Typical AIR system of 2F engine
1. Thermal vacuum distributor; 2. Air bypass valve (ABV valve); 3. Pneumatic switch; 4. Vacuum distributor; 5. Air control valve; 6. Pressure reducing valve; 7. Air pump
Typical AIR system of the 3F-E engine
1, 6. Control pneumatic valve; 2. Vacuum distributor; 3. pneumatic switch; 4. Muffler; 5. Air pump
(The text is quoted from the source website: www.TOYOTAMAN.ru)
The system is designed for forced oxidation (afterburning) of hydrocarbons and carbon monoxide by supplying fresh air under pressure.