Alcohol As An Alternative Fuel in I.C Engines
Content
3rd Year Seminar Report On ALCOHOL AS AN ALTERNATIVE FUEL IN I.C ENGINES
Undertaken by: MITHUN SARKAR Roll No -071020107006
DEPARTMENT OF MECHANICAL ENGINEERING KALYANI GOVERNMENT ENGINEERING COLLEGE KALYANI, NADIA, PIN-741235
May, 2010
CONTENTS Ch. Nos.
Topics Introducon
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1.1 Methan Methanol ol 1.2 Ethano Ethanoll 1.3 Butanol Butanol and Propanol Propanol 1.4 ALCOHOL FOR SI ENGINES 1.5 REFORMULATED GASOLINE FOR SI ENGINES 1.6 ALCOHOL FOR CI ENGINES 1.7 SURFACE-IGN SURFACE-IGNITION ITION ALCOHOL CI ENGINES
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Reference List
Page Nos. 1
INTRODUCTION In this century, it is believed that crude oil and petroleum products will become very scarce and costly. Day-to-day, fuel economy of engines is geng improved and will connue to improve. However, enormous increase in number of vehicles has started dictang the demand for fuel. With increased use and depleon of fossil fuels, alternave fuel technology will become more common in the coming decades. Because of the high cost of petroleum products, emission problems some developing countries are trying to use alternate fuels for their vehicles. DIFFICULTIES: 1. Extens Extensive ive rese research arch an and d develo development pment iiss dicu dicult lt to jusf jusfyy unl the fu fuels els are acc accepted epted aass viable for large numbers of engines. 2. Most aalterna lternate te fuels aare re very cos costly tly at pr present esent ssince ince the qu quant antyy used is ver veryy less. 3. There is lack of dis distribu tribuon on poin points ts (serv (service ice stao staons) ns) wher wheree fuel is availa available ble to the pub public. lic.
LIQUID FUELS:
Liquid fuels are preferred for IC engines because they are easy to store and have reasonably good caloric value. The main alternave is the alcohol ALCOHOL:
Alcohols are aracve alternate fuels because they can be obtained from both natural and manufactured sources. Methanol and ethanol are two kinds of alcohols that seem most promising. ADVANTAGES:
1. It is a high oct octane ane fue fuell with anan-knock knock ind index ex numb numbers ers of ove overr 100.En 100.Engines gines u using sing hig high h octane fuel can run more eciently by using higher compression raos. Alcohols have higher ameless speed. 2. It pro produces duces o overal veralll emiss emissions ions co compar mpared ed to ggasoli asoline. ne.
3. When al alcohols cohols aare re burn burned, ed, it for forms ms more mo moles les of exha exhaust ust gas gases, es, which ggives ives hig higher her pressure and more power in the expansion stroke. 4. It has hig high h latent h heat eat of va vaporiz porizaon aon wh which ich resu results lts in a cool cooler er inta intake ke proce process. ss. This raises the volumetric eciency of the engine and reduces the required work input in the compression stroke. 5. Alcoho Alcohols ls ha have ve lo low w su sulphur lphur conte content nt in the fuel. 6. Reduce Reduced dp petrol etroleum eum impor imports ts aand nd ttrans ransport portaon aon.. DISADVANTAGES:
1. Alcoho Alcohols ls have low en energy ergy con content tent or in o other ther wor words ds the cal caloric oric va value lue of the fu fuel el is almost half. This means that almost twice as much as gasoline must be burned to give the same energy input to the engine. With Wi th equal thermal eciency and similar engine output usage, twice as much fuel would have to be purchased, and he distance which could be driven with a given fuel tank volume would be cut in half. Automobiles as well as distribuon staons would require twice as much storage capacity, twice the number of storage facilies, twice the volume of storage at the service staons, twice as many tank trucks and pipelines, etc. Even with the low energy content c ontent of the fuel, engine power a given displacement about the same.and Thisthus is because theair lower air-fuelfor rao needed by alcohol. would Alcoholbecontains oxygen requiresofless for stoichiometric combuson. More fuel can be burned with the same amount of air. 2. Combu Combuson son of alco alcohols hols pro produces duces mo more re aldehy aldehydes des in the exha exhaust. ust. If as much al alcohol cohol fue fuell was consumed as gasoline. Aldehyde emissions would be a serious problem. 3. Alcoho Alcoholl is much more corr corrosive osive tha than n gasol gasoline ine on coppe copper, r, brass brass,, aluminu aluminum, m, rubbe rubber, r, and many plascs. This puts some restricons on the design and manufacturing of engines to be used with this fuel. Fuel lines and tanks, gaskets, and even metal engine parts can deteriorate with long-term alcohol use (resulng in cracked fuel lines, the need for special fuel tank, etc). Methanol is very corrosive on metals. 4. It has poo poorr cold wea weather ther sta starng rng cha characte racteriscs riscs d due ue to low va vapor por pres pressure sure aand nd evaporaon. Alcohol-fuelled engines generally have diculty in starng at temperatures
5. 6. 7. 8.
9.
below 10 C. Oen a small amount of gasoline added fuel, f uel,reduces which greatly improves cold-weather starng. However, theisneed to to doalcohol this greatly the aracveness of alcohol. Alcoho Alcohols ls ha have ve po poor or ig ignion nion chara characteris cteriscs cs n gener general. al. Alcoho Alcohols ls have an almo almost st invis invisible ible ame ame,, which is consid considered ered da dangero ngerous us when han handling dling fuel. A small amount of gasoline removes this danger. There is th thee dang danger er of stora storage ge tank a ammab mmability, ility, du duee to low vap vapor or press pressure. ure. Air ca can n leak into storage tanks and create combusble mixtures. There wi willll be less NOx em emissio issions ns beca because use of low a ame me temp temperatu eratures. res. How However, ever, th thee resulng lower exhaust temperatures take longer me to heat the catalyc converter to ecient operang temperatures. Many peo people ple nd the st strong rong od odor or of alcoho alcoholl very oens oensive. ive. Head Headaches aches an and d drizzle drizzless have
been experienced when refueling automobile. 10. There is a po possibility ssibility of vapo vapor r lock an in fuel delivery ssystems. ystems.
1.1 METHANOL: Of all the fuels being considered as an alternate to gasoline, methanol is one of the most promising and has experienced major research and development. Pure methanol and mixtures of methanol and gasoline in various percentages have been extensively tested in engines and vehicles for a number of years. The most common mixtures are M85 (85% methanol and 15% gasoline). The data of these tests which include performance and emission level levels are compared with pure gasoline (M0) and pure methanol (M100). Some smart exible fuel (or variable fuel) engines are capable of using any random mixture combinaon of methanol and gasoline ranging from methanol to pure gasoline. Two fuel tanks are used and various ow rates of the two fuels can be pumped to the engine, passing through a mixing chamber. Using informaon from sensors in the intake and exhaust, the electronic monitoring systems (EMS) adjust to the proper air-fuel rao, ignion rao, ignion ming, injecon ming, and valve ming (where possible) for the fuel mixture being used. Methanol can be obtained from many sources, both fossil and renewable. These include include coal, petroleum, natural gas, biomass, wood, landlls, and even the ocean. However, any source that requires extensive manufacturing manufacturing or processing raises the price of the fuel. Emissions from an engine using M10 fuel are about the same as those using gasoline. The advantage (and disadvantage) of using this fuel is mainly 10% decrease in HC and CO exhaust emissions. However, there is an increase in NOx and a large (500%) increase in formaldehyde emissions.
