EXHAUST PURIFYING DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide technique for an exhaust purifying device of an internal combustion engine which can accurately match an air-fuel ratio of the exhaust passing through a NOx catalyst with a target air-fuel ratio at the time of fuel supply to the NOx catalyst.

SOLUTION: A correction of the amount of fuel loading is made by making the air-fuel ratio of the exhaust flowing into the NOx catalyst a second predetermined air-fuel ratio that is leaner than a first predetermined air-fuel ratio before reducing NOx by making the air-fuel ratio of the exhaust flowing into the NOx catalyst the first predetermined air-fuel ratio. The fuel is loaded by applying the correction value determined at this time even when making the air-fuel ratio of the exhaust flowing into the NOx catalyst the first predetermined air-fuel ratio. Since an air-fuel ratio sensor can determine the correction value of the amount of the fuel loading at the air-fuel ratio not deviating from a lean condition, the correction of the amount of fuel loading with high accuracy is made possible.

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