E10 fuel

Ethanol (ethyl alcohol) and methanol (methyl alcohol) are two types of alcohol fuels. The use of pure alcohols in internal combustion engines is only possible if the engine is designed or modified for that purpose. However, in their anhydrous or pure forms, they can be mixed with gasoline (petrol) in various ratios for use in unmodified automobile engines. Typically, only ethanol is used widely in this manner, particularly since methanol is toxic.

E5, E7, E10

E10, sometimes called gasohol, is a fuel mixture of 10% ethanol and 90% gasoline that can be used in the internal combustion engines of most modern automobiles. E10 blends are typically rated as 2 to 3 octane higher than regular gasoline and are approved for use in all new US automobiles, and are mandated in some areas for emissions and other reasons. [3] E10 and other blends of ethanol are considered to be useful in decreasing US dependence on foreign oil, and can reduce carbon monoxide (CO) emissions by 20 to 30% under the right conditions. [4] Although E10 does decrease emissions of CO and green house gases such as CO2 by an estimated 2% over regular gasoline it can cause increases in evaporative emissions and some pollutants depending on factors like the age of the vehicle and weather conditions. [5] 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.^[1] On October 27, 2006, though, the Federal Aviation Administration published their Special Airworthiness Information Bulletin - Automobile gasoline containing alcohol (Ethanol or Methanol) is not allowed to be used in aircraft.

It has been introduced nationwide in Thailand, and has replaced high octane pure gasoline in that country in 2007. It is also commonly available in the Midwestern United States. It is the only type of gasoline (besides aviation grade fuels) allowed to be sold in the states of Connecticut and Minnesota, along with E85.^{dubious – discuss} E10 has also been mandated for use in all standard automobile fuel in the state of Florida by the end of 2010.[6] About half of the gasoline used in the U.S. contains ethanol. [7] As of spring of 2006, due to the phasing out of MTBE as a gasoline additive, E10 use has increased throughout the United States. [8]

Similar blends include E5 and E7. These concentrations are generally safe for recent engines that run on pure gasoline. Some regions and municipalities mandate that the locally-sold fuels contain limited amounts of ethanol. One way to measure alternative fuels in the US is the "gasoline-equivalent gallons" (GEG). In 2002, the U.S. used as fuel an amount of ethanol equal to 137 petajoules (PJ), the energy of 1.13 billion US gallons (4.28 GL) of gasoline. This was less than 1% of the total fuel used that year.^[2]

The Tesco chain of supermarkets in the UK have started selling an E5 brand of gasoline marketed as 99 RON super-unleaded. Price-wise it is cheaper than the other two forms of high-octane unleaded on the market, Shell's V-Power (99 RON) and BP's Ultimate (97 RON).

Many petrol stations throughout Australia are now also selling E10, typically at a few cents cheaper per litre than regular unleaded. It is more commonly found throughout the state of Queensland due to its large sugar cane farming regions. The use of E10 is also subsidised by the Queensland government. Some Shell service stations are also selling a 100 RON E5 blend called V-Power Racing (as opposed to the normal ethanol-free 98 RON V-Power). This is typically a fair bit more expensive, approximately 17 cents dearer than regular unleaded.

In Sweden, all 95-octane gasoline is in fact E5, while the status of the 98-octane fuel is unclear for the moment. The product data sheets of the major fuel chains do not clearly state anything related to ethanol contents of the 98-octane gasoline. In the early-mid nineties some fuel chains marketed E10. The EU mandates that until 2010 E10 has to be reintroduced for 95 RON fuel.^{citation needed}

E15

E15 contains 15% ethanol and 85% gasoline. This is generally the greatest ratio of ethanol to gas that is recommended by auto manufacturers that sell vehicles in the United States, though it is possible that many vehicles can handle higher mixtures without trouble.^{citation needed}

E20, E25

E20 contains 20% ethanol and 80% gasoline, while E25 contains 25% of ethanol. These blends have been widely used in Brazil since tha late seventies.^[3] As a response to the 1973 oil crisis, the Brazilian government made mandatory the blend of ethanol fuel with gasoline, fluctuating between 10% to 22% from 1976 until 1992.^[3] Due to this mandatory minimum gasoline blend, no longer pure gasoline (E0) is sold in Brazil. A federal law was passed in October 1993 establishing a mandatory blend of 22% anhydrous ethanol (E22) in the entire country. This law also authorized the Executive to set different percentages of ethanol within pre-established boundaries, and since 2003 these limits were fixed at a maximum of 25% (E25) and a minimum of 20% (E20) by volume.^[4]^[3] Since then, the government has set the percentage on the ethanol blend according to the results of the sugarcane harvest and ethanol production from sugarcane, resulting in blend variations even within the same year.^[3] By Executive Decree the mandatory blend was set at 25% of anhydrous ethanol (E25) since July 1st, 2007,^[5] and this is the standard gasoline blend sold throughout Brazil today.^[6]