Methanol is used some dual-fuel CI engines. Methanol by itself is not a good CI engine fuel because of its high octane number, but if a small amount of diesel oil is used for ignion, it can c an be used with good results. This is very aracve for developing countries, because methanol can oen be obtained from much cheaper source than diesel oil. Methanol fuel has received less aenon than ethanol fuel as an alternave to petroleum based fuels.[1] Use in racing
Methanol fuel is also used extensively in drag racing, primarily in the Top Alcohol category. Formula One racing connues to use gasoline as its fuel, but in pre war grand prix racing methanol was oen used in the fuel. Use as internal combuson engine fuel
Both methanol and ethanol burn at lower temperatures than gasoline, and both are less volale, making engine starng in cold weather more dicult. Using methanol as a fuel in spark ignion engines can oer an increased thermal eciency and increased power output (as compared to low gasoline) to its high octane rang and high air heat of rao vaporisaon. However, its energydue content of 19.7 MJ/kg and (114) stoichiometric stoichiometric air fuel of 6.42:1 mean
that fuel consumpon (on volume or mass basis) will be higher than hydrocarbon fuels. The extra water produced also makes the charge rather wet (similar to hydrogen/oxygen combuson engines)and combined with the formaon of acidic products during combuson, the wearing of valves, valve seats and cylinder c ylinder might be higher than with hydrocarbon burning. Certain addives may be added to motor oil in i n order to neutralize these acids. Methanol, just like ethanol, e thanol, contains soluble and insoluble contaminants. These soluble contaminants, halide ions such as chloride ions, have a large eect on the corrosivity of alcohol fuels. Halide ions increase corrosion in two ways; they chemically aack passivang oxide lms on several metals causing ping corrosion, and they increase the conducvity of the fuel. Increased electrical conducvity promotes electric, galvanic, and ordinary corrosion in the fuel system. Soluble contaminants, such as aluminium hydroxide, itself a product of corrosion by halide ions, clog the fuel system over me. Methanol is hygroscopic, meaning it will absorb water vapor directly from the atmosphere. Because absorbed water dilutes the fuel value of the methanol (although, it suppresses engine knock), and may cause phase separaon of methanol-gasoline blends, containers of methanol fuels must be kept ghtly sealed. Toxicity
Methanol is poisonous; ingeson of only 10 ml can cause blindness and 60-100 ml can be fatal, and it doesn't have to be swallowed to be dangerous since the liquid can be absorbed through the skin, and the vapors through the lungs. US maximum allowed exposure in air (40 h/week) iiss 1900 mg/m³ for ethanol, 900 mg/m³ for gasoline, and 1260 mg/m³ for methanol. However, it is less volale than gasoline, and therefore decreases evaporave emissions. Use of methanol, like ethanol, signicantly reduces the emissions of certain hydrocarbon-related toxins such as benzene and 1, 3 butadiene. But as gasoline and ethanol are already quite toxic, safety protocol is the same. Safety
Since methanol vapour is heavier than air, it will wi ll linger close to the ground or in a pit unless there is good venlaon, and if the concentraon of methanol is above 6.7% in air it can be lit by a spark, and will explode above 54 F / 12 C. Once ablaze, the ames give out very lile light li ght making it very hard to see the re or even esmate its size, especially in bright daylight. If you are unlucky enough to be exposed to the poisonous substance through your respiratory respiratory system, its pungent odor should give you some warning of its presence. However, it is dicult to smell methanol in the air at less than 2,000 ppm (0.2%), and it can be dangerous at lower concentraons than that.[3] 1.2 ETHANOL
Ethanol has been used as automobile fuel for many years in various countries of the world. Brazil is probably the leading user, where in the early 1990s. 1 990s. About 5 million vehicles operated on fuels that were 93% ethanol. For a number of years gasohol (gasoline+alcohol) has been available at service staons in the United States. Gasohol is a mixture of 90% gasoline and 10% ethanol. As with methanol, the development of systems using mixtures of gasoline and ethanol connues. Two mixture combinaons that are important are E85 (85% ethanol) and e10 (gasohol). E85 is basically an alcohol fuel with 15% gasoline added to eliminate some of the problems of pure alcohol (i.e., cold starng, tank ammability, etc.E10 reduces the use of gasoline with no modicaon needed to the automobile engine. Flexible-fuel Flexible-fuel engines are being tested which can operate on any rao of ethanolgasoline.[1]
1.3 Butanol and Propanol Propanol and butanol are considerably less toxic and less volale than methanol. In parcular, butanol has a high ashpoint of 35 °C, which is a benet for re safety, but may be a dicult for starng engines in cold weather. The concept of ash point is however not directly applicable to engines as the compression of the air in i n the cylinder means that the temperature is several hundred degrees Celsius before ignion takes place. The fermentaon processes to produce propanol and butanol from cellulose are fairly tricky to execute, and the Weizmann organism (Clostridium acetobutylicum) currently used to perform these conversions produces an extremely unpleasant smell, and this must be taken into consideraon when designing and locang a fermentaon plant. This organism also dies when the butanol content of whatever it is fermenng rises to 7%. For comparison, yeast dies when the ethanol content of its feedstock hits 14%. Specialized strains can tolerate even greater ethanol concentraons - so-called turbo yeast can withstand up to 16% ethanol. However, if ordinary Saccharomyces yeast can be modied to improve its ethanol resistance, sciensts may yet one day produce a strain of the Weizmann organism with a butanol resistance higher than the natural boundary of 7%. This would be useful because butanol has a higher energy density than ethanol, and because waste bre le over from sugar crops used to make ethanol could be made into butanol, raising the alcohol yield of fuel crops without there being a need for f or more crops to be planted. Despite these drawbacks, DuPont and Brish Petroleum have recently announced that they are jointly to build a small small scale butanol fuel demons demonstraon traon plant along alongside side the large bioethanol bioethanol plant they are jointly developing with Associated Brish Foods. Energy Environment Internaonal developed a method for f or producing butanol from biomass, which involves the use of two separate micro-organisms in sequence to minimize producon of acetone and ethanol by-products.
The Swiss company Butalco GmbH uses a special technology to modify yeasts in order to produce butanol instead of ethanol. Yeasts as producon organisms for butanol have decisive decisi ve advantages compared to bacteria. Butanol combuson is: C4H9OH + 6O2 → 4CO2 + 5H2O + heat[4] 1.4 ALCOHOL FOR SI ENGINES:
Alcohol have higher anknock characterisc compared to gasoline. As such with an alcohol fuel, engine compression raos between 11:1 and 13:1 are usual. Today’s gasoline engines use a compression rao of around 7:1 or 9:1, much too low for pure alcohol. In a properly designed engine and fuel system, alcohol produces fewer harmful exhaust emissions. Alcohol contains about half the heat energy of gasoline per liter. The stoichiometric air fuel rao is lesser for alcohol than for gasoline. To provide a proper fuel air mixture, a carburetor or fuel injector fuel passage should be doubled in area to allow extra fuel ow. Alcohol does not vaporize as easily as gasoline. Its latent heat of vaporizaon is much greater. This aects cold weather starng. If the alcohol liquees in the engine then it will not burn properly. Thus, the engine may be dicult or even impossible to start in extremely cold climate. To overcome this, gasoline is introduced in the engine unl the engine starts and warms up. Once the engines warms, alcohols when introduced will vaporize quickly and completely and normally. Even during normal operaon, addional heat may have to be supplied to completely vaporize alcohol. alcohol. Alcohol burns at about half the speed of gasoline. As such, ignion ming must be changed, so that more spark advance is provided. This will give the slow burning alcohol more me to develop the pressure and power in the cylinder. Moreover, corrosion resistant materials are required for fuel systems since alcohols are corrosive in nature. 1.5 REFORMULATED GASOLINE FOR SI ENGINES:
Reformulated gasoline is normal type of gasoline with a slightly modied formulaon and help addives to help reduce engine emissions. Addives in the fuel include oxidaon inhibitors, corrosion inhibitors, metal deacvators, detergents, and deposit control addives. Oxygenates such as methyl terary-butyl ether (MTBE) and alcohols are mixed, such that there is 1-3% oxygen by weight. This to help in reducing CO in the exhaust. Levels of benzene, aromac, and high boiling components are reduced, as in the vapor pressure.Recognising that engine deposits contribute to emissions, cleaning addives are included. Some addives clean carburetors, some clean fuel injectors, and some intake valves, each of which oen does not clean other components. MTBE is now prohibited for ground water contaminaon. Of the posive side is that all gasoline-fuelled gasoline-fuelled engines, old and new, can use this fuel without modicaon. On the negave side is that only moderate emissions reducon is realized, cost is increased, and the only moderate emission reducon is realized, cost is increased, and the use of petroleum products is not considerably reduced.
