Air Regulator
WARNING: This page is about a different car, the 1985 Nissan 200SX. However, it is still accessible from the selected car via links, so may be relevant.
The air regulator by-passes the throttle valve to control the quantity of the air for engine idling speed when starting the engine at bimetal strip temperature of below 176°F (80°C). When ignition is turned to "START" position or engine is running, bimetal strip moves shutter to close the air passage as it heats up.