Exhaust Gas Recirculation: Description and Operation

Fig. 32 Exhaust gas recirculation system.:

This system, Fig. 32, is used to reduce oxides of nitrogen emissions by lowering the peak combustion temperature in the engine. This is accomplished by introducing a metered amount of exhaust gasses into the intake manifold at speeds above idle. This system consists of an EGR valve, two vacuum switching valves, vacuum regulator valve, vacuum pump, thermo vacuum valve, EGR controller, control lever position sensor and engine speed sensor.