Catalytic Converter: Description and Operation

The catalytic converter is an emission control device added to the exhaust system to effectively reduce the levels of HC, CO and in some cases, NOx released into the atmosphere.
Two basic type of catalytic converters are used. The oxidation catalyst reduces HC and CO through catalytic oxidation, reducing them into water and carbon dioxide. The three-way catalyst reduces oxides of nitrogen (NOx) levels as well as HC and CO, producing dinitrogen, water and carbon dioxide. Depending on application, either type converter, or a combination of the two may be used.