Diesel engine catalyst sub=divided into low and high temperature zones

摘要

A diesel engine (1) exhaust oxidation catalyst assembly incorporates a catalyst substrate (14) covered by a layer (15) incorporating platinum. The catalyst is sub-divided into a high temperature zone (3) for hot exhaust gases, and a low temperature zone (5) for cooler gases. The diameter (2-4 nm) of the platinum particles is smaller in the low-temperature zone (5) (20 nm) than in the high temperature zone (3). The platinum content (30 g/l) is preferably less in the low-temperature zone (5) (120-160 g/l) than in the high-temperature zone (3).