Audi Centre Doncaster Audi Glossary

The oxidising catalytic converter for diesel vehicles reduces the levels of carbon monoxide and hydrocarbons in the exhaust and also lowers particulate (soot) emissions. Unlike the closed-loop, three-way catalytic converter for spark-ignition engines it cannot convert oxides of nitrogen into environmentally more compatible nitrogen (Reason: this is a chemical reduction process, the opposite of the oxidation process here). For this reason, diesel engines are equipped with exhaust gas recirculation that takes place during the combustion process to reduce the amount of oxides of nitrogen.