| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal combustion engine control device using an air-fuel ratio sensor capable of precisely detecting when an absolute value of an exhaust air-fuel ratio reaches a predetermined air-fuel ratio richer than a stoichiometric air-fuel ratio.SOLUTION: An internal combustion engine control device comprises an exhaust emission control catalyst 20 provided on an exhaust passage of an internal combustion engine; a downstream side air-fuel ratio sensor 41 provided nearer a downstream side than the exhaust emission control catalyst; and an air-fuel ratio control device for controlling an air-fuel ratio of the exhaust gas flowing in the exhaust emission control catalyst to a target air-fuel ratio. The downstream side air-fuel ratio sensor is constituted so that an application voltage at which an output current becomes zero gets lower as the exhaust air-fuel ratio gets higher. The voltage applied to the downstream side air-fuel ratio sensor is set higher than the voltage at which the output current becomes zero when the exhaust air-fuel ratio is the stoichiometric air-fuel ratio, if the target air-fuel ratio is richer than a reference air-fuel ratio, and is set lower than the voltage at which the output current becomes zero when the exhaust air-fuel ratio is the stoichiometric air-fuel ratio, if the target air-fuel ratio is more lean than a reference air-fuel ratio. |
