An exhaust gas purification device for an internal combustion engine

摘要

According to the present invention, there is provided an exhaust gas purification device for an engine having an exhaust passage, the device comprising a catalyst arranged in the exhaust passage and having an upstream end and a downstream end, a purification ratio of exhaust gas by the catalyst becoming more than a predetermined ratio when a temperature of the catalyst is within a predetermined temperature range, cooling means for cooling the upstream end of the catalyst, heating means for heating the downstream end of the catalyst, and control means for controlling the cooling means and the heating means to maintain the temperature of a portion of the catalyst, which portion is positioned between the upstream end and the downstream end, in the predetermined temperature range. <IMAGE>