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E95 Bus in Sweden running on a modified diesel engine.(courtesy www.greenfleet.info) [2].

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 gasoline engines, and with minor modifications can also be use with a higher content of ethanol. Typically, only ethanol is used widely in this manner, particularly since methanol is toxic.

Ethanol fuel mixtures have "E" numbers which describe the percentage of ethanol in the mixture, 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 gasohol refers to the E10 blend.

E5, E7, E10

Low ethanol blends used around the world (E5 to E25)
Country/ Region(1)	Ethanol blend	Legal use
Australia1	E10	Optional
Brazil2	E20-E25	Mandated
Canada3	E5/E10	Optional
China4	E10	Nine provinces
Colombia5	E10	Mandated(1)
Costa Rica6	E7	Mandated(2)
India7	E5	Mandated
Jamaica8	E10	Mandated(3)
New Zealand9	E10	Optional
Paraguay10	E12	Mandated
Thailand11	E10/E20	Mandated
European Union12
Austria	E10	Optional
Denmark	E5	Optional
Finland	E5	Optional
Sweden	E5	Mandated
United States (states where mandatory only(4)) 1314
Florida	E10	Minnesota	E10
Hawaii	E10	Missouri	E10
Iowa	E10	Montana	E10
Kansas	E10	Oregon	E10
Louisiana	E10	Washington	E10
Notes: (1)In Colombia mandatory blend was enforced only in cities with more than 500.000 inhabitants.15 (2) Mandatory blend in Costa Rica will take effect in 2009. (3) Since November 1st, 2008 became available in some cities and will become mandatory in May 2009. (4) Though mandated only in 10 states, ethanol blends in the US are available in other states as optional or added without any labeling, making E blends present in two- thirds of the US gas supply.14 Florida effective in 2010.

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 and light-duty vehicles without need for any modification on the engine or fuel system. 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] 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 crises that have taken place since the 1973 oil crisis.

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.¹⁶

E10 Logo required on Delaware fuel dispensers

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.¹⁷ 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]

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).

Typical manufacture's statement in the car owner's manual regarding the vehicle's capability of using up to E10.

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.

E15

E15 contains 15% ethanol and 85% gasoline. This is generally the highest ratio of ethanol to gasoline that is possible to use in vehicles recommended by auto manufacturers to run on E10 in the US,¹⁸¹⁹ though it is possible that many vehicles can handle higher mixtures without trouble.

As a result of the Energy Independence and Security Act of 2007, which mandates an increase in renewable fuels for the transport sector, the U.S. Department of Energy began assessments for the feasibility of using intermediate ethanol blends in the existing vehicle fleet as a way to allow higher consumption of ethanol fuel.²⁰ The National Renewable Energy Laboratory (NREL) is conducting tests to evaluate the potential impacts of intermediate ethanol blends on legacy vehicles and other engines.²⁰²¹ In a preliminary report released in October 2008, the NREL presented the results of the first evaluations of the effects of E10, E15 and E20 gasoline blends on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials.²¹²⁰ This preliminary report found that none of the vehicles displayed a malfunction indicator light as a result of the ethanol blend used; no fuel filter plugging symptoms were observed; no cold start problems were observed at 24°C (75°F) and 10°C (50°F) laboratory conditions; and as expected, all test vehicles exhibited a loss in fuel economy proportional with the lower energy density of ethanol, for example, with E20, the average reduction in fuel economy was 7.7% when compared to the miles per gallon achieved by the gasoline only (E0) test vehicles.²⁰

E20, E25

E20 contains 20% ethanol and 80% gasoline, while E25 contains 25% of ethanol. These blends have been widely used in Brazil since the late seventies.²³ 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 1992.²³ Due to this mandatory minimum gasoline blend, no longer is pure gasoline (E0) 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.²²³ 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.²³ By Executive Decree the mandatory blend was set at 25% of anhydrous ethanol (E25) since July 1st, 2007,²² and this is the standard gasoline blend sold throughout Brazil today.²⁴

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 C".²⁵²⁶ 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.²⁷ 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,²⁸ and only two models are built with a flex-fuel engine optimized to operate with pure gasoline (E0), the Renault Clio Hi-Flex²⁹²⁷ and the Fiat Siena Tetrafuel.³⁰³¹

Thailand introduced E20 in 2008,³² 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.³³

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 E10.³⁴

E70, E75

When the vapor pressure in the ethanol blend drops below 45 kPa fuel ignition cannot be guaranteed on cold winter days, limiting the maximum ethanol blend percentage during the winter months to E75.³⁵

E70 contains 70% ethanol and 30% gasoline, while E75 contains 75% of ethanol. These are the winter blends used in the United States and Sweden for E85 flexible-fuel vehicles during the cold weather, but still sold at the pump labeled as E85.³⁶ The seasonal reduction of the ethanol content to a E85 winter blend is mandated to avoid cold starting problems at low temperatures.³⁶³⁷

In the US this seasonal reduction of the ethanol content to E70 applies only in cold regions, where temperatures fall below 32 °F (0 °C) during the winter.³⁸³⁹ In Wyoming for example, E70 is sold as E85 from October to May.³⁶⁴⁰ In Sweden, all E85 flexible-fuel vehicles use a E75 winter blend.³⁷ This blend was introduced since the winter 2006-07 and E75 is used from November until March.⁴¹

For temperature below -15 ° Celsius (5 °F) all E85 flex vehicles require an engine block heater to avoid cold starting problems.⁴¹ The use of this device is also recommended for gasoline vehicles when temperatures drop below -23 ° Celsius (- 10 °F).⁴² Another option when extreme cold weather is expected is to add more pure gasoline in the tank, thus reducing the ethanol content below the E70 winter blend, or simply not to use E85 during extreme low temperature spells.⁴¹⁴²

E85

For more details on this topic, see E85.

