Auxiliary Air Valve (Idle Speed): Description and Operation

Idle Air Control Valve (IACV)-Air Regulator:

PURPOSE
The Idle Air Control Valve (IACV)-Air regulator provides an air by-pass when the engine is cold for a fast idle during warm-up.

OPERATION
The bimetal spring bends as its temperature changes. When ambient air temperature is low, the air bypass port opens. As the engine starts and electric current flows through a heater, the bimetal begins to turn the shutter to close the by-pass port. The air passage remains closed until the engine stops and the bimetal temperature drops.

CONSTRUCTION
A bimetal, heater and rotary shutter are built into the (IACV)-Air regulator.