Compressor HVAC: Description and Operation

Compressor
The vehicle uses an HD-6 compressor which is a 10 cubic inch displacement six cylinder axial-type mechanism consisting of three double-ended pistons actuated by a swash plate shaft assembly. The compressor is located on the lower right of the engine centerline (right-front corner of the engine compartment), and is belt-driven from the crankshaft pulley. The compressor performs two main functions. It provides pressure and temperature levels at which heat exchange can take place in the condenser by compressing the low-pressure refrigerant vapor from the evaporator into a high-pressure, high-temperature vapor. It also pumps refrigerant (and refrigerant oil) through the A/C system.

A magnetic clutch is used to engage the compressor shaft. when voltage is applied to the clutch coil (by closing contacts in the thermostatic switch), the clutch plate and hub assembly (which is solidly coupled to the compressor shaft), is drawn by magnetic force rearward toward the pulley which rotates freely on the front head casting. The magnetic force holds the clutch plate and pulley together as one unit. The compressor shaft then turns with the pulley. When the PCM removes the voltage from the clutch coil, springs in the clutch plate and hub assembly move the clutch plate away from the pulley and the clutch plate and compressor shaft cease to rotate.