Air Injection Vacuum Control Solenoid Valve: Description and Operation

The Cold Air Induction System is designed to send secondary air to the exhaust manifold to promote afterburning of the exhaust gases, reducing CO and HC.
The exhaust pressure in the manifold pulsates in response to the opening and closing of the exhaust valves and decreases periodically below atmospheric pressure creating a vacuum effect.

Fig. 3 Solenoid Valve:

Fig. 7 AIV Operation:

When the ECU senses the predetermined conditions for AIV operation, it energizes the AIV solenoid, redirecting vacuum from the source port and vent port to the source port and valve port applying vacuum to the AIV.

Fig. 6 Air Induction Valve:

The vacuum being transmitted to the AIV acts upon a diaphragm opening the AIV port allowing the system to operate.
The exhaust flow then draws filtered air into the manifold through the piping and AIV, promoting afterburning of the unburned exhaust gasses.
A set of reed valves are mounted in the AIV to prevent exhaust gas from being sent back into the AIV when the exhaust pressure exceeds atmospheric pressure.