California

PURPOSE
The Exhaust Gas Recirculation (EGR) system is used to dilute the incoming air/fuel mixture with recirculated exhaust gases. Dilution of the incoming mixture lowers the peak flame temperature in the combustion chamber and thus, limits the formation of nitrous oxides (NOx).

OPERATION
At specific times determined by the Engine Control Module (ECM) the Vacuum Switching Valve (VSV) opens and allows vacuum to open the EGR Valve. The amount of exhaust gas introduced to the intake system is directly relative to pressure in the exhaust system as controlled by the EGR Vacuum Modulator.