What is the primary function of an exhaust gas recirculation (EGR) system?

The primary function of an exhaust gas recirculation (EGR) system is to reduce nitrogen oxide (NOx) emissions. EGR works by recirculating a portion of the engine's exhaust gas back into the intake manifold, which lowers the combustion temperature. Lower combustion temperatures are essential because NOx emissions are formed at high temperatures during the combustion process. By reintroducing exhaust gases that are generally lower in oxygen, the EGR system dilutes the air-fuel mixture, thereby reducing peak combustion temperatures and ultimately leading to lower NOx emissions.

The significance of controlling NOx emissions is crucial in meeting stringent environmental regulations that govern air quality and emissions from vehicles. This technological solution not only helps in reducing pollution but also complies with laws aimed at keeping harmful emissions in check, making it an important component in modern diesel and gasoline engines aimed at sustainability and compliance with environmental standards.