EXHAUST EMISSION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine which can more favorably restore the HC-poisoning of an oxidation catalyst than a device which starts control for restoring the HC-poisoning of the oxidation catalyst by comparing an HC-adhesion amount and a fixed value.SOLUTION: An exhaust emission control device of an internal combustion engine comprises: an oxidation catalyst 31 arranged in an exhaust passage of the internal combustion engine 10; and a control part 40 which estimates an HC-adhesion amount of the oxidation catalyst 31, lowers a concentration of oxygen in exhaust emission which flows into the oxidation catalyst 31 when the estimated HC-adhesion amount exceeds a threshold, and raises a temperature of the exhaust emission. The control part 40 increases the threshold as an average bed temperature of the oxidation catalyst at a time zone at which temperature-rise control including the control of the HC-poisoning restoration during an operation of the internal combustion engine 10 is not performed related to the oxidation catalyst is high.SELECTED DRAWING: Figure 1