FILTER CONTROL METHOD AND DEVICE

Increase in quantity of particulates during a prescribed time period is acquired as first difference data (DX) that is based on pressure differential ΔP across a filter (32) and derived from first estimation data (D2) obtained from a first estimation calculator (52) and is simultaneously acquired as second difference data (DY) that is based on integration of the quantity of particulate generation per unit time and derived from second estimation data (D3) obtained from a second estimation calculator (53), and the second estimation data (D3) is corrected using correction data (D4) calculated from the first and second difference data (DX, DY) to acquire corrected second estimation data (D6). A discriminator (73) determines which of the first estimation data (D2) and corrected second estimation data (D6) is suitable data and the regeneration control of the filter is conducted using the so-selected estimation data (Q).