Exhaust gas cleaning system for diesel engines

摘要

The wall surfaces of the flow channels of the honeycomb bodies are provided with a catalytically active coating. The upstream first catalyser (5) has a cell density of less than 40 to 80 flow channels per square centimetre of cross-sectional surface. The cell density of the downstream second catalyser (6) is greater than that of the first. The first catalyser may have 4 to 70 and the second catalyser may have more than 40 to 300 flow channels per square centimetre of cross-sectional surface. Both catalysers can be of the diesel oxidation or the reduction type.