In the fall of 2008, Yale graduate student Henry Misas and three other students organized a club to participate in the Society of Automotive Engineers’ Formula Hybrid competition. The Formula Hybrid competition is an inter-collegiate engineering challenge in which students design and build a hybrid car to complete a series of tasks. Since then, the team has grown to roughly a dozen participants and achieved impressive results. Last May, the team earned a tenth place overall finish, along with a second place finish in the Best Engineered Hybrid System category.
The Yale Team
The team currently works out of a Yale laboratory on Hillhouse Avenue and Professor John Morrell serves as the team’s advisor. At the beginning of the school year, the team works primarily on Saturdays, but the students will extend work into the school week as the May competition date nears. “It’s a large time commitment,” commented team president, Jonathan Biagiotti. Students fabricate almost all components of the car except for the engine, brake pads, and a few other isolated parts. The car must have both gas and electric power but, other than safety considerations, there are few limitations on how the team can design the vehicle. 2011 marks the second consecutive year that the club team will compete in the international challenge held in Loudon, New Hampshire.
Construction of the current car began in the fall of 2008, and the team has made improvements and adjustments to the vehicle since then. There are sub-teams for the chassis, drive-train, electrical, suspension, and body of the car. The students welded a steel chassis and molded a sleek carbon fiber body for the vehicle, measuring roughly eight feet in length and seating one driver. The team also set up an intricate electrical system for the car with a unique electric throttle connection. The initial building took almost two years, and the team was ready for its first competition in May 2010.
The Formula Hybrid competition occurs every year in New Hampshire, and teams typically participate every year or in alternate years. Previously, Yale’s participation spawned from a senior mechanical engineering course, but the Formula Hybrid Club has assumed the responsibility for car construction. Last year, approximately thirty teams competed; many more are expected this year. The safety requirements for entry are significant, as each car must pass brake, tilt, mechanical, and electrical inspections before it is cleared to participate. These requirements serve as prerequisites for competition while the evaluation of the car is primarily based on performance.
The cars are judged through participation in five events. There are two static events, business pitch and design evaluation, and three dynamic events, acceleration, autocross, and endurance. Each team receives a score in the five events, and the final rankings are calculated with the total score from these independent categories. The business pitch event requires the team to advertise and promote the car to judges as though it were a commercial product. Last year, the Yale team had significant success in the static design evaluation, in which professionals and professors judge the car on its design efficiency and innovation in all major subsystems of the machine. Biagiotti observed that the judges were impressed with the parallel construction of the engine, which allows the electricity and gas to work more efficiently in tandem than in a series construction. The team earned a fourth place finish in the design event.
The three dynamic events require human operation. The first event tests the car’s ability to accelerate rapidly on a straight track using only electric power, followed by a retest using a combination of electricity and gas. The autocross event requires the driver to complete a racecourse in as little time as possible, so skilled operation of the vehicle is paramount. Endurance is the final and most important event of the competition. Teams must complete two circuits of thirteen laps on the track, but most cars are unable to finish. The Yale team completed the first circuit in good time last year before experiencing technical problems in the second circuit. Biagiotti indicated that the team is focused on improving the dynamic events this year to raise its overall score.
Improvements to the Car
Since the 2010 competition, the Yale group has revisited and fixed a number of systems in the car. The team replaced the heavy car batteries with small lithium ion batteries and added an electrical starter to the engine. In addition, improvements were made for driver ergonomics. The students use the Yale West Campus facilities and parking lots to test the car and allow the drivers to practice before the competition. Biagiotti expects sustainability to be more important in this year’s competition, and his team is ready to meet that challenge. Through the use of a device known as a dynamometer, which measures engine power, the students plan to test the fuel efficiency of the car and optimize its performance on the track.
The Yale group is comprised of members from a variety of major disciplines, including mechanical engineering, com¬puter science, electrical engineering, biomedical engineering, and even art. The construction of the car serves as a unique and valuable experience for all involved. In designing systems, students are able to utilize their engineering knowledge from academic courses and apply it in a physical setting.
Biagiotti observed, “I may have learned more through [Formula Hybrid] than I did in some classes. You learn that there’s no set way to solve problems, and here you have to figure it out for yourself. You really learn how an [engineering] project works.” There is little technical background required for students joining the team, as the necessary skills are learned through participation. “The only requirements are commitment and patience,” said Biagiotti.
Under the guidance of Yale machinists Nick Bernardo and Dave Johnson, the students have access to Yale’s machine shops, where they learn to weld, lathe, and machine various parts. Yale engineer Edward Jackson assisted with the assembly of the car’s electrical system. Through the mentorship of these professionals, students are able to fabricate and design the complete car. The team’s budget can run up to ten thousand dollars, with most of the support coming from the Yale School of Engineering and Applied Science and the Yale Science and Engineering Association. Local companies donate some parts for the car as well.
As the competition nears, the team is meeting frequently in preparation. With the new modifications to the vehicle and one year’s experience upon which to build, the team members are optimistic about their car’s chances for a stellar performance at the international event in May.
About the Author
JONATHAN GRECO is a junior in Berkeley College majoring in Physics and Mechanical Engineering. He works in Professor Tipton’s high-energy physics lab studying the mass properties of a subatomic particle, the top quark.
The author would like to thank Jonathan Biagiotti for his time and dedication to the Formula Hybrid team.
Thayer School of Engineering at Dartmouth College and SAE Interna¬tional. “Formula Hybrid International Competition.” http://www.formula-hybrid.org/
Bulldogs Racing Team. http://www.yale.edu/fsae/