1.6 WATER-GASOLINE MIXTURE FOR SI ENGINES:
The development of the spark-ignion engine has been accompanied by the desire to raise the compression rao for increased eciency and fuel economy. One obstacle to this gain in economy at mes has been the octane quality of the available gasoline. To circumven circumventt this limitaon, water was proposed as an anknock addive. Water addion to gasoline slows down the burning rate and reduces the gas temperature in the cylinder which probably suppresses detonaon. Engine combuson chamber deposit reducons have also been reported when water was added to the intake charge. With respect to nitric oxide emissions, dramac reducons were reported. Conversely, water addion probably increases hydrocarbon emissions. Finally, with respect to carbon monoxide emissions, water addions seem to have minimal eect. Only a very limited work has been carried out with the addion of water via an emulsion with the fuel rather than independently. Emulsion could eliminate the need for a separate tank, provide improved atomizaon and increase fuel safety. However, a water-fuel separaon problem may exist. 1.7 ALCOHOL FOR CI ENGINES:
Techniques of using alcohol in diesel engines are 1. 2. 3. 4. 5. 6. 7.
Alcoho Alcohol/d l/dies iesel el fuel fuel solu soluon ons. s. Al Alco coho holl dies diesel el emul emulsi sion ons. s. Alco Al coho holl ffum umig iga aon on Dual Dual fu fuel el inje injec con on Su Surf rfac acee igni ignio on n of of alco alcoho hols ls Sp Spar arkk igni ignio on n of alc alcoh ohol olss Alcohols Alcohols containin containingg ignion ignion improving improving addives. addives.
Both ethyl and methyl alcohols have high self ignion temperatures. Hence, very high compression raos (25-27) will be required to self ignite them. Since this would make the engine extremely heavy and expensive, the beer method is to ulize them in dual fuel operaon. In the dual fuel engine, alcohol is carbureted or injected into the inducted air. Due to high self ignion temperature of alcohols three will be no combuson with the usual diesel compression raos of 16 to 18. A lile before the end of compression stroke, a small quanty of diesel oil is injected into the compression stroke, a quanty of diesel oil is injected into the combuson chamber through the normal diesel pump and spray nozzle. The diesel oil readily ignites and iniates combuson in the alcohol air mixtures also. Several methods are adopted for inducon of alcohol into the intake manifold. They are micro fog unit, pneumac spray nozzles, vaporizer, carburetor and fuel injector. The degree of neness in mixing of fuel and air are dierent for the above methods.
Another method tried is to inject alcohol into the combuson chamber aer diesel fuel injecon. This way of alcohol inducon avoids the alcohol cooling the charge in the cylinder to a degree which will jeopardize the ignion ignion of the diesel fue fuel.l. However, this design design calls for two complete and separate fuel systems with tank, fuel pump, injecon pump and injectors. In the dual fuel engines menoned above, major poron of the heat release is by the alcohol is ignited by a pilot spray of diesel oil injecon. Hence, if the alcohol inducon rate exceeds a limit, the injected diesel will not be able to ignite and hence, the engine will fail to funcon. 1.8 SURFACE-IGNITION ALCOHOL CI ENGINES:
A slab of insulator material, wound with a few strands of heang wire is xed on the combuson chamber with the wire running on the face exposed to the gases. The fuel injector is located such that a part of the spray impinges head on this surface. Ignion is thus iniated. The combuson chamber, which is in the cylinder head, is made relavely narrow so that the combuson spreads quickly to the rest of the space. Since a part of the fuel burns on the insulator surface and the heat losses from the plate are low, the surface aer some minutes of operaons reaches a temperature sucient to iniate ignion without the aid of external electrical supply. The power consumpon of the coil is about 50W at 6 volts. The engine lends itself easily to the use of wide variety of fuels, including methanol, ethanol and gasoline. The engine was found to run smoothly on methanol with a performance comparable to diesel operaon. The engine operates more smoothly at lower speeds than at higher speeds. [1]
2.1 Flexible-fuel vehicle A exible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a ex-fuel vehicle) is an alternave fuel vehicle with an internal combuson c ombuson engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels f uels are stored in the same common tank. Flex-fuel engines are capable of burning any proporon of the resulng blend in the combuson chamber as fuel injecon and spark ming are adjusted automacally according to the actual blend detected by electronic sensors. Flex-fuel vehicles are disnguished from vehicles, where two fuels are stored separate and the engine runs on one fuelbi-fuel at a me, for example, compressed naturalingas (CNG), tanks liqueed petroleum gas (LPG), or hydrogen. The most common commercially available FFV in the world market is the ethanol exible-fuel vehicle, with w ith around 18 million automobiles and light duty trucks on the roads by 2009, and concentrated c oncentrated in four markets, Brazil (9.3 million), the United States (around 8 million), Canada (600,000), and Europe, led by Sweden (181,458). Also a total of 183,375 exible-fuel motorcycles were sold in Brazil in 2009. In addion to ex-fuel vehicles running with ethanol, in Europe and the US, mainly in California, there have been successful test programs with methanol ex-fuel vehicles, known as M85 ex-fuel vehicles. Though technology exists to allow ethanol FFVs to run on any mixture of gasoline and ethanol, from pure gasoline up to 100% ethanol (E100), North American and European ex-fuel vehicles are opmized runinon a maximum blend is ofset 15% with 85% anhydrous ethanol (called E85 fuel). This to limit the ethanol content togasoline reduce ethanol emissions at low
temperatures and to avoid cold starng problems during cold weather, at temperatures lower than 11 °C (52 °F). The alcohol content is reduced during the winter wi nter in regions where temperatures fall below 0 °C (32 °F) to a winter blend of E70 in the U.S. or to E75 in Sweden from November unl March. Brazilian ex fuel vehicles are opmized to run on any mix of E20E25 gasoline and up to 100% hydrous ethanol fuel (E100). The Brazilian ex vehicles are built-in with a small gasoline reservoir for cold starng the engine when temperatures drop below 15 °C for (59 the °F). secondary An improved motor generaon was launched in 2009 which eliminated the need gasex tank.
