Patent ID: 7051519

Claim:
An exhaust gas cleaning device for an internal combustion engine, the exhaust gas cleaning device comprising: a particulate filter that is arranged in an exhaust gas passage of the engine to collect particulate matter contained in exhaust gas, which is exhausted from the engine; a regenerating means for regenerating the particulate filter based on an amount of accumulated particulate matter, which is accumulated in the particulate filter, wherein the regenerating means at least uses an oxidizing reaction of the accumulated particulate matter with NOx, which is supplied along with the exhaust gas, to regenerate the particulate filter; and an accumulated amount estimating means for estimating the amount of accumulated particulate matter in the particulate filter based on: an amount of increased particulate matter that is increased in the particulate filter by exhaustion of the exhaust gas from the engine; and an amount of reduced particulate matter that is reduced in the particulate filter through the oxidizing reaction of the accumulated particulate matter with the NOx, wherein the accumulated amount estimating means includes a reduced amount computing means for computing the amount of reduced particulate matter, which is reduced through the oxidizing reaction of the accumulated particulate matter with the NOx, based on: a first sub-amount of reduced particulate matter, which is an amount of reduced particulate matter that is reduced from the particulate filter through oxidizing reaction of the particulate matter with a non-adsorbed group of the NOx, which is present in a surrounding atmosphere that surrounds the accumulate particulate matter; and a second sub-amount of reduced particulate matter, which is an amount of reduced particulate matter that is reduced from the particulate filter through oxidizing reaction of the particulate matter with an adsorbed group of the NOx, which is supplied to the particulate filter along with the exhaust gas and is adsorbed by the accumulated particulate matter.