EGR Valve: Description and Operation

PURPOSE
To assist in the control of oxides of nitrogen (NOx) in engine exhaust, all engines are equipped with an exhaust gas recirculation system. The use of exhaust gas to dilute incoming air/fuel mixtures lowers peak flame temperatures during combustion, thus limiting the formation of NOx.

OPERATION
Exhaust gases are taken from the number four exhaust port through a hole in the end of the cylinder head.