Catalytic Converter Development for Motorcycle Emission Control

Catalytic control of motorcycle vehicle emissions requires that the catalytic element be carefully integrated into the exhaust system. The catalyst element physical parameters are optimized to achieve specific exhaust tuning requirements. Since the converter is located inside the muffler, the peak temperatures can severely stress both the catalytic active washcoat materials and the currently used metal monolith structure under some operating conditions. This paper addresses the development of an alternative ceramic monolithic catalyst that can be used for 2 and 4-stroke motorcycle applications.

A new mounting technique was developed to contain the ceramic catalytic unit within a holder or converter shell with sufficient strength and durability to withstand the severe environment of 2-stroke engine exhaust. The catalytic layer, which utilizes the segregated washcoat technology, was specifically designed for high temperature thermal resistance, low temperature performance and oil ash resistance. The new mounting technique and the catalyst formulations had proved to provide stable performance in laboratory reactor, engine dynamometer and on-road testing. The results of this work provide a new freedom for matching specific engineered washcoats to either ceramic or metal monolith catalysts to meet the specific requirements of a particular application.