Exhaust Gas Recirculation (EGR) Valves re-circulate metered amounts of exhaust gas into engines's intake system to help limit the formation of nitrogen oxide (NOx) emissions,also control driveability,octane rating and fuel economy. The reducation of NOx is accomplished by lowering engine combustion emperature by recirculating metered amounts of burned
exhaust gases back through the Intake Manifold where they ate mixed with fresh air-fuel mixture. The EGR device with position sensor provides feedback tothe engine computer so that precise flow control is possible in order to achieve desirable operating conditions and have quick response in the dynamic mode.