EGR System: Description

Purpose of the Exhaust Gas Recirculation (EGR) system is to limit formation of oxides of nitrogen (NOx) emissions. This is done by reducing high peak combustion temperatures at which NOx is formed. By reintroducing some exhaust gas back into combustion chamber, high temperatures are avoided. Thus NOx emissions formation is reduced.

System consists of vacuum-operated EGR valve and coolant temperature override (CTO) switch. In addition, some models are equipped with air cleaner-mounted thermal vacuum switch (TVS), and some are equipped with an EGR vacuum dump valve.