| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem of a conventional technique wherein soot in exhaust gas of a diesel engine is removed by using a fine and porous filter, and when complete combustion at the inside of the filter is uncertain (when performing a light load operation of the diesel engine), soot stays in the filter, the removing measure is required to cause high expense. <P>SOLUTION: An internal circulating flow layer is formed by passing of exhaust gas, soot combustion is ensured by catalyst combustion, and ash content of the soot combustion is collected by a fixed layer on a discharge side of the internal circulating flow layer. By using a NOx selection and reduction catalyst for particles of the fixed layer, dimethyl ether or urea water as reducing agent is sprayed in mist-like state, and NOx is selectively reduced within the fixed layer to be separated into N<SB>2</SB>and O<SB>2</SB>by ammonia due to hydrolysis of urea. <P>COPYRIGHT: (C)2003,JPO |
