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.
Topics
Nos. Introduction
1
1.1 Methanol 1.2 Ethanol 1.3 Butanol and Propanol 1.4 1.5 1.6 1.7
ALCOHOL FOR SI ENGINES REFORMULATED GASOLINE FOR SI ENGINES ALCOHOL FOR CI ENGINES SURFACE-IGNITION SURFACE-IGNITION ALCOHOL CI C I ENGINES
2
3
4
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 getting improved and will continue to improve . However, enormous increase in number of ve hicles has started dictating t he demand for fuel . With increased use and depletion of fossil fuels, alternative al ternative fuel tec hnology 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 t heir vehicles. DIFFICULTIES:
1. Extensive research and development is difficult to justify until t he fuels are accepted as viable for large numbers of engines . 2. Most alternate fuels are very costly at present since t he quantity used is very less . 3. There is lack of distribution points (service stations) w here fuel is available to the public.
LIQUID FUELS: Liquid
fuels are preferred for IC engines because t hey are easy to store s tore and have reasonably good calorific value . The main alternative is t he alcohol ALCOHOL:
Alcohols are attractive alternate fuels because t hey can be obtained from bot h natural and manufactured manufactured sources . Methanol and et hanol are two kinds of alco hols that seem most promising. ADVANTAGES:
1. It is a high octane fuel with anti-knock index numbers of over 100.Engines using high octane fuel can run more efficiently by using higher compression ratios . Alcohols have higher flame speed. 2. It produces less overall emissions compared to gasoline .
3. When alcohols are burned, it forms more moles of ex haust gases, w hich gives higher pressure and more power in t he expansion stroke . 4. It has high latent heat of vaporization w hich results in a cooler intake process . This raises the volumetric efficiency of the engine and reduces t he required work input in t he compression stroke . 5. Alcohols have low sulp hur content in t he fuel. 6. Reduced petroleum imports and transportation . DISADVANTAGES:
1. Alcohols have low energy content or in ot her words the calorific value of t he fuel is almost half . This means t hat almost twice as muc h as gasoline must be burned to give the same energy input to t he engine. With equal t hermal efficiency and similar engine output usage, twice as muc h fuel would have to be purc hased, and he distance which could be driven with a given fuel tank volume would be cut in half . Automobiles as well as distribution stations would require twice as muc h storage capacity, twice t he number of storage facilities, twice the volume of storage at t he service stations, twice as many tank trucks and pipelines, etc . Even with the low energy content of t he fuel, engine power for a given displacement would be about t he same. This is because of t he lower air-fuel ratio needed by alco hol. Alcohol contains oxygen and t hus requires less air for stoichiometric combustion. More fuel can be burned wit h the same amount of air . 2. Combustion of alco hols produces more alde hydes in the exhaust. If as muc h alcohol fuel was consumed as gasoline . Aldehyde emissions would be a serious ser ious problem. 3. Alcohol is much more corrosive than gasoline on copper, brass, aluminum, rubber, and many plastics . This puts some restrictions on t he design and manufacturing of engines to be used wit h this fuel. Fuel lines and tanks, gaskets, and even metal engine parts can deteriorate with long-term alcohol use (resulting in cracked fuel lines, t he need for special fuel tank, etc). Methanol is very corrosive on metals . 4. It has poor cold weat her starting c haracteristics due to low vapor pressure and evaporation. Alcohol-fuelled engines generally have difficulty in starting at temperatures below 10 C. Often a small amount of gasoline is added to alco al co hol fuel, which greatly improves cold-weat her starting. However, the need to do this greatly reduces the attractiveness of alco hol. 5. Alcohols have poor ignition c haracteristics n general . 6. Alcohols have an almost invisible flame, w hich is considered dangerous w hen handling fuel. A small amount of gasoline removes t his danger. 7. There is the danger of storage tank flammability, due to low vapor pressure . Air can leak into storage tanks and create combustible mixtures . 8. There will be less NOx emissions because of low flame temperatures te mperatures. However, the resulting lower ex haust temperatures take longer time to heat the catalytic converter to efficient operating temperatures . 9. Many people find t he strong odor of alco hol very offensive. Headaches and drizzles have been experienced when refueling an automobile . 10. There is a possibility of vapor lock in fuel delivery systems.
1.1 METHANOL:
Of all the fuels being considered as an alternate to gasoline, g asoline, 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 flexible fuel (or variable fuel) engines are capable of using any random mixture combination of methanol and gasoline ranging from methanol to pure gasoline. Two fuel tanks are used and various flow rates of the two fuels can be pumped to the engine, passing through a mixing chamber. Using information from sensors in the intake and ex haust, the electronic monitoring systems (EMS) adjust to the proper air-fuel ratio, ignition ratio, r atio, ignition timing, injection timing, and valve timing (where possible) for t he fuel mixture being used . Methanol can be obtained from many sources, both fossil and renewable. These include coal,
petroleum, natural gas, biomass, wood, landfills, and a nd even the ocean. However, any source that requires extensive 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 formalde hyde emissions.
go od CI engine fuel Methanol is used some dual-fuel CI engines. Methanol by itself is not a good because of its high octane number, but if a small amount of diesel oil is used for ignition, it can be used with good results . This is very attractive for f or developing countries, because met hanol can often be obtained from muc h cheaper source than diesel oil. Methanol fuel has received less attention t han ethanol fuel as an alternative to petroleum based fuels .[1] Use in racing Methanol fuel is also used extensively in drag racing, primarily in t he Top Alcohol category.
Formula One racing continues to use gasoline as its fuel, but in pre war grand prix racing methanol was often used in t he fuel. Use as internal combustion engine fuel
Both methanol and et hanol burn at lower temperatures t han gasoline, and bot h are less volatile, making engine starting in cold weat her more difficult. Using methanol as a fuel in spark ignition engines can offer an increased t hermal efficiency and increased power output (as compared to gasoline) due to its high octane rating (11 4) and high heat of vaporisation . However, its low energy content of 19.7 MJ/kg and stoichiometric air fuel ratio of 6.42:1 mean
that fuel consumption (on volume or mass basis) will w ill be higher than hydrocarbon fuels . The extra water produced also makes t he charge rather wet (similar to hydrogen/oxygen combustion engines)and combined wit h the formation of acidic products during combustion, the wearing of valves, valve seats and cylinder mig ht be higher than with hydrocarbon burning . Certain additives may be added to motor oil in order to neutralize t hese acids. Methanol, just like et hanol, contains soluble and insoluble contaminants . These soluble contaminants, halide ions suc h as chloride ions, have a large effect on t he corrosivity of alco hol fuels. Halide ions increase corrosion in two ways; t hey chemically attack passivating oxide films on several metals causing pitting corrosion, and t hey increase the conductivity of t he fuel. Increased electrical conductivity promotes electric, galvanic, and ordinary corrosion in t he fuel system. Soluble contaminants, suc h as aluminium hydroxide, itself a product of corrosion by halide ions, clog the fuel system over time . Methanol is hygroscopic, meaning it will absorb water vapor directly from t he atmosphere. Because absorbed water dilutes t he fuel value of t he methanol (although, it suppresses engine knock), and may cause p hase separation of met hanol-gasoline blends, containers of met hanol fuels must be kept tig htly sealed.
