Three-Way Catalytic Converter

The three-way catalytic converter is currently the safest, most efficient, and most reliable form of exhaust emission control available for petrol engines. As its name indicates, the three-way catalytic converter converts three pollutants - hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx), into less harmful gases. It's made of a metallic or ceramic material coated with a precious metal (platinum, rhodium, iridium). The catalytic converter converts around 90 per cent of the pollutants into carbon dioxide (CO2), nitrogen (N2) and water (H2O). To perform efficiently it must first reach a certain temperature. This is why cars are often fitted with close-coupled preliminary catalytic converters which are able to reduce harmful emissions while the engine is still warming up. The oxygen sensor works with the engine management unit to keep the composition of the fuel/air mixture at an ideal level for the conversion process.