Patent ID: 7998261

Claim:
An exhaust gas purifying apparatus for an internal combustion engine, which includes an exhaust system for exhaust gas from the internal combustion engine, the exhaust gas purifying apparatus comprising: a collector that is provided in the exhaust system of the internal combustion engine and includes a porous partition wall for capturing exhaust particles in the exhaust gas when the exhaust gas passes through the partition wall; a regeneration determining device configured to determine that the exhaust particles captured in the collector need to be forcibly combusted to regenerate the collector in a regular manner when an accumulation amount of the exhaust particles captured in the collector exceeds a predetermined value; a first regenerating device configured to forcibly combust the exhaust particles captured in the collector to regenerate the collector in the regular manner when the regeneration determining device determines that the exhaust particles captured in the collector need to be forcibly combusted; a differential pressure sensing device configured to sense a differential pressure across the collector; a differential pressure based estimating device configured to estimate the accumulation amount of the exhaust particles based on the differential pressure across the collector using an accumulation characteristic map that defines a relation between the accumulation amount and the differential pressure; a second regenerating device configured to forcibly completely combust the exhaust particles captured in the collector; and an operational history based estimating device configured to estimate the accumulation amount of the exhaust particles based on operational state information of the internal combustion engine and a temperature of the collector, when a temperature of the exhaust gas downstream of the collector is equal to or higher than a predetermined temperature value, the second regenerating device forcibly completely combusts the exhaust particles captured in the collector, and the operational history based estimating device estimates the accumulation amount of the exhaust particles.