Shortly after the first installment of Circle Track's Project G.R.E.E.N. hit the newsstand it became apparent that the project had a multitude of different dimensions, all of which can positively impact the oval track racing marketplace. One of those dimensions that rose to the top very quickly was fuel and fuel choices-more specifically alternative fuels.
Our Motivation
We have gotten a number of reader letters asking us to investigate ethanol vs. methanol vs. gas a little deeper than what was presented in the first article of Project G.R.E.E.N. Among the requests, these letters also demonstrated that there are a lot of misconceptions about how good, bad, or green these fuels may be in the context of racing applications.
Let's start with the magazine's fundamental motivation for going down this alternative fuels route. Today, the United States imports approximately 60 percent of all the oil it consumes. Using domestically produced ethanol will reduce our country's dependence on foreign oil. For a variety of political and non-political reasons, that is a good thing. In a nutshell, having a domestically produced, renewable source of fuel available for racers removes the power to control prices from those organizations outside our borders.
This chart shows the sources...
This chart shows the sources for various fuels. Note what can be produced from cellulosic biomass, a fancy term for yard waste.
In the development of Project G.R.E.E.N. the Circle Track team always knew we wanted to run the engine on an alternative fuel such as ethanol. However, as we delved deeper into the concept of ethanol as a race fuel our team began to realize that the tangible benefits of domestically produced ethanol make it the perfect race fuel. But before we get into the down and dirty of why ethanol is such a great candidate for a race fuel let's step back for a minute.
Alternative Fuel
We have thrown the words "alternative fuel" around a lot in this project. Now simply put, an alternative fuel is any fuel that may be used that displaces the current use of liquid-petroleum-based energy sources. An alternative fuel may be natural gas, propane, ethanol, methanol, biodiesel, hydrogen, or even energy carriers, such as electricity. For the purpose of this article, we will focus on ethanol, or ethyl alcohol, with comparisons to race fuel and methanol, a fuel that has been commonly used in circle track racing for years.
Ethanol-A Chemistry Lesson
In the United States, ethanol (EtOH) is traditionally obtained from corn because it's a low-cost source of sugar. That sugar can be converted to ethanol at the large volumes needed for commercial fuel. The chemical composition of ethanol is C2H5OH and is no different from the alcohol one drinks in a cocktail during a happy hour at the local watering hole. In comparison, methanol (CH3OH) is toxic to humans, and consuming as little as 10 ml can cause blindness-consuming 100 ml can cause death.
Today, soybeans and even the...
Today, soybeans and even the post-harvest plant matter not used can be a source of ethanol, an alcohol that some racers are currently running on today. Courtesy Of Argonne National Laboratory
Now, to sell ethanol as a fuel, it must be denatured so that it is not consumable. Denaturing of EtOH is typically done by blending it with a small portion of gasoline. E85 is actually just a blend of approximately 85 percent denatured ethanol and 15 percent gasoline. The gasoline is added to improve cold starting, which can be difficult with ethanol that reaches near 100 percent pure levels; it also adds to the energy density of the blend. If you see E10 on a fuel pump, you've most likely guessed it: approximately 10 percent is ethanol, and the remaining 90 percent is gasoline.
Benefits
The benefits of ethanol relative to race fuel and/or methanol are multifold, but let's start with the one many of you already have guessed-power. A typical (R+M)/2 octane rating of E85 is around 100. The naturally high octane allows for greater compression and expansion ratios-the power and efficiency benefits to the racer of higher octane are well known and widely published.
Second, ethanol has a higher heat of vaporization relative to gasoline-a significantly higher value. A typical heat of vaporization for gasoline may be on the order of 59 kilojoules per kilogram of fuel. For ethanol, it's approximately 130 kilojoules per kilogram, which is more than twice that value for gasoline.