Durability of Three-Way Catalysts with Precious Metals Loaded on Different Location

It is necessary to mount a three-way catalyst at a place near the engine such as a close coupled converter or manifold converter to decrease cold-start emission. Naturally, in that case the catalyst of course is used under considerable A/F fluctuations at higher temperatures. We have developed a catalyst with excellent durability under such severe conditions. Three types of catalysts, made with different loading locations of precious metals, were evaluated using model gases. Durability was found to strongly depend on the loading location, and thus it should be possible to design an optimal catalyst for close coupled and manifold converters.