Apparatus and method for regenerating particulate filter that removes particulates out of exhaust gas for internal combustion engine

Abstract

A particulate deposit amount Spm on a particulate filter disposed in an exhaust passage is estimated during a usual period different from a regeneration period of the particulate filter and during the regeneration period thereof respectively. An increase value Dpm per unit time of the Spm during the usual period is estimated based upon an engine operating condition and a total amount of the Spm is determined by integration thereof (S). On the other hand, a particulate deposit amount Spm decreasing by burning during the regeneration period is determined by, one by one, subtracting a decrease value Dpm per unit time estimated based upon a particulate deposit amount Spmi that is determined by the above integration at a starting point of the regeneration period from the Spmi (S).