SECONDARY AIR INJECTION (AIR) SYSTEM CONSTRUCTION/OPERATION


BHE011600116T02

• The AIR system is controlled by the PCM.

• If the engine is started when the conditions for actuating the AIR system are satisfied, the AIR pump operates, pumping air to the AIR control valve. At this point, the PCM turns on the AIR solenoid valve, causing negative pressure in the vacuum chamber to open the AIR control valve. Due to this, the air pumped by the AIR pump is passed through the secondary air ports and introduced into the exhaust ports in the side housing as secondary air. The secondary air reacts with unburnt gas discharged from the rotor housing thereby raising exhaust gas temperature and enhancing catalyst activation. When the AIR pump stops, the AIR solenoid valve turns off, closing the AIR control valve and preventing the reverse flow of exhaust gas from the exhaust ports to the AIR pump.

System Diagram

1
AIR solenoid valve
2
Vacuum chamber
3
AIR port
4
Exhaust port
5
AIR pump
6
AIR control valve
7
TWC