Researchers at the NTRC strive for more efficient cars and cleaner air
by Mike Gibson
Perhaps it's fitting that a research facility that could play an integral role in reducing air pollution the world over has taken root in one of the nation's 10 most polluted metropolitan areas, in the shadow of its smoggiest national park.
A robust 83,000 square foot structure just north of the Pellissippi Parkway Interchange on Hardin Valley Road, the National Transportation Research Center, or NTRC, is a collaborative effort of the Department of Energy, Oak Ridge National Laboratory, the University of Tennessee and The Development Corporation of Knox County.
A handful of ORNL scientists first suggested such a collaborative in 1993, as a way to unite under one roof researchers from the lab's disconnected but potentially symbiotic transportation initiatives, programs such as the Advanced Propulsion Technology Center, or the Center for Transportation Analysis. The project finally gained momentum in the late '90s, and the $15 million facility broke ground in April 1999.
Opened in 2001, NTRC is also a component of DOE's ongoing attempt to preserve and proliferate the wealth of its intellectual resources in the wake of the cutbacks to which the department's Oak Ridge facilities were subjected throughout the 1990s.
"It's part of our trying to get away from the 'behind the fence' way of doing things," says ORNL mechanical engineer Ed Grostick. "Our claim to fame is that under one roof, we have a greater variety of transportation-related research, we believe, than any other single facility in the United States."
With research dollars funneling in from federal agencies and private industry alike, NTRC's 200 researchers (140 from ORNL, and 60 from UT) seek solutions to disparate transportation problems, from the intricacies of inventory tracking to the dynamics of vehicular crash safety. But more than any other single task, NTRC researchers see it as their lot to try to narrow what they call "The Gap"—the growing imbalance between domestic oil consumption and domestic oil production—and thereby address all of the social and environmental problems that deficit creates.
"What we're really all about is reducing The Gap; it's our overriding mission," says ORNL fuels and emissions researcher Brian West. "Can we do something about global warming? About the presence of CO2 in the air? About our dependence on foreign oil? Those are the kinds of questions we're trying to find answers to."
The test cells in the NTRC's Fuels, Engines and Emissions Laboratory look like nothing so much as some Giger-esque mechanized reptilian fantasy—hapless diesel engines engulfed in a snaky tangle of wires and menacing metallic fixtures. From the ceiling hang enormous segmented steel and plastic tubes, descending like serpents to extract the lifeblood from trapped quarry.
The clusters of ensnaring wires and working parts are actually components in one of NTRC's four stationary engine dynamometers, liberated from the Advanced Propulsion Technology Center, a DOE user facility on the ORNL compound.
The dynamometers operate the disembodied engines by simulating the stresses of normal working conditions, with the ability to vary simulated workloads as well as engine speed. The kind of testing that goes on here has been an indispensable component of the Environmental Protection Agency's continued introduction of ever-more-stringent emissions standards for domestic automobiles.
Studies show that the U.S. transportation system devours about one third of the energy we consume as a nation, and is responsible for a third of the carbon dioxide emissions that contribute to poor air quality as well as unwanted climate changes.
The EPA has responded to those kinds of statistics by enacting the progressively more restrictive Tier One (1994) and Tier Two (2004) Emissions standards for light-duty trucks and automobiles, with a concomitant increase in the standards for heavy-duty vehicles as well. According to West, Tier One standards reduced light-duty auto emissions by more than half, and should they prove effective, the more recent Tier Two restrictions would reduce them by at least the same percentage yet again.
The U.S. Big Three auto manufacturers have also responded to the crisis of The Gap by agreeing in partnership with DOE to create a new generation of vehicles that would meet Tier Two admissions standards several years ahead of schedule. West says that NTRC researchers have been heavily involved with both formulating EPA standards and with aiding manufacturers in their new quest.
