New Mazda Catalytic Converter Uses 70 Percent Less Precious Metals

By KBB.com Editors on January 9, 2009 5:29 AM

Mazda has developed a new catalytic converter design that cuts manufacturing costs as effectively as it trims tailpipe emissions by reducing the amount of precious metals required to get the job done. Employing what Mazda calls "single-nanocatalyst technology," the new converter lowers the content of pricey metals like platinum and rhodium by 70 percent compared to a conventional counterpart. The first of these new single-nanocatalyst scrubbers will used on the new MAZDA3 that goes on sale next month.

As in any converter, precious metals that react with the exhausts gases are used to coat a base material substrate. The problem is that exposing them to high levels of heat causes these "active" metals to aggregate into larger clumps, a condition that decreases their exposed surface area -- and their efficacy. Until now, the only way to counteract that condition was to increase the amount of the rare earth metals used. Mazda's solution involved creating a proprietary catalyst material structure and coating it with a series of much smaller -- less then five nanometers (5nm) in diameter -- precious-metal particles that are embedded in a fixed position. Ensuring that these particles always remain separated and have their maximum surface areas exposed permits the same amount of exhaust cleanup work to be accomplished with a significantly smaller amount catalyzing material. Of equal importance, this new single-nanocatalyst technology is robust enough to handle the rigors of even harsh duty cycles over extended periods of time. Mazda plans to introduce this new converter design throughout its vehicle lineup throughout the world.

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