Portland, Ore. -- Engineering students have entered the final phase of Challenge X: Crossover to Sustainable Mobility. The three-year competition aims to increase the efficiency of hybrid-energy-powered automobiles, eliminate their noxious emissions and lower their cost.
For the just-ended 2006 midterm competition, Virginia Polytechnic Institute and State University (Virginia Tech; Blacksburg) took first place with its split parallel hybrid design. The University of Wisconsin (Madison) took second place with its through-the-road parallel hybrid car. Third place went to Mississippi State University with its through-the-road parallel hybrid vehicle.
The ultimate goal of the competition is to gain consumers' acceptance of hybrids. "Right now, two groups are buying hybrids. Engineers are buying hybrids because they are intrigued by the technology, and environmentalists are buying them because they are interested in saving fossil fuel. But most consumers won't buy a hybrid unless there is a cost savings," said Glenn Bower, the second-place Challenge X team's adviser and a faculty associate in the College of Engineering at the University of Wisconsin. "Our add-on modifications will provide that savings to consumers, since it will cost only about a $4,000 to $5,000 premium, which would save about $1,000 to $1,500 per year in gasoline over a lifetime of ownership between five to six years."
The 17 teams, chosen from a field of 60 applicants, spent the first year, 2005, simulating proposed modifications to their vehicles. This year, they incorporated those improvements for a preliminary competition. Next year they will refine their designs and enter the final competitive evaluation in mid-2007.
Challenge X is sponsored by the U.S. Department of Energy, General Motors, Freescale Semiconductor and National Instruments, among others.
"We are in the second year of a three-year competition," said Bower, "so all your major components--the engine, the motor and the battery--can't be changed beyond this point. So during the last year, we will be focusing on tuning our control systems and software."
The most successful alternative-fuel automobiles to date include the Toyota Prius and Honda hybrids, which combine a gasoline engine with an electric motor. This approach has also been adopted by all three winners of this year's Challenge X competition.
So far, so good
This year's winner, the Hybrid Electric Vehicle Team, sought "to realize a 30 percent increase in fuel economy while maintaining superior vehicle performance and low emissions," said Steven Boyd, Virginia Tech's team leader. As did all 17 teams, the Virginia Tech team began its effort with a 2005 Chevrolet Equinox donated by GM. The team added two electric motors and converted the gasoline engine to run on E85 fuel, which is 85 percent ethanol and only 15 percent gasoline. The fuel is "expected to reduce petroleum use by an incredible 80 percent," said Boyd. This year's vehicle yielded a well-to-wheels reduction of petroleum use of 74 percent.
In Virginia Tech's split parallel hybrid approach, the team used a turbocharged 2-liter Saab engine, two electric motors and a nickel metal hydride (NiMH) battery pack for energy storage. As with all parallel designs, the electric motor and gasoline engine are used simultaneously. In contrast, the internal combustion engines of series hybrids are not directly connected to the drivetrain. Instead, the engine powers an electric generator; the generator charges batteries and supplies electricity to the motor, which in turn runs the drivetrain.