Toxicity
ca n cause blindness and 60-100 ml can be fatal, Methanol is poisonous; ingestion of only 10 ml can and it doesn't have to be swallowed sw allowed to be dangerous since t he liquid can be absorbed through the skin, and the vapors through the lungs. US maximum allowed exposure in air ( 40 h/week) is 1900 mg/m³ for ethanol, 900 mg/m³ for gasoline, and 1 260 mg/m³ for methanol. However, it is less volatile than gasoline, and t herefore decreases evaporative emissions . Use of methanol, like ethanol, significantly reduces t he emissions of certain hydrocarbon-related toxins suc h as benzene and 1, 3 butadiene. But as gasoline and et hanol are already quite toxic, safety protocol is the same. Safety
Since methanol vapour is heavier than air, it will linger close to t he ground or in a pit unless there is good ventilation, and if t he concentration of met hanol is above 6.7% in air it can be lit by a spark, and will explode exp lode above 54 F / 12 C. Once ablaze, t he flames give out very little lig ht making it very hard to see t he fire or even estimate its size, especially in brig ht daylight. If you are unlucky enoug h to be exposed to t he poisonous substance t hrough your respiratory system, its pungent odor s hould give you some warning of its presence . However, it is difficult to smell methanol in the air at less than 2,000 ppm (0.2%), and it can be dangerous at lower concentrations t han 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. About 5 million vehicles operated on fuels that were 93% ethanol. For a number of years gasohol (gasoline+alcohol) has been available at service stations 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 g asoline and ethanol continues. Two mixture combinations that are important are E85 (85% ethanol) and e10 (gasohol). E85 is basically an alcohol fuel with 15% gasoline added to eliminate some of t he problems of pure alco hol (i.e., cold starting, tank flammability, etc.E10 reduces the use of gasoline wit h no modification needed to t he automobile engine. Flexible-fuel engines are being tested w hich can operate on any ratio of ethanolgasoline.[1]
1.3 Butanol and Propanol Propanol and butanol are considerably less toxic and less volatile t han methanol. In particular, butanol has a high flashpoint of 3 5 °C, which is a benefit for fire safety, but may be a difficult for starting engines in cold weat her. The concept of flash point is however not directly applicable to engines as t he compression of t he air in t he cylinder means t hat the temperature is several hundred degrees Celsius before ignition takes place . The fermentation processes to produce propanol and butanol from cellulose are fairly tricky to execute, and the Weizmann organism ( Clostridium acetobutylicum) currently used to perform pe rform these conversions produces an extremely unpleasant smell, and t his must be taken into consideration w hen designing and locating a fermentation plant . This organism also dies w hen the butanol content of w hatever it is fermenting rises to 7%. For comparison, yeast dies w hen the ethanol content of its feedstock hits 14%. Specialized strains can tolerate even greater ethanol concentrations - so-called turbo yeast can wit hstand up to 1 6% ethanol. However, if ordinary Sacc haromyces yeast can be modified to improve its et hanol resistance, scientists may yet one day produce a strain of t he Weizmann organism wit h 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 fibre left over from sugar crops used to make et hanol could be made into butanol, raising t he alcohol yield of fuel crops wit hout there being a need for more crops to be planted . Despite these drawbacks, DuPont and Britis h Petroleum have recently announced t hat they are jointly to build a small scale butanol fuel demonstration plant alongside t he large bioethanol plant t hey are jointly developing with Associated Britis h Foods. Energy Environment International developed a met hod for producing butanol from biomass, which involves the use of two separate s eparate micro-organisms in sequence to minimize production of acetone and et hanol by-products .
The Swiss company Butalco GmbH uses a special tec hnology to modify yeasts in order to produce butanol instead of et hanol. Yeasts as production organisms for butanol have decisive advantages compared to bacteria . Butanol combustion is: C4H9OH + 6O2 4CO2 + 5H2O + heat[4] 1.4 ALCOHOL FOR SI ENGINES:
Alcohol have higher antiknock characteristic compared to gasoline. As such with an alcohol fuel, engine compression ratios between 11:1 and 13:1 are usual. Todays gasoline engines use a compression ratio 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 ratio is lesser for alcohol than for gasoline. To provide a proper fuel air mixture, m ixture, a carburetor or fuel injector fuel passage should be doubled in area to allow extra fuel flow. Alcohol does not vaporize as easily as gasoline. Its latent heat of vaporization is much greater. This affects cold weather starting. If the alcohol liquefies in t he engine then it will not burn properly. Thus, the engine may be difficult or even impossible to start in extremely cold climate. To overcome this, gasoline is introduced in the engine until the engine starts and warms up. Once the engines warms, alcohols when introduced will vaporize quickly and completely and normally. Even during normal operation, additional heat may have to be supplied to completely vaporize alcohol. Alcohol burns at about half the speed of gasoline. As such, ignition timing must be changed, so that more spark advance is provided. This will give the slow burning alcohol more time 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 g asoline with a slightly modified formulation and help additives to help reduce engine emissions. Additives in the fuel include oxidation inhibitors, corrosion inhibitors, metal deactivators, detergents, and deposit control additives. Oxygenates such as methyl tertiary-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, aromatic, and hig h boiling components are reduced, as in the vapor pressure.Recognising that engine deposits contribute to emissions, cleaning additives are included. Some additives clean carburetors, some clean fuel injectors, and some intake valves, eac h of which often does not clean other components. MTBE is now prohibited for ground water contamination. Of the positive side is t hat all gasoline-fuelled engines, old and new, can use t his fuel without modification. On the negative side is that only moderate emissions reduction is realized, cost is increased, and the only moderate emission reduction 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-ignition engine has been accompanied by the desire to raise the compression ratio for increased efficiency and fuel economy. One obstacle to this gain in economy at times has been the octane quality of the available gasoline. To circumvent this limitation, water was proposed as an antiknock additive. Water addition to gasoline slows down the burning rate and reduces the gas temperature in the cylinder which probably suppresses detonation. Engine combustion chamber deposit reductions have also been reported when water was added to the intake charge. With respect to nitric oxide emissions, dramatic reductions were reported. Conversely, water addition probably increases i ncreases hydrocarbon emissions. Finally, with respect to carbon monoxide emissions, water additions seem to have minimal effect. Only a very limited work has been carried out with the addition of water via an emulsion with the fuel rather than independently. Emulsion could eliminate t he need for a separate tank, provide improved atomization and increase fuel safety. However, a water-fuel separation problem may exist. 1.7 ALCOHOL FOR CI ENGINES:
Techniques of using alco hol in diesel engines are 1. Alcohol/diesel fuel solutions . 2. Alcohol diesel emulsions . 3. Alcohol fumigation 4. Dual fuel injection 5. Surface ignition of alcohols 6. Spark ignition of alco hols 7. Alcohols containing ignition improving additives . Both ethyl and methyl alcohols have high self ignition temperatures. Hence, very high compression ratios (25-27) will be required to self ignite them. Since this would make the engine extremely heavy and expensive, the better method is to utilize them in dual fuel operation . In
the dual fuel engine, alco hol is carbureted or injected into the inducted air. Due to high self ignition temperature of alcohols three will be no combustion with the usual diesel compression ratios of 1 6 to 18. A little before the end of compression stroke, a small sm all quantity of diesel oil is injected into the compression stroke, a quantity of diesel oil is injected into the combustion chamber through the normal diesel pump and spray nozzle. The diesel oil readily ignites and initiates combustion in t he alcohol air mixtures also. Several methods are adopted for induction of alcohol into the intake manifold. They are micro fog unit, pneumatic spray nozzles, vaporizer, carburetor and fuel injector. The degree of fineness in mixing of fuel and air are different for the above methods.
