Air Injection: Description and Operation

Managed Thermactor Air System Operation:

The Secondary Air Injection (AIR) System helps with the reduction of HC and CO emissions, by supplying additional oxygen into the exhaust system. This allows the hot exhaust gases to continue the combustion process of remaining unburned air/fuel charge, or to begin oxidizing HC and CO emissions.


The air pump supplies additional air to a bypass valve, directing air to a diverter valve or to the atmosphere, via a "dumping" action. Air supplied to the diverter valve is either directed upstream to the exhaust manifold or downstream to the catalytic converter.
Valve operation is controlled by internal diaphragms, and dependent upon manifold vacuum, which is supplied and regulated by computer controlled solenoid valves.

During cold engine warm-up, thermactor air is routed to the exhaust manifold. The secondary air is needed to help continue the combustion process of a rich air/fuel mixture. Also, this action helps the catalytic converter to reach its operating temperature quicker.