Diverter Valve
The purpose of the diverter valve is to prevent backfire in the exhaust system during sudden deceleration. The valve senses sudden increase in the intake manifold vacuum causing the valve to open, allowing air from the pump to pass through the valve and silencer to the atmosphere.
A pressure relief valve, incorporated in the diverter valve housing, controls pressure within the system by diverting excessive pump output at higher engine speeds to the atmosphere through the silencer.