ABNORMALITY DETECTOR OF EXHAUST GAS PURIFIER, AND ITS DETECTION METHOD

摘要

An abnormality detector of a filter in an exhaust gas filtering device and its detection method in which abnormality of a filter can be detected accurately at all times. The exhaust gas purifier comprises a filter provided in the exhaust passage of an internal combustion engine in order to collect fine particles in the exhaust gas, and a differential pressure sensor for detecting the pressure difference occurring between the upstream side and the downstream side of the filter. The abnormality detector of an exhaust gas purifier comprises a differential pressure value calculating means for calculating the pressure difference between the upstream side and the downstream side of the filter based on the operational state of the internal combustion engine, and a judgment means for calculating the difference P between the actual measurement of the pressure difference between the upstream side and the downstream side of the filter detected by the differential pressure sensor and the calculated differential pressure value from the differential pressure value calculation means, and detecting abnormality of the filter by comparing the difference P with a threshold.