News - The Growing Number of Hybrids on The Roads - Technical differences

Last updated 13/06/2012 11:15 AM Article Ref: 1889

Wednesday 13/06/2012 11:15 AM

The Growing Number of Hybrids on The Roads - Technical differences

The A/C systems in alternatively fuelled vehicles are different from those in standard combustion vehicles. This week we are going to highlight what you need to know about the differences between the A/C systems on the two types of vehicles. The final installment will focus on the different equipment that is required to service the A/C systems.

Compressors

In electric vehicles and some hybrids, the compressor used in the A/C system is powered by a high-voltage three phase electric motor. This is different to the traditional compressors whichare driven from the crankshaft through a drive belt. As a result of having a high voltage part on the vehicle, different health and safety procedures must be followed.

Where is the motor?

The electric motor is located inside the compressor case and is in contact with the refrigerant oil. The refrigerant oil that the vehicle manufacturer specifies will have unique electrical properties that will protect you from electrical shock off the motor.

The additives in the OE oil reduce the electrical conductivity of the oil (it becomes more of an insulator)

Refrigerant Oil

Ordinary PAG refrigerant oils (PAG 46, 100 and 150) cannot be introduced into electric and many hybrid A/C systems. Oils specified by the vehicle manufacturer must be used.

The use of the wrong oil will contaminate the A/C system, the severity of the damage will depend on whether or not you switch on the A/C. If you do not run the A/C, then only the compressor will need to be replaced. However, if you do run the A/C, you will need to replace the compressor, condenser, evaporator, and all the pipes.

As little as 1% contamination can lead to electrical problems such as fault codes or, in extreme cases, total vehicle shutdown.

UV dye

Standard UV leak detection dye that is used in standard combustion vehicles should not be added to systems that use an electrical compressor. The adding of any standard UV dye can considerably reduce the refrigerant oil's electrical insulation properties.

It is important to use dye that is approved by vehicle manufacturer for use in alternatively fuelled vehicles A/C systems.