Exhaust Gas Recirculation (EGR) System Description: Notes

The exhaust gas recirculation (EGR) system controls the formation of oxides of nitrogen (NOx) emissions by recirculating the exhaust gases into the combustion chamber. NOx emissions increase with combustion chamber temperatures. Controlling the high combustion chamber temperatures will help limit the formation of NOx emissions. The EGR system accomplishes this by admitting controlled amounts of exhaust gas into the intake manifold to mix with the incoming air. Mixing exhaust gases with incoming air/fuel mixture modifies the combustion process resulting in lower combustion chamber temperatures.