Logo used in the United States for E85 fuel

E85 is (usually, see above) 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 fuel for flexible-fuel vehicles. This mixture has an octane rating of about 105, which is significantly lower than pure ethanol but still much higher than normal gasoline 87 octane. 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.^{citation needed}

The 85% limit in the ethanol content was set to reduce ethanol emissions at low temperatures and to avoid cold starting problems during cold weather, at temperatures lower than 11 ° Celsius (52 °F).³⁸ A further reduction in the ethanol content is used during the winter in regions where temperatures fall below 0 ° Celsius (32 °F)³⁹ and this blend is called Winter E85, as the fuel is still sold under the E85 label. A winter blend of E70 is mandated in some regions in the US,³⁶⁴⁰ while Swedensh mandates E75.³⁷⁴¹

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

Typical Brazilian flexible-fuel engine with secondary gasoline reservoir for cold starting the engine at temperatures below 15° Celsius.

The Brazilian 2008 Honda Civic flex-fuel has outside access to the secondary reservoir gasoline tank in the front right side shown by the arrow.

E100 is pure ethanol fuel. Straight hydrated ethanol as an automotive fuel has been widely used in Brazil since the late seventies for ethanol-only vehicles²³⁴³ and more recently for flexible-fuel vehicles.⁴⁴⁴⁵ The ethanol fuel used in Brazil is actually the highest concentration of ethanol that can be achieved via distillation (azeotrope mixture), and contains up to 4.9% of water by volume.⁴⁶ The E nomenclature is not adopted in Brazil, but hydrated ethanol can be tagged as E100 meaning that it does not have any gasoline, because the water content is not an additive but rather a residue from the distillation process. However, straight hydrous ethanol is also called E95 by some authors.⁴⁷⁴⁸

The first commercial vehicle capable of running on pure ethanol was the Ford Model T, produced from 1908 through 1927. It was fitted with a carburetor with adjustable jetting, allowing use of gasoline or ethanol, or a combination of both.^42495051 At that time, other car manufactures also provided engines for ethanol fuel use.⁴² Thereafter, and as a response to the 1973 and 1979 energy crises, the first modern vehicle capable of running with pure hydrous ethanol (E100) was launched in the Brazilian market, the Fiat 147,⁵² after testing with several prototypes developed by the Brazilian subsidiaries of Fiat, Volkswagen, General Motors and Ford.⁴³ Since 2003, Brazilian newer flexible-fuel vehicles are capable of running on pure hydrous ethanol (E100) or blended with any combination of E20 to E25 gasoline⁴⁴⁴⁵ (a mixture made with anhydrous ethanol), the national mandatory blend.²²²

E100 imposes a limitation on normal vehicle operation as ethanol lower evaporative pressure (as compared to gasoline) causes problems when cold starting the engine at temperatures below 15 ° Celsius (59 °F).⁵³ For this reason both pure ethanol and E100 flexible-fuel vehicles are built-in with an additional small gasoline reservoir in the engine compartment to help starting when cold by injecting gasoline momentarily to permit starting the engine. Once started, the engine is then switched back to neat ethanol.⁵³ An improved flex engine generation that will be launched in 2009 is designed to eliminate the need for the secondary gas tank by warming the ethanol fuel during starting,⁵⁴⁵⁵ and allowing flex vehicles to do a normal cold start at temperatures as low as minus 5 ° Celsius (23 °F),⁵⁶ the lowest temperature expected anywhere in the Brazilian territory.⁵⁷

The Koenigsegg CCXR Edition at the 2008 Geneva Motor Show. This is a version of the CCX, converted to use E85 or E100, as well as standard 98 octane gasoline.

Swedish carmakers have developed ethanol only capable engines for the new Saab Aero X BioPower 100 Concept E100, with a V6 engine which is fuelled entirely by E100 bioethanol,⁵⁸⁵⁹ and the limited editon of the Koenigsegg CCXR, a version of the CCX converted to use E85 or E100, as well as standard 98 octane gasoline, and currently the fastest and most powerful flexible fuel vehicle with its twin-supercharged V8 producing 1018 hp when running on biofuel, as compared to 806 hp on 91 octane unleaded gasoline.⁶⁰⁶¹

The higher fuel efficiency of E100 in high performance race cars resulted in Indianapolis 500 races in 2007 and 2008 being run on 100 percent fuel grade ethanol.⁶²

Modifications to engines

The use of ethanol blends in conventional gasoline vehicles is restricted to low mixtures, as ethanol is corrosive and can degrade some of the materials in the engine and fuel system. Also the engine has to be adjusted for a higher compression ratio as compared to a pure gasoline engine, in order to take advantage of ethanol’s higher oxygen content, thus allowing an improvement in fuel efficiency and a reduction of tailpipe emissions.³⁵ The following table shows the required modifications to gasoline engines to run smoothly and without degrading any materials. This information is based on the modifications made by the Brazilian automotive industry at the beginning of the ethanol program in that country in the late seventies, and reflects the experience of Volkswagen do Brasil.³⁵

See also

energy portal

• Ethanol fuel
• Ethanol fuel in Brazil
• Ethanol fuel in the United States

References

External links

Bioenergywiki: Renewable fuel targets at bioenergywiki. See here a complete list of mandatory blends that will go into effect in several countries and regions on 2010 and thereafter

Wikipedia content modification information:

• This page was last modified on 21 November 2008, at 01:32.

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