Detroit Series 60 EGR Diagram
The purpose of the EGR system is to reduce engine exhaust gas emissions in accordance with EPA regulations.
EGR (exhaust gas recirculation) allows a percentage of the exhaust gases to remix with the air coming into the intake manifold. The exhaust gas dilutes the incoming air, displacing some of the oxygen in the air. Less oxygen results in a slower burn and a reduced peak cylinder temperature which reduces NOx (nitrogen oxides).