EGR Valve: Description and Operation

Exhaust Gas Recirculation Valve:

Purpose
The valve increases or decreases the flow of exhaust gas recirculation.

Description
The EGR valve in the Differential Pressure Feedback EGR system is a conventional vacuum actuated EGR valve, and serves only as a pressure regulator rather than a flow metering device.

Operation
As vacuum applied to the EGR valve diaphragm overcomes the spring force, the valve begins to open. As the vacuum signal weakens, at 1.6 in (41 mm) Hg or less, the spring force closes the valve. The EGR valve is fully open at about 4.5 in (114 mm) Hg.