Catalytic Converter: Description and Operation

The three way oxidation catalytic converter is an emission control device added to the gasoline engine exhaust system to reduce hydrocarbon, carbon monoxide, and oxides of nitrogen (NOx) emissions. The converter contains a honeycomb network coated with catalytic material containing platinum, palladium and rhodium. The catalytic material promotes oxidation and reduction of the pollutants as the exhaust gasses pass through the converter on their way to the tailpipe.

A fill pipe restrictor is used on catalytic converter equipped vehicles, to prevent the larger service station pump nozzle, used for leaded fuels, being inserted into the filler tube. Since the use of leaded fuels contaminates the catalysts, rendering them ineffective, the use of unleaded fuels is mandatory in catalytic converter equipped vehicles.