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Universal Tech – Alcohol Fuels Part II
universal
TECH
Photos & Text by Vahok Hill
UNDERSTANDING ALCOHOL FUELS PART II
In issue number five of Dirt Empire Magazine, Vahok Hill introduced the subject of why alcohol is a popular racing fuel. In this concluding section, he looks at some of the particular properties of alcohol fuels and the potential for new ways of producing alcohol fuels in the future.
IT IS OFTEN THOUGHT that alcohol makes power because it has a greater amount of energy. This is not completely true; in fact, the types of alcohols that are commonly used in racing have less heat energy than gasoline based on the volume. There are in fact four types of alcohols, but only methanol and ethanol are currently used as fuels in the racing world. The other two types of alcohols, propanol and butanal, are not used commonly used as fuel. Propanol has more uses as an industrial solvent than as a fuel.
Butanol, however, has some unique characteristics; it is the one alcohol that most closely mimics gasoline from an energy density perspective. That is one of the reasons that the Stochiometric air fuel ratio is the closest to gasoline. Butanol due to its chemical makeup is not as corrosive as methanol or ethanol. While all of this sounds really great, as with most things there are some issues that prevent butanol to be a viable racing fuel at this point in time. First is that it has a fairly high melting point and at cooler room temperatures more closely resembles light grease or jell, than a liquid fuel. However, it does mix well with gasoline and that has some real positives for the passenger car world; however, it is not a real boon to the racing world, yet. For those reasons, we will still focus our attention on methanol and ethanol.
From a race car handling perspective, alcohol will cause the racer a bit more problems. Since alcohol contains less heat energy than gasoline, you will be required to run more of it, that means more weight at the start of the race and due to the higher consumption rate the car will become lighter more quickly as the race progresses. Why is this a bad thing? Because it will change your weight and balance to a greater degree than you would have with gasoline, as the fuel burns off, yes gasoline burns off and the car will get lighter as well, it is just that with alcohol it will happen at a greater rate, and not only will you have to deal with the ever-changing track conditions you will have to develop a set up that will not go away as the car gets lighter. Or you can develop a setup that favors the car later in the race. The point is that the use of alcohol will not only mandate fuel system changes it will also mandate a different setup than gasoline. This is just one more problem for the chassis guy to chase / solve, as if their job is not difficult enough.
So, just why does alcohol make more power than gasoline if it has less energy per pound than gasoline? Good Question. Obviously, you will have to run more of the alcohol-based fuels to get the same power, how much more will depend on the type of alcohol you are running. With methanol and ethanol, it is about 40% more than gasoline. Let me espouse some of the good characteristics that alcohol brings to the table. First, when you burn alcohol, one of the byproducts of combustion is oxygen. This helps propagate the combustion process and is a power adder. Another is the cooling effect of alcohol as it “vaporizes” in the inlet track. This helps create denser air as the fuel/air enters the engine, another positive. The cooling effect also helps to cool the engine, at least on the inlet side of the equation. Remember producing horsepower is all about creating and controlling heat. Another positive feature about alcohol that is seldom discussed but is a very key reason that more power is generated with alcohol, is that the incoming fuel charge, the mixture of air and alcohol, is easier to compress
than a mixture of gasoline and air. The alcohol does not vaporize as well or completely as gasoline as it comes out of the carburetor or the injector. While gasoline forms a more complete vapor, alcohol forms a “vapor” made up of many very small droplets of fuel suspended in the incoming air/fuel stream entering the engine. Then during the compression stroke, the heat of simply compressing the incoming fuel air mixture completes the vaporization process. So, from a mechanical perspective, your engine uses a smaller percentage of the power it is making to sustain continued operation. This can be a significant power adder. Long story short an alcohol mixture takes less energy to compress than a gasoline mixture. And, as an added bonus the last vaporization step also helps to further cool the mixture. Remember cool, in this case is a relative term as compared to a gasoline mixture.
