Patent ID: 7703278

Claim:
A method of controlling exhaust emissions by removing particulates accumulated in a particulate filter disposed in an exhaust passage of an internal combustion engine to regenerate the particulate filter, the method comprising: increasing a temperature of the particulate filter; estimating the temperature of the particulate filter; estimating a quantity of particulates accumulated in the particulate filter; controlling a quantity of a temperature increase of the particulate filter when the quantity of accumulated particulates is estimated to exceed a predetermined value; computing a time ratio of performance of a temperature increasing operation to a base period and a time ratio of interruption of the temperature increasing operation to the base period, the base period being a sum of a period of said performance and a period of said interruption; computing the base period that varies from time to time and repeatedly switching between performance and the interruption of the temperature increasing operation based on the time ratios and the base period.