Frankly, standardization is often the only option given the limits of a universal technology standard. 1  1. Standardization lag: It takes time to understand a problem domain well enough to make a proper standard.
A flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank.
Only flex-fuel vehicles can use gasoline with an ethanol content greater than E15. The energy content of ethanol is about 33% less than pure gasoline, although this varies depending on the amount of denaturant that is added to the ethanol. Therefore, vehicle fuel economy may decrease by up to 3.3% when using E10.n general, the ethanol content of motor gasoline does not exceed 10% by volume. Gasoline with 10% ethanol content is referred to as E10, and gasoline with 15% ethanol content is called E15.