Air Injection: Description and Operation

Fig.8a - Air Injection Reactor System, California:

Fig.8b - Air Injector Reaction System, Exc California:

This system reduces hydrocarbon and carbon monoxide content in the exhaust gases by adding a controlled amount of pressurized air at the exhaust ports. Causing the exhaust gases to self ignite when brought into contact with the additional oxygen--due to the high temperatures in the exhaust system.

This system consists of; an air pump, air injection nozzles, a check valve, a mixture control valve, air bypass valve or air switching valve, a vacuum switching valve and hoses necessary to connect the various components--Figs 8a & b.

Fig.9 - Sectional View Of Air Pump:

The belt driven air pump--Fig 9--draws in ambient air from the air cleaner and supplies pressurized air into the exhaust system through the injection nozzles.

Fig.10 - Check Valve:

The check valve, Fig. 10 permits air flow in one direction only. The valve opens when air pump pressure overcomes spring tension and closes when backpressure from the exhaust system overcomes air pump pressure. The check valve also protects the air pump and hoses from damage due to high temperatures should a drive belt break or backfire occur which would cause exhaust gases to flow in reverse direction.

Fig.11a - Mixture Control Valve:

To prevent after-burning in the exhaust system due to an overrich air fuel mixture during deceleration, the mixture control valve, Fig 11a is used. The mixture control valve prevents after-burning in the exhaust system by supplying additional air into the intake manifold to dilute the air-fuel mixture.

1982 models incorporate two types of air switching valves, one of which is used in Calif. models and the other which is used in all other models. Calif. models also use a vacuum switching valve.

Fig.12b - Air Switching Valve:

The air switching valve for Calif. models, Fig. 12b, switches air flow from pump and operates on intake manifold vacuum and air pump pressure which are regulated by a vacuum switching valve. When manifold vacuum flows to pipe (1) through vacuum switching valve, this valve allows air to flow from air pump to check valve. When air pump pressure flows to pipe (1), air valve shuts manifold air passage and switches air flow to air cleaner.

Fig.12a - Air Switching Valve:

The air switching valve used on other models, Fig. 12A, switches air flow from air pump and is operated by intake manifold vacuum. If manifold vacuum exceeds specified value, air flows from air pump to check valve. When manifold vacuum is below specified value, air valve shuts check valve air passage and allows air to flow into atmosphere.

Fig.12c - Vacuum Switching Valve:

The vacuum switching valve, Fig. 12C, has 3-way ports, two of which are regulated by an electrically controlled solenoid plunger. The solenoid plunger becomes operable when catalytic converter temperature reaches 1350° F, and causes vacuum switching valve to connect diaphragm chamber "B" of air switching valve to intake manifold. This permits application of manifold vacuum to chamber. At temperatures below 1350° F, diaphragm chamber "B" is connected to diaphragm chamber "A."