EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To suppress deterioration of fuel economy by shortening time for performing particulate removing control and sulfur emission control.

SOLUTION: This exhaust emission control device is equipped with an exhaust emission control means having a filter and a NOx occlusion agent and a reducing agent addition means adding a reducing agent to exhaust gas flowing into the exhaust emission control means. When particulate accumulation amount is increased or sulfur occlusion amount is increased, the particulate removing control for maintaining the temperature of the filter to exceed particulate combustion temperature and controlling an air fuel ratio of exhaust gas flowing into the exhaust emission control means to be lean is performed. Then, after predetermined time passes, the sulfur emission control for maintaining the temperature of the NOx occlusion agent to exceed sulfur emission temperature and controlling the air fuel ratio of the exhaust gas flowing into the exhaust emission control means to be an approximately theoretical air fuel ratio or rich and the particulate removing control are alternately repeated for a plurality of times.

COPYRIGHT: (C)2005,JPO&NCIPI