The air conditioning compressor, also known as the compressor, is the central element of the air conditioning system. This is because it compresses and conveys the refrigerant through the air conditioning system's cooling circuit. As electric cars do not have a belt drive, there are both conventionally and electrically driven compressors.
The air conditioning compressor compresses the gaseous refrigerant coming from the evaporator. This heats it up considerably. In this form, it is fed from the compressor into the condenser at the front of the vehicle and cooled by the airstream and the fan. When it cools down, the refrigerant liquefies again. It then goes into the filter dryer, where it is cleaned. Any water is also removed in the process.
The next station is the expansion valve. This regulates the amount of refrigerant that is injected into the evaporator. In the evaporator, the refrigerant changes its physical state again - back to gaseous. This change of state removes so much heat from the ambient air that it can be used to cool the interior. From the evaporator, the refrigerant gas finally returns to the compressor - and the cycle starts all over again.
The most common types of air conditioning compressors are swash plate compressors, scroll compressors or vane compressors (rotary vane compressors). Wobble plate compressors with pistons are mainly used in passenger cars.
Insufficient lubrication due to leaks and the associated loss of refrigerant and oil as well as a lack of maintenance are the most common causes of air conditioning compressor failure. The consequences are customer complaints such as "poor cooling performance" or "loud noises when switching on the air conditioning", visible leaks, error codes in the A/C control unit or in the engine/central control unit (such as too low or too high refrigerant pressure, electrical faults) as well as a negative result in the A/C performance test with a MAHLE ArcticPRO® A/C service unit.
The most common causes of failure:
R134a or R1234yf? MAHLE offers air conditioning compressors that can work with both refrigerants. The refrigerants R134a and R1234yf differ in their chemical composition, among other things. However, the working pressure and the technical design, for example of piston compressors, are identical for both systems. This is why the same MAHLE air conditioning compressor can be used for both refrigerants.
MAHLE air conditioning compressors that are suitable for both refrigerants are filled with PAGYF oil ex works. This oil can be used with both R134a and R1234yf. However, it should be noted that some UV contrast agents in systems filled with R134a are not compatible with PAGYF oil. In this case, it is essential to flush the system before installing the new air conditioning compressor.
Alternatively, the oil in the new compressor can also be replaced with a PAG oil that is explicitly suitable for R134a and the UV contrast agents used in it.