Development of Oxidation Catalyst for Diesel Engine

In developing an oxidation catalyst for reducing diesel particulates, it is necessary to balance two conflicting characteristics. One is high oxidizing activity so that the catalyst can reduce the Soluble Organic Fraction (SOF) efficiency even at low exhaust temperatures. The other is the suppression of sulphate formation at high exhaust temperatures.

First it was studied that active metals and coating materials are given effects on the reduction of SOF, the formulation of sulphate and durability, by using catalysts equivalent in composition to the oxidation catalyst for gasoline-engines.

Based on these findings, a two-stage catalyst wasdeveloped. It satisfies the two characteristics at a comparatively high levelby slecting materials and optimizing the catalyst composition.