EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a technology capable of increasing opportunities to carry out the control for regeneration of an NOx catalyst poisoned by sulfur and also suppressing the deterioration of the catalyst caused by sulfur poisoning. SOLUTION: This exhaust emission control device is provided with an NOx absorbent which absorbs NOx in an exhaust gas when the air/fuel ratio of the inflowing exhaust gas is lean and releases the absorbed NOx when the above air/fuel ratio is theoretical or rich, and a control means for carrying out the temperature elevation control of the NOx absorbent and the control of regenerating the catalyst poisoned by sulfur. Since the control means releases oxygen (O2 ) stored in the NOx absorbent by lowering the air/fuel ratio in the exhaust gas when the temperature elevation control is carried out before the start of regeneration control of the poisoned NOx absorbent, the delay thereof is eliminated. The NOx absorbent may be carried on a filter capable of temporarily capturing particulates.