Fuel for Thought: UW Engineers on Trail of 80 MPG Car

Engineers at the University of Wisconsin–Madison are looking under the hood for a revolution in automobile fuel efficiency.

UW–Madison’s Engine Research Center (ERC) has received a three-year grant from the U.S. Department of Energy to study how to triple the average mileage of American family cars. The project is part of the Clinton Administration’s Partnership for a New Generation of Vehicles, formed in 1993 with the goal of producing no less than an 80 mpg car by the year 2004.

That’s no idle dream, says mechanical engineer Rolf Reitz, who is leading the engine simulation and testing project. Some European car manufacturers already have created cars that get up to 60 miles per gallon, he says.

The difference, however, is the European models run on diesel engines. While inherently more fuel-efficient than gas-burning engines, Reitz says they are also inherently bigger polluters.

Reitz’ projects will focus on how to reduce diesel engine emissions to acceptable levels and maintain their impressive fuel efficiency. In recent years, the ERC has found ways to do exactly that with heavy-duty diesel engines for machinery, semi trucks and defense equipment.

This new line of research will be the ERC’s first attempt at applying those clean-burning principles in big machines to their pint-sized counterparts in cars.

“The diesel engine is the most efficient engine in the world,” Reitz says. “No other car engine offers even the hope of reaching 80 miles per gallon. Diesel is getting a lot of attention by the automotive industry.”

Diesel cars enjoy wider acceptance in Europe than in the United States. An attempt to introduce them to U.S. consumers bombed in the early 1980s, Reitz says, primarily because the cars were poorly and hastily designed. Only about 1 percent of all U.S. cars have diesel engines, compared to 30 percent of all cars in Europe.

The Partnership for a New Generation Vehicle includes all three U.S. car manufacturers. In addition to UW–Madison, the public side of this partnership includes Wayne State University and Sandia National Laboratory. With public researchers and the Big Three auto makers now working together, Reitz says, the odds are good the partnership will produce a quality diesel car that competes with standard models. And we’re not talking about puddle-jumpers here: The goal is to create a standard six-passenger car that gets 80 mpg, without any corresponding change in performance, safety and cost.

The two nastiest pollutants from diesel are nitrogen oxide and soot, Reitz says. Nitrogen oxide is a problem in bigger cities, where it contributes to ozone depletion and smog. Soot is a carcinogen when it’s in particles small enough to be breathable. Researchers have been able to greatly reduce emissions of both those pollutants in their heavy-machine projects, Reitz says.They are controlling nitrogen oxides by rerouting some of the engine’s exhaust back into the combustion chamber. And through new “pulsing” fuel injectors developed at ERC, they created a better mix of fuel during combustion that almost eliminates soot.

The ERC will be conducting the research on both a supercomputer, which can create precise simulations of engine functions, and diesel engines donated by European car manufacturers, including Fiat. ERC will receive its first engine from Fiat this month.

Beyond pure energy savings, the partnership’s goal of tripling the fuel efficiency of cars is also crucial to future United States security, Reitz says. The U.S. currently imports about 55 percent of all oil, and in 15 years that figure will reach 70 percent. That puts the U.S. at the mercy of a shrinking number of oil-rich countries, many of them politically unstable, to sustain its transportation needs.

“This goal is only eight years away, so it makes sense to work with diesel engines over some unproven technology,” Reitz says. “This isn’t a mandate to car manufacturers, but they have made a commitment that these are worthy goals.”

CONTACT: Rolf Reitz, (608) 262-0145