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Why is ethanol a better fuel?

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UM university, Ford research, and Advanced Engineering Group had interesting test results for DI engine and ethanol ability to reduce PM emissions. It discloses why ethanol is superior fuel. If you get into discussion with the "pure gasoline now " folks explain to them that ethanol is makes their gasoline a better fuel. Also, the discussion on BTU and those that attempt to imply the best fuel has highest BTU rating. High points of study:

 

- Ethanol produces a magnitude less PM pollution. This may be the best or most important fuel character fact as health studies are continuing to evolve to fossil fuel health concerns.

 

- Ethanol has higher laminar flame speed which presents shorter combustion duration that results in higher thermal efficiency of the engine.

 

- Ethanol has simple chemical structure that results in lower exery destruction, meaning the chemical nature of ethanol has more potential available energy to release. IOWS the fuel releases more engery than the BTU rating would suggest as compared to gasoline.

 

- Ethanol has lower boiling point and lower combustion temperatures that naturally produce less NOX and less UHC (unburned hydro carbon).

 

- Ethanol has strong ability to suppress formation of benzens and sooting both of which are serious health hazards

 

One challenge of combustion efficiency for flex engines that attempt to run all blends of ethanol is the direct injection spray pattern. The two fuels have different requirements for optimum spray pattern. Spray breakup, atomization, vapoization, turbulence changes will result in high ethanol blends impinging more fuel on metal surfaces of combustion chamber and charge stratification. So, again we learn the benefits of optimized E85 engine increasing efficiency and lowering emissions as compared to general flex engine.

 

http://www.greencarcongress.com/2015/04/20150426-etohdisi.html

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A couple more:

 

-Ethanol fueled engines will push more HP out of turbo per the increased density of exhaust and upon optimized ethanol engines higher exhaust temperatures. The Cummings E85 engine experienced a 20% something boost in turbo power. More so than would was demanded for air pumping, thus offering advantage to the new turbo generator technology still in development. 

 

_Ethanol carries liquid oxygen that directly replaces a portion of intake air that contains much nitrogen. This chemical attribute of ethanol will naturally cut down NOX emissions. Compare this to Shell premium grade gasoline tha purposely entrains nitrogen within the fuel for purpose of cleaning the mess left behind by fossil fuels. Something ethanol does upon the low cost fuel of unleaded. 

 

- Since Ethanol carries liquid oxygen within the fuel itself and releases the component upon chemical combustion the fuel acts to improve combustion of hydro carbons. It makes plain gasoline burn better and results in less UHC pollution. This point made on first post, but I explained better here.

 

_ Since Ethanol carries liquid oxygen within the fuel, the ICE can be managed to farther impact low horspower MPG and high Hp delivery per EGR process. The optimized ethanol engine can produce more power than other fuels when eliminating EGR as the engine CI dispacment for combustion air is aided by the chemical oxygen already in the fuel. A smaller engine fueled on ethanol behaves like a bigger CI engine. Conversely, the ethanol fueled engine if optimised can throttle down oxygen content within the cyclinder per adding oxygen free exhaust. Putting in 27% exhaust would bring the engine to normal gas engine specs. So, if exhaust gas was to be utilized to control horspower there would be no BTU advantage to gasoline. But, the other advantages to ethanol would still apply such as ability to increase engine efficiency and lower pollution.

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Fossil fuels have had a long road of R&D efforts to standardise and provide uniform quality. The product relies on additives to make the fuel capable. Oxygenates, usually ethanol, is required as you know by law to make the fuel preform better. Petrol fuels need stabilizers to improve the fuel storage life, such as antioxidants. Compare this to purity of ethanol that has extreme stability. Basically only one common molecule throughout vs petrols hundreds of varing compositions. Petrol fuels utilize metal deactivators and corrosion inhibitors. So, petrol has a problem with corrosion in natural state? I'm guessing they add these for a reason. Tramp water has always been a problem, at least before the days of E10. Detergents of prime importance of petrol per the natural occuring gums, varnish, and carbon or sulfur deposits. These affect engine performance, especially valves and injectors. Detergents such as the amines group usually added to gasoline within 300 ppm concentration. The additives are regulated by EPA, but scientist post of not having a good handle on health effects, especially per the derivatives, some of which are known harmful. Compare the science and effort put forth over hundreds of years to improve gasoline  and disel fuel and know ethanol out of the box is superior in most all respects. My guess even corrosion and material compatability. Just look at the Parker O ring application guide for service compatability fluids. Alcohol or ethanol doesn't appear as a concern for most O ring materials, unlike gasoline. Also, if water if absorbed within alcohol, it is not considered corrosive. Free water within stand alone gasoline is a problem and will promote corrosion and problem chemical acids. Gasoline can absob water, but a greatly reduced ability. I know of no additives required by ethanol to make it perform better other than gasoline per the fuels ability to ignite at lower temperatures. Engineers will explain the typical ICE is not designed for ethanol and even E85 performs better with the portion of gasoline for cold starts. If the Engineering talent was ever unleashed to maximize the ICE per ethanol only fuel this would not be the case. Also, not much R&D upon ethanol only fuel per emissions, but the potential is enormous given the pollution free chemical combustion upon ideal conditions that compare to hydrogen fuel cell.

