104 ENGINE COMPONENT AND LOCATION Exhaust Gas Recirculation System W2033359 1.EGR Valve 5. Differential Pressure Sensors 2. EGR Cooler Inlet Pipe 6. EGR Cooler Outlet Pipe 3. EGR Cooler 7. EGR Mixer 4. Venturi Nitrous oxide (NOx) emission levels increase with combustion temperature. The primary function of the Exhaust Gas Recirculation (EGR) system is to cool exhaust gas and send it back to the combustion chamber to lower the combustion temperature thereby to reduce NOx emissions. The mixer where the recirculated exhaust joins the inlet air, mounts at the front of the inlet manifold for the conventional chassis engines.