2.2 Terminology As ethanol FFVs became commercially available during the late 1990s, the common use of the
term "exible-fuel vehicle" became synonymous with ethanol FFVs. In the United States exfuel vehicles are also known as "E85 vehicles". In Brazil, the FFVs are popularly known as "total ex" or simply "ex" cars. In I n Europe, FFVs are also known as "exi fuel" vehicles. Automakers, parcularly in Brazil and the European market, use badging in their FFV models with the some variant of the word "ex", such as Volvo Flexi fuel , or Volkswagen Total Flex , or Chevrolet Flex Power or or Renault Hi-Flex , and Ford sells its Focus model in Europe as Flexi fuel and and as Flex in in Brazil. In the US, only newer FFV models feature a yellow gas cap with the label "E85/Gasoline" wrien on the top of the cap to dierenate E85s from gasoline only models, and just recently, GM introduced badging with the text "Flex fuel/E85 Ethanol". Flexible-fuel vehicles (FFVs) are based on dual-fuel systems that supply both fuels into the combuson chamber at the same me in various calibrated proporons. The most common fuels used by FFVs today are unleaded gasoline and ethanol fuel. Ethanol FFVs can run on pure gasoline, pure ethanol (E100) or any combinaon of both. Methanol has also been blended with gasoline in ex-fuel vehicles known as M85 FFVs, but their use has been limited mainly to demonstraon projects and small government eets, parcularly in i n California.
Mulfuel vehicles are capable of operang with more than two fuels. In 2004 GM do Brasil introduced the Chevrolet Astra 2.0 with a "MulPower" engine built on ex fuel technology developed by Bosch of Brazil, and capable c apable of using CNG, ethanol and gasoline (E20-E25 blend) as fuel. In 2006 Fiat introduced the Fiat Siena Tetra fuel, a fourfuel car developed under Magne Marelli of Fiat Brazil. This automobile can run as a ex-fuel on 100% ethanol (E100); or on E-20 to E25, Brazil's normal ethanol gasoline blend; on pure gasoline (though no longer available in Brazil since 1993, it is sll used in neighboring countries); or just on natural natural gas. Siena Tetrafuel was engineered to switch from any gasoline-ethanol blend to CNG automacally, depending on the power required by road condions. Another exisng opon is to retrot an ethanol exible-fuel vehicle to add a natural gas tank and the corresponding injecon system. This opon is popular among taxicab owners in São Paulo and Rio de Janeiro, Brazil, allowing users to choose among three fuels (E25, E100 and CNG) according to current market prices at the pump. Vehicles with this adaptaon are known in Brazil as "tri-fuel" cars.
Flex-fuel hybrid electric and ex-fuel plug-in hybrid are two types of hybrid vehicles built with a combuson engine capable of running on gasoline, E-85, or E-100 to help drive the wheels in conjuncon with the electric engine or to recharge the baery pack that powers the electric engine. In 2007 Ford produced 20 demonstraon Escape Hybrid E85s for real-world tesng in eets in i n the U.S. Also as a demonstraon project, Ford delivered in 2008 the rst exible-fuel plug-in hybrid SUV to the U.S. Department of Energy (DOE), a Ford Escape Plug-in Hybrid,hybrid, which expected runs on gasoline or E85. GM announced that the Chevrolet Volt plug-in to be launched in 2010, would be the rst commercially available ex-fuel plug-in capable of adapng the propulsion to several world markets such as the U.S., Brazil or Sweden, as the combuson engine can be adapted to run on E85, E100 E 100 or diesel respecvely. In the North American market the Volt will be sold as an E85 ex-fuel-capable ex-f uel-capable plug-in about a year aer its rst introducon.
2.3History The rst commercial exible fuel vehicle was the Ford Model T, produced from 1908 through 1927. It was ed with a carburetor with adjustable jeng, allowing use of gasoline or ethanol, both.. Other car manufactures also provided engines for ethanol fuel use. or a combinaon of both Henry Ford connued to advocate for ethanol as fuel even during the prohibion. However, cheaper oil caused gasoline to prevail, unl the 1973 oil crisis resulted in gasoline shortages and awareness on the dangers of oil dependence. This crisis opened a new opportunity for ethanol and other alternave fuels, such as methanol, gaseous fuels such as CNG and LPG, and also hydrogen. Ethanol, methanol and natural gas CNG were the three alternave fuels that received more aenon for research and development, and government support. Since 1975, and as a response to the shock caused by the rst oil crisis, the Brazilian government implemented the Naonal Alcohol Program -Pró-Álcool- (Portuguese: Programa Nacional do Álcool )),, a naonwide program nanced by the government to phase out automove fuels derived from fossil fuels in favor of ethanol made from sugar cane. It began with a low blend of anhydrous alcohol with regular gasoline in 1976, and since July 2007 the mandatory blend is 25% of alcohol or gasohol E25. In 1979, and as a response to the second oil crisis, the rst vehicle capable c apable of running with pure hydrous ethanol (E100) was launched to the market, the Fiat 147, aer tesng with several prototypes developed by Fiat, Volkswagen, GM and Ford. The Brazilian government provided three important inial drivers for the ethanol industry: guaranteed purchases by the state-owned oil company Petrobras, low-interest loans for agro-industrial ethanol rms, and xed gasoline and ethanol prices. Aer reaching more than 4 million cars and light trucks running on pure ethanol by the late 1980s, the use of E100only vehicles sharply declined aer increases in sugar prices produced shortages of ethanol fuel. Aer extensive research that began in the 90s, a second push took place in March 2003, when w hen the Brazilian subsidiary of Volkswagen launched to the market the rst full exible-fuel car, the
Gol 1.6 Total Flex. Several months later was followed by other Brazilian automakers, and by 2009 General Motors, Fiat, Ford, Peugeot, Renault, Volkswagen, Honda, Mitsubishi, Toyota, Citröen and Nissan were producing popular models of ex cars c ars and light trucks. The adopon of ethanol ex fuel vehicles was so successful, that producon of ex cars went from f rom almost 40 thousand in 2003 to 1.7 million in 2007. This rapid adopon of the ex technology was facilitated by the fuel distribuon infrastructure already in place, as around 27,000 lling staons countrywide Pró-Álcool program. were available by 1997 with at least one ethanol pump, a heritage of the program. In the United States, inial support to develop alternave fuels by the government was also a response to the rst oil crisis, and some me later, as a goal to improve air quality. Also, liquid fuels were preferred over gaseous fuels not only because they have a beer volumetric energy density but also because they were the most compable c ompable fuels with exisng distribuon systems and engines, thus avoiding a big departure from the exisng technologies and taking advantage of the vehicle and the refuelling infrastructure. California led the search of sustainable alternaves with interest focused in methanol. Ford Motor Company and other automakers responded to California's request for vehicles that run on methanol. In 1981, Ford delivered 40 dedicated methanol fuel (M100) Escorts to Los Angeles County, but only four refueling staons were installed. the development ofhigher alcoholchemical vehicle technology geng all of theThe fuelbiggest systemchallenge materialsincompable with the reacvity ofwas the fuel. Methanol was even more of a challenge than ethanol but, fortunately, much of the early experience gained with ethanol vehicle producon in Brazil was transferable to methanol. The success of this small experimental eet of M100s led California to request more of these vehicles, mainly for government eets. In 1983, Ford built 582 M100 vehicles; 501 went to California, and the remaining to New Zealand, Sweden, Norway, United Kingdom, and Canada. As an answer to the lack of refueling infrastructure, Ford began development of a exible-fuel vehicle in 1982, and between 1985 and 1992, 705 experimental FFVs were built and delivered to California and Canada, including the 1.6L Ford Escort, the 3.0L Taurus, and the 5.0L LTD Crown Victoria. These vehicles could c ould operate on either gasoline or methanol with only one fuel system. Legislaon wasM85 passed toat encourage the US autoFFV industry beginwas producon, which started in 1993 for the FFVs Ford. In 1996, a new Ford to Taurus developed, with models fully capable of running on either methanol or ethanol blended with gasoline. This ethanol version of the Taurus became the rst commercial producon of an E85 FFV. The momentum of the FFV producon programs at the American car companies connued, although by the end of the 1990s, the emphasis shied to the FFV E85 version, as it is today. Ethanol was preferred over methanol because there is a large support from the farming community, and thanks to the government's incenve programs and corn-based ethanol subsidies. Sweden also tested both the M85 and the E85 exifuel vehicles, but due to agriculture policy, in the end emphasis was given to the ethanol exifuel vehicles. Support for ethanol also comes from the fact that it is i s a biomass fuel, which addresses climate change concerns and greenhouse gas emissions, though these benets are now highly debated depending on the feedstock used for ethanol producon.
