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Several common ethanol fuel mixtures are in use around the world. The use of pure hydrous or anhydrous ethanol in internal combustion engines (ICEs) is only possible if the engines are designed or modified for that purpose, and used only in automobiles, light-duty trucks and motorcycles. Anhydrous ethanol can be blended with gasoline (petrol) for use in gasoline engines, but with high ethanol content only after minor engine modifications. Ethanol fuel mixtures have "E" numbers which describe the percentage of ethanol fuel in the mixture by volume, for example, E85 is 85% anhydrous ethanol and 15% gasoline. Low-ethanol blends, from E5 to E25, are also known as gasohol, though internationally the most common use of the term refers to the E10 blend. Blends of E10 or less are used in more than 20 countries around the world, led by the United States, where ethanol represented 10% of the U.S. gasoline fuel supply in 2011.〔 ''See pp. 10''〕 Blends from E20 to E25 have been used in Brazil since the late 1970s. E85 is commonly used in the U.S. and Europe for flexible-fuel vehicles. Hydrous ethanol or E100 is used in Brazilian neat ethanol vehicles and flex-fuel light vehicles and hydrous E15 called hE15 for modern petrol cars in the Netherlands.〔 == E10 or less == E10, a fuel mixture of 10% anhydrous ethanol and 90% gasoline sometimes called gasohol, can be used in the internal combustion engines of most modern automobiles and light-duty vehicles without need for any modification on the engine or fuel system. E10 blends are typically rated as being 2 to 3 octane numbers higher than regular gasoline and are approved for use in all new U.S. automobiles, and mandated in some areas for emissions and other reasons.〔(E10: Every vehicle's ethanol blend ), drivingethanol.org. 〕 The E10 blend and lower ethanol content mixtures have been used in several countries, and its use has been primarily driven by the several world energy shortages that have taken place since the 1973 oil crisis. Other common blends include E5 and E7. These concentrations are generally safe for recent engines that should run on pure gasoline. As of 2006, mandates for blending bioethanol into vehicle fuels had been enacted in at least 36 states/provinces and 17 countries at the national level, with most mandates requiring a blend of 10 to 15% ethanol with gasoline. One measure of alternative fuels in the U.S. is the "gasoline-equivalent gallon" (GEG). In 2002, the U.S. used as motor fuel, ethanol equal to 137,000 terajoules (TJ), the energy equivalent of 1.13 billion U.S. gallons (4.3 billion liters) of gasoline. This was less than 1% of the total fuel used that year.〔()〕 E10 and other blends of ethanol are considered to be useful in decreasing U.S. dependence on foreign oil, and can reduce carbon monoxide (CO) emissions by 20 to 30% under the right conditions.〔(Low-Level Ethanol Fuel Blends ), Clean Cities fact sheet, April 2005.〕 Although E10 does decrease emissions of CO and greenhouse gases such as CO2 by an estimated 2% over regular gasoline, it can cause increases in evaporative emissions and some pollutants depending on factors such as the age of the vehicle and weather conditions.〔(E10 Emissions ), U.S. Department of Energy.〕 According to the Philippine Department of Energy, the use of not more than a 10% ethanol-gasoline mixture is not harmful to cars' fuel systems. Generally, automobile gasoline containing alcohol (ethanol or methanol) is not allowed to be used in U.S. certificated aircraft.〔(Special Airworthiness Information Bulletin CE-07-06 ) (October 27, 2006), Federal Aviation Administration. 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Common ethanol fuel mixtures」の詳細全文を読む スポンサード リンク
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