Patent ID: 6820418
Filing Date: 2004-11-23
Classification: F01N,F02D,Y02T,Y10S

Abstract:
An exhaust gas purification apparatus of an internal combustion engine in which a particulate filter for trapping and removing particulate in an exhaust gas is arranged in an engine exhaust passage and in which burning is continued under a lean air-fuel ratio, said apparatus comprising predicting means for predicting if the particulate deposited on the particulate filter has changed in property to a property harder to oxidize compared with right after deposition, air-fuel ratio switching means for temporarily switching the air-fuel ratio of exhaust gas flowing into the particulate filter from lean to rich to cause the particulate deposited on the particulate filter to change in property to a property of easy oxidation when it is predicted that the particulate deposited on the particulate filter has changed in property to a property harder to oxidize compared with right after deposition, judging means for judging if the amount of particulate deposited on the particulate filter has exceeded a predetermined amount, and temperature control means for causing the temperature of the particulate filter to rise under a lean air-fuel ratio so as to remove by oxidation the particulate deposited on the particulate filter when the amount of the particulate deposited on the particulate filter has exceeded a predetermined amount.