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

The primary function of the exhaust gas recirculation (EGR) system is to introduce a portion of the engine's exhaust gases back into the combustion chamber. This process helps reduce nitrogen oxide (NOx) emissions, which are harmful pollutants formed during the combustion of fuel at high temperatures. By recirculating exhaust gases, the EGR system lowers the combustion temperature, which leads to a decrease in NOx formation.

Additionally, the EGR system can have a positive impact on fuel efficiency by promoting a more complete combustion process. However, its primary and most crucial role is focused on emissions control, specifically targeting the reduction of NOx emissions in order to comply with environmental regulations. The introduction of exhaust into the intake system not only assists in lowering emissions but helps maintain optimal engine operation under various driving conditions.