All Brazilian automakers have adapted their gasoline engines to run smoothly with these range of mixtures, thus, all gasoline vehicles are built to run with blends from E20 to E25, defined by local law as "Common gasoline type A".^[7] Some vehicles might work properly with lower concentrations of ethanol, however, with a few exceptions, they are unable to run smoothly with pure gasoline which causes engine knocking, as vehicles traveling to neighboring South American countries have demonstrated.^[8] In July 2008, 86% of all new light vehicles sold in Brazil were flexible-fuel which can run on any mixed of gasoline E20-E25 up to 100% hydrous ethanol (E100 or hydrated ethanol) ratios,^[9] and only two models are built with a flex-fuel engine optimized to operate with pure gasoline (E0), the Renault Clio Hi-Flex^[10]^[8] and the Fiat Siena Tetrafuel.^[11]^[12]

Thailand introduced E20 in 2008,^[13] and around 150,000 vehicles are already running on this blend. However, shortages in ethanol supplies by mid-208 caused a delay in the expansion of the E20 fueling station network in the country.^[14]

A state law approved in Minnesota in 2005 mandates that ethanol comprise 20 percent of all gasoline sold in this American state beginning in 2013. Successful tests have been conducted to determined the performance under E20 by current vehicles and fuel dispensing equipment designed for E10.^[15]

E70, E75

E70 contains 70% ethanol and 30% gasoline, while E75 contains 75% of ethanol. These are common blends used in the United States and Sweden during the winter in regions with harsh weather, yet sold at the pump as E85.^[16] In the US this seasonal reduction of the ethanol content of E85 applies only in very cold regions, where temperatures fall below 10 °F (-12 °C), such as Winconsin.^[16]^[17] This limit is set to avoid cold starting problems during very cold weather, and the alcohol content is reduced to E70 in the US and to E75 in Sweden.^[16]^[17]^[18]

E85

E85 is a mixture of 85% ethanol and 15% gasoline, and is generally the highest ethanol fuel mixture found in the United States and several European countries, particularly in Sweden, as this blend is the standard for flexible-fuel vehicles. There are 1,766 public E85 fuel pumps in the U.S. as of August 2008, mostly concentrated in the Midwest, with over half of those in Minnesota. In Europe, by mid 2008 there are 1,200 E85 pump stations in Sweden, 219 in Germany, and 211 in France.

This mixture has an octane rating of about 105. This is down significantly from pure ethanol but still much higher than normal gasoline 87 octane. The addition of a small amount of gasoline helps a conventional engine start when using this fuel under cold conditions and reduce ethanol emissions at such temperatures. E85 does not always contain exactly 85% ethanol. In winter, especially during very cold weather, additional gasoline is added to facilitate cold starting the engine. Winter E85 in the US is usually E70 while Sweden uses E75.

By the third quarter of 2008 Thailand will introduce E85 gasohol on the local market.^{citation needed}

E95

E95 designates a blend of 95% ethanol and 5% ignition improver and is used in some diesel engines where high compression is used to ignite the fuel, as opposed to the operation of gasoline engines where spark plugs are used. Because of the high ignition temperatures of pure ethanol, the addition of ignition improver is necessary for successful diesel engine operation. This fuel has been used with success in many Swedish buses since the 1980s.

E100

E100 is pure ethanol fuel, widely used in Brazil and Argentina with up to 4% water. Operation in temperatures below 15 ° Celsius (59 °F) causes cold starting problems with pure, or so-called neat, ethanol. The most common cold weather solution is to add an additional small gasoline reservoir to increase the gasoline content momentarily to permit starting the engine. Once started, the engine is then switched back to neat ethanol.

Since 2003, Brazilian newer full flexible-fuel vehicles are capable of running on hydrous or hydrated E100 or on any combination in between of ethanol and gasoline E20 to E25 (this blend is made with anhydrous ethanol), the national mandatory blend.^[19] These flex vehicles have kept the secondary gasoline reservoir to avoid starting problems, particularly for users of the southern and central states, where winter temperatures can drop below 15 ° Celsius (59 °F). An improved flex motor generation that will be launched in 2009 will eliminate the need for this secondary gas storage tank.^[20]^[21]

Ethanol used as a fuel in Brazil is the azeotrope (the highest concentration of ethanol that can be achieved via distillation) and contains 4% of water. However, since the E nomenclature is not adopted in the country, as local law defines it "Gasoline type C",^[7] hydrated ethanol can be tagged as E100 so as to say that it does not have any gasoline.

Contents

E5, E7, E10

E15

E20, E25

E70, E75

E85

E95

E100

See also

References