Auxiliary Air Valve

The auxiliary air valve is used to increase airflow when the engine is started up at a low temperature. It consists of a coiled bi-metallic spring. The bi-metallic spring operates a shutter valve, and an electric heater element.

The airflow is increased as the temperature becomes lower. After engine start-up, heating is performed by a heater. The current to the heater is supplied by the fuel pump relay circuit. Thus, the shutter valve turns gradually to decrease the airflow. After a certain elapsed time the shutter valve is closed.