Another method tried is to inject alcohol into the combustion chamber after diesel fuel injection . This way of alcohol induction avoids the alcohol cooling the charge in the cylinder to a degree which will jeopardize the ignition of the diesel fuel. However, this design calls for two complete and separate fuel systems with tank, fuel pump, injection pump and injectors. In
the dual fuel engines mentioned above, major portion of the heat release is by the alcohol is ignited by a pilot spray of diesel oil injection. Hence, if the alcohol induction rate exceeds a limit, the injected diesel will not be able to ignite and hence, the engine will fail to function. 1.8 SURFACE-IGNITION ALCOHOL CI ENGINES:
A slab of insulator material, wound with a few strands of heating wire is fixed on the combustion chamber with the wire running on the face exposed to the gases. The fuel injector is located suc h that a part of the spray impinges head on this surface. Ignition is thus initiated. The combustion chamber, which is in the cylinder head, is made relatively narrow so that the combustion spreads quickly to t he 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 after some minutes of operations opera tions reaches a temperature sufficient to initiate ignition without the aid of external ex ternal electrical supply. The power consumption 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 operation. The engine operates more smoothly at lower speeds than at higher speeds. [1] 2.1
Flexible-fuel vehicle
A flexible-fuel flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle ) is an alternative fuel ve hicle with an internal combustion engine designed to run on more t han one fuel, usually gasoline blended wit h either ethanol or met hanol fuel, and bot h fuels are stored in the same common tank . Flex-fuel engines are capable of burning any proportion of t he resulting blend in t he combustion c hamber as fuel injection and spark timing are adjusted a djusted automatically according to t he actual blend detected by electronic e lectronic sensors . Flex-fuel vehicles are distinguis hed from bi-fuel ve hicles, where two fuels are stored in separate tanks and t he engine runs on one fuel at a time, for example, compressed natural gas ( CNG), liquefied petroleum gas ( LPG), or hydrogen. The most common commercially available FFV in t he world market is the ethanol flexible-fuel vehicle, with around 18 million automobiles and lig ht duty trucks on the roads by 2009, and concentrated in four markets, Brazil (9 .3 million), t he United States (around 8 million), Canada (600,000), and Europe, led by Sweden (181, 458). Also a total of 183,375 flexible-fuel motorcycles were sold in Brazil in 2009. In addition to flex-fuel ve hicles running with ethanol, in Europe and t he US, mainly in California, there have been successful test programs wit h methanol flex-fuel vehicles, known as M85 flex-fuel vehicles. Though technology exists to allow et hanol FFVs to run on any mixture of gasoline and et hanol, from pure gasoline up to 100 % ethanol (E100), Nort h American and European flex-fuel vehicles are optimized to run on a maximum blend of 1 5% gasoline with 85% anhydrous ethanol (called E85 fuel). This limit in t he ethanol content is set to reduce ethanol emissions at low
temperatures and to avoid cold starting problems during cold weat her, at temperatures lower than 11 °C (52 °F). The alcohol content is reduced during t he winter in regions w here temperatures fall below 0 ° C (32 °F) to a winter blend of E 70 in the U.S. or to E75 in Sweden from November until March. Brazilian flex fuel ve hicles are optimized to run on any mix of E 20E25 gasoline and up to 100 % hydrous ethanol fuel (E100). The Brazilian flex vehicles are built-in with a small gasoline reservoir for cold starting t he engine when temperatures drop below 15 °C (59 °F). An improved flex motor generation g eneration was launc hed in 2009 which eliminated the need for t he secondary gas tank .
2.2 Terminology As ethanol FFVs became commercially available during the late 1990s, t he common use of t he term "flexible-fuel vehicle" became synonymous wit h ethanol FFVs . In the United States flexfuel vehicles are also known as "E85 vehicles". In Brazil, the FFVs are popularly known as "total flex" or simply "flex" cars . In Europe, FFVs are also known as "flexi fuel" ve hicles. Automakers, particularly in Brazil and t he European market, use badging in t heir FFV models with the some variant of the word "flex", such as Volvo Flexi fuel , or Volkswagen Total Flex , or Chevrolet Flex Power or Power or Renault Hi-Flex , and Ford sells its Focus model in Europe as Flexi fuel and fuel and as Flex in Flex in Brazil. In the US, only newer FFV models feature a yellow gas cap wit h the label "E85/Gasoline" written on t he top of the cap to differentiate E8 5s from gasoline only models, and just recently, GM introduced badging wit h the text "Flex fuel/E85 Ethanol". Flexible-fuel vehicles (FFVs) are based on dual-fuel systems sys tems t hat supply bot h fuels into the combustion chamber at t he same time in various v arious calibrated proportions . The most common fuels used by FFVs today are unleaded gasoline and et hanol fuel. Ethanol FFVs can run on pure gasoline, pure et hanol (E100) or any combination of bot h. Methanol has also been blended with gasoline in flex-fuel vehicles known as M85 FFVs, but their use has been limited mainly to demonstration demonstration projects and small government fleets, particularly in California. y
Multifuel vehicles are capable of operating wit h more than two fuels . In 2004 GM do Brasil introduced t he Chevrolet Astra 2.0 with a "MultiPower" engine built on flex fuel technology developed by Bosc h of Brazil, and capable of using CNG, ethanol and gasoline (E20-E25 blend) as fuel. In 2006 Fiat introduced t he Fiat Siena Tetra fuel, a fourfuel car developed under Magneti Marelli of Fiat Brazil. This automobile can run as a flex-fuel on 100% ethanol (E100); or on E- 20 to E25, Brazil's normal et hanol gasoline blend; on pure gasoline (t hough no longer available in Brazil since 1993, it is still used in neighboring countries); or just on natural gas . Siena Tetrafuel was engineered to switc h from any gasoline-et hanol blend to CNG automatically, depending on t he power required by road conditions . Another existing option is to retrofit an et hanol flexiblefuel vehicle to add a natural gas tank and t he corresponding injection system . This option is popular among taxicab owners in São Paulo and Rio de Janeiro, Brazil, allowing users to c hoose among t hree fuels (E25, E100 and CNG) according to current market prices at the pump. Vehicles with this adaptation are known in Brazil as "tri-fuel" cars .
