EXHAUST EMISSION CONTROL SYSTEM AND CONTROL METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device and a control method therefor capable of easily resetting a determining value such as a pressure determining value and a pressure ratio determining value for determining a mesh-clogging state of a filter for scavenging PM in exhaust gas to an optimal value, and capable of purifying the exhaust gas at a high removing rate by always efficiently switching a PM scavenging filter and a regenerating filter. SOLUTION: In this exhaust emission control system for continuously scavenging a particulate-like substance in the exhaust gas G while switching the filter 20 for scavenging the PM in the exhaust gas G of an engine 10 and the filter 20 regenerated by burning the scavenged PM, the exhaust emission control system comprises a determining value resetting means 40 for correcting and resetting prescribed reference determining values P0 and Pr0 used for determining regeneration starting time of the filter 20 when an external signal S is inputted.