Simple system may curb auto emissions By the middle of this decade, some

cars and trucks may carry their own oil refinery as standard equipment. Al- though the miniature distillery won’t re- alize science fiction’s dream of convert- ing garbage into gasoline, it may provide a way to significantly reduce the hydro- carbon emissions in exhaust from inter- nal combustion engines.

Gasoline is a mixture of liquid hydro- carbons that have a variety of boiling points. Only the most volatile compo- nents of gasoline vaporize and burn when a cold engine first turns over, says Ronald D. Matthews, a mechanical engineer at the University of Texas in Austin and a codeveloper of the new system. The rest of the fuel forms a puddle in the engine’s intake manifold and then, as the engine warms, gradu- ally evaporates and goes out the ex- haust pipe.

Up to 80 percent of the unburned hy- drocarbons emitted during a typical 30- minute drive is generated during the first 2 minutes of engine warm-up, Matthews notes. The researchers’ new system could eliminate almost half of these emissions, he estimates.

Here’s how it works: While the engine runs warm, the onboard distillery col- lects the most highly volatile portions of the gasoline, which vaporize at an in- termediate temperature. The system condenses them and routes them into a small tank under the hood. On future cold starts, the engine pulls its fuel only from this reservoir of easy-to-evaporate components. Over the next few min- utes, the fuel system shifts to pull gaso- line from the main fuel tank. This tech- nique provides the benefits of using two fuels without the hassle of filling two tanks at the gas pump, Matthews notes.

Besides the 1-gallon reservoir, which will hold enough fuel for two cold starts, t he relatively unobtrusive sys- tem will require only two fuel switches and one small distillation device. “Most people looking under the hood wouldn’t recognize anything differ- ent,” says Matthews.

The system will add less than 5 pounds to the engine and be relatively inexpensive, Matthews claims. He says his team bought the four components in the prototype system for about $400 retail, but costs for a production ver- sion of the onboard refinery could drop to around $60.

Matthews and his colleagues plan next t o install the emissions-trimming equipment on a 2001 Lincoln Navigator. During laboratory tests of the vehicle over an 18-month period, the researchers will refine the device’s performance and evaluate the cost-effectiveness of the system. It could be ready for vehicles rolling off the production line in 3 to 4

JANUARY 20,2001

years, Matthews says. By using catalytic converters and

other equipment, automobile manufac- turers have made great strides in re- ducing emissions of unburned hydro- carbons, says Donald E. Zinger, assistant director of the Environmental Protec-

SCIENCE NEWS, VOL. 159

tion Agency’s Office of Transportation and Air Quality in Washington, D.C. Cutting those emissions even further will help automakers meet the agency’s tougher tailpipe standards scheduled to be phased in beginning in 2004, he adds.

“Anything [automakers] can do to cut cold-start emissions is going to be helpful,” he notes. -S. Perkins

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