EGR Valve: Description and Operation

EGR Valve:

PURPOSE
The Exhaust Gas Recirculation (EGR) valve controls the amount of exhaust gas that will be allowed back into the combustion chamber.

OPERATION
The EGR valve contains a spring loaded diaphragm that will move upward when vacuum is applied in response to the opening of the throttle valve. The upward movement will lift a tapered valve off it's seat and allow some exhaust gas to pass through into the intake manifold.