EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To certainly reduce NOX while restraining a reducer from being excessive. SOLUTION: NOX is certainly reduced while the reducer is restrained from being excessive by balancing timing that NOX discharged from a NOX catalyst 15 becomes excessive against the reducer in exhaust gas at the time when it is transferred from lean driving to driving at a logical air-fuel ratio or a rich air-fuel ratio, timing that NOX to be discharged becomes excessive by controlling working time of pulse injection to supply an additional reducer in accordance with delay time that the reducer to be supplied by working of a reducer supply means 33 reaches the NOX catalyst 15 and timing that the additional reducer reaches the NOX catalyst 15.