| 摘要 |
PROBLEM TO BE SOLVED: To provide a lean combustion type internal combustion engine which incorporates storage type NOX catalyst and which can surely emit NOX from the storage type NOX catalyst storing therein NOX without causing deterioration of drivability and fuel consumption. SOLUTION: A lean combustion type internal combustion engine comprises storage type NOX catalyst 6A provided in an exhaust passage of the internal combustion engine, an NOX storage quantity estimating means 21 for estimating a quantity of NOX stored in the catalyst 6A, an air-fuel ratio setting means 23 for setting an air-fuel ratio of the engine between a lean air-fuel ratio and a rich air-fuel ratio, and an air-fuel ratio correcting means 29 for temporarily correcting an air-fuel ratio set by the air-fuel ratio setting means 23 in accordance with an NOX storage quantity estimated by the NOX storage quantity estimating means 21 when the air-fuel ratio set by the air-fuel ratio comparing means 23 is changed over from a lean air-fuel ratio into a stoichiometric air-fuel ratio or a rich air-fuel ratio.
|