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I'd like to know what some of the choices are for petrol fuel  distillers , when it comes time to blend fuels for a 

 

given market or locale.   If ethanol,   to 10% is an assumed ingredient , and base gasoline ( the REALLY basic stuff from low

 

 on the column) , the second component --- what remains, to get a final product of 85 to 89 octane gasoline?

 

 Pentene is in the mix, likely,  but how would a fuel blender control RVP, or other concerns??

 

 Endpoint:  how do we know a fuel marketer is not pushing bad product , at the same price as good,  using ethanol to bring

 

  what would be crappy fuel, to within spec ????

 

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As I understand gasoline formations vary a lot. It depends on regional crude oil use at refinery. Region variations large and produce a wide range of chemicals. The industry continues to invest within technology to improve the final product, but to date the required certifications, crude. They have a wide range of formulations for gas to enable use of oversupply fraction of distillation. Maybe that's why they hate ethanol, because the fuel replaces their hard to get rid of chemicals. They can crack larger more valuable chemicals to lighter, but not the other way around. They use a lot of lighter chemicals to replace ethanol such as the high aromatics like benzene or toluene. Coincidentally, these chemicals high on list of unhealthy tailpipe emissions, but EPA not so  concerned of human life hazards. The tail pipe emissions control crude also and seem to focus on smog, acid, and particulates. Carcinogens apparently not bad for environment.     

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Another factor on value of ethanol being a better fuel, the recent testing by ICM and the Urban Air Initiative shows emphatically that ethanol free gas is not good for your engine as compare to typical E10 unleaded. The higher content of aromatics utilized within ethanol free gas will attack polymer seals common in engines. This ethanol free gas is harder on your engine and even promotes more engine metal wear.  So, another misconception bites the dust! Ethanol is better for your engine. 

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Did you read of E10 and the discovery of oxygenate character of ethanol improves the gasoline burn? That ethanol makes gasoline burn complete and the net energy loss of the lower btu fuel is only half of what simple btu math calculations would indicate?  Also, the point made below in which ethanol's simple chemical structure will result in lower exery destruction. Meaning the fuel offers more energy than btu would indicate as the fuel will oxidize easier. 

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How often we read of ethanol ability to attack metals. Has anybody read of chemical ability of ethanol to do such a thing? I was reading a chemistry bog in which the subject came up.  The less informed or bias of the group just reiterated the typical anti-ethanol propaganda, but the chemist could offer no such chemistry that would empower ethanol to do such a thing other than magnesium and aluminum are protected by oxide film that quickly forms upon atmospheric conditions. Neat ethanol can remove this layer in which would cause the metals to oxidize. But, any trace of water within ethanol solves the problem as film would regenerate from the water portion. Water or moisture can cause typical cathodic (rusting) corrosion upon carbon metals. But, here ethanol the friend as the fuel absorbs moisture and deter the corrosion. Gasoline can absorb moisture also, but a mere fraction as compared. The dreaded phase change of water dropping out of suspension occurs with both gasoline and ethanol, but gasoline complex chemistry will host a wide range of corrosive (acids) as compared to ethanol and lets not forget the moisture itself set free at the bottom of the tank. Before ethanol, I had always seen the portable outboard motor tanks with bubble of water at bottom. These steel tanks always subject to leaking per the crevice corrosion set in place by pure gasoline inability to absorb water. Also, the white cloudy phase change sediment. This doesn't happen current day, with E10. Lawn mower tanks and other seasonal equipment, very common to see a portion of water residing at tank bottom. Cars stalled out with water slug in winter months and boat motors conked out upon lake. This doesn't happen anymore with unleaded. Old motorcycle tanks did rust out and leak, not because of modern day E10, but of the legacy fuel without ethanol. Rust can self sustain once started, creating its' own moisture. Old motor cycle tanks can rust out present day but the damage occurred many years ago. Pipelines prohibit ethanol, but I think most of that is to handicap ethanol sales per power of petrol's influence. They can make a case that pipelines are gummed up with crude oil contaminates that will come free once ethanol introduced. That may cause some excess debris upon startup, but that is typical of petrol pipelines. Tar sands crude contains abrasives (sand) that wreak much wear. Kalamazoo pipeline had a blow out from such. Opponents claimed the same event for those car owners whom wanted to use E10. A large list of dangerous possibilities to plug your fuel system. I never seen it or heard anyone else suffering any of it. My daughters '91 Tempo during her college years made the transition with no maintenance or concern and that car has steel gas line. She put another 100k on a rebuilt motor with E10-E85 blends with no problem, not even a gas line filter change.      

