Air Injection: Description and Operation

Fig. 5 Pulse air feed system diagram:

Pulse air feeder (PAF) secondary air is used by the catalytic converter to complete oxidation and reduction of exhaust gas emissions, Fig. 5. The main reed valve is actuated in response to movement of a diaphragm from pressure pulsations generated by the reciprocating motion of the piston in the number 3 cylinder crankcase. The crankcase is sealed by a cover plate with a small orifice for oil return and ventilation of blow by gasses. The sub reed is actuated by vacuum generated from pulsations in exhaust system pressure.