| 摘要 |
<p>The invention relates to a system for the purification of diesel engine exhaust gases, the system being maintenance-free and comprising a first honeycomb catalyst (3) and a second honeycomb catalyst (5) fitted downstream of the first honeycomb catalyst in the flow direction of the exhaust gases, both of which honeycombs (3, 5) contain a catalyst material active for the selective reduction of nitrogen oxides, the formation of NO2, and the oxidation of hydrocarbons, carbon monoxide and hydrogen, and the system having additionally one or more of the following features, by means of which the combustion of soot and the reduction of nitrogen oxides are further promoted: (i) a bypass channel (4) by means of which a portion of the exhaust gases is directed past the first catalyst to the second catalyst, (ii) the cell density of the first honeycomb catalyst (3) is higher than the cell density of the second honeycomb catalyst (5). (iii) at least one of the honeycombs contains a compound which binds soot and/or sulphur oxides and/or nitrogen oxides. <IMAGE></p> |
