Effects of Fuel Ethanol Quality on Vehicle System Components

Corn ethanol has been used for fuel blending as both an oxygenate and octane booster and in most U.S. states conform to the ASTM D5798 fuel ethanol quality standard. Today the fuel ethanol market is expanding the types of feedstocks used to make ethanol and changing the processing techniques. These non-corn alternative feedstocks used to produce fuel ethanol bring new chemical components into the product that are not monitored under the D5798 standard, and it is unclear if they will result in material compatibility challenges for vehicle fuel systems that could affect performance and emissions. The vehicle contains a variety of plastic, metallic, and polymeric materials in the fuel tank, fuel pump, engine, and exhaust system that are sensitive to water, ions, acids, and high molecular weight compounds. The purpose of this paper is to present the detailed chemical analysis results from a survey of E85 fuel samples obtained from service stations across North America, and show the trends where the samples do not meet the current D5798 standard. Also presented are the detailed chemical analysis results of “Ed98” 98 percent purity denatured ethanol samples from various feedstocks per the ASTM D4806 standard. Lastly, correlations between some of the specific standard test parameter results and the effects on vehicle component performance will be discussed. The fuel ethanol and automotive industries can both learn from the fuel chemistry and vehicle component material interactions in order to provide optimal customer satisfaction with their vehicle.