Pulse Air Injection System: Operation
Each one of the check valves in the pulse air valve is connected to an exhaust port. The firing of the engine creates a pulsating flow of exhaust gases.
When positive exhaust pressure is felt, the check valve will be forced closed and no exhaust gas will flow past the valve into the fresh air supply line.
With negative exhaust pressure (vacuum), the check valve will open and fresh air will be drawn in and mixed with the exhaust gases. During high engine RPM, such as under heavy acceleration, the check valve will remain closed.
Air supply to the pulse air system is controlled by an electric and vacuum shut-off valve operated by the Computer Command Control (CCC) system.
When the engine starts and is operating in the open loop mode, the valve is energized and the fresh air line is opened.
When the CCC switches into the closed loop mode, the valve is de-energized and the fresh air line is closed.
A deceleration valve is used to prevent backfiring in the exhaust system during deceleration and to reduce emissions of unburned hydrocarbons.