Catalytic Converters

Catalytic converters were introduced to Australian vehicles in 1986 to clean up the noxious exhaust gases produced by petrol engines.

Catalytic converters are fitted into vehicle exhaust systems and resemble a small muffler. Their outer body is stainless steel, while inside is a honeycombed ceramic block, containing a variety of noble metals such as platinum, palladium and rhodium. These metals cause a chemical reaction with the passing exhaust gases.

There are two types of catalytic converters.

The two-way, or oxidising, converter changes unburnt or partially burnt fuel to water and carbon dioxide, while three way converters utilise the oxidising process, and in addition, convert oxides of nitrogen into harmless nitrogen. The converter type fitted to a particular vehicle depends on its emission system.

Catalytic converters are sensitive to engine-related problems, such as misfires and rich fuel mixtures and may be easily destroyed by impacts with road hazards and speed bumps. In normal service they have a long life, however, they do eventually wear out and need to be replaced.

Because they typically operate at between 375°C and 600°C, vehicles fitted with them should not be parked near dry grass due the risk of fire.

Catalytic converters are an integral part of a vehicles emission control system and they should not be removed or tampered with.