Control system of internal combustion engine

    公开(公告)号:US10167760B2

    公开(公告)日:2019-01-01

    申请号:US15110427

    申请日:2014-12-18

    Abstract: An internal combustion engine comprises an exhaust purification catalyst. The control system comprises a temperature detecting means for detecting or estimating a temperature of the exhaust purification catalyst, performs feedback control so that an air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst becomes a target air-fuel ratio, and performs target air-fuel ratio setting control which alternately sets the target air-fuel ratio to a rich set air-fuel ratio and a lean set air-fuel ratio. In addition, the control system increases a variation difference, obtained by subtracting a rich degree of the rich set air-fuel ratio from a lean degree of a lean set air-fuel ratio, when a temperature of the exhaust purification catalyst detected or estimated by the temperature detecting means is a predetermined upper limit temperature or less compared with when it is higher than the upper limit temperature. As a result, a sulfur ingredient storage amount of an exhaust purification catalyst is maintained low.

    Abnormality diagnosis system of air-fuel ratio sensors

    公开(公告)号:US10151262B2

    公开(公告)日:2018-12-11

    申请号:US15038133

    申请日:2014-11-20

    Abstract: An internal combustion engine comprises an exhaust purification catalyst arranged in an exhaust passage of the internal combustion engine; an upstream side air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst; and a downstream side air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas flowing out from the exhaust purification catalyst. An abnormality diagnosis system of air-fuel ratio sensors judges that at least one of the air-fuel ratio sensors has become abnormal when a difference or ratio between an output value of said upstream side air-fuel ratio sensor and an output value of said downstream side air-fuel ratio sensor becomes outside a predetermined range of normal difference or predetermined range of normal ratio during atmospheric gas introduction control where the exhaust gas flowing into the exhaust purification catalyst becomes atmospheric gas.

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