EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine capable of effectively performing the reduction of NOX and the oxidation of particulates according to an operation state and not discharging a large quantity of an untreated fuel reducing agent after the reduction of NOX is finished. SOLUTION: This exhaust emission control device is provided with a filter 22 carrying an NOX absorbent absorbing NOX or releasing the absorbed NOX and an active oxygen releasing agent accelerating the oxidation of the particulates in the exhaust gas and capable of temporarily trapping the particulates in the exhaust gas, an exhaust switching means 71 capable of switching a first flow 76 feeding the exhaust gas from one side of the filter 22 and a second flow 77 feeding the exhaust gas from the other side of the filter 22 in turn and feeding the exhaust gas to a bypass passage 73 detouring the filter 22 during the switching, a reducing agent feeding means 80 feeding the reducing agent to an exhaust passage 76 on the upstream side of the filter, and a control means guiding only part of the exhaust gas to the filter 22 and feeding the flow of the other exhaust gas to the bypass passage 73 to control the feed of the reducing agent for the reducing atmosphere when the particulate oxidizing/removing quantity of the filter 22 is estimated to be decreased.