catalytic converter

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Device fitted to the exhaust system of a motor vehicle in order to reduce toxic emissions from the engine. It converts the harmful exhaust products that cause air pollution to relatively harmless ones.

It does this by passing them over a mixture of catalysts coated on a metal or ceramic honeycomb (a structure that increases the surface area and therefore the amount of active catalyst with which the exhaust gases will come into contact). Oxidation catalysts (small amounts of palladium and platinum) convert hydrocarbons (unburnt fuel) and carbon monoxide into carbon dioxide and water, but do not affect nitrogen oxide emissions. Three-way catalysts (platinum and rhodium metals) also convert nitrogen oxide gases into nitrogen and oxygen.

The bison's head, star, rose, and crescent are traditional symbols of Moldavia. The colours are based on the Romanian flag. Effective date: 3 November 1990. >>