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As challenging as powering a small car by chemical reaction can be, this science experiment on wheels turns out to be a real blast. By Dan Tuohy
The students affectionately named their vehicle for the robot character in “Futurama,” Matt Groening’s animated television sci-fi comedy, because it has some bendable parts. But the nickname also tells the story of the annual Chem-E-Car competition: As challenging as powering a small car by chemical reaction can be, this science experiment on wheels turns out to be a real blast. “It’s purely for fun,” says Yang Lu, Cornell’s past team chairman, who graduated in May. The American Institute of Chemical Engineers organizes the Chem-E-Car competition, in which students design and build a car powered with a chemical energy source that will carry a specified load over a given distance and stop. At the finish line, there is no checkered flag nor winner’s circle. It’s a competition, not a race. As the first T-shirt for the Cornell University team proclaimed, “Speed is not an option!” The national competition in November kicks off the institute's annual meeting in Salt Lake City, Utah. University teams win a berth via regional conferences. Cornell qualified at the Northeast Regional Conference held at Northeastern University in March. In that race, Lu says Bender traveled only a short way, but the car was able to stop within the required two minutes and the team won a third place. Stopping on time is crucial because it demonstrates precise calculation of the chemical reaction involved. “One of the toughest challenges is the cars have to start and stop within two minutes,” says Lu, who hails from Brookline, Mass.
The model car must fit into a shoe box with dimensions no larger than 40 centimeters by 30 centimeters by 18 centimeters. The cost of the contents of the box, including the chemicals, must not exceed $2,000. Chemical cars cannot be controlled remotely. Brakes, internal flames, and smoke are prohibited. And it may go without saying, but the rules underscore that the drive system have no commercial batteries and no mechanical or electronic timing devices. Competition rules get tougher every year and Lu welcomed the challenge. “That’s what the real world is all about, so it’s good for students,” Lu says. Before the Cornell creation can zoom away on a straight track, judges will put the team to the test with a thorough technology review and environmental and safety checks. The event begins with a poster presentation in which each team explains the chemical reactions at play and details their attention to performance and safety issues.
Attention to detail and the ability to think fast pays off during competition. Lu recounted how during the Northeast Regional his team neglected to account for secondary containment for a dilute acid, as a precautionary backup. After the judges’ scrutiny during the inspection phase, the team manufactured one out of a plastic lunch box and it worked just fine. “Such on-the-spot actions can make or break a team in the performance segment as well. The teams do not know beforehand exactly how far their car will have to travel or how much it will have to carry, only that the distance this year will be between 50 and 100 feet, while the load will be between zero and 500 ml of water. Once the teams learn the exact distance and load, they have just one hour to calculate the necessary adjustments to fuel or reactants.
Awards are given for the most creative drive system, the most consistent performance, and competitive spirit. There is also the “Golden Tire Award,” a peer-elected award for the team with the most creative Chem-E-Car. Cornell has participated in the competition for several years, experimenting with a variety of car designs and chemical reactions. The competition is so stiff that no university has won more than once since it was launched in 1999. Cornell has never won the national trophy. Adding to the challenge, the same car cannot be used from year to year. Last year, Cornell entered a piston-based car driven by the production of oxygen gas from the dissociation of hydrogen peroxide. Bender is powered by a hydrogen fuel cell connected to a motor with a kind of acid switch in between. Hydrogen is stored at 20 psi and released into the fuel cell at 3 psi to generate power for the motor that moves the car. To close the circuit connecting the fuel cell to the motor, a magnesium strip is dipped into acid. Once the magnesium strip dissolves, the top of the car pops open, disconnecting the fuel cell from the motor. By adjusting the length of the strip, the students can control the distance the car travels. Bender will undergo several modifications before the national competition, partly because it was the team’s first attempt at designing and building a fuel-cell vehicle. The overhaul includes studying ways to drop its weight, acquiring a new motor, and adding new fuel cell stacks, according to the team’s post-race review. In the days after the regional competition, the team set about trying to acquire a sponsor to help subsidize the costs of the fuel cells. The team has enjoyed the support of the School of Chemical and Biomolecular Engineering. Besides the Chem-E-Car materials and parts, travel expenses for the regional and national competitions are the big cost. Many college teams are leaning toward the use of fuel cells, rather than a pressurized system or action, Lu noted. If the Cornell University team gets more members, it may choose to launch a second car for future competitions. Lu envisioned the team leveraging mechanical engineering students and support to improve the gear ratio of future cars.
The University of Puerto Rico won first place last year, followed by the University of Dayton and the University of Maine. The top three teams, in order of success, win $2,000, $1,000 and $500. The top three last year all used hydrogen fuel cells to power their cars. Of several ancillary awards this year, the Society of Biological Engineers sponsors a $1,000 prize for the best use of a biological reaction to power a car. With America so focused on alternative fuels, the Chem-E-Car competition serves as an important avenue for college students to learn about the chemical reactions that can move vehicles, according to the American Institute of Chemical Engineers. The institute created the competition as a fun and practical way for students to apply their knowledge of chemical engineering principles. A national competition also gives the public a better understanding of alternative fuels, says Tim McCreight, AIChE marketing director. For the mainstream media, it is an appealing news hook. For the competitors, McCreight says, “the benefits are they learn how to work as a team in a very real-world environment.” AIChE President-elect Dale Keairns is enthusiastic about the competition for its focus on energy as the grand challenge of our time. Students must work with process and systems integration, while experiencing the ups and downs of innovation, which Keairns called the reality of the real world. “It’s a very practical application of chemical principles,” he says. “It provides students an opportunity to experience the joy of accomplishment. These students really have fun.” The other reality is that the industry, with its aging workforce, has a demand for young engineers in existing roles as well as emerging technologies, says Keairns.  Past competitors have pursued related endeavors after college. Students from Michigan Technological University, who won a regional competition in 2002, went on to launch their own company developing prototype hydrogen fuel-cell vehicles for a corporate client list that included Chrysler and John Deere.Paulette Clancy, the William C. Hooey Director and Professor at Cornell University’s School of Chemical and Biomolecular Engineering, says the student competitors may not be developing new technologies, but they are learning the issues involved in a moving vehicle, which the school hopes will generate enthusiasm for creating new systems for transportation. The human skills necessary to participate in, lead, and work cooperatively in a vehicle prototype design team are invaluable,” Clancy, co-adviser of the program, wrote in an e-mail. She says the student engineers need to understand reaction kinetics, process control, and thermodynamics—part of the core chemical engineering curriculum.
Students invest a lot of time—that precious spare time out of class—in the Chem-E-Car competition and its requisite preparations. A dozen students participated on the team last spring, including several women. “This is a unique program which enriches our educational experience,” says Clancy, noting with pride the strong participation by women students. Lu says the competition also builds camaraderie. “You can’t do everything by yourself,” he says. “What is really rewarding for me is to see guys develop.” Before he graduated to put his chemical engineering degree to work, Lu named Ka Yip and Daniel Lee to serve as co-chairs as they start their senior years at Cornell. The best part of the challenge at the national competition, says Lee, is the hands-on work and the immediacy. He sees it as a reprieve from the theoretical in the classroom, and relishes being forced to engineer around problems as they arise. “The fun part,” Lee says, “is that once we do something we can immediately see if it works.”  |
