Thermostatic Air Cleaner: Description and Operation

Fig.5 - Controlled Combustion System:

THERMOSTATICALLY CONTROLLED AIR CLEANER SYSTEM, CONTROLLED COMBUSTION SYSTEM (CCS)

These systems consist primarily of a thermo sensor, vacuum motor, hot air valve and hot idle compensator--mounted on the air cleaner body and snorkel--Figure 5.

When the engine is off no vacuum is present at the sensor or vacuum motor and the force of the vacuum motor spring closes off the "heated air" passage from the exhaust manifold heat stove.

When the engine is started cold the thermo sensor is cool and allows maximum vacuum to the vacuum motor completely opening the hot air control valve, closing off the ambient air passage through the snorkel and opening the air passage from the manifold heat stove.

Should the engine be heavily accelerated--sudden throttle opening--the vacuum level in the system will drop to a level low enough for the diaphragm spring to overcome the vacuum and push the hot air control bleed closed.

As the engine warms up and the air at the thermo sensor reaches about 100-111° F (38-44° C), the thermo sensor begins to bleed off the vacuum from the manifold.

At about 111° F (44° C), the thermo sensor completely bleeds off all vacuum to the vacuum motor so the diaphragm spring closes the hot air control valve to the heat stove passage and opens the ambient air passage through the snorkel.

The hot idle compensator installed in the air cleaner prevents excessive fuel vapors from entering the intake manifold if an excessive increase in engine temperature occurs.
- As the engine heats up and the air passing over the hot idle compensator reaches a specified temperature, the compensator opens to allow ambient air into the intake manifold to lean out the temporarily rich mixture.