Patent ID: 7076944

Claim:
An exhaust gas cleaning system of an internal combustion engine, the exhaust gas cleaning system comprising: a particulate filter disposed in an exhaust passage of the internal combustion engine; temperature increasing means for increasing temperature of the particulate filter; temperature estimating means for estimating the temperature of the particulate filter; particulate matter accumulation quantity estimating means for estimating a quantity of particulate matters accumulated in the particulate filter; and regenerating means for regenerating the particulate filter by increasing the temperature of the particulate filter to a predetermined value through an operation of the temperature increasing means and by eliminating the particulate matters accumulated in the particulate filter through combustion when the quantity of the particulate matters accumulated in the particulate filter, which is estimated by the particulate matter accumulation quantity estimating means, exceeds a predetermined value, wherein the regenerating means includes energy input amount determining means for determining an amount of energy inputted by the temperature increasing means in accordance with the temperature of the particulate filter estimate by the temperature estimating means; and wherein the energy input amount determining means includes duty ratio determining means for determining a duty ratio between a performing period and an interrupting period of the temperature increasing operation performed by the temperature increasing means in accordance with the temperature of the particulate filter estimated by the temperature estimating means.