What Is Flex Fuel? A Look at the Past, Present, and Future of E85

Business News/Analysis History of Advanced Biofuels

April 03, 2020

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by Frank Markus (Motor Trend) A brief history of the ethanol-gasoline blend as a motor fuel. Did you know Henry Ford's iconic Model T, built from 1908 to 1927, featured carburetor jets that could be adjusted to let the engine run on gasoline, ethanol, or a mix of the two? Yes, that capability made it the first commercially produced "flex-fuel" vehicle, though "flexing" it may have required some under-hood screwdriver fiddling.

Way back in the early 1900s, gasoline, diesel, alcohols, electricity, and other fuels were all vying for the automotive transportation market. Petroleum obviously won out and dominated without question until the 1973 oil crisis spurred an interest in increased national energy independence.

This opened the door to methanol and ethanol produced here at home, and between these two alcohols, ethanol emerged the winner owing to its lower toxicity, potentially greener production process, and the formidable political heft of the Iowa corn growers lobby.

In 2007, we looked at E85 flex fuel technology as a potential "fuel of the future." Now that it's 2020, let's take a hindsight look at just what flex fuel is, how it works, and what the future holds for it.

What Is Flex Fuel?

The short answer in an automotive context, circa 2020, is that it's a technology that allows an engine to burn any mixture of alcohol in gasoline ranging from 15 to 85 percent anhydrous ethanol. Equipment required include fuel-system plumbing that can tolerate the more corrosive alcohol and an onboard sensor suite that can determine the precise mixture percentage in real time and adjust the engine ignition system accordingly (so the driver need not manually re-jet the carbs as on a Model T).

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(I)t's possible to run more spark advance and thereby extract slightly more power out of an engine running on E85 than the same engine can produce when burning regular or premium unleaded gasoline.

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The Department of Energy reports that there are currently more than 22 million E85-compatible vehicles on the road, but the EPA's list of 2020 model vehicle/powertrain combinations certified for E85 use only includes: