Air Injection Control Valve: Description and Operation
OPERATIONThe air switch, or control, valve located between the diverter valve and air injection manifold, is controlled by the CT0 valve on 1981 vehicles and by the upstream solenoid on 1982 vehicles. The valve directs system pressure either "upstream" (into the air injection manifold attached to the exhaust manifold), or "downstream" (directly into the catalytic converter) when vacuum is not applied to it.
When air is directed "upstream", it mixes with the hot exhaust and causes a further burning of the mixture, reducing hydrocarbons and carbon monoxide emission.
During "downstream" operation, the additional air reacts with the hydrocarbons and carbon monoxide in the rear half of the catalytic converter to create carbon dioxide and water vapor, reducing undesirable emissions.