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We often read of E10 affecting mileage, but not so fast. First ethanol is utilized as an oxygenate that propels gasoline to better burn rate that decreases unburned hydrocarbon pollution. Since E10 is standard fare, EPA did away with the regulation, as the requirement is more that met with E10 blend. This alone eliminates half the difference in BTU loss. So were getting very trivial physical differences for MPG comparison. Also, the exergy gain from ethanol’s consistent molecules belies the BTU rating. Meaning more real energy than what the BTU rating suggest per efficient molecular decomposition. Also, factor in the mix, reformulated gas blend stock “which is cleaner and gets slightly better mileage for your car. Why? Gas is made up of a mix of molecules—all in the same family, but some short and some long. You get energy by breaking the molecules apart. Short ones, like butane, have less energy, and they cost less (so it makes sense that a company would want to add more of them). The part the EPA cares about is that short molecules also evaporate more easily, contributing to pollution. So in summer, the EPA restricts how many short-chain molecules can be in the blend, and your mileage increases because there’s more energy in the gasoline overall. Unfortunately, it also makes the gas slightly more expensive” *.

So, blend stock such as RBOB, and a whole host of boutique blends change BTU rating of fuel and would make the job of comparing E10 mpg loss just about impossible.  When a poster claim a wonderful MPG jump upon fueling up on ethanol free, it’s just a indication of the particular petrol blend and not much to do with ethanol. It could be impressive or lower depending on butane content. One thing for sure this grade would pollute air more, cost more, and be harder on your engine.

 

*http://www.anl.gov/articles/5-properties-physics-affect-your-gas-mileage

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We know the environmental benefits of ethanol blended fuel, but the growing concern of petrol fuel health concerns may be a larger factor. Consider the recent London health studies that estimate deaths per ICE powered cars to be 3,000 / year. The latest health studies of diesel emissions are increasing the anger upon environmental choices which lack concerns of human health. All of Europe has embraced diesel engine power per preceived benefit to CO2 emissions. Problem is surfacing as health concerns of air quality in metro areas that rate diesel exhaust 10x more harmful to human health and on par with second hand tobacco smoke. This even with the stricter Euro 5 standards for tail pipe emissions. London has or in process of banning dieel powered vehicles.

A reading the benefits of ethanol, one can only conclude all concerns lead to increase use of the fuel. That more technology should be directed to exploit the fuel's superior environmental and health benefits. For example particulate emissions are surfacing as primary problem for both rainfall and health. The miro particles empower cloud water droplet water ability with resulting down pour and loss of more frequent rainfall. This phenomina is rizing to top of list to explain the intense flooding and drought conditions. Ethanol has exponetially higher ability to limit this emission as compared to fossil fuel. NOX emissions continue to maintain same levels of air pollution. Ethanol has high ability per onboard oxygen content and higher cooling effect to minimize the production of NOX. Diesel is moving to popularity per auto companies per jumping through Mpg hoop of EPA, but it's a faux benefit. Gasoline will generate 19.64# Co2/gal vs diesel fuel 22.38#, but diesel gets better Mpg and will result in less CO2 emission. I would estimate 17% less? Well big whoop as ethanol sits at 12.73 # CO2 per gallon. Consider a optimized engine like the Cummins E85 2.8 L engine can match gasoline mileage, that would enter into the realm of 35% reduction and at a cost savings of fuel and less expensive engine. Consider the above health concerns of diesel engines and the need to have a high torque alternaive fueled engine and one sure could conclude ethanol fuel should rize to top of list to exploit. Battery technology can't power heavy duty trucks. Natural gas is a fossil fuel with high costs of refueling.

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