Ethanol

Argonne engineer Steve McConnell refills the fuel cart of the omnivorous engine – for this particular test with 100 percent ethanol.

Ethanol, one of the most familiar renewable fuels, has the potential to significantly displace our nation's demand for petroleum. Argonne's research objective is to systematically evaluate the effects of various ethanol/gasoline blends on engine efficiency, combustion behavior and engine-out emissions in a modern, spark-ignited, direct-injected engine.

Current levels of ethanol in gasoline are typically 10% by volume (for example, E10), with limited access and usability of 85% by volume (for example, E85). There are many advantages to pursuing higher blend ratios of ethanol in gasoline, such as increased displacement of petroleum products, reduced emissions, and improved engine operation.

However, the advantages also present unique challenges. Production concerns include increased cost and limited production capability. The corrosiveness and hydrophilic nature of ethanol may have effects on distribution. Engine factors such as fuel system compatibility, cold start, and energy density issues are also concerns.

Simply replacing gasoline with ethanol without specifically redesigning the engine to use the new fuel properties results in reduced vehicle range. However, properly designing the engine to use the higher octane rating of ethanol and its increased latent heat of vaporization may result in an engine with greater fuel conversion efficiency and overall improved vehicle range compared to current engine technology.

Brazilian Vehicle Testing with Ethanol Blends

The Zaphira, one of the Brazilian vehicles evaluated by Argonne.

Brazil is unique in that its government has mandated that the minimum ethanol content of its fuel must be 22 percent ethanol. It also encourages the use of 100 percent ethanol as a transportation fuel. Brazil's sugar industry has made the use of ethanol a viable option for the country. Brazil's average income is relatively low ($9,700 per year, with 31 percent of the population below poverty level), limiting the number of consumers of the technologies available to efficiently use ethanol as a fuel.

Argonne's research evaluated the techniques used in flexible fuel vehicles (using E22 – E100) developed for the Brazilian market. Production Brazilian FFV vehicles were tested for fuel economy, emissions, control differences and technology benefits.

Data collected from this research was fed into the GREET and PSAT modeling programs, as well as into the Omnivorous Engine Program.

Enhanced Ethanol Blends Study

Several states are promoting legislation to increase the maximum concentration of ethanol in gasoline from 10% up to as high as 20%. They hope this will rapidly reduce the need for refinement of imported crude, oil as well as the additional need for local farming and related industries within their districts.

At this time there is insufficient data to predict the impacts of intermediate blends of gasoline and ethanol (E15 or E20) on existing U.S. vehicles. Potential problem areas include increased emissions, Malfunction Indicator Light (MIL) illumination, emissions control system durability, solvency issues, and consumer acceptance due to a perceived difference in vehicle operation.

Current U.S. vehicles are designed to tolerate up to 10% ethanol and are warranted to remain clean and functional when used exclusively on this fuel. However, it is suspected that concentrations of ethanol higher than 10% could have durability and performance impacts.

Argonne's research will help explain the extent to which vehicles are vulnerable to potential problems and poor emissions characteristics. E20 will be evaluated, as will 15% ethanol, 10% ethanol, and a base 0% ethanol fuel in three late model light duty trucks. This research is in support of a larger study for the Department of Energy, in cooperation with Oak Ridge National Laboratory and the National Renewable Energy Laboratory.

Funding

These projects are supported by the U.S. Department of Energy's Vehicle Technologies Program under the direction of Kevin Stork.

More

• 'Omnivorous engine' hopes to run on many fuels
• Omnivorous Engine Project (1 MB pdf)

February 2010