Thermostatic Air Cleaner Actuator: Description and Operation

Fig. 34 Intake air temperature control system:

This system, Fig. 34, consists of a thermo-wax and damper which controls the intake air temperature by mixing warm pre-heated air with colder outside air to improve fuel vaporization and engine warm-up.
When the engine is started in cold weather, the thermo-wax is contracted because the temperature of the intake air in the air cleaner is low and the damper linked to the thermo-wax closes the cold air duct and opens the warm air duct fully. As the engine temperature rises, the temperature of the intake air coming through the warm air duct rises and the thermo-wax expands. The damper then opens the cold air duct gradually to admit cold air which is mixed with the warmer air. In this manner, the temperature of the intake air is controlled.