| abstract |
In an internal combustion engine or a combustion apparatus mainly operating in an excess air condition, an exhaust gas purification device capable of efficiently removing nitrogen oxides in exhaust gas is provided at a low cost. In the exhaust gas purification device installed in the exhaust passage of the internal combustion engine or combustion apparatus,n n n Nitrogen oxide is temporarily adsorbed even in an excess air atmosphere, and the nitrogen oxide adsorbent which desorbs the adsorbed nitrogen oxides from an elevated temperature or reduction atmosphere is disposed on the upstream side of the exhaust than the nitrogen oxide adsorbent, and the temperature is raised or reduced in the exhaust passage. And a combustion device disposed downstream of the exhaust gas from the nitrogen oxide adsorbent, wherein the nitrogen oxide adsorbent is made of a metal oxide that does not contain platinum. |