y
Flex-fuel hybrid electric and flex-fuel plug-in hybrid are two types of hybrid vehicles built with a combustion engine capable of running on gasoline, E-8 5, or E-100 to help drive the wheels in conjunction wit h the electric engine or to rec harge the battery pack that powers the electric engine. In 2007 Ford produced 20 demonstration Escape Hybrid E85s for real-world testing in fleets in t he U.S. Also as a demonstration project, Ford delivered in 2008 the first flexible-fuel plug-in hybrid SUV to t he U.S. Department of Energy (DOE), a Ford Escape Plug-in Hybrid, Hyb rid, which runs on gasoline or E8 5. GM announced t hat the Chevrolet Volt plug-in hybrid, expected to be launched in 2010, would be the first commercially available flex-fuel plug-in capable of adapting t he propulsion to several world markets suc h as the U.S., Brazil or Sweden, as t he combustion engine can be adapted to run on E8 5, E100 or diesel respectively. In the North American market t he Volt will be sold as an E8 5 flex-fuel-capable plug-in about a year after its first introduction .
2.3History The first commercial flexible fuel vehicle was the Ford Model T, produced from 1908 t hrough 1927. It was fitted wit h a carburetor wit h adjustable jetting, allowing use of gasoline or et hanol, or a combination of bot of both. Other car manufactures also provided engines for f or et hanol fuel use . Henry Ford continued to advocate for et hanol as fuel even during t he prohibition. However, cheaper oil caused gasoline to prevail, until t he 1973 oil crisis resulted in gasoline s hortages and awareness on t he dangers of oil dependence . This crisis opened a new opportunity for et hanol and other alternative fuels, suc h as methanol, gaseous fuels suc h as CNG and LPG, and also hydrogen. Ethanol, methanol and natural gas CNG were the three alternative fuels t hat received more attention for researc h and development, and government support . Since 1975, and as a response to t he shock caused by t he first oil crisis, t he Brazilian government implemented t he National Alcohol Program -Pró-Álcool- (Portuguese: Programa Nacional do Álcool ), ), a nationwide program financed by t he government to phase out automotive fuels derived from fossil fuels in favor of et hanol made from sugar cane . It began with a low blend of anhydrous alcohol with regular gasoline in 19 76, and since July 2007 the mandatory blend is 25% of alcohol or gasohol E25. In 1979, and as a response to t he second oil crisis, the first vehicle capable of running wit h pure hydrous ethanol (E100) was launc hed to the market, the Fiat 147, after testing wit h several prototypes developed by Fiat, Volkswagen, G M and Ford. The Brazilian government provided t hree important initial drivers for t he ethanol industry: guaranteed purc hases by t he state-owned oil company Petrobras, low-interest loans for agro-industrial et hanol firms, and fixed gasoline and et hanol prices. After reaching more than 4 million cars and lig ht trucks running on pure et hanol by t he late 1980s, t he use of E100only vehicles sharply declined after increases in sugar prices produced s hortages of et hanol fuel. After extensive research that began in t he 90s, a second pus h took place in March 2003, when the Brazilian subsidiary of Volkswagen launc hed to the market the first full flexible-fuel car, the
Gol 1.6 Total Flex. Several mont hs later was followed by ot her Brazilian automakers, and by 2009 General Motors, Fiat, Ford, Peugeot, Renault, Volkswagen, Honda, Mitsubishi, Toyota, Citröen and Nissan were producing popular models of flex cars and lig ht trucks. The adoption of ethanol flex fuel vehicles was so successful, t hat production of flex cars went from almost 40 thousand in 2003 to 1.7 million in 2007. This rapid adoption of t he flex technology was facilitated by t he fuel distribution infrastructure already in place, as around 27,000 filling stations countrywide were available by 199 7 with at least one et hanol pump, a heritage of t he Pró-Álcool program Pró-Álcool program . In
the United States, initial support to develop alternative fuels by t he government was also a response to t he first oil crisis, and some time later, as a goal to improve air quality . Also, liquid fuels were preferred over gaseous fuels not only because t hey have a better volumetric energy density but also because t hey were the most compatible fuels wit h existing distribution systems and engines, t hus avoiding a big departure from t he existing technologies and taking advantage of the vehicle and the refuelling infrastructure. California led t he search of sustainable alternatives with interest focused in met hanol. Ford Motor Company and ot her automakers responded to California's request for ve hicles that run on met hanol. In 1981, Ford delivered 40 dedicated methanol fuel (M100) Escorts to Los Angeles County, but only four refueling stations s tations were installed. The biggest challenge in the development of alcohol vehicle technology was getting all of the fuel system materials compatible wit h the higher chemical reactivity of the fuel. Methanol was even more of a c hallenge than ethanol but, fortunately, muc h of the early experience gained with ethanol vehicle production in Brazil was transferable to met hanol. The success of this small experimental fleet of M100s led California to request more of t hese vehicles, mainly for government fleets . In 1983, Ford built 582 M100 vehicles; 501 went to California, and t he remaining to New Zealand, Sweden, Norway, United Kingdom, and Canada . As an answer to t he lack of refueling infrastructure, Ford began development of a flexible-fuel vehicle in 1982, and between 198 5 and 199 2, 705 experimental FFVs were built and delivered to California and Canada, including t he 1.6L Ford Escort, the 3.0L Taurus, and t he 5.0L LTD Crown Victoria. These vehicles could operate on eit her gasoline or met hanol with only one fuel system. Legislation was passed to encourage t he US auto industry to begin production, w hich started in 1993 for t he M85 FFVs at Ford . In 1996, a new FFV Ford Taurus was developed, wit h models fully capable of running on eit her methanol or ethanol blended wit h gasoline. This ethanol version of t he Taurus became t he first commercial production of an E8 5 FFV. The momentum of t he FFV production programs at t he American car companies continued, although by the end of t he 1990s, the emphasis shifted to the FFV E85 version, as it is today . Ethanol was preferred over met hanol because t here is a large support s upport from the farming community, and t hanks to t he government's incentive programs and corn-based et hanol subsidies. Sweden also tested bot h the M85 and t he E85 flexifuel vehicles, but due to agriculture policy, in t he end emphasis was given to t he ethanol flexifuel vehicles. Support for ethanol also comes from t he fact that it is a biomass fuel, w hich addresses climate change concerns and green house gas emissions, t hough these benefits are now highly debated depending on t he feedstock used for et hanol production .
The demand for et hanol fuel produced from field corn in t he United States was stimulated by the discovery in the late 90s that methyl tertiary butyl et her (MTBE), an oxygenate additive in gasoline, was contaminating groundwater . Due to the risks of widespread w idespread and costly litigation, and because MTBE use in gasoline was banned in almost 20 states by 2006, the substitution of MTBE opened a new market for et hanol fuel. This demand s hift for ethanol as an oxygenate additive took place at a time w hen oil prices were already significantly rising . By 2006, about 50 percent of t he gasoline used in t he U.S. contains ethanol at different proportions, and et hanol production grew so fast t hat the US became t he world's first et hanol producer, overtaking Brazil in 2005. This shift also contributed to a s harp increase in t he production and sale of E8 5 flex vehicles since 2002.
