Air Injection: Description and Operation

SYSTEM DESCRIPTION

This system is used to reduce Carbon Monoxide (CO), Hydrocarbon (HC), and Nitrous Oxide (NOx) emissions. It also heats up the catalytic converter quickly, on engine start-up, so the conversion of exhaust gases will occur faster.

The A.I.R. system includes:

1. An Air Pump:
A belt driven pump on the front of the engine supplies the air to the system. Intake air passes through a centrifugal filter fan at the front of the pump, where foreign material is separated from the air by centrifugal force.
2. A Control Valve:
Air flows from the pump through an ECM controlled valve, through a valve on the exhaust ports or to atmosphere.
3. Check Valve:
The check valve prevents the back flow of exhaust into the pump in the event of an exhaust backfire or pump drive belt failure.
4. Necessary plumbing.

Electric Air Control Valve:

A.I.R. CONTROL VALVE DESCRIPTION

ELECTRIC AIR CONTROL VALVE (EAC)

The EAC valve combines an electronic controlled valve with normal (vacuum controlled) diverter valve function. When the solenoid is energized, the air control (divert) valve performs as a standard diverter valve. The A.I.R. pump directs air to the exhaust ports, unless there is a sudden rise in manifold vacuum due to vehicle deceleration.
When the solenoid is de-energized, the pressurized air from the air pump is allowed to enter the decel timing chamber. This places sufficient pressure on the valve diaphragm to overcome spring pressure which allows air to divert to the atmosphere. At high engine speeds, excess air is allowed to exhaust to atmosphere through the pressure relief valve.