| 摘要 |
PROBLEM TO BE SOLVED: To stably supply a gaseous component of low molecular weight and improve reduction efficiency of nitrogen oxides controlling catalyst by providing a conversion means converting a reducing agent introduced by an adding device to a gaseous component of low molecular weight, and adding the gaseous component to the upper stream side of nitrogen oxides controlling catalyst in an exhaust passage. SOLUTION: Nitrogen oxides controlling catalyst 25 is arranged in a chamber 23 provided on the way of the exhaust passage 21 of a diesel engine. Three feed tubes 29 are arranged on the upper stream side of the chamber 23, as an adding means 27 adding a gaseous component of low molecular weight resolved out of light oil (reducing agent) by a conversion means 31, for example propane or the like, to the upper stream side of the catalyst 25. The conversion means 31 is constituted of two plug bodies made of porous ceramics provided in the feed tube 29, preprocessing catalyst 37 for oxidation cracking or catalytic cracking of light oil filled between both plug bodies, and a heating means 39 heating the feed tubes 29 at prescribed temperature. Light oil sucked from a fuel tank 41 by a pump as an adding device 33 is fed to the conversion means 31.
|
