Auto Service Professional

APR 2018

Magazine for the auto service professional

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32 | ASP April 2018 Technical replaced and especially of the evaporator is so important. With regard to hybrid A/C service, it's important to note that many hybrid vehicles feature all-electric, high voltage A/C com- pressors. Windings are in direct contact with oil, requiring the use of special POE (polyoles- ter) oil with high dielectric properties. e industry is currently at the front end of a transition from R134a to R1234yf. Fiat Chrysler Automobiles (FCA) has taken the lead in this regard. About half of its 2014 model year vehicles feature R-1234yf and with a few legacy exceptions, virtually the entire 2018 fleet is now R-1234yf. Most other car makers have at least one model using R1234yf, with this number increasing as the transition occurs. In order to service the new refrigerant systems, shops must purchase all new recovery/recycling/recharging machines that meet SAE J2843, with either a built-in or off- board portable refrigerant identifier. Portable identifiers are appealing due to quick use and flexibility. ey will also need leak detectors that will work with the new refrigerant. A conventional style R-1234yf manifold gauge set is highly recommended for fast diagnostic pressure checks. Most modern compressors feature internal valving that retains more of the oil within the compressor body. is reduces the total amount of oil required and improves system efficiency by reducing the thermal insulating film of oil coating the heat exchange surfaces of the condenser and evaporator. We are also seeing electronically controlled variable displacement compressors (ECVs) that can vary pumping displacement as the heat load changes. e computer varies the duty cycle command to the ECV solenoid to increase or decrease the piston stroke as necessary. Many shops don't realize this computer control issue, often replacing a compressor when in fact the concern is an issue with the command/control system. is is an example of how the need for more sophisticated diagnostics is so critical. A/C system complexity is increasing at an exponential rate. Rather than the stand-alone A/C system of the past, the A/C system is increasingly called upon to integrate with other systems and components. For example the 2018 Supercharged Dodge Demon can divert the A/C system refrigerant to an intake "Air-charge Chiller" during "Drag Mode" operation to improve performance. It is common for the A/C system on hybrid vehi- cles to be called upon to cool the high voltage batteries, power inverter, etc. Servicing modern A/C systems now requires special- ized equipment and training to understand and utilize network scan data. Additional update information (e following was provided by Tim Wagaman, product manager for A/C and fluid exchange for Robinair.) Starting in 2012 with 2013 model year vehicles, OEMs began introducing vehicles that used new refrigerant within the vehicle's A/C system called R-1234yf. is new refrigerant is different from R134a and new service equipment requirements were created to ensure the refrigerant is handled properly and service is performed correctly. New A/C recovery/recycling/recharging (RRR) machines were introduced to work on these new vehicles that use this new refrigerant. Examples include the new R-1234yf A/C machines which include new couplers that allow the connection to the vehicle's A/C system. ese couplers are different than those found on R134a vehicles. One of the require- ments for R1234yf service equipment is refrigerant identification anytime refrigerant On the Prius pictured here, the bright orange wire harness leads to the electric air compressor.

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