Servicing HV Compressors

Servicing HV Compressors

A SAE stPhoto Credit: Motor Ageandard is in place, but questions over servicing electric compressors persist.

Motor Age — In the early days of hybrid cars, a conventional belt-driven compressor provided cool air to the passenger compartment. The only problem with that? The gasoline engine (ICE) had to be running in order to turn the compressor and that limited, if not eliminated, the fuel savings hybrid owners saw in city driving. No idle stop mode. Toyota figured out a way around that by being the first to use an electric A/C compressor on the 2004 Prius. Now, almost half of all hybrids in the marketplace use electric compressors (some older Honda hybrids use a combination electric/belt driven compressor) and of course, all the EV offerings use them.

The primary issue you need to be critically aware of when servicing these systems centers around one word: oil.

What’s So Special?

The oil used to lubricate an electric compressor is not the same as that used in a conventional one. According to Kelvin Butz, vice president of marketing and technical services for RTI Technologies, Inc., “To understand the importance (of using the correct oil), one must visualize what’s going on inside a high voltage compressor. The windings in these compressors become immersed in lubrication oil. To prevent electrical leakage, this oil must be of the type that prevents electrical conductance.”

According to a Denso spokesperson, a manufacturer of electric compressors for both the OE and aftermarket, the mixture of PAG and R134a refrigerant is conductive. Hybrid vehicles are designed to detect any “shorts” in the electrical system. This can set DTCs and shut down the power to the compressor and the vehicle.

Click here to read the complete article at Motor Age Online.

Source: Motor Age

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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.