Compressor oils for car air conditioning – new trends and development directions

Compressor oils pose a technological challenge due to the extreme operating conditions of compressors. Such oil operates at a very high temperature while mixing with hot air, which creates ideal conditions for its oxidation and, consequently, accelerated degradation.

Compressor oils pose a technological challenge due to the extreme operating conditions of compressors. Such oil works at a very high temperature while mixing with hot air, which creates ideal conditions for its oxidation, and, consequently, accelerated degradation. Rapid degradation resulted in the need to use raw materials with appropriate parameters. The use of synthetic bases turned out to be a good solution. Their advantages are:

• saturated structure of chemical compounds that are part of synthetic bases, increasing their resistance to oxidation and degradation compared to mineral bases that also contain unsaturated bonds; this allows you to extend the operating time between oil changes,
• high viscosity index and lower pour point, thanks to which the range of permissible operating temperature is extended, and therefore the oil behaves properly
• at high operating temperatures as well as low winter start-up temperatures,
• higher ignition temperature, which increases safety of use by minimizing the risk of vapor ignition,
• chemical homogeneity of the bases, which translates into less carbon deposits and filter blocking.

Additionally, just like in mineral oils, appropriate packages of enriching additives are used, whose main purpose is to increase thermal stability
and improve lubricating properties, which translates into a reduction in energy consumption needed to
power the compressor..

Specol, following global trends, has created a line of Compresso A/C car air conditioning oils. These are fully synthetic products. Our product line includes oils:

• Compresso A/C PAO – produced on the basis of polyalphaolefins (PAO) and a package of refining additives. These are oils that, apart from excellent rheological properties and oxidation stability, are also characterized by very low conductivity, which allows them to be used in car compressors with electric and hybrid drive.
• Compresso A/C POE – manufactured on the basis of polyolesters (POE) and a package of refining additives. The oils have very low conductivity, so they can be used in compressors of electric cars and hybrid. They are characterized by excellent rheological properties and oxidation stability. They are environmentally friendly
• Compresso A/C PAG – produced on the basis of polyalkyl glycols (PAG) and a package of enriching additives. The oils are characterized by excellent rheological properties and thermal stability. However, they are not suitable for use in compressors of electric and hybrid cars, due to hygroscopicity and the associated increased conductivity, which is very undesirable - puncture may occur and the user may be shocked.

The Compresso A/C product line is offered in a wide range of viscosity grades. Each product is produced with or without UV dye.

UV dye is extremely helpful when servicing the air conditioning system, but is not recommended for use in compressors of cars with an electric or hybrid engine, because due to the solvents used, it may reduce resistivity, increasing the risk of electric shock.

Compresso A/C POE and Compresso A/C PAG are products compatible with the new R1234yf refrigerant, which is currently used in new installations by most car manufacturers.

Michał Świątek

Bibliography:

[1] Synthetic Base Stocks Provide Benefis for Air Compressor Lubricants, “Lube Magazine” 2011 (December), No. 106, p. 19-21.

[2] Lubricating oil and dye in hybrid vehicles using electric A/C compressors, “Cool Change” 2013 (December), Issue 31.

[3] Being refrigerant ready – automotive workshops, “Cool Change” 2016 (October), Issue 42.