Oxidation catalyst for diesel engine

摘要

An oxidizing catalytic converter is provided in an exhaust passage of a diesel engine. A catalyst is formed by coating a wash coat comprising platinum onto a substrate The converter is divided into a high temperature part through which high temperature exhaust is circulated and a low temperature part through which low temperature exhaust is circulated, and the platinum particle diameter of the catalyst in the low temperature part is arranged to be less than that in the high temperature part. It is preferable that the wash coat amount of the low temperature part is less than that of the high temperature part. It is moreover preferable that the platinum amount in the low temperature part is greater than that in the high temperature part. In this way, the soluble organic fraction, hydrocarbons and carbon monoxide are effectively and continuously purged from the exhaust.