EGR Valve: Description and Operation

EGR System Operations:

PURPOSE
The EGR valve is a vacuum operated. When the valve opens, a passage from the exhaust manifold to the intake manifold is opened. Exhaust gases are drawn into the combustion chamber which dilutes the air/fuel charge. The reduced fuel charge results in lower chamber temperatures and reduced NOx emissions.

OPERATION
The EGR valve is controlled by the vacuum modulator and the vacuum switching valve.