Auxiliary Air Valve (Idle Speed): Description and Operation

PURPOSE
Provide cold engine, fast idle. When the engine is cold, it sends the air from the air cleaner to the intake manifold without letting it pass through the throttle valve to increase the engine speed, and thus the engine is warmed up.

LOCATION
On the throttle chamber.

OPERATION
When the engine is cold (or engine cooling water is lower than about 60°C (140°F)), the thermowax contracts.

Air Valve (Open):

In this state, the valve opens by the spring force and opens the air passage, allowing the air from the air cleaner to be drawn into the intake manifold. Thus the amount of intake air increases even when the throttle valve is at the idle position and the engine speed rises to the fast idle state which is higher than the idle speed.

Air Valve (Closed):

As the engine is warmed up, the thermo-wax expands gradually, then the piston is pushed to move the valve down gradually, and the amount of air passing through the air passage decreases and so does the engine speed. When the engine cooling water temperature reaches about 6O°C (140°F), the valve is fully closed and the engine speed is back to the normal idle speed.


CONSTRUCTION
The air valve consists of thermo-wax, springs and valve
.