DEVICE OF CALCULATING DIFFERENTIAL PRESSURE BETWEEN PRESSURES ON UPSTREAM AND DOWNSTREAM SIDES OF FILTER AND DEVICE OF ESTIMATING DEPOSITED AMOUNT OF PARTICULATE MATTER IN THE FILTER

摘要

PPROBLEM TO BE SOLVED: To provide a differential pressure calculation device used in an exhaust emission control device of an internal combustion engine and accurately calculating a differential pressure between the pressures on the upstream and the downstream sides of a filter for collecting particulate matters and a deposited amount estimating device for accurately estimating the deposited amount of particulate matters in the filter. PSOLUTION: The exhaust emission control device has a DPF 24 disposed in the exhaust gas passage 14 of an internal combustion engine 10 and collecting PM discharged from the internal combustion engine 10. A differential pressure calculation device for the pressures on the upstream side and the downstream side of the DPF 24 of the exhaust emission control device comprises a pressure sensor 33 for detecting the pressure on the upstream side of the filter and a pressure estimating means for deriving the total pressure loss in the exhaust gas passage on the downstream side of the DPF 24 and estimating the pressure on the downstream side of the DPF 24 by adding the total pressure loss to the atmospheric pressure. The differential pressure calculation device comprises the calculation means for calculating the differential pressure between the pressures on the upstream side and the downstream side of the DPF 24 from the pressure on the upstream side of the DPF 24 detected by the pressure sensor 33 and the pressure on the downstream side of the DPF 24 estimated by the pressure estimating means. PCOPYRIGHT: (C)2008,JPO&INPIT