2.4 Flexible-fuel vehicles by country Brazil
After the 1973 oil crisis, the Brazilian government made mandatory t he use of et hanol blends with gasoline, and 100 % ethanol powered cars (E100 only) were launched to the market in 1979, after testing wit h several prototypes developed by four carmakers . Brazilian carmakers modified gasoline engines to support et hanol characteristics and c hanges included compression ratio, amount of fuel injected, replacement of materials mate rials t hat would get corroded by t he contact with ethanol, use of colder spark plugs suitable for dissipating heat due to higher flame temperatures, and an auxiliary cold-start system t hat injects gasoline from a small tank in t he engine compartment to help starting w hen cold. Flexible-fuel technology started being developed only by t he end of t he 1990s by Brazilian Brazil ian engineers. The Brazilian flexible fuel car is built with an ethanol-ready engine and one fuel tank for bot h fuels. The small gasoline reservoir for starting t he engine with pure ethanol in cold weat her, used in earlier et hanol-only vehicles, was kept in the first generation of Brazilian flexible-fuel cars, mainly for users of t he central and sout hern regions, where winter temperatures normally drop below 1 5 °C (59 °F). An improved flex motor generation t hat will be launched in 2009 will eliminate the need for this secondary gas reservoir tank A key innovation in the Brazilian flex tec hnology was avoiding t he need for an additional dedicated sensor to monitor t he ethanol-gasoline mix, w hich made the first American M85 flex fuel vehicles too expensive. This was accomplis hed through the lambda probe, used to measure the quality of combustion in conventional engines, is also a lso required to tell t he engine control unit (ECU) which blend of gasoline and alco hol is being burned . This task is accomplis hed automatically through software developed by Brazilian engineers, called "Software Fuel Sensor" (SFS), fed with data from t he standard sensors already built-in t he vehicle .A similar fuel injection technology was developed by t he Brazilian subsidiary of Delphi Automotive Systems, and it is called "Multifuel", based on researc h conducted at its facility in Piracicaba, P iracicaba, São Paulo . This technology allows t he controller to regulate t he amount of fuel injected and spark time, time , as fuel flow needs to be decreased and also self-combustion needs to be avoided w hen gasoline is used because et hanol engines have compression ratio around 1 2:1, too high for gasoline .
Brazilian flex 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 combination of bot h fuels. Pure gasoline is no longer sold in t he country because t hese high ethanol blends are mandatory since 1993. Therefore, all Brazilian automakers have optimized flex vehicles to run with gasoline blends from E20 to E25, and with a few exceptions, t hese FFVs are unable to run smoot hly with pure gasoline w hich causes engine knocking, as ve hicles traveling to neig hboring Sout h American countries have demonstrated . Only two models are specifically built with a flex-fuel engine optimized to operate also wit h pure gasoline (E0), t he Renault Clio Hi-Flex and the Fiat Siena Tetrafuel. The flexibility of Brazilian FFVs empowers t he consumers to c hoose the fuel depending on current market prices . As ethanol fuel economy is lower t han gasoline because of et hanol's energy content is close to 3 4% less per unit volume t han gasoline, flex cars running on et hanol get a lower mileage t han when running on pure gasoline . However, this effect is partially offset by the usually lower price per liter of et hanol fuel. As a rule of t humb, Brazilian consumers are frequently advised by t he media to use more alco hol than gasoline in t heir mix only when ethanol prices are 30 % lower or more t han gasoline, as et hanol price fluctuates heavily depending on t he result of seasonal sugar cane harvests . The rapid success of flex ve hicles was made possible by t he existence of 33,000 filling stations with at least one et hanol pump available by 2006, a heritage of the early Pró-Álcool et Pró-Álcool ethanol program . These facts, together with the mandatory use of E 25 blend of gasoline t hroughout the country, allowed Brazil in 2008 to achieve more than 50% of fuel consumption in t he gasoline market from sugar cane-based et hanol. According to two separate researc h studies conducted in 2009, at t he national level 65% of the flex-fuel registered ve hicles regularly use et hanol fuel, and the usage increases to 93 % in São Paulo, t he main ethanol producer state w here local taxes are lower, and prices at t he pump are more competitive t han gasoline .
Latest developments The latest innovation wit hin the Brazilian flexible-fuel technology is the development of flexfuel motorcycles. In 2007 Magneti Marelli presented t he first motorcycle with flex technology, adapted on a Kasinski Seta 1 25, and based on t he Software Fuel Sensor (SFS) t he firm developed for flex-fuel cars in Brazil. Delphi Automotive Systems also presented in 2007 its Multifuel injection technology for motorcycles . Besides the flexibility in the choice of fuels, a main objective of t he fuel-flex motorcycles is to reduce CO2 emissions by 20 percent, and savings in fuel consumption in t he order of 5% to 10% are expected. AME Amazonas Motocicletas announced t hat sales of its motorcycle A ME GA (G stands for gasoline and A for alcohol) were scheduled for 2009, but t he first flex-fuel motorcycle was actually launc hed by Honda in March 2009. Produced by its Brazilian subsidiary Moto Honda da Amazônia, t he CG 150 Titan Mix is sold for around a round US$2,700. Because the CG 150 Titan Mix does not have a secondary gas tank for a cold c old start like t he Brazilian flex cars do, t he tank must have at least 20% of gasoline to avoid start up problems at
temperatures below 15 °C (59 °F). The motorcycles panel includes a gauge to t o warn t he driver about the actual ethanol-gasoline mix in t he storage tank . The Brazilian subsidiaries of Magneti Marelli, Delphi and Bosch have developed and announced the introduction in 2009 of a new flex engine generation t hat eliminates t he need for t he secondary gasoline tank by warming t he ethanol fuel during starting, and allowing flex ve hicles to do a normal cold start at temperatures te mperatures as low as 5 °C (23.0 °F), the lowest temperature expected anywhere in the Brazilian territory. Anot her improvement is t he reduction of fuel consumption and tailpipe emissions, between 10 % to 15% as compared to flex motors sold in 2008. In March 2009 Volkswagen do Brasil launc hed the Polo E-Flex, the first flex fuel model without an auxiliary tank for cold start s tart . The Flex Start system used by t he Polo was developed by Bosch. Brazilian flex engines are being designed wit h higher compression ratios, taking advantage of the higher ethanol blends and maximizing t he benefits of t he higher oxygen content of et hanol, resulting in lower emissions and improving fuel efficiency . The following table s hows the evolution and improvement of t he different generations of flex engines developed in Brazil .
