EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To efficiently executing continuous regeneration of an exhaust particulate filter using nitrogen dioxide NO2by simultaneously controlling the temperature of the exhaust particulate filer and nitrogen dioxide NO2concentration in the filter to optimal values. SOLUTION: This device is provided with: an exhaust gas recirculation control valve installed in the exhaust gas recirculation passage and controlling quantity of exhaust gas re-circulated to an intake system; a cooler cooling exhaust gas re-circulated via an exhaust gas recirculation passage; a bypass passage re-circulating exhaust gas with bypassing the cooler; and a change-over valve changing ratio of quantity of exhaust gas passing through the cooler and quantity of exhaust gas bypassing the cooler. Temperature and nitrogen dioxide NO2concentration of the exhaust particulate filter are controlled to the optimal values respectively by a re-circulated exhaust gas quantity controlled by the exhaust gas recirculation control valve and a bypass exhaust gas quantity controlled by the change-over valve. COPYRIGHT: (C)2009,JPO&INPIT