When shopping for a catalytic converter for your vehicle, there are a few different variations you should be aware of. There are three key types of catalytic converters:
Two-way oxidation instruments perform two tasks: oxidation of carbon monoxide to carbon dioxide and oxidation of hydrocarbons to carbon dioxide and water. This type of converter is typically used on diesel engines to reduce hydrocarbon and carbon monoxide emissions. It is no longer used in the United States and Canada due to its inability to control oxides of nitrogen.
These devices are used in vehicle emission control systems in most parts of the world. Strict vehicle emission regulations have made it almost mandatory to use three-way converters on gasoline-powered vehicles. They perform three simultaneous tasks: the reduction of nitrogen oxides to nitrogen and oxygen, oxidation of carbon monoxide to carbon dioxide, and oxidation of unburnt hydrocarbons to carbon dioxide and water.
Diesel oxidation catalysts are mostly used for compression-ignition such as diesel engines. It uses oxygen in the exhaust gas stream to convert carbon monoxide to carbon dioxide and hydrocarbons to water and carbon carbon dioxide. These devices are known to perform at 90% efficiency, removing diesel odor and reducing visible particulates.