NREL Team Tests Higher Ethanol Fuel Mix (Sept. 21, 2009) — Researchers have demonstrated that the traditional fuel blended with increased levels of ethanol will be good for the environment and economy without hurting cars and small engines. They showed that as ethanol increased, tailpipe emissions stayed largely the same.

nrel_logoResearchers at National Renewable Energy Laboratory (NREL)’s are trying to find out because new ethanol blends could play a starring role in reducing petroleum use.

“We’re pushed right now to find ways to get more ethanol into the fuel stream,” said Keith Knoll, senior project leader for NREL’s Fuels Performance Group.

Currently, ethanol is the most widely used and readily available renewable fuel. Ethanol as a motor fuel is commonly found in E85, a fuel intended for use only in Flexible Fuel Vehicles (FFVs).

Ethanol also is widely used as a 10 percent blend in standard gasoline (E10) to reduce carbon monoxide emissions and smog. But, increasing ethanol from the current 10 percent blend to a proposed blend of E15 or even E20, brings up a whole host of questions and issues.

Study results showed that as ethanol increased, tailpipe emissions stayed largely the same. There was no significant change in nitrogen oxides or non-methane organic gas emissions. Carbon monoxide emissions declined for all of the ethanol blends. There were increases in ethanol and acetaldehyde emissions, but these were balanced with reductions in other hydrocarbon air-toxic emissions.

When it came to how catalytic converters reacted to increased ethanol, results depended on how the engine control system regulated the fuel-to-air ratio during high power operation such as heavy accelerations or long hill climbs.

Cars that adapted to the increased ethanol during these activities showed no change in catalyst operation — in fact some even ran cooler at higher ethanol blend levels.

The ethanol industry is currently seeking a waiver from EPA that would allow for widespread use of E15 in all automobile types. Right now, most gas stations across the country already sell blends using 10 percent ethanol.

“I think that for a long-term solution our focus for consumers is on E85,” Knoll said. “Right now E85 use is limited because of the few fueling stations that are available and the limited number of flex-fuel vehicles that are on the road.

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