Air Injection: Description and Operation

Air Injection System:

A. DIVERTER (BYPASS) VALVE
B. AIR INJECTION MANIFOLD (LEFT)
C. AIR HOSE - DIVERTER VALVE-TO-AIR INJECTION MANIFOLD (LEFT)
D. AIR PUMP
E. AIR HOSE - AIR PUMP-TO-DIVERTER VALVE
F. AIR HOSE - DIVERTER VALVE-TO-AIR INJECTION MANIFOLD (RIGHT)
G. AIR INJECTION MANIFOLD (RIGHT)
H. CHECK VALVE
J. VACUUM HOSE FROM INTAKE MANIFOLD




This system is used to reduce carbon monoxide (CO) and hydrocarbon (HC) emissions by adding a controlled amount of air to the exhaust gases in the exhaust system. This addition of air causes further oxidation of the exhaust gases with an appreciable reduction of carbon monoxide and hydrocarbon emissions. The air injection system is designed so that air injection will not interfere with the ability of the EGR system to control NOx emissions and to ensure air-fuel distribution for maximum fuel economy.

The air injection system consist of an air injection pump, a diverter (by-pass) valve, check valves, air manifolds, and the tubes and hoses necessary to connect the various components.

Air Pump:

AIR PUMP
The belt driven air pump is mounted on the front of the engine. Intake air passes through a centrifugal fan at the front of the pump, where foreign materials are separated from the air by a centrifugal force. Air is delivered to the air injection manifold and tube assembly by a rubber hose through the diverter (by-pass) valve. The fresh air ignites and burns the unburned portion of the exhaust gases in the exhaust system, thus minimizing exhaust pollutants.

Diverter Valve:

DIVERTER (BYPASS) VALVE
The diverter (by-pass) valve is designed to route air from the air pump to either the air injection manifolds or the atmosphere. During periods of rapid deceleration a sharp increase in manifold vacuum momentarily shuts off the injected air to the exhaust port areas and prevents backfiring during this richer period. On engine overrun the total air supply is dumped through the diverter (by-pass) valve to the atmosphere.

Check Valve:

CHECK VALVE
The check valve is an integral part of the air injection manifold assembly that is attached to the exhaust manifold. This one-way valve allows fresh air to enter the exhaust system and prevents exhaust from escaping. The check valve will protect the system in the event of pump belt failure, excessively high exhaust system pressure, or air hose rupture.