What is the function of an exhaust gas recirculation valve in an Audi?

Looking into purchasing an Audi and want to understand the role and importance of the exhaust gas recirculation valve in their engines.

The exhaust gas recirculation (EGR) valve is responsible for recirculating a portion of the exhaust gases back into the engine cylinders to reduce emissions. It helps to lower the temperature of combustion and decrease the amount of pollutants in the exhaust gas.

The EGR valve also helps to improve fuel efficiency and engine performance by allowing a precise amount of exhaust gas to enter the combustion chamber. This can result in better overall engine operation.