One Step Closer To Ultralow-Emission Automobiles

EMBARGOED FOR RELEASE: Tues., Sept. 9, 10:00 a.m. PDT/1:00 P.M. EDT

For further information, contact:
Jim Bohning, 202/872-6041
Las Vegas Convention Center, N118
702/732-5868 (phone); 702/892-3262(fax)
Fri., 8/12: Phone: 702/774-0025
FAX: 702/774-0027

ONE STEP CLOSER TO ULTRALOW-EMISSION AUTOMOBILES
A solution to make catalytic converters more efficient, and to monitor them on-board

LAS VEGAS, Sept. 9--A new application of a chemical process called sol-gel technology shows promise for making automobile catalytic converters dramatically more efficient in reducing harmful air pollution emissions, by targeting the first minute-and-a-half in which your car is running after a cold start, according to research presented here today at a national meeting of the American Chemical Society.

Most catalytic converters turn harmful combustion products such as hydrocarbons, carbon monoxide and nitrogen oxides into benign water, carbon dioxide and nitrogen. But during the first 90 seconds, while the converter has not reached optimum operating conditions and maximum conversion efficiency, up to 70 percent of the total air pollutants discharged during a normal driving cycle are exhausted to the atmosphere.

This brief window of pollution emission has been targeted by Dr. Chaitanya Narula and his colleagues in the Chemistry Department at the Ford Motor Company Research Laboratory in Dearborn, Michigan, as the point of attack, in order to meet upcoming goals for ultralow automobile emissions.

One potential solution is to move the catalytic converter closer to the car's engine, where it will warm up more quickly. But that only raises the operating temperature of the entire converter, shortening the lifetime of the catalyst responsible for promoting the degradation of the pollutants. Narula has created a more porous catalyst that will withstand the higher operating temperatures and has more surface area for treating the pollutants. He has also made a form of praseodynium oxide that more efficiently stores oxygen that is subsequently used in the conversion reactions. In both cases the Ford group used sol-gel technology, which is a method for making ceramic and glass-like materials at room temperature, rather than the traditional high temperatures used in the past.

Another way of attacking the 90-second delay is to heat the converter electrolytically. Narula points out that "the only thing that needs to be warm is the catalyst, not the entire converter unit." So his group has developed an electrical conducting layer that a manufacturer could apply to the honeycomb structure of the converter before the catalyst layer. Current tests suggest a full-size converter could warm to operating temperatures in about 10 seconds without taxing the battery.

Finally, an on-board sensor to monitor the performance of the catalytic unit continuously (as opposed to yearly testing at an inspection station) appears promising in current tests. Narula used a sol-gel process to apply a thin layer of catalyst to one side of a silicon membrane, mounted near the tailpipe of the exhaust system. If hydrocarbon pollutants slip through the converter, that side will warm up, and the resulting change in electric potential will alert the car's computer.

Paper I&EC 50 will be presented at 9:30 a.m., Tues., Sept. 9, in the Convention Center, Room N241, Level Two.

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The national meeting of the American Chemical Society, the world's largest scientific society, will be held in Las Vegas Sept. 7 - 11. This paper is among 4,500 presentations that will be made.