EGR Valve: Description and Operation

Exhaust Gas Recirculation Valve:

PURPOSE
The Exhaust Gas Recirculation (EGR) Valve, located at the right side of the intake manifold near the throttle body, allows a measured amount of exhaust gas to be recycled into the intake flow.

OPERATION
The EGR valve has a diaphragm with a pintle rod attached to one end of it and a spring pushing on the other end of it (keeping the valve closed). When vacuum is applied to the diaphragm, it overcomes the spring pressure, pulling the pintle rod out of it's seat. This opens the passage, allowing gas recirculation. The amount of recirculation is directly relative to applied vacuum.