On April 25, Dr. Andrew Randolph, technical director of ECR engines, joined UNC Charlotte for the last EPIC speaker series of the semester to provide some insight on why the E15 biofuel is a valuable alternative for a variety of vehicles, from NASCAR vehicles to the everyday driver.
Randolph’s research focuses on the combustion properties of alcohol/diesel and alcohol/oil blends and has contributed to five NASCAR Cup championships with three different teams as technical director of ECR engines. His analysis was based around a comparison of ethanol and gasoline.
“With ethanol, hydrogen burns very clean,” he explained. “Having some oxygen bound to the fuel increases oxidation efficiency. Gasoline, however, produces more carbon emissions when burned.”
Randolph demonstrated this by burning both ethanol and gasoline in different plates and showing the imprint of carbon emissions. For ethanol, the oxygen that is contained in the fuel reduces CO emissions.
He explained that ethanol’s high octane number, which quantifies the susceptibility of a fuel to autoignite, reduces this susceptibility and aligns with automotive industry trends toward smaller displacement, high specific power engines.
Ethanol also has a high heat of vaporization that further increases Octane above published values and provides a power boost via charge cooling.
“Ethanol is the safest, least expensive octane booster,” said Randolph. “Ethanol has nearly three times the Hvap as gasoline. Power also increases with a cooler intake charge because the density increases.”
He then presented the disadvantages of ethanol. He began by acknowledging the higher heating value of ethanol that results in 34 percent less fuel economy than pure gasoline, but argued that the cost of fuel drops faster than the fuel mileage, making ethanol/gasoline blends a bargain.
Another counterargument posed is that water is not soluble in gasoline, making it harmful to boat engines, but Randolph noted that any water in the fuel system is only an issue for boaters operating on pure gasoline.
Randolph also addressed the notion that ethanol ruins small engines, by explaining that small engines are calibrated extremely rich so the fuel can aid with cooling.
When ECR implemented fuel with higher ethanol into NASCAR, the engine power increased slightly. This was because the ethanol provided more cooling so the post-race piston hardness increased.
When asked about the potential shift from 10-15 percent ethanol, Randolph explained that it’s a slow transition because of older model cars.
“We have to work our way up slowly because of potential difficulty with the calibration in older cars,” he said. “But I do think we will go national. There will be no problems associated with it in the future.”
Jamie Wren of Growth Energy, who helped organize the event, explained the availability of E15 in the US market.
“E15 is available in 29 states, North Carolina adopted it and is fifth in the nation,” she said. “There are 700 stations and it’s set to double by the end of the year.”