Catalytic Converter: Description and Operation

Exhaust System:

Two three way catalytic converters are used to oxidize carbon monoxide (CO) and hydrocarbons (HC), and reduce oxides of nitrogen (NOx) emissions. The front converter is placed close to the exhaust manifold so that it will heat up quickly and operate efficiently when the engine is running at idle. The front converter also protects the main converter from damage by acting as a phosphorus and lead filter. The converters contain the catalyst elements platinum, rhodium and palladium which promote oxidation and reduction reactions at high temperatures. Emissions are converted into carbon dioxide, water vapor and nitrogen

When the engine (and the catalyst) is warmed up, fresh air is supplied to the main converter from the air Injection System (AIS) to help promote oxidation of hydrocarbons and carbon monoxide.