Engine exhaust gas purification apparatus

Abstract

An engine exhaust gas purification apparatus includes a fuel injection valve for supplying fuel to a combustion chamber, an exhaust passage for discharging exhaust gas from the combustion chamber, a catalyst device provided on the exhaust passage for purifying the exhaust gas, a linear air-fuel (A/F) sensor that is provided on the exhaust passage downstream of the catalyst device and is configured to detect an air-fuel ratio of the exhaust gas, and a control device configured to control the fuel injection valve on the basis of the air-fuel ratio detected by the linear A/F sensor to set the air-fuel ratio of the exhaust gas to a target air-fuel ratio. The control device calculates a fluctuation range of the air-fuel ratio detected by the linear A/F sensor within a predetermined time, and corrects the target air-fuel ratio on the basis of the fluctuation range.

Dependencies are inferred from the claim text.