New Three-way Catalyst

Mazda Motor Corporation has developed a new three-way catalyst for gasoline engines to improve its performance of purifying pollutants in exhaust emissions.

Mazda's New Three-way Catalyst

A catalyst, in general, starts to react to purify pollutants such as hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxides (NOx) in emissions when its temperature reaches between 250°C-300°C. For greater environmental protection, it is necessary to reduce these pollutants before the temperature reaches this level during the engine's cold driving cycle.

Current three-way catalysts are located as near as possible to the engine in order to make the temperature of catalysts rise sooner. But, under engine conditions such as high-speed driving, deterioration of the catalyst accelerates due to the high temperature of exhaust emissions from the engine. Usually, the temperature of emissions are lowered by injecting additional amounts of fuel into the engine's combustion chamber.


Mazda's new three-way catalyst can start to react at a lower temperature and suppress thermal deterioration. This new catalyst is made from unique ratios of precious metals such as palladium, platinum, and rhodium. An increased ratio of palladium has resulted in hastening purification of the pollutants. The new catalyst has high thermal resistance due to the use of a newly developed, thermal stabilized material.

Highlighted features of the new three-way catalyst :

Reduces HC, CO and NOx by half.
The new three-way catalyst starts to purify pollutants from a 70°C lower temperature than current catalysts. It reduces HC, CO and NOx gases by 50 percent during the engine's cold driving cycle.

Increases fuel economy and lowers CO2 by 15 percent
The new three-way catalyst achieves greater heat resistant performance, 100°C higher than current catalysts, and the engine does not need additional amounts of fuel injected into its combustion chamber to eventually lower the catalyst's temperature. As a result, fuel economy is improved and CO2 emissions are lowered by 15 percent, under such a condition as 160 km/h high speed cruising on the Autobahn in Germany.

Increases engine performance
The new three-way catalyst starts to react at a lower temperature, thereby increasing overall conversion capability. Accordingly, the size of the catalyst has been reduced by 40 percent : thus permitting a smoother flow of emissions when going through the catalyst and increasing overall engine performance.

Mazda's new three-way catalyst will enable their vehicles to meet future stringent emission regulations in various countries while enhancing engine performance. Mazda plans to start to apply this new three-way catalyst to their vehicles soon.

Find more news and information at www.mazda.com