United States By early 2009 there are almost 8 million E8 5 flex fuel vehicles running on t he US roads, up from almost 5 million in 2005. The E85 blend is used in gasoline engines modified to accept suc h higher concentrations of et hanol, and t he fuel injection is regulated t hroug h a dedicated sensor, which automatically detects t he amount of et hanol in the fuel, allowing adjusting bot h fuel injection and sparking timing accordingly to t he actual blend available in t he vehicle's tank. The American E85 flex 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 in t he same tank, and E85 is sold already blended . In order to reduce et hanol evaporative emissions and to avoid problems starting t he engine during cold weat her, the maximum blend of et hanol was set to 85%. There is also a seasonal reduction of t he ethanol content to E 70 (called winter E85 blend) in very cold regions, w here temperatures fall below 0 °C (32 °F) during t he winter. In Wyoming for example, E70 is sold as E8 5 from October to May. E85 flex-fuel vehicles are becoming increasingly common in t he Midwest, where corn is a major crop and is t he primary feedstock for et hanol fuel production . Also the US government has been using flex-fuel vehicles for many years .
Latest developments In
2008 Chrysler, General Motors, and Ford pledged to manufacture 50 percent of t heir entire vehicle line as flexible fuel in model year 2012, if enough fueling infrastructure develops . In early 2010 GM reaffirmed its commitment to bio fuels f uels and its determination to deliver more than half of its 2012 production in t he U.S. market as E85 flex-fuel capable vehicles. GM will
begin introducing E-8 5-capable direct-injected and turboc harged power trains, and urged t he deployment of more E8 5 stations, as "ninety " ninety percent of registered flex-fuel vehicles don't have an E85 station in their zip code, and nearly 50%, don't have E85 in their county ." In
2008 Ford delivered t he first flex-fuel plug-in hybrid as part of a demonstration project, a Ford Escape Plug-in Hybrid capable of running on E8 5 or gasoline. General Motors announced that the new plug-in hybrid electric vehicle Chevrolet Volt, expected to be launc hed in the North American market in 2010, will be flex-fuel-capable flex-fuel-c apable about a year after it is introduced. The Volt propulsion arc hitecture allows adapting t he propulsion to ot her world markets suc h as Brazils E100 or to Europes commonly using clean diesel .
On May 2009, President Barack Obama signed a Presidential Directive Directiv e wit h the aim to advance biofuels research and improve t heir commercialization. The Directive established a Biofuels Interagency Working Group comprises of t hree agencies, t he Department of Agriculture, t he Environmental Protection Agency, and t he Department of Energy . This group will develop a plan to increase flexible fuel vehicle use and assist in retail marketing efforts . Also they will coordinate infrastructure policies impacting t he supply, secure transport, and distribution of biofuels in order to increase t he number of fueling stations t hroughout the country. OTHER COUNTRIES: 1. 2. 3. 4. 5. 6. 7. 8. 9.
Sweden France Germany Ireland Spain United Kingdom Australia Canada Colombia
List of flexible-fuel vehicles by car manufacturer 1. Chevrolet 2. Fiat 3. Ford 4. Honda 5. Mitsubishi 6. Nissan 7. Renault 8. Toyota 9. Volkswagen 10. Mercedes Benz
11. Chrysler 12. General Motors [5]
3. Sources Prod ucti on process ucti on Presently, methanol is usually produced using methane (the chief constituent of natural gas) as a raw material. Methanol is made from coal in China for fuel.
"Biomethanol" may be produced by gasification of organic materials to synt hesis gas followed by conventional met hanol synthesis. Production of met hanol from synt hesis gas using BiomassTo-Liquid can offer met hanol production from biomass at efficiencies up to 75%. Widespread production by t his route has a postulated potential (see Hagen, SABD & Ola h references below) to offer met hanol fuel at a low cost and wit h benefits to t he environment. These production methods, however, are not suitable for small smal l scale production . Ethanol is a renewable energy source s ource because t he energy is generated by using a resource, sunlig ht, which is naturally replenis hed. Creation of et hanol starts wit h photosynthesis causing a feedstock, such as sugar cane or corn, to grow . These feedstocks are processed into et hanol. About 5% of the ethanol produced in t he world in 2003 was actually a petroleum product . It is made by t he catalytic hydration of et hylene with sulphuric acid as the catalyst. It can also be obtained via et hylene or acetylene, from calcium carbide, coal, oil gas, and ot her sources. Two million tons of petroleum-derived et hanol is produced p roduced annually. The principal suppliers are plants in t he United States, Europe, and Sout h Africa. Petroleum derived et hanol (synthetic ethanol) is chemically identical to bio-ethanol and can be differentiated only by radiocarbon dating . Bio-ethanol is usually obtained from t he conversion of carbon based feedstock Energy crop c rop or rops. Agricultural feedstocks are considered renewable because t hey get energy from E nergy c ro the sun using p hotosynthesis, provided that all minerals required for growt h (such as nitrogen and phosphorus) are returned to t he land. Ethanol can be produced from a variety of feedstocks suc h as sugar cane, bagasse, miscant hus, sugar beet, sorg hum, grain sorg hum, switchgrass, barley, hemp, kenaf, potatoes, sweet potatoes, cassava, sunflower, fruit, molasses, corn, stover, grain, w heat, straw, cotton, ot her biomass, as well as many types of cellulose waste and harvestings, w hichever has the best well-to-wheel assessment. An alternative process to produce bio-et hanol from algae is being developed by t he company Algenol. Rather than grow din mor algae and t hen harvest and ferment it t he algae grow in sunlig ht and produce et hanol directly w hich is removed without killing the algae. It is claimed the process can produce 6000 gallons per acre per year compared wit h 400 gallons for corn production.
Currently, the first generation processes for t he production of et hanol from corn use only a small part of t he corn plant: t he corn kernels are taken from t he corn plant and only t he starch, which represents about 50% of the dry kernel mass, is transformed into et hanol. Two types of second generation processes are under development . The first type uses enzymes and yeast to convert the plant cellulose into et hanol while the second type uses pyrolysis to convert t he whole plant to eit her a liquid bio-oil or a syngas . Second generation processes can also be used with plants such as grasses, wood or agricultural waste material suc h as straw .
