely, at the time of detecting the element resistance, the detected value of the oxygen concentration is prevented from becoming abnormal. As a result, an accurate A/F control can be executed using the detected element resistance.