 GM will continue using HFO-1234yf refrigerant in the Cadillac XTS. Daimler has announced it will not use the automotive refrigerant HFO-1234yf in new vehicles, and is recalling Mercedes-Benz vehicles that already use the chemical because of safety concerns regarding flammability. Spurred by Benz's findings, Volkswagen, too, is delaying the use of the coolant until further notice, Bloomberg reports. Both manufacturers intend to continue using an older, less-efficient coolant, HFC-134a, defying a European Union directive. General Motors told Car and Driver that it's currently using HFO-1234yf in the U.S.-market Cadillac XTS, and will continue to roll out the introduction of the new coolant across its global product portfolio over the next few years while "continuing to review" Mercedes' findings. Despite more than two years of testing by an SAE International cooperative research project sponsored by 13 global automakers—including Daimler and Volkswagen—and passing all industry standards including the German Automotive Association's and the EPA's evaluations, Daimler decided to carry out a series of in-house tests designed to replicate real-life scenarios beyond the legally prescribed requirements. Daimler told us that its results indicate that in "a serious head-on collision in which the refrigerant line is severed . . . the reproducible results demonstrate that refrigerant, which is otherwise difficult to ignite under laboratory conditions, can indeed prove to be flammable in a hot engine compartment. Similar tests of the current HFC-134a refrigerant did not result in ignition." In a video on its website, Honeywell—who developed HFO-1234yf in conjunction with DuPont—contends that Daimler conducted its testing in secret with no reputable third party present. Although initial research indicated that HFO-1234yf may exhibit mild flammability, repeated testing found it to be significantly less combustible than highly flammable materials already present under the hood such as motor oil, transmission fluid, brake fluid, and compressor lubricant. Further testing in the lab and engine compartment at temperatures of up to 1100 degrees Fahrenheit failed to cause the refrigerant to ignite. DuPont echoes the sentiment, telling Car and Driver, "The mild flammability of HFO-1234yf has been thoroughly considered in a number of rigorous evaluations by the global automotive industry and by independent third-party laboratories. According to an SAE International presentation, 'flammability testing . . . has demonstrated the difficulty in igniting the HFO-1234yf refrigerant under the most severe testing conditions.' The risk assessments concluded that HFO-1234yf can be safely used in mobile air-conditioning."
To address these concerns, SAE International recently established a new cooperative research project team to perform an updated engineering review project of the HFO-1234yf refrigerant and to ensure that newly identified information and testing from each of the OEMs is incorporated in the study. Those findings will be published in the second quarter of 2013. However, SAE says that neither it nor the majority of OEMs involved in the study believe the new information will result in a change in the risk assessment surrounding the refrigerant. Its ability or inability to catch fire aside, much of the hubbub surrounding HFO-1234yf has to do with its environmental sustainability. DuPont and Honeywell's latest refrigerant reduces the amount of heat-trapping gasses by 99.7 percent compared to HFC-134a. from Car and Driver Blog http://blog.caranddriver.com | |||
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Friday, January 4, 2013
Daimler Claims DuPont and Honeywell–Developed Refrigerant is Flammable; GM Continues Use
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