Air Injection System: Operation
Air is drawn from the clean side of the air cleaner by the air pump and directed to the air control valve under pressure. The No. 1 relief valve of the control valve directs cooling air to outer portion of thermal reactor to reduce high heat deterioration. The No. 2 relief valve (controlled by the relief valve solenoid) controls the amount of air injected into thermal reactor according to intake manifold vacuum. Under normal operating conditions, part of the secondary air supplied from the air pump is directed back to the air cleaner.
The preheated air is mixed with the hot exhaust gas at the exhaust port of rotor housing. From the exhaust port, the exhaust gases burn more completely in the thermal reactor before entering exhaust system. The check valve prevents exhaust gas from leaking back into the air pump.