Air Injection: Description and Operation

Emission Control Schematic:

PURPOSE
The air injection reactor system pumps air through a maintenance-free dry air filter mounted on the pump into the exhaust ports of the cylinder head to promote oxidation of CO and HC. The heat created by the oxidation process also brings the catalytic converter up to operating temperature more quickly.

OPERATION
Air Injection takes place for a about 155 seconds after start up and only when the coolant temperature is between 10°C (50°F) and 44°C (111°F), the engine speed is less than 2750 RPM, a specific intake air mass is not exceeded and the oxygen sensor is in open-loop.

Under these conditions the electromagnetic clutch of the air pump (125) is switched on by the right LH control (N3/3). The LH control module simultaneously powers the air injection switch-over valve (Y32) which provides vacuum to the air injection shut-off valve (126) in the pump circuit. Air is then pumped through the check valves (127 and 127a) and into the exhaust ports of #3 and 10 cylinder in the cylinder head.