Additionally, an engine that is burning Methanol or Ethanol can support a much higher compression ratio. It is not uncommon to see alcohol engines using as high as 13 or 15 to 1 compression rations with little or no fuel caused problems; destructive detonation comes to mind. Of course, high compression engines have other mechanical issues that are not related to fuel. That said alcohol can support some very high compression engines without the fuel causing detonation issues that can happen if the wrong grade of gasoline is used in the engine. This allows the engine builder to adjust the components and the state of tune of the engine, to maximize the power output due to the positive features of alcohol fuel.
Currently the majority of alcohol products are manufactured from petroleum products, in this case natural gas, more specifically the methane that is a component of natural gas. It can also be manufactured from the pyrolysis of wood, wood is used a general term, (it would be better to say cellulose). A process that utilizes pressure, high temperature and an absence of oxygen, one of the byproducts is methanol another is charcoal. The term wood alcohol is derived from this process. There are other methods of manufacturing alcohol, the use of agricultural products like corn or beets or sugar cane. But this, manufacturing alcohol from food or feed stocks derived from human food products is not the panacea that the main line media and the political pundits / AgraIndustry Lobbyist, would have us believe.
In fact, we, the public, have been bombarded by the mainstream media and this media has been pandering to the various agricultural lobbyists to use various domestically produced grains, like some types of corn and or wheat to make alcohol. This has also caused a huge spike in the price of many of the agro crops that has contributed in the spike in prices that you are seeing at the checkout lines at the local supermarket. While this is a highly popular story in the agricultural parts of the country, it is not a very efficient method to produce alcohol, in this case ethanol. This would, they say, “release our country from the grips of the oil producing nations of the world”. And, “minimize or eliminate our country’s dependencies on foreign oil producers”. While on the surface this may sound good and is a very popular sentiment it is far from true. It is more of what “we” would like to hear rather than being wholly true. Remove the Government incentives and tax benefits and the fuel generated from grain using the current technologies for production would yield a fuel with a very high cost, much greater than the current prices that many racers are now paying for alcohol. To make ethanol from this type of agricultural product seems energy negative, i.e., it would take more energy to plant, fertilize, harvest and move the raw materials to the distillation facility to make the ethanol than the finished product can produce. Don’t forget to add on the cost of the subsidies. It seems much more economic to use feed stocks that are lower in cost or essentially free and that we already have in our hands, than to grow or divert new feed stocks to produce the ethanol. Products that are byproduct of other processes that generate a product that would be considered a waste, for example; whey is a waste product from milk when it is processed into other products, cheese for example. For the most part the whey is seen as a byproduct with little or no value. Many times, the remaining whey is simply dumped on fields. But there are still sugars remaining in the whey that can be turned into ethanol. It seems infinitely smarter to use this waste, or free, feedstock product or products and get all the value possible out of this resource. Rather than spending time, effort and other valuable resources to make fuel from grain that would place the grain in a tug of war for fuel or food. Currently there are farms in other countries that are exploring increasing the amount of corn they are planting as they will be able to get more dollars for the corn as a raw stock for the production of alcohol than as a food product for humans and animals. Not really helping with our dependence on foreign governments for energy.
As far as the racer is concerned, the more demand for alcohol fuel products the more technology will be devoted to improving the product and creating better and hopefully more economical methods for creating alcohol from waste products or easily renewable and obtainable agricultural products, that are not in competition for food producing crops or lands. The future does look promising in this field of developing new methodologies for creating fuel from alternative sources. Fuel, or biofuel, was developed using Camelina. Camelina is an agro crop that does not compete in the food chain and is used as a rotational crop in wheat farming. Another benefit is that Camelina can be grown on farm land that is considered marginal and not have to compete with crops that require the best land for production. While this is currently not an alcohol-based product, it does showcase some very sound American technology that will have effects on how we develop new technologies for creating new fuel feed stocks and this will have implications in how alcohol products are developed as new feed stocks are discovered and put into productions. It may not be too far off into the future that we see alcohol-based fuels that are created from algae feed stocks or cellulous waste products. The idea that we could take garbage and turn it into the feed stocks that are used to develop fuel is not just a pipe dream, it may become a reality. Who knows landfills may be the next American energy fields? Who knows garbage may be the next black gold?
Moving forward, it will not only be the general consumer that will benefit from this type of new technology development but racers as well. The future does indeed look very bright and the light may be blue.
