Challenge X: The Last Lap
The Challenge X: Crossover to Sustainable Mobility competition completed its fourth and final year in May. EPM talked with some of the teams who used E85 to gauge their opinions about using the renewable fuel.
Their assignment is to change the future of the automotive and transportation industries by reinventing a vehicle and making it more environmentally friendly and energy efficient.
The resources the students had to work with were a Chevrolet Equinox, $25,000 in seed money, a General Motors Corp. adviser and the freedom to deploy any novel technology they choose. This is the task that GM and the U.S. DOE gave to 17 student engineering teams across the United States and Canada during the Challenge X: Crossover to Sustainable Mobility competition. Since 1987, the DOE, Natural Resources Canada and various academic and industry partners have sponsored more than two dozen engineering competitions.
For the Challenge X competition, students followed a modified version of GM's Global Vehicle Development Process—the automaker's real-world vehicle development and engineering process—to guide their design and development activities using a GM-donated 2005 Equinox. The event challenged students to develop innovative advanced propulsion systems to maximize the vehicle's fuel economy and reduce emissions and greenhouse gases (GHGs) while maintaining or exceeding the vehicle's stock utility and performance. The challenge was co-sponsored by GM and the DOE along with several others, who supplied cutting-edge technology and support, including software and hardware components.
The first year of the program, which began in 2004, focused on vehicle simulation, modeling and subsystem development, and testing. Year two focused on powertrain development and demonstration of the energy use and emissions goals of the competition. The third year required further refinement with the goal of delivering a "showroom" vehicle that was appealing to consumers. In this, the fourth and final year, students focused on customer acceptability, and over-the-road reliability and durability of their advanced propulsion systems. The vehicles were then tested by participating in drag racing, autocross and a 400-mile road rally from New York City to Washington, D.C.
Mississippi State University, for the second consecutive year, took first place honors using B20 in tandem with a 2.0-liter four-cylinder spark ignition engine. The other 16 teams that participated included: University of California, Davis; Michigan Tech University; University of Akron, Ohio; Texas Tech University; Pennsylvania State University; University of Waterloo, Canada; University of Michigan; University of Tennessee; Rose-Hulman Institute of Technology; West Virginia University; University of Tulsa; Virginia Tech University; San Diego State University; University of Texas; Ohio State University; and University of Wisconsin, Madison.
MSU earned 817.1 points out of a possible 1,000 while the runner-up, the University of Wisconsin, was awarded 742.8 points. Ohio State University came in third, while the
University of Waterloo and the University of Tulsa came in fourth and fifth respectively to round out the top five. Twelve teams used some sort of biodiesel blend while only three teams—Texas Tech University, Virginia Tech University and the University of California, Davis—used E85 in their tanks. UC-Davis was the only team to employ plug-in hybrid technology as its energy source in conjunction with E85.
GM recognizes how valuable the competition is for advancing the growth of tomorrow's vehicles. Not only do the students gain precious knowledge from hands-on experience, they
also acquire the skill sets needed to find a career with automakers such as GM, according to Forrest Jehlik, Challenge X lead technical coordinator and research engineer for the Advanced Powertrain Research Facility at Argonne National Laboratory, a competition sponsor.
"The forefront of everything anybody in the industry is doing, these students are doing right out of the gate and some of them have rapidly become experts in this field," Jehlik tells EPM. He is also a veteran competitor of the event and participated in the 1997 Propane Vehicle Challenge and the 1998 Ethanol Vehicle Challenge. He was the team captain for both years for UC-Davis. "Simply because of the competition, they're able to get that skill set, where they can jump right in and get to work and make a significant contribution immediately to the industry," he says.
The teams that used E85 addressed the advantages and disadvantages they encountered in their efforts to improve the future of E85-capable vehicles.
Taking on Technical Challenges and Reaping the Benefits
The participants employed several novel ideas into their designs, and used technologies that could lead to real-world solutions to reduce well-to-wheel energy consumption, petroleum consumption and tailpipe and GHG emissions, and increase pump-to-wheel fuel economy. In addition, all 17 teams selected hybrid vehicle designs, some of which go beyond those being considered by the original equipment manufacturers (OEMs). Their designs spanned the scope of parallel through-the-road designs and other hybrid electric vehicle series designs.
