MMT Plugging of Oxidation Catalysts on Ceramic and Metal Supports During Engine Dyno Studies of Catalyst Durability

DURING ENGINE DYNO durability testing of oxidation catalysts, manganese deposition on the catalyst hot faces sufficient to affect catalyst performance for HC and CO conversions was observed. The severity of the problem is related to the MMT level in the fuel, the cell density of the catalyst's monolithic support, and engine aging time. The nature of manganese deposition in these studies and how it affects catalyst performance is explored.

Apart from the MMT phenomenon, comparative studies of oxidation catalysts on conventional ceramic and high cell density, thin-wall metallic supports indicate that the latter offer significantly improved HC conversion durability.