Quietly causing a stir in the world of refrigerant suppliers is the new “HFO-1234yf,” a compound developed by Honeywell in conjunction with DuPont for use in vehicle air conditioning units. Recently, Daimler has announced it will not use the HFO-1234yf in new vehicles due to safety concerns over flammability, as engineers discovered after a crash test simulation that a mixture of the chemical and oil from the compressor could ignite by contact of a hot engine surface, while also creating a toxic gas.
What’s more, Mercedes-Benz is taking steps to recall vehicles that already use the chemical. Following suit, Volkswagen AG has also suspended use of the refrigerant. Meanwhile, General Motors isn’t phased, and will continue to use HFO-1234yf in the Cadillac XTS sedan.
This is because HFO-1234yf was subjected to a full two years of testing by an SAE International cooperative research project, a movement sponsored by 13 global automakers that include Daimler, GM and Volkswagen. The compound has also passed all industry standards including the German Automotive Association’s and evaluations done by the EPA.
Still, there’s no denying the findings from Daimler: in every one of the over 20 tests conducted, fires emerged from the engine bay, according to a report from Bloomberg. Specifically, the automaker was testing Mercedes-Benz B-Class sedans in head-on crash scenarios that could transpire on the Autobahn or a high-speed Texas highway in hot weather, at 99 miles per hour, heating the engine compartment to 1,229 degrees Fahrenheit. In most of America, these speeds are obviously illegal, and go beyond the limits of most regulatory tests, if not all of them.
As a result of the claims, the SAE will evaluate the Daimler findings. An update will be announced in February with a final, independently reviewed report out by June.