The demand for ethanol fuel produced from eld corn in the United States was smulated by the discovery in the late 90s that methyl terary butyl ether (MTBE), an oxygenate addive in gasoline, was contaminang groundwater. Due to the risks of widespread and costly ligaon, and because MTBE use in gasoline was banned in almost 20 states by 2006, the substuon of MTBE opened a new market for ethanol fuel. This demand shi for ethanol as an oxygenate addive took place at a me when oil prices were already signicantly rising. By 2006, about 50 percent of the gasoline contains ethanolrst at dierent and ethanol producon grew so fastused that in thethe USU.S. became the world's ethanol proporons, producer, overtaking Brazil in 2005. This shi also contributed to a sharp increase in the producon and sale of E85 ex vehicles since 2002.
2.4 Flexible-fuel vehicles by country Brazil Aer the 1973 oil crisis, the Brazilian government made mandatory the use of ethanol blends with gasoline, and 100% ethanol powered cars (E100 only) were launched to the market in 1979, aer tesng with several prototypes developed by four carmakers. Brazilian carmakers modied gasoline engines to support ethanol characteriscs and changes included compression rao, amount of fuel injected, replacement of materials that would get corroded by the contact with ethanol, use of colder spark plugs suitable for dissipang heat due to higher ame temperatures, and an auxiliary cold-start system that injects gasoline from a small tank in the engine compartment to help starng when cold. Flexible-fuel technology started being developed only by the end of the 1990s by Brazilian engineers. The Brazilian exible fuel car is built with an ethanol-ready engine and one fuel tank for both fuels. The small gasoline reservoir for starng the engine with pure ethanol in cold weather, used in earlier ethanol-only vehicles, was kept in the rst generaon of Brazilian exible-fuel cars, mainly for users of the central and southern regions, where winter temperatures normally drop below 15 °C (59 °F). An improved ex motor generaon that will be launched l aunched in 2009 will eliminate the need for this secondary gas reservoir tank A key innovaon in the Brazilian ex technology was avoiding the need for an addional dedicated sensor to monitor the ethanol-gasoline mix, which made the rst American M85 ex fuel vehicles too expensive. This was accomplished through the lambda probe, used to measure the quality of combuson in convenonal engines, is also required to tell the engine control unit (ECU) which blend of gasoline and alcohol is being burned. This task is accomplished automacally through soware developed by Brazilian engineers, called "Soware Fuel Sensor" (SFS), fed with data from the standard sensors already built-in the vehicle .A similar fuel injecon technology was developed by the Brazilian subsidiary of Delphi Automove Systems, and it is called "Mulfuel", based on research conducted at its facility in Piracicaba, São Paulo. This technology allows the controller to regulate the amount of fuel injected and spark me, as fuel ow needs to be decreased and also self-combuson needs to be avoided when gasoline is used because ethanol engines have compression rao around 12:1, too high for gasoline.
Brazilian ex cars are capable of running on just hydrated ethanol (E100), or just on a blend of gasoline with 20 to 25% anhydrous ethanol, or on any arbitrary combinaon of both fuels. Pure gasoline is no longer sold in the country because these high ethanol blends are mandatory since 1993. Therefore, all Brazilian automakers have opmized ex vehicles to run with gasoline blends from E20 to E25, and with a few excepons, these FFVs are unable to run smoothly with pure gasoline which causes engine knocking, as vehicles traveling to neighboring South American countries demonstrated. Only two models areRenault specically with a ex-fuel engine opmized tohave operate also with pure gasoline (E0), the Cliobuilt Hi-Flex and the Fiat Siena Tetrafuel. The exibility of Brazilian FFVs empowers the consumers to choose the fuel depending on current market prices. As ethanol fuel economy is i s lower than gasoline because of ethanol's energy content is close to 34% less per unit volume than gasoline, ex cars c ars running on ethanol get a lower mileage than when running on pure gasoline. However, this eect is parally oset by the usually lower price per liter of ethanol fuel. As a rule of thumb, Brazilian consumers c onsumers are frequently advised by the media to use more alcohol than gasoline in their mix only w when hen ethanol prices are 30% lower or more than gasoline, as ethanol price uctuates heavily depending on the result of seasonal sugar cane harvests. The rapid success of ex vehicles was made possible by the existence of 33,000 lling staons with at least one ethanol pump available by 2006, a heritage of the early Pró-Álcool ethanol ethanol program. These facts, together with the mandatory use of E25 blend of gasoline throughout the country, allowed Brazil in 2008 to achieve more than 50% of fuel consumpon in the gasoline market from sugar cane-based ethanol. According to two separate research studies conducted in 2009, at the naonal level 65% of the ex-fuel registered vehicles regularly use ethanol fuel, and the usage increases to 93% in São Paulo, the main ethanol producer state where local taxes are lower, and prices at the pump are more compeve than gasoline.
Latest developments The latest innovaon within the Brazilian exible-fuel technology is the development of exfuel motorcycles. In 2007 Magne Marelli presented the rst motorcycle with ex technology, adapted on a Kasinski Seta 125, and based on the Soware Fuel Sensor (SFS) the rm developed for ex-fuel cars in Brazil. Delphi Automove Systems also presented in 2007 its Mulfuel injecon technology for motorcycles. Besides the exibility in the choice of fuels, a main objecve of the fuel-ex motorcycles is to reduce CO 2 emissions by 20 percent, and savings in fuel consumpon in the order of 5% to 10% are expected. AME Amazonas Motocicletas announced that sales of its motorcycle AME GA (G stands for gasoline and A for alcohol) were scheduled for 2009, but the rst ex-fuel motorcycle was actually launched by Honda in March 2009. Produced by its Brazilian subsidiary Moto Honda da Amazônia, the CG 150 Titan Mix is sold for around US$2,700. Because the CG 150 Titan Mix does not have a secondary gas tank for a cold start like the Brazilian ex cars do, the tank must have at least 20% of gasoline to avoid start up problems at
temperatures below 15 °C (59 °F). The motorcycle’s panel includes a gauge to warn the driver about the actual ethanol-gasoline mix in the storage tank. The Brazilian subsidiaries of Magne Marelli, Delphi and Bosch have developed and announced the introducon in 2009 of a new ex engine generaon that eliminates the need for the secondary gasoline tank by warming the ethanol fuel during starng, and allowing ex vehicles to do a normal cold start temperatures as low as −5improvement °C (23.0 °F), the lowest temperature expected anywhere in theatBrazilian territory. Another is the reducon of fuel consumpon and tailpipe emissions, between 10% to 15% as compared to ex motors sold in 2008. In March 2009 Volkswagen do Brasil launched the Polo E-Flex, the rst ex fuel model without an auxiliary tank for cold start. The Flex Start system used by the Polo was developed by Bosch. Brazilian ex engines are being designed with higher compression raos, taking advantag advantagee of the higher ethanol blends and maximizing the benets of the higher oxygen content of ethanol, resulng in lower emissions and improving fuel eciency. The following table shows the evoluon and improvement of the dierent generaons of ex engines developed in Brazil.
