EGR Valve

EGR valve is mounted to intake manifold. It controls exhaust gas flow into intake manifold. Vacuum diaphragm chamber is connected to carburetor flange vacuum port through thermal vacuum valve. Opening throttle valve applies a vacuum to vacuum diaphragm.

When force of vacuum reaches a specified value, diaphragm overcomes holding force of spring and moves to its fully raised position. Upward motion of diaphragm opens EGR valve. Exhaust gases are pulled into engine intake.