The basic steps for large scale sc ale production of et hanol are: microbial (yeast) fermentation of sugars, distillation, and de hydration (requirements vary, see Et hanol fuel mixtures, below), and denaturing (optional) . Prior to fermentation, some crops require sacc harification or hydrolysis of carbohydrates such as cellulose and starc h into sugars . Saccharification of cellulose is called cellulolysis (see cellulosic ethanol). Enzymes are used to convert starc h into sugar. Cellulosic ethanol offers promise as cellulose fibers, a major and universal component in plant cells walls, can be used to produce ethanol. According to the International Energy Agency, cellulosic ethanol could allow ethanol fuels to play a muc h bigger role in the future t han previously thought
Distillation
For the ethanol to be usable as a fuel, water must be removed . Most of the water is removed by distillation, but t he purity is limited to 9 5-96% due to t he formation 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 be used as a fuel alone, but unlike an hydrous ethanol, is immiscible in gasoline, so t he water fraction is typically removed in furt f urther treatment in order to burn in i n combination wit h gasoline in gasoline engines . Dehydration There are basically five dehydration processes to remove t he water from an azeotropic ethanol/water mixture. The first process, used in many early fuel et hanol plants, is called azeotropic distillation and consists of adding benzene or cyclo hexane to the mixture. When these components are added to t he mixture, it forms a heterogeneous azeotropic mixture in vapor-liquid-liquid equilibrium, w hich when distilled produces an hydrous ethanol in t he column bottom, and a vapor mixture of water and cyclo hexane/benzene. When condensed, t his becomes a two-phase liquid mixture. Another early method, called extractive distillation, consists of adding a ternary component w hich will increase ethanol's relative volatility . When the ternary mixture is distilled, it will produce an hydrous et hanol on the top stream of t he column. With increasing attention being paid to saving energy, many met hods have been proposed t hat avoid distillation all toget her for de hydration. Of these methods, a third method has emerged and has been adopted by t he majority of modern et hanol plants . This new process uses molecular sieves to remove water from fuel et hanol. In this process, ethanol vapor under pressure passes t hrough a bed of molecular sieve beads. The bead's pores are sized to allow
absorption of water w hile excluding ethanol. After a period of time, t he bed is regenerated under vacuum to remove t he absorbed water. Two beds are used so t hat one is available to absorb water w hile the other is being regenerated . This dehydration technology can account for energy saving of 3,000 btus /gallon (840 kJ/l) compared to earlier azeotropic distillation .
4. Technology 4.1 Ethanol-based engines
Ethanol is most commonly used to power automobiles, t hough it may be used to power ot her vehicles, such as farm tractors, boats and airplanes . Ethanol (E100) consumption in an engine is approximately 51% higher than for gasoline since t he energy per unit volume of et hanol is 34% lower than for gasoline . However, the higher compression ratios in an et hanol-only engine allow for increased power output and better fuel economy t han could be obtained wit h lower compression ratios . In general, et hanol-only engines are tuned to give slig htly better power and torque output t han gasoline-powered engines . In flexible fuel vehicles, the lower compression ratio requires tunings t hat give the same output w hen using either gasoline or hydrated ethanol. For maximum use of et hanol's benefits, a muc h higher compression ratio s hould be used, Current high compression neat et hanol engine designs are approximately 20-30% less fuel efficient than their gasoline-only counterparts c ounterparts. A 2004 MIT study and an earlier paper publis hed by the Society of Automotive Engineers identify a met hod to exploit t he characteristics of fuel et hanol substantially better t han mixing it with gasoline. The method presents t he possibility of leveraging t he use of alcohol to ac hieve definite improvement over the cost-effectiveness of hybrid electric. The improvement consists of using dual-fuel direct-injection of pure alco hol (or the azeotrope or E85) and gasoline, in any ratio up to 100 % of either, in a turboc harged, high compression-ratio, small-displacement engine having performance similar to an engine having twice the displacement. Each fuel is carried separately, with a muc h smaller tank for alco hol. The high-compression (w hich increases efficiency) engine will run on ordinary gasoline under low-power cruise conditions . Alcohol is directly injected into the cylinders (and the gasoline injection simultaneously reduced) only when necessary to suppress knock suc h as when significantly accelerating. Direct cylinder injection raises the already high octane rating of et hanol up to an effective 130 . The calculated over-all reduction of gasoline use and a nd CO2 emission is 30%. The consumer cost payback time s hows a 4:1 improvement over turbo-diesel and a 5:1 improvement over hybrid. In addition, t he problems of water absorption into pre-mixed gasoline (causing p hase separation), supply issues of multiple mix ratios and cold-weat her starting are avoided . Ethanol's higher octane rating allows an increase of an engine's compression ratio for increased thermal efficiency. In one study, complex engine controls and increased ex haust gas recirculation allowed a compression ratio of 19 .5 with fuels ranging from neat et hanol to E 50. Thermal efficiency up to approximately that for a diesel was ac hieved. This would result in the fuel economy of a neat et hanol vehicle to be about t he same as one burning gasoline .
Since 1989 there have also been ethanol engines based on t he diesel principle operating in Sweden. They are used primarily in city buses, but also in distribution trucks and waste w aste collectors. The engines, made by Scania, have a modified compression ratio, and t he fuel (known as ED95) used is a mix of 93 .6 % ethanol and 3 .6 % ignition improver, and 2.8% denaturants . The ignition improver makes it possible for t he fuel to ignite in t he diesel combustion cycle. It is then also possible to use t he energy efficiency of t he diesel principle with ethanol. These engines have been used in t he United Kingdom by Reading Transport but t he use of bioet hanol fuel is now being p hased out. 4.2 Engine cold start during the winter
High ethanol blends present a problem to ac hieve enough vapor pressure for t he fuel to evaporate and spark t he ignition during cold weat her (since ethanol tends to increase fuel enthalpy of vaporization) . When vapor pressure is below 45 kPa starting a cold engine becomes difficult. In order to avoid t his problem at temperatures below 11 ° Celsius (59 °F), and to reduce ethanol higher emissions during cold weat her, both the US and t he European markets adopted E85 as the maximum blend to be used in t heir flexible fuel vehicles, and they are optimized to run at suc h a blend. At places with harsh cold weather, the ethanol blend in t he US has a seasonal reduction to E 70 for these very cold regions, t hough it is still sold as E8 5. At places where temperatures fall below -1 2 °C (10 °F) during t he winter, it is recommended to install an engine heater system, bot h for gasoline and E8 5 vehicles. Sweden has a similar seasonal reduction, but t he ethanol content in t he blend is reduced to E 75 during t he winter months.
4.3 Ethanol fuel mixtures To avoid engine stall due to "slugs" of water in t he fuel lines interrupting fuel flow, t he fuel must exist as a single p hase. The fraction of water t hat an et hanol-gasoline fuel can contain without phase separation increases wit h 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 proportion of water or gasoline and a nd p hase separation will not occur . However, the fuel mileage declines with increased water content . The increased solubility of water with higher ethanol content permits E30 and hydrated ethanol to be put in t he same tank since any combination of t hem always results in a single p hase. 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 mixt ures of et hanol. 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 t his (or a smaller amount) in all gasoline sold . Other countries have adopted t heir own requirements . Beginning with the model year 1999, an increasing number of vehicles in the world are manufactured wit h engines which can run on any fuel from 0 % ethanol
up to 100% ethanol without modification. Many cars and lig ht trucks (a class containing minivans, SUVs and pickup trucks) are designed to be flexible-fuel ve hicles (also called dual-fuel vehicles). In older model years, t heir engine systems contained alco hol sensors in t he fuel and/or oxygen sensors in t he exhaust that provide input to t he engine control computer to adjust the fuel injection to achieve stochiometric (no residual fuel or free oxygen in t he exhaust) air-to-fuel ratio for any fuel mix . In newer models, t he alcohol sensors have been removed, with the computer using only oxygen and airflow sensor feedback to estimate alco hol content. The engine control computer can also adjust a djust (advance) t he ignition timing to ac hieve a higher output wit hout pre-ignition w hen 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 w hether they're designed to use et hanol or not - that detect pre-ignition and detonation .
