The vehicles are equipped with a special sensor that determines which type of fuel is being used and accordingly adjusts how the vehicle should run. Whereas a regular vehicle has to run on gasoline, flex-fuel vehicles are able to run on ethanol, gasoline, or a mixture of the two.

The biggest difference between regular fuel and flex-fuel is that consumers have a choice in the way in which they choose to operate their vehicles. The first mass produced flex-fuel vehicle was the 1994 Ford Taurus. Ethanol, methanol, and natural gas CNG were the three alternative fuels that garnered attention and research. An oil crisis opened a new opportunity for ethanol and other alternative fuels, such as methanol, gaseous fuels such as CNG and LPG, and hydrogen. Henry Ford was one of the advocates for ethanol as fuel. Modern flex-fuel engines are capable of burning any proportion of the resulting blend in the combustion chamber as fuel injection and spark timing are adjusted automatically according to the actual blend detected by a fuel composition sensor. It is known to burn cleaner than regular gasoline, making it a more environmentally friendly choice and popular among eco-conscious drivers. Ethanol is an alcohol-based fuel that has become more commonly used over the years. At its core, flex-fuel is a mixture of gasoline and ethanol.

Ford flex type of gas