Thermostatic Air Cleaner: Description and Operation

Fig. 13:

PURPOSE
Allows for use of leaner air/fuel mixture, while improving engine warm-up characteristics and minimizing carburetor icing.

OPERATION
This system, Fig. 13, uses a thermostatically controlled air cleaner to maintain a predetermined air temperature entering the carburetor when underhood temperatures are less than 100° F.

Temperature is controlled by intake manifold vacuum, a temperature sensor and a vacuum diaphragm which operates the heat control door in the air cleaner snorkel.

During engine warm-up;
- Air heated by the shroud surrounding the exhaust manifold, is piped through the air cleaner snorkel into the carburetor.
- The vacuum diaphragm controls the air control valve which is closed to outside air. Therefore all air entering the carburetor is heated.

During normal operation;
- As the temperature of the air entering the air cleaner increases, the air control valve opens to allow cold air to mix with the heated air, keeping the air entering the carburetor at the specified temperature.