Air Injection Check Valve: Description and Operation

Air Injection System:

SYSTEM OPERATION

The air injection system supplies secondary air into the exhaust system to burn (oxidize) CO and HC in the exhaust gas and to control the oxygen signal for the engine control unit. The main components of the air injection system are the air pump, the check valves, the air control valve, the anti-afterburn valve, the solenoid switching valve, the solenoid relief valve, the heat hazard sensor, the split air solenoid valve, and the port air solenoid valve.

AIR PUMP

The air pump is a belt driven pump that is used to supply air to the air injection system.

CHECK VALVE

There are two check valves located in the air injection system. One is located in the air line going to the exhaust ports and the other is located in the air line going to the catalytic converter. The check valves allow air from the air pump to be delivered to their respective destinations while preventing the exhaust gases from backfeeding and damaging the components of the air injection system.

AIR CONTROL VALVE

The air control valve directs air to either the exhaust port, main converter, or the relief air silencer.

ANTI-AFTERBURN VALVE

The anti-afterburn valve is a vacuum operated valve that supplies fresh air to the rear port during deceleration.

SOLENOID SWITCHING VALVE

The solenoid switching valve controls the operation of the switching valve section of the air control valve.

SOLENOID RELIEF VALVE

The solenoid relief valve controls the operation of the relief valve section of the air control valve.

HEAT HAZARD SENSOR

The heat hazard sensor monitors the floor temperature and sends a signal to the control unit. If the heat sensor is turned on, then the air being delivered to the catalytic converter is turned off.

SPLIT AIR SOLENOID VALVE

The split air solenoid valve is a part of the air control valve. It controls the amount of air that is allowed to flow to the catalytic converter.

PORT AIR SOLENOID VALVE

The port air solenoid valve diverts a measured quantity of air to the exhaust manifold under certain conditions.