"Whenever you set new standards, the auto manufacturers say 'Oh, we can't do that!' or 'Give us more time!'," West says with a laugh. "Then there's a lot of fighting between manufacturers, oil companies, and the regulatory agencies, and they usually figure out how to make it happen. If you described what we put in cars today to someone back in the '60s, they would tell you, 'You're a heretic; there's no way you could do that with a car.'"
The biggest problem researchers face is the difficulty inherent in manufacturing engines that are at once fuel-efficient yet relatively free of noxious emissions, West says. Diesel engines are most fuel efficient, and many researchers believe the future of automobile engines inevitably lies in some sort of diesel hybrid.
But the burning of diesel fuels releases more pollutants, especially particulate matter, nitrous oxide (NOx), and hydrocarbons, all of which contribute to smog and the accumulation of poisonous ground-level ozone. And while today's catalytic converters are designed to reduce those emissions, their effectiveness is hampered by the same factor that makes diesel fuel more efficient—a high oxygen content.
NTRC research such as that conducted in the Engines/Emissions Laboratory has been key to advancing the technology of the NOx adsorber, a new-generation catalytic converter which separates, stores and releases the nitrous oxide that would otherwise interfere with catalytic efficiency. West says the NOx adsorber is already in production in Japan and Europe, but that the technology still falls short of meeting federal standards in the U.S.
But further complicating the chemical conundrums of diesel fuel and the NOx adsorber is the sulfuric content of both diesel and some grades of petroleum-based gasoline. Over time, sulfur degrades the performance of the adsorber and other diesel particle filters. ORNL/NTRC research factored heavily in an EPA mandate that manufacturers of both diesel and gasoline fuels reduce the sulfur content of their product by 90 percent by mid-2006. At the Engines/Emissions lab, NTRC engineers continue to seek ways to increase the durability of NOx adsorbers, and to identify what level of sulfur reduction is necessary for the current technology to work optimally.
"Reducing nitrous oxide is the biggest challenge we face," West says with the earnest enthusiasm of someone who actually looked forward to chemistry class in high school. "NOx is the most difficult of the emissions to control, and that's what makes the adsorber so exciting. If we can work out the bugs, we can enable diesel engines to meet the same emissions standards as gasoline."
Ultimately, NTRC researchers hope to contribute to DOE's Partnership for a New Generation of Vehicles, a collaborative effort that also has among its chief participants the Ford, Chrysler and General Motors corporations. The PGNV's goal is to create an environmentally friendly full-size family sedan with fuel efficiency approaching 80 miles per gallon. Such a car would likely have a hybrid diesel engine that draws some of its power from an electric motor; Toyota and Honda are already marketing similar models abroad, but DOE hopes the American version will be both more efficient and less costly.
If it is, some of the credit will surely belong to the NTRC's Power Electronics and Electric Machinery Laboratory, where researchers are testing the efficiency of several types of electric motors, as well as finding new ways to test them.
But while all of the NTRC's projects sound promising, none of them would seem to have any immediate bearing on the research center's own home city, which for several years running has held the dubious distinction of being one of the nation's top 10 most polluted cities, according to many sources. Ironically, nitrous oxide and hydrocarbons—focal points of NTRC research—are chief culprits in perpetuating the region's now-notoriously poor air quality.
But West says the NTRC has made inroads toward becoming more involved in local transportation issues. An upcoming emissions testing project at I-40's Watt Road exit will gauge the efficacy of various clean-up measures. In the meantime, NTRC officials have offered their services to Knox County should it seek to institute a vehicle emissions inspection and maintenance program to improve air quality.
With the county on the verge of suffering federal sanctions due to an over-abundance of ground-level ozone (one of the byproducts of nitrous oxide), local officials believe such an inspection program aimed at individual vehicle owners may be a key to avoiding trouble with the feds in 2004.
"We've already had some conversations with the county," West says. "There are a number of ways we could help them with an inspections and maintenance program, from assessing the technologies they already have to suggesting new ways of measuring. Anything we can do, we're willing and able to help."
January 22, 2003 * Vol. 14, No. 4
© 2004 Metro Pulse
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