During the program's first year, Virginia Tech's Hybrid Electric Vehicle Team, which took eighth overall in the event and first place in 2006, decided to use a split-parallel hybrid architecture that would use E85 fuel with the help of two electric motors. Its high-voltage belted alternator/starter (BAS) was belted directly to a SAAB 2.3-liter engine coupled to a five-speed manual transmission that powered the front wheels. At the same time a rear traction motor supplied power to the rear wheels in order to maintain all-wheel-drive capabilities and to provide performance assistance. The configuration also enabled the vehicle to use both motors in parallel power paths to assist the engine or allow use of a series of power paths when the BAS is used to charge the 336-volt nickel metal hydride battery pack.
According to Mark Johnson, a mechanical engineering graduate student and Challenge X team leader for Virginia Tech, his team took advantage of E85's inherently high octane
level. "Our engine is calibrated by SAAB and it's manufactured to run at a higher power level on E85 compared with premium unleaded so we get about 25 extra horsepower—or about 10 percent extra power using E85," Johnson says.
As for disadvantages, Johnson says the team had to increase the size of the fuel tank because E85 isn't as energy dense as regular gasoline. "That's the disadvantage of the energy content and the upstream energy content of the fuel," Johnson says. "Since we were judged on a well-to-wheel basis, the production energy required to make E85 was a big hindrance to us."
Despite encountering an electrical system failure, Virginia Tech had one of the highest well-to-wheel petroleum displacement evaluations this year. Last year, the team achieved a 77 percent reduction in petroleum energy use, which was a critical win for the team, according to Johnson. "I'd say the major improvement from 2007 to 2008, despite the fact that we broke down at the competition, was reliability," Johnson says. "We had put a few thousand miles on the vehicle during the spring semester, which is something we never did in the past. We were able to get a lot of test data from that and to really refine our system."
Eleventh-place finisher Texas Tech just completed its 20th year as a participant, designing a hybrid-electric vehicle powered by a GM-donated 2.4-liter I-4 (L61) SI engine fueled with both hydrogen and E85. According to Tim Maxwell, Texas Tech's mechanical engineering faculty adviser for the Red Raider Challenge X team, the students chose hydrogen with E85 mainly as an assist for cold starts. The team also tried injecting small amounts of hydrogen in cruising conditions with E85 being used later, he says.
"We chose E85 with hydrogen because of the well-to-pump and the pump-to-wheels advantages and they seem to match because we got the carbon dioxide reductions from the E85 and then we got clobbered a bit for the hydrogen on board," Maxwell says. "We wanted to get the best power we could. We didn't do anything to the engine other than change the injection system so we probably lost a little power there."
UC-Davis designed a front powertrain by replacing the stock 3.4-liter engine with an E85 tuned 1.5-liter Atkinson cycle engine, a UC-Davis-specific custom design continuously variable transmission (CVT) and a UQM Technologies Inc. electric motor. The vehicle's battery pack was an easily rechargeable 346-volt, 16 kilowatt per hour GAIA Technologies lithium-ion battery that provided 40 miles of electric range. The team placed 16th overall in the field.
"UC-Davis probably had one of the most complex configurations with their plug-in hybrid," Jehlik says. "That team came a long way this year."
Looking Ahead to ‘NeXt' Year
With the Challenge X series completed, the students are now turning their focus to next year's competition aptly dubbed "EcoCAR: The NeXt Challenge." Students who participate in EcoCAR will design and build advanced propulsion systems into a GM-donated 2009 Saturn Vue crossover based on the California Air Resources Board's zero emission vehicle regulations. Similar to Challenge X, students are encouraged to explore a variety of solutions, including electric, hybrid, plug-in hybrid and fuel cells. Additionally, they will incorporate lightweight materials, improve aerodynamics and utilize alternative fuels such as ethanol, biodiesel and hydrogen. Some schools have already begun the initial design work of their vehicles for the new three-year competition.
As for Challenge X, the hard work that went into it by the students, their advisers, sponsors and everyone involved won't be forgotten, according to Jehlik.
"It's been an amazing competition and it's been an honor to work with these students and sponsors who have put their hearts and souls into the event," Jehlik says. "At the end of the day, for every ounce of sweat and tears, these students are coming out and going into the industry becoming the change that we all need and want to see."
Maxwell echoes Jehlik's sentiments. "It's been a lot of fun," he says. "The students learn a tremendous amount that you just can't learn in the classroom."
Bryan Sims is an Ethanol Producer Magazine staff writer. Reach him at firstname.lastname@example.org or (701) 738-4950.