PURPOSE: To precisely grasp a volume of particles trapped in a filter by measuring a rate of volumetric flow passing through the filter and a pressure differential across the filter, and by compensating the differential pressure with the flow rate of volumetric flow passing through the filter with respect to a reference flow rate of volumetric flow so as to calculate a compensated pressure differntial.
CONSTITUTION: An exhaust emission control device 5 which operates a heating device so as to burn trapped fine particles when a filter 7 made of ceramic porous materials is detected clogging, is provided thereto with pressure sensors 8, 9 for detecting pressures upstream and downstream of the filter 7, and a temperature sensor 19 for detecting a temperature of inflow gas. Signals from these sensors are delivered to an ECU 11 together with an output signal from an intake-air flow rate sensor 3. A trapped volume computing part 13 computes a volumetric flow rate of exhaust gas from the intake-air flow rate, the upstream pressure, and the inflow gas temperature, and a pressure differential from the upstream and downstream pressures. Then, the pressure differential is compensated with the volumetric flow rate of exhaust gas passing through the filter, with respect to a reference volumetric flow rate so as to obtain a compensated pressure differential from which a volume of trapped particles is obtained. Thus obtained volume of trapped particles is used for a regenerating process.
YASUURA NOBUSHI
YOSHIDA HIDEJI
KATO KEIICHI
MORITA NAOHARU
