Patent ID: 6990802

Claim:
An apparatus for regenerating a particulate filter in an exhaust passage for an internal combustion engine, the particulate filter removing particulates out of an exhaust gas therein, comprising: a controller that estimates a particulate deposit amount of the particulate filter during an engine operating period, the engine operating period including a regeneration period of the particulate filter, where the particulate filter is regenerated, and a usual period other than the regeneration period, wherein, when the controller judges that the estimated particulate deposit amount is greater than a first predetermined value during the usual period, the controller starts a process that burns particulates deposited on the particulate filter, and sets a particulate deposit amount as a first amount at a starting point of the regeneration period, wherein the controller estimates a particulate deposit amount during the regeneration period based upon the first amount, and wherein the particulate deposit amount during the regeneration period is estimated as a sum of the first amount and a decrease amount, the decrease amount estimated based upon the first amount.