Ethanol has received both positive and negative attention as a renewable fuel for spark ignition engines. Studies of ethanol have shown improved volumetric efficiency, knock tolerance, and favorable burn curves[1]. Nevertheless, little research has been published exploring the impact of ethanol blends on race engine performance coupled with the impact on well-to-wheels (WTW) greenhouse gases, emissions, and petroleum reduction.
In this work, a circle track race vehicle powered by a GM Performance Parts 6.2L OHV CT-525 engine was tested using 100 octane race fuel and E85 over a matrix of configurations. Carburetion vs. fuel injection configurations were benchmarked with both fuels, with the addition of 100- and 300-cells-per-inch catalytic convertors. Testing involved both dynamometer testing and on-track testing utilizing a portable emissions measurement system. These data were used to determine the WTW greenhouse gas reduction, petroleum displacement, and criteria emission reduction, as well as the performance benefit, of E85 vs. race fuel over a matrix of technologies.
Results show an increase in power for 87% of the drive cycle using E85 as compared to 100 octane race fuel. Using 85% cellulosic ethanol, WTW greenhouse gas reductions are on the order of 63%, and petroleum reductions are on the order of 81%. Additionally, performance increases are maintained using catalytic convertors and E85 relative to 100 octane race fuel and carburetion. For comparison, it is shown that utilizing an 85% blend of cellulosic ethanol, petroleum consumption and greenhouse gas impacts are similar in magnitude to those of a mid-sized, four-door sedan using standard fuel driving over mixed city/highway cycles.