United States By early 2009 there are almost 8 million E85 ex fuel vehicles running on the US roads, up from almost 5 million in 2005. The E85 blend is used iin n gasoline engines modied to accept such higher concentraons of ethanol, and the fuel injecon is regulated through a dedicated sensor, which automacally detects the amount of ethanol in the fuel, allowing adjusng both fuel injecon and sparking ming accordingly to the actual blend available in the vehicle's tank. The American E85 ex fuel vehicle was developed to run on any mixture of unleaded gasoline and ethanol, anywhere from 0% to 85% ethanol by volume. Both fuels are mixed iin n the same tank, and E85 is sold already blended. In order to reduce ethanol evaporave emissions and to avoid problems starng the engine during cold weather, the maximum blend of ethanol was set to 85%. There is also a seasonal reducon of the ethanol content to E70 (calle (called d winter E85 blend) in very cold regions, where temperatures fall below 0 °C (32 °F) during the winter. In Wyoming for example, E70 is sold as E85 from October to May. E85 ex-fuel vehicles are becoming increasingly common in the Midwest, where corn is a major crop and is the primary feedstock for ethanol fuel producon. Also the US government has been using ex-fuel vehicles for many years.
Latest developments In 2008 Chrysler, General Motors, and Ford pledged to manufacture 50 percent of their enre vehicle line as exible fuel in model year 2012, if enough fueling infrastructure develops. In early 2010 GM rearmed its commitment to bio fuels and its determinaon to deliver more than half of its 2012 producon in the U.S. market as E85 ex-fuel capable vehicles. GM will
begin introducing E-85-capable direct-injected and turbocharged power trains, and urged the deployment of more E85 staons, as "ninety " ninety percent of registered ex-fuel vehicles don't have an E85 staon in their zip code, and nearly 50%, don't have E85 in their county .."" In 2008 Ford delivered the rst ex-fuel plug-in hybrid as part of a demonstraon project, a Ford Escape Plug-in Hybrid capable of running on E85 or gasoline. General Motors announced that new plug-in hybrid electric Chevrolet Volt,about expected be launched in the The Norththe American market in 2010, willvehicle be ex-fuel-capable a yeartoaer it is introduced. Volt propulsion architecture allows adapng the propulsion to other world markets such as Brazil’s E100 or to Europe’s commonly using clean c lean diesel. On May 2009, President Barack Obama signed a Presidenal Direcve with the aim to advance biofuels research and improve their commercializaon. The Direcve established a Biofuels Interagency Working Group comprises of three agencies, the Department of Agriculture, the Environmental Protecon Agency, and the Department of Energy. This group will develop a plan to increase exible fuel vehicle use and assist in retail markeng eorts. Also they w will ill coordinate infrastructure policies impacng the supply, secure transport, and distribuon of biofuels in order to increase the number of fueling staons throughout the country. OTHER COUNTRIES: 1. Sweden 2. France 3. Germany 4. Ireland 5. Spain 6. Uni Unite ted d King Kingdo dom m
7. Australia 8. Canada 9. Colombia
List of exible-fuel vehicles by car manufacture manufacturerr 1. Chevrol rolet 2. Fiat 3. Ford 4. Honda
5. Mitsubishi 6. Nissan 7. Renault 8. Toyota 9. Volkswa swagen 10. Mercedes Mercedes Benz 11. Chrysle Chryslerr 12. General General Motors Motors [5]
3. Sources Producton process Presently, methanol is usually produced using methane (the chief constuent of natural gas) as a raw material. Methanol is made from coal in China for fuel.
"Biomethanol" may be produced by gasicaon of organic materials to synthesis gas followed by convenonal methanol synthesis. Producon of methanol from synthesis gas using BiomassBi omassTo-Liquid can oer methanol producon from biomass at eciencies up to 75%. Widespread producon by this route has a postulated potenal (see Hagen, SABD & Olah references below) to oer methanol fuel at a low cost and with benets to the environment. These producon methods, however, are not suitable for small scale producon. Ethanol is a renewable energy source because the energy is generated by using a resource, sunlight, which is naturally replenished. Creaon of ethanol starts with photosynthesis causing a feedstock, such as sugar cane or corn, to grow. These feedstocks are processed into ethanol. About 5% of the ethanol produced in the world in 2003 was actually a petroleum product. It is made by the catalyc hydraon of ethylene with wi th sulphuric acid as the catalyst. It can c an also be obtained via ethylene or acetylene, from calcium carbide, c arbide, coal, oil gas, and other sources. Two million tons of petroleum-derived ethanol is produced annually. The principal suppliers are plants in the United States, Europe, and South Africa. Petroleum derived ethanol (synthec ethanol) is chemically idencal to bio-ethanol and can be dierenated only by radiocarbon dang. Bio-ethanol is usually obtained from the conversion of carbon based feedstock Energy crop or Energy crops. Agricultural feedstocks are considered renewable because they get energy from the sun using photosynthesis, provided that all minerals required for growth (such as nitrogen and phosphorus) are returned to the land. Ethanol can be produced from a variety of feedstocks such as sugar cane, c ane, bagasse, miscanthus, sugar beet, sorghum, grain sorghum, switchgrass, barley, hemp, kenaf, potatoes, sweet potatoes, cassava, sunower, fruit, molasses, corn, stover, grain, wheat, straw, coon, other biomass, as well as many types of cellulose waste and harvesngs, whichever has the best well-to-wheel assessment.
An alternave process to produce bio-ethanol from algae is being developed by the company Algenol. Rather than grow din mor algae and then harvest and ferment it the algae grow in sunlight and produce ethanol directly which is removed without killing killi ng the algae. It is claimed the process can produce 6000 gallons per acre per year compared with 400 gallons for corn producon. Currently, thethe rst generaon processes for the ethanol fromand cornonly usethe onlystarch, a small part of corn plant: the corn kernels areproducon taken fromofthe corn plant which represents about 50% of the dry kernel mass, is transformed into ethanol. Two types of second generaon processes are under development. The rst type uses enzymes and yeast to convert the plant cellulose into ethanol while the second type uses pyrolysis to convert the whole plant to either a liquid bio-oil or a syngas. Second generaon processes can also be used with plants such as grasses, wood or agricultural waste material such as straw. The basic steps for large scale producon of ethanol are: microbial (yeast) fermentaon of sugars, disllaon, and dehydraon (requirements vary, see Ethanol fuel mixtures, below), and denaturing (oponal). Prior to fermentaon, some crops c rops require saccharicaon or hydrolysis of carbohydrates such as cellulose and starch into sugars. Saccharicaon of cellulose is called cellulolysis (see cellulosic ethanol). Enzymes are used to convert starch into sugar. Cellulosic ethanol oers promise as cellulose bers, a major and universal component in plant cells walls, can be used to produce ethanol. According to the Internaonal Energy Agency, cellulosic ethanol could allow ethanol fuels to play a much bigger role in the future than previously thought Disllaon
For the ethanol to be usable as a fuel, water must be removed. Most of the water is removed by disllaon, but the purity is limited l imited to 95-96% due to the formaon of a low-boiling waterethanol azeotrope. The 95.6% m/m (96.5% v/v) ethanol, 4.4% m/m (3.5% v/v) water mixture may used asisatypically fuel alone, but unlike anhydrous ethanol, is immiscible in combinaon gasoline, so the waterbefracon removed in further treatment in order to burn in with gasoline in gasoline engines. Dehydraon There are basically ve dehydraon processes to remove the water from an azeotropic ethanol/water mixture. The rst process, used in many early fuel ethanol plants, is called azeotropic disllaon and consists of adding benzene or cyclohexane to the mixture. When these components are added to the mixture, it forms a heterogeneous azeotro azeotropic pic mixture in vapor-liquid-liquid equilibrium, which when dislled produces anhydrous ethanol in the column boom, and a vapor mixture of water and cyclohexane/benzene. c yclohexane/benzene. When condensed, this becomes a two-phase liquid mixture. Another early method, called extracve disllaon, consists of adding a ternary component which will increase ethanol's e thanol's relave volality. When the ternary mixture is dislled, it will produce anhydrous ethanol on the top stream of the column.
