Automotive - a.k.a Auto AC Compressor

Auto AC compressor performs similar function in car air conditioning, as "land" AC compressors.

On the other hand, there are glaring differences between the two compressor categories. The differences are:

  • body material,

  • power supply, and

  • common types of compressor and refrigerant used


Body material Power supply Common types & refrigerant
Common AC compressor Cold drawn steel Electrical motor, in hermetic, semi-hermetic, or open configuration Rotary, Piston, Scroll.

Utilising R-22, R-134a, R-404A, R-407C and R-507 refrigerants

Auto Air Conditioner Compressor Cast aluminium, cast iron Engine driven using belt, attached to auto air conditioner compressor's pulley (open type compressor) Rotary, Swash plate.

Utilising R-134a refrigerant


Auto AC compressor power supply: Solution to a problem:

The compressor needs to be switched-on, and switched-off through electromagneic coupling and decoupling, as the compressor's pulley is directly connected to the engine through a belt.

One end of the compressor will be fitted with electromagnetic coil. Adjacent to the coil will be the pulley, and adjacent to the pulley is the magnetic clutch (which drives the compressor shaft).

By default, pulley would be able to rotate freely. However, when the coil is energised by signal from the thermostat, the magnetic clutch will be coupled with the ever-rotating pulley and, voila! Refrigerant will be circulating in your car air conditioner system.


Swash Plate compressor:

This is the type of compressor that is seen only in automotive air conditioning systems.

Swash plate is a symmetrical plate that is attached to the compressor shaft.

As the shaft rotates, the plate will axially displace sets of pistons back and forth, and compress the refrigerant.

Hence, the amount of power required to compress the refrigerant is reduced as rotaty motion is used to transfer to axial motion - analogous to worm gears.




Top of Auto AC Compressor page

Back to Automotive Air Conditioning page