Exhaust purification device for internal combustion engine

Abstract

An exhaust purification device for an internal combustion engine is provided that can promote the reduction of NOx in a NOx purification catalyst from immediately after startup of the internal combustion engine. The exhaust purification device includes: a fuel reformer that is provided separately from exhaust plumbing, reforms fuel and produces a reducing gas that contains carbon monoxide, hydrogen and hydrocarbons, and supplies the reducing gas upstream of the NOx purification catalyst into the exhaust path; an exhaust gas temperature sensorthat detects a temperature Tof the exhaust flowing in the exhaust plumbing; and a reformer control partthat starts supply of the reducing gas to the exhaust plumbingby starting control of the fuel reformerin a case where the temperature Tthus detected by this exhaust gas temperature sensoris no higher than a predetermined first determination temperature T, and stops the supply of reducing gas to the exhaust plumbingby stopping control of the fuel reformerin a case where the temperature detected by the exhaust gas temperature sensoris at least a second determination temperature T, which is higher than the first determination temperature.