With increasing aenon being paid to saving energy, many methods have been proposed that avoid disllaon all together for dehydraon. Of these methods, a third method has emerged and has been adopted by the majority of modern ethanol plants. This new process uses molecular sieves to remove water from fuel ethanol. In this process, ethanol vapor under pressure passes through a bed of molecular sieve beads. The bead's pores are sized to allow absorpon of water while excluding ethanol. Aer a period of me, the bed is regenerated under vacuum to remove the is absorbed water. Two beds are used so that one is available to absorb water while the other being regenerated. This dehydraon technology can account for energy saving of 3,000 btus/gallon (840 kJ/l) compared to earlier azeotropic disllaon.
4. Technology 4.1 Ethanol-based engines
Ethanol is most commonly used to power automobiles, though it may be used to power other vehicles, such as farm tractors, boats and airplanes. Ethanol (E100) consumpon in an engine is approximately 51% higher than for gasoline since the energy per unit volume of ethanol is 34% lower than for gasoline. However, the higher compression c ompression raos in an ethanol-only engine allow for increased power output and beer fuel economy e conomy than could be obtained with lower compression raos. In general, ethanol-only engines are tuned to give slightly beer power and torque output than gasoline-powered engines. In exible fuel vehicles, the lower compression rao requires tunings that give the same output when using either gasoline or hydrated ethanol. For maximum use of ethanol's benets, a much higher compression rao should be used, Current high compression neat ethanol engine designs are approximately 20-30% less fuel ecient than their gasoline-only counterparts. A 2004 MIT study and an earlier paper published by the Society of Automove Engineers E ngineers idenfy a method to exploit the characteriscs of fuel ethanol substanally beer than mixing it with gasoline. The method presents the possibility of leveraging the use of alcohol to achieve denite improvement over the cost-eecveness of hybrid electric. The improvement consists of using dual-fuel direct-injecon of pure alcohol (or the azeotrope or E85) and gasoline, in any rao up to 100% of either, in a turbocharged, high compression-rao, small-displacement engine having performance similar to an engine having twice the displacement. Each fuel is carried separately, with a much smaller tank for alcohol. The high-compression (which increases eciency) engine will run on ordinary gasoline under low-power cruise condions. Alcohol is directly injected into the cylinders (and the gasoline injecon simultaneously reduced) only when necessary to suppress ‘knock’ such as when w hen signicantly accelerang. Direct cylinder injecon raises the already high octane rang of ethanol up to an eecve 130. The calculated over-all reducon of gasoline use and CO 2 emission is 30%. The consumer cost payback me shows a 4:1 improvement over turbo-diesel and a 5:1 improvement over hybrid. In addion, the problems of water absorpon into pre-mixed gasoline (causing phase separaon), supply issues of mulple mix raos and cold-weather starng are avoided.
Ethanol's higher octane rang allows an increase of an engine's compression rao for increased thermal eciency. In one study, complex engine controls and increased exhaust gas recirculaon allowed a compression rao of 19.5 with fuels ranging from neat ethanol to E50. Thermal eciency up to approximately that for a diesel was achieved. This would result in the fuel economy of a neat ethanol vehicle to be about the same as one burning gasoline. Since 1989 there been ethanol engines the diesel principle operang Sweden. They arehave usedalso primarily in city buses, butbased also inondistribuon trucks and waste in collectors. The engines, made by Scania, have a modied compression rao, and the fuel (known as ED95) used is a mix of 93.6 % ethanol and 3.6 % ignion improver, and 2.8% denaturants. denaturant s. The ignion iimprover mprover makes it possible for the fuel to ignite in the diesel combuson cycle. It is then also possible to use the energy eciency of the diesel principle with ethanol. These engines have been used in the United Kingdom by Reading Transport but the use of bioethanol fuel is now being phased out. 4.2 Engine cold start during the winter
High ethanol blends present a problem to achieve enough vapor pressure for the fuel f uel to evaporate and spark the ignion during cold weather (since ethanol tends to increase fuel enthalpy of vaporizaon). When vapor pressure is below 45 kPa starng a cold engine becomes dicult. In order to avoid this problem at temperatures below 11 ° Celsius (59 °F), and to reduce ethanol higher emissions during cold weather, both the US and the European E uropean markets adopted E85 as the maximum blend to be used in their exible fuel vehicles, vehicl es, and they are opmized to run at such a blend. At places with harsh cold weather, the ethanol blend in the US has a seasonal reducon to E70 for these very cold regions, though it is sll sold as E85. At places where temperatures fall below -12 °C (10 °F) during the winter, it is recommended to install an engine heater system, both for gasoline and E85 vehicles. Sweden has a similar seasonal reducon, but the ethanol content in the blend is reduced to E75 during the winter months.
4.3 Ethanol fuel mixtures To avoid engine stall due to "slugs" of water in the fuel lines interrupng fuel ow, the fuel must exist as a single phase. The fracon of water that an ethanol-gasoline fuel can contain without phase separaon increases with the percentage of ethanol.. This shows, for example, that E30 can have up to about 2% water. If there is more than about 71% ethanol, the remainder can be any proporon of water or gasoline and phase separaon will not occur. However, the fuel mileage declines with w ith increased water content. The increased solubility of water with higher ethanol content permits E30 and hydrated ethanol to be put in i n the same tank since any combinaon of them always results in a single phase. Somewhat less water is tolerated at lower temperatures. For E10 it is about 0.5% v/v at 70 F and decreases to about 0.23% v/v at -30 F.
In many countries cars are mandated to run on mixtures of ethanol. Brazil requires cars be suitable for a 25% ethanol blend, and has required various mixtures between 22% and 25% ethanol, since of July 2007 25% is required. The United States allows up to 10% blends, and some states require this (or a smaller amount) in all gasoline sold. Other countries have adopted their own requirements. Beginning with the model year 1999, an increasing number of vehicles in the world are manufactured with engines which can run on any fuel from 0% ethanol up to 100%SUVs ethanol withouttrucks) modicaon. Manyto cars light trucks (a class containing minivans, and pickup are designed beand exible-fuel vehicles (also called dual-fuel vehicles). In older model years, their engine systems contained alcohol sensors in the fuel and/or oxygen sensors in the exhaust that provide input to the engine control c ontrol computer to adjust the fuel injecon to achieve stochiometric (no residual fuel or free oxygen in the exhaust) air-to-fuel rao for any fuel mix. In newer models, the alcohol sensors have been removed, with the computer using only oxygen and airow sensor feedback to esmate alcohol content. The engine control computer can also adjust (advance) the ignion ming to achieve a higher output without pre-ignion when it predicts that higher alcohol percentages are present in the fuel being burned. This method is backed up by advanced knock sensors - used in most high performance gasoline engines regardless of whether they're designed to use ethanol or not - that detect pre-ignion and detonaon.