4.5 Fuel economy In
theory, all fuel-driven vehicles have a fuel economy (measured as miles mi les per US gallon, or liters per 100 km) that is directly proportional p roportional to t he fuel's energy content . In reality, there are many other variables that come in to play t hat affect t he performance of a particular fuel in a particular engine . Ethanol contains approx . 34% less energy per unit volume t han gasoline, and therefore in theory, burning pure et hanol in a ve hicle will result in a 3 4% reduction in miles per US gallon, given t he same fuel economy, ec onomy, compared to burning pure gasoline . Since ethanol has a higher octane rating, t he engine can be made m more ore efficient by raising its compression ratio . In fact using a variable turboc harger, the compression ratio can be optimized for t he fuel being used, making fuel economy almost constant for any blend . For E10 (10% ethanol and 90% gasoline), the effect is small (~3 %) when compared to conventional gasoline, and even smaller (1-2%) when compared to oxygenated and reformulated blends . However, for E85 (85% ethanol), the effect becomes significant. E85 will produce lower mileage than gasoline, and will require more frequent refueling . Actual performance may vary depending on t he vehicle. Based on EPA tests for all 2006 E85 models, the average fuel economy for E8 5 vehicles resulted 25.56% lower than unleaded gasoline . The EPA-rated mileage of current USA flex-fuel ve hicles should be considered w hen making price comparisons, but it must be noted t hat E85 is a high performance fuel, with an octane rating of about 10 4, and s hould be compared to premium . In one estimate t he US retail price for E8 5 ethanol is 2.62 US dollar per gallon or 3 .71 dollar corrected for energy equivalency compared to a gallon g allon of gasoline priced at 3 .03 dollar. Brazilian cane et hanol (100%) is priced at 3 .88 dollar against 4.91 dollar for E 25 (as July 2007). The ethanol industry in Brazil is more t han 30 year-old and even t hough it is no longer subsidized, production and use of et hanol was stimulated t hrough: y y
Low -i -i nter est est
l oan ucti on istiller ies ies oans f or or the c on onst r r ucti on of ethanol d istille Guaranteed pur ch chase of ethanol by the st ate-owned o d oil c om ompany a any at a r easonable pr ice ice
y
y
Ret ail pr ici ici ng ng of neat ethanol so it is c om ompetitive if not sli ghtl y y f av ora orable t o the gasoli ne-ethanol blend T ax i ncentives provi d ing g the 1980 s t o sti mul ate the pur ch chase of neat de d d d d ur i n ethanol vehicles.
Guaranteed purc hase and price regulation were ended some years ago, wit h relatively positive results. In addition to t hese other policies, ethanol producers in t he state of São Paulo established a researc h and technology transfer center t hat has been effective in improving sugar cane and et hanol yields. 4.6 Fuel system problems
Several of the outstanding et hanol fuel issues are linked specifically to fuel systems syste ms. Fuels with more than 10% ethanol are not compatible wit h non E85-ready fuel system components and may cause corrosion of iron components . Ethanol fuel can negatively affect electric fuel pumps by increasing internal wear, cause undesirable spark generation, and is not compatible w it h capacitance fuel level gauging indicators and may cause erroneous fuel quantity indications in vehicles that employ t hat system. It is also not always compatible wit h marine craft, especially those that use fiberglass fuel tanks . Ethanol is also not used in aaircraft ircraft for t hese same reasons . Using 100% ethanol fuel decreases fuel-economy by 1 5-30% over using 100% gasoline; this can be avoided using certain modifications t hat would, however, render the engine inoperable on regular petrol without the addition of an adjustable E CU. Tough materials are needed to accommodate a higher compression ratio to make an et hanol engine as efficient as it would be on petrol; these would be similar to t hose used in diesel engines w hich 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 t hrough at least some of t hese 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 t he process compared to t he energy released by burning t he resulting ethanol fuel is known as t he energy balance (or "Net energy gain") . Figures compiled in a 2007 by National Geographic Magazine point to modest results for corn et hanol produced in the US: one unit of fossil-fuel energy is required to create 1 .3 energy units from t he resulting ethanol. The energy balance for sugarcane s ugarcane ethanol produced in Brazil is more favorable, 1:8 . Energy balance estimates are not easily produced, t hus numerous suc h reports have been generated that are contradictory . For instance, a separate survey reports t hat production of ethanol from sugarcane, w hich requires a tropical climate to grow productively, returns from 8 to 9 units of energy for eac h unit expended, as compared to corn w hich only returns about 1 .34 units of fuel energy for eac h unit of energy expended .
Carbon dioxide, a green house gas, is emitted during fermentation and combustion . However, this is canceled out by t he greater uptake of carbon dioxide by t he plants as t hey grow to produce the biomass . When compared to gasoline, depending on t he production met hod, ethanol releases less greenhouse gases .
5.2 Change in land use Large-scale
farming is necessary to produce agricultural alco hol and this requires substantial amounts of cultivated land . University of Minnesota researc hers report t hat if all corn grown in the U.S. were used to make ethanol it would displace 1 2% of current U.S. gasoline consumption. There are claims t hat land for et hanol production is acquired t hrough deforestation, w hile others have observed t hat areas currently supporting forests are usually not suitable for growing crops . In any case, farming may involve a decline in soil fertility due to reduction of organic matter, a decrease in water availability and quality, an increase in t he use of pesticides and fertilizers, and potential dislocation of local communities . However, new technology enables farmers and processors to increasingly produce t he same output using less input . Many analysts suggest t hat, whichever ethanol fuel production strategy is used, fuel
conservation efforts are also needed to make a large impact on reducing petroleum fuel use .
5.3Criticism and controversy: F ood ood vs. fuel There are various current issues with ethanol production and use, which are presently being discussed in the popular media and scientific journals. These include: t he effect of moderating oil prices, the "food vs fuel" debate, carbon emissions levels, sustainable biofuel production, deforestation deforestation and soil erosion, impact on water resources, human rights issues, poverty reduction potential, ethanol prices, energy balance and efficiency, and centralised vs . decentralised decentralised production models.
Food vs fuel is fuel is about t he price and availability impact of diverting farmland or crops for et hanol production to t he detriment of t he food supply . The debate is internationally controversial, with good-and-valid arguments on all sides of t his ongoing debate . There is disagreement about how significant t his is what is causing it, w hat the impact is, and w hat can or s hould be done about it . [3]
References
1. 2. 3. 4. 5.
V Ganesan, IC Engines, e3, Tata Mcgrawhill, M cgrawhill, pp 201-210. http://en.wikipedia.org/wiki/Methanol_fuel http://en.wikipedia.org/wiki/Methanol_fuel (visited on 19.05.2010) http://en.wikipedia.org/wiki/Ethanol_fuel http://en.wikipedia.org/wiki/Ethanol_fuel (do) http://en.wikipedia.org/wiki/Alcohol_fuel http://en.wikipedia.org/wiki/Alcohol_fuel (do) http://en.wikipedia.org/wiki/Flexible-fuel_vehi http://en.wikipedia.org/wiki/Flexible-fuel_vehicle cle (do)
