Gasolineethanol

Gasolineethanol is a liquid automotive fuel produced by blending ethanol with conventional gasoline. The blend is commonly referred to as gasohol, with ethanol content typically expressed as a percentage by volume. The most widespread form is E10, containing about 10% ethanol, 90% gasoline. Higher blends such as E15 and E20 are available in some regions, and E85 is marketed for flex-fuel vehicles that can adjust to varying ethanol levels. Ethanol used in these blends is usually produced from fermentable crops such as corn, sugarcane, or other biomass feedstocks.

Engine compatibility and performance vary with ethanol content. Most modern gasoline engines are designed to run on E10 and higher blends, although older vehicles may have restrictions. Ethanol has a higher octane rating, which can improve resistance to knocking, but it has a lower energy density than gasoline, leading to a reduction in fuel economy. Ethanol also absorbs water and can affect certain engine materials and fuel-system components if misused or stored improperly. Flex-fuel vehicles are equipped to adapt to high-ethanol blends and often have dedicated fuel systems.

Environmental and economic considerations are mixed. Ethanol acts as an oxygenate, reducing some tailpipe emissions, but its life-cycle greenhouse gas benefits depend on production methods and feedstock, with debates over land-use impacts and energy inputs. In practice, gasohol blends are used to diversify fuel sources, support agricultural markets, and reduce dependence on purely fossil fuels, while requiring appropriate vehicle compatibility and infrastructure considerations.