4.5 Fuel economy In theory, all fuel-driven vehicles have a fuel economy (measured as miles per US gallon, or liters per 100 km) that is directly proporonal to the fuel's energy content. In reality, there are many other variables that come in to play that aect the performance of a parcular fuel in a parcular engine. Ethanol contains approx. 34% less energy per unit volume than gasoline, and therefore in theory, burning pure ethanol in a vehicle will result in a 34% reducon in miles per US gallon, given the same fuel economy, ec onomy, compared to burning pure gasoline. Since ethanol has a higher octane rang, the engine can be made more ecient by raising its compression c ompression rao. In fact using a variable turbocharger, the compression rao can be opmized for the fuel being used, making fuel economy almost almost constant for aany ny blend. For E10 (10% ethanol an and d 90% gasoline), the eect is small (~3%) when compared to convenonal gasoline, and even smaller (1-2%) when compared to oxygenated and reformulated blends. However, for E85 (85% ethanol), the eect becomes signicant. E85 will produce lower mileage than gasoline, and will require more frequent refueling. Actual performance may vary depending on the vehicle. Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles resulted 25.56% lower than unleaded gasoline. The EPA-rated mileage of current USA ex-fuel vehicles should be considered when making price comparisons, but it must be noted that E85 is a high performance fuel, with an octane rang of about 104, and should be compared to premium. In one esmate the US retail price for E85 ethanol is 2.62 US dollar per gallon or 3.71 dollar corrected for energy equivalency compared to a gallon of gasoline priced at 3.03 dollar. Brazilian cane ethanol (100%) is priced at 3.88 dollar against 4.91 dollar for E25 (as July 2007). The ethanol industry in Brazil is more than 30 year-old and even though it is no longer subsidized, producon and use of ethanol was smulated through:
Low-ineres loans for he consructon of ehanol distlleries Guaraneed purchase of ehanol by he sae-owned sae-owned oil company a a reasonable price Reail pricing of nea ehanol so i is compettve if no slighly favorable o he gasoline-ehanol blend Tax incentves provided during he 1980s o stmulae he purchase of nea ehanol vehicles.
Guaranteed purchase and price regulaon were ended some years ago, with relavely posive results. In addion to these other policies, ethanol producers in the state of São Paulo established a research and technology transfer center that has been eecve in improving sugar cane and ethanol yields. 4.6 Fuel system problems
Several of the outstanding ethanol fuel issues are linked specically to fuel systems. Fuels with more than 10% ethanol are not compable with non E85-ready fuel system components and may cause corrosion of iron components. Ethanol fuel can negavely aect electric fuel pumps by increasing internal wear, cause undesirable spark generaon, and is not compable with capacitance fuel level gauging indicators and may cause erroneous fuel quanty indicaons in vehicles that employ that system. It is also not always compable with marine cra, especially those that use berglass fuel tanks. Ethanol is also not used in aircra for these same reasons. Using 100% ethanol fuel decreases fuel-economy by 15-30% over using 100% gasoline; this can be avoided using certain modicaons that would, however, render the engine inoperable on regular petrol without the addion of an adjustable ECU. Tough materials are needed to accommodate a higher compression rao to make an ethanol engine as ecient as it would be on petrol; these would be similar to those used in diesel engines which typically run at a CR of 20:1, vs. about 8-12:1 for petrol engines.
5 Environment 5.1 Energy balance
All biomass goes through at least some of these steps: it needs to be grown, collected, dried, fermented, and burned. All of these steps require resources and an infrastructure. The total amount of energy input into the process compared to the energy released by burning the resulng ethanol fuel is known as the energy balance (or "Net energy gain"). Figures compiled in a 2007 by Naonal Geographic Magazine point Magazine point to modest results for corn ethanol produced in the US: one unit of fossil-fuel energy is required to create 1.3 energy units from the resulng ethanol. The energy balance for sugarcane ethanol produced in Brazil is more favorable, 1:8. Energy balance esmates are not easily produced, thus numerous such reports have been generated that are contradictory. For instance, a separate survey reports that producon of
ethanol from sugarcane, which requires a tropical climate to grow producvely, returns from 8 to 9 units of energy for each unit expended, as compared to corn which only returns about 1.34 units of fuel energy for each unit of energy expended. Carbon dioxide, a greenhouse gas, is emied during fermentaon and combuson. However, this is canceled out by the greater uptake of carbon dioxide by the plants as they grow to produce the biomass. When compared c ompared ethanol releases less greenhouse gases.to gasoline, depending on the producon method,
5.2 Change in land use Large-scale farming is necessary to produce agricultural alcohol and this requires substanal amounts of culvated land. University of Minnesota researchers report that if all corn grown in the U.S. were used to make ethanol it would displace 12% of current U.S. gasoline consumpon. There are claims that land for ethanol producon is acquired through deforestaon, while others have observed that areas currently supporng forests are usually not suitable for growing crops. In any case, farming may involve a decline in i n soil ferlity due to reducon of organic maer, a decrease in water w ater availability and quality, an increase in the use of pescides and ferlizers, and potenal dislocaon of local communies. However, new technology enables farmers and processors to increasingly produce the same output using less input. Many analysts suggest that, whichever ethanol fuel producon strategy is used, fuel conservaon eorts are also needed to make a large impact on reducing petroleum fuel use.
5.3Cricism and controversy: Food vs. fuel There are various current issues with ethanol producon and use, which are presently being discussed in the popular media and scienc journals. These include: the eect of moderang oil prices, the "food vs fuel" debate, carbon emissions levels, sustainable biofuel producon, deforestaon and soil erosion, impact on water resources, human rights issues, poverty reducon potenal, ethanol prices, energy balance and eciency, and centralised vs. decentralised producon models.
Food vs fuel is is about the price and availability impact of diverng farmland or crops for ethanol producon to the detriment of the food supply. The debate is internaonally controversial, with good-and-valid arguments on all sides of this ongoing debate. There is disagreement about how signicant this is what is causing c ausing it, what the impact is, and what can or should be done about it. [3]
References
1. V Ganesan, Ganesan, IC Engines, Engines, e3, Tata Mcgrawhill, Mcgrawhill, pp 201-210. 201-210. 2. hp://en.wiki hp://en.wikipedia. pedia.org/wi org/wiki/Met ki/Methanol hanol_fuel _fuel (visite (visited d on 19.05. 19.05.2010) 2010) 3. hp://en.wiki hp://en.wikipedia. pedia.org/wi org/wiki/Eth ki/Ethanol_ anol_fuel fuel (do) 4. hp://en.wiki hp://en.wikipedia. pedia.org/wi org/wiki/Al ki/Alcohol cohol_fuel _fuel (do) 5. hp://en.wiki hp://en.wikipedia. pedia.org/wi org/wiki/Fl ki/Flexibl exible-fue e-fuel_vehi l_vehicle cle (do)
