EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To prevent a particulate filter from being excessively cooled when the flow of the exhaust gas is returned from a bypass condition to the condition via the particulate filter in an exhaust emission control device comprising the particulate filter having the function of oxidizing the particulate contained in the exhaust gas and a mechanism switching the flow of the exhaust gas so that the exhaust gas flows bypassing the particulate filter when the exhaust gas temperature is low. SOLUTION: The exhaust emission control device of an internal combustion engine prevents the temperature drop of an exhaust gas passage located on the upstream side of the particulate filter by reducing the flow rate of the exhaust gas or raising the exhaust gas temperature when the flow of the exhaust gas bypasses the particulate filter, and prevents the heat of the exhaust gas from being absorbed by the exhaust gas passage when the exhaust gas flow is returned to the particulate filter from the bypassing condition, and prevents the exhaust gas at a low temperature from flowing into the particulate filter.