Exhaust emission control system of internal combustion engine

摘要

An exhaust emission control system of an internal combustion engine is provided which controls the oxygen concentration of exhaust passing through the exhaust emission control device according to the flow rate of exhaust flowing through an exhaust passage when the exhaust emission control device is regenerated, so that the regeneration is completed within a short period of time while the filter is prevented from being damaged by melting during the regeneration. This improves the exhaust emission control performance and reliability of the filter.