ENGINE EXHAUST GAS PURIFICATION DEVICE

PURPOSE:To restrain the generation of NOx so as to improve exhaust gas purification performance, by allowing an exhaust gas reflux amount to be subjected to an incremental control for a given time, after a high loading condition in an engine has been continuously maintained, and before an air-fuel ratio is subjected to concentration. CONSTITUTION:An air-fuel ratio regulating means (a fuel injection valve or the like) 12 is provided for regulating the air-fuel ratio, and said air-fuel ratio regulating means 12 is controlled so that the air-fuel ratio may be concentrated in excess of a given air-fuel ratio by means of an air-fuel ratio concentration means 41, when an engine load detected by a load detecting means 30 is judged to have been under a high loading condition during a given time. Further, an exhaust gas reflux amount regulating means an (EGR-control valve or the like) 17 is provided for regulating an exhaust gas reflux amount, and said exhaust gas reflux amount regulating means 17 is controlled so as to have the exhaust gas reflux amount increased by means of an exhaust gas reflux amount incremental means 42 during a given time. The aforesaid constitution enables the generation of NOx in the exhaust gas to be retrained as far as practicable so as to improve exhaust gas purification performance.