Air Injection: Description and Operation

Pulse Air Injection:

SYSTEM OPERATION

The system uses the natural pulses of the exhaust system to draw air into the exhaust manifold. The system is regulated by a Pulse Air Valve. The valve is connected to the air cleaner with a hose and to the exhaust manifold with a metal tube. Some Pulse Air Valves closely resemble the standard Thermactor Check Valves, but are not interchangeable with them.
When pressure inside the exhaust manifold is more than the pressure in the air cleaner, the reed in the pulse air valve is closed. When pressure in the exhaust manifold is lower than in the air cleaner, the reed opens and allows air to be drawn in the exhaust manifold.

Anti-Backfire (GULP) Valve:

ANTI-BACKFIRE (GULP) VALVE

The Gulp Valve increases air flow to the intake manifold when it is triggered by intake manifold vacuum on deceleration. The valve operates only during sudden decrease in intake manifold pressure (high vacuum).

Pulse Air Control Valve:

PULSE AIR CONTROL VALVE

The Pulse Air Control Valve consists of a vacuum diaphragm that when subjected to manifold vacuum, opens a passage between the air cleaner and exhaust manifold allowing the reed valves to inject secondary air into the exhaust flow. Vacuum to the pulse air control valve is controlled by a control solenoid which opens and closes the vacuum passage upon signals from the Electronic Control Assembly (ECA).



REED VALVES

The Reed Valves are one-way valves that close to prevent exhaust gas from flowing into the air cleaner as back pressure becomes positive. Installed in a housing and mounted to the air cleaner, the Reed Valves operate on exhaust pulses to provide air injection to the exhaust manifold and catalytic converter. This action assists in controlling HC and CO emissions.