TransForum Vol. 9, No. 1

This Omnivore Likes a Variety of Fuels, Not Foods

Argonne research engineer Thomas Wallner adjusts the delay on an ion-sensing circuit used to get real-time combustion feedback.

When it comes to fuel, Argonne’s omnivorous engine doesn’t play favorites. It can take down any blend of gasoline, ethanol, butanol and other types of spark-ignited fuel.

Though flexible-fuel vehicles have been around since Ford manufactured its Model T to run on both gasoline and ethanol, the omnivorous engine takes the concept to a whole new level. With this project, researchers are working to fashion an engine that allows spark-ignition vehicles to run more efficiently on ethanol and other next-generation alternative fuels.

“Just because an engine is compatible with different fuels doesn’t mean that it has the ability to run at peak efficiency regardless of the fuel mixture,” said Thomas Wallner, a mechanical engineer at Argonne. “That’s where the benefits of the omnivorous engine lie.”

The goal is to enable the omnivorous engine to calibrate itself so that it burns available fuel at maximum efficiency. This would be achieved through a suite of sensors in the combustion chamber and exhaust that tell the engine what kinds of fuels are used.

Wallner and his colleagues are also collecting ion-sensing signals for all the test fuels and blends to determine whether the signals can be used to optimize combustion, or even derive fuel composition.

“However, the ultimate goal is not to know what’s in the tank, but to have it run as efficiently as possible on whatever comes down the fuel line,” Wallner said. “This engine can run on pretty much any liquid fuel that can be ignited with a spark.”

But Argonne engineers are not only concerned with what goes in the engine; they’re also taking a close look at what comes out of the tailpipe. This aspect of the project involves analyzing exhaust gases for a wide variety of fuels and fuel blends. Wallner pointed out that alcohol fuels are expected to show increased emissions of constituents that are currently not regulated, so they are measuring both regulated emissions like oxides of nitrogen, carbon monoxide and hydrocarbons, and several non-regulated emissions like aldehydes.

To help with this process, engineers are using a newly commissioned piece of equipment called the Fourier Transform Infrared Spectroscopy (FTIR), an optical measurement tool that can analyze up to 25 different exhaust components simultaneously.

Wallner and his fellow researchers recently completed a report, “Effects of Blending Gasoline With Ethanol and Butanol On Engine Efficiency Using a Direct-Injection, Spark-Ignited Engine,” to be presented in May at the 2009 American Society of Mechanical Engineers’ Spring Technical Conference in Milwaukee, Wisconsin.

They are currently working on two more reports which focus on the ion-sensing analysis and non-regulated emissions.

And there is still much work to be done on the omnivorous engine.

“We are just completing the baseline testing, which is meant to help us understand what the ion-sensing traces look like for different operation conditions and fuel blends,” Wallner said. “This will be used to determine what processing is necessary to derive the information needed for real-time optimization.”

The omnivorous engine research is funded by the Department of Energy’s Office of Vehicle Technologies under Gurpreet Singh and Kevin Stork.

May 2009