U.S. consumers were still reeling from the 1970s oil embargo that caused gasoline prices to soar when the top SAE Supermileage team fielded a car that snared 558 mpg at the inaugural competition.
Thirty-five years later, SAE Supermileage collegiate students are still scoring triple-digit mpg via their team-created, -designed, and -built vehicles. At the 2014 event, five teams fielded vehicles that exceeded four-digit mpg.
Since that first hyper-mileage contest in 1980, a slew of single-seaters have traveled Eaton’s 1.6-mi (2.6-km) test track in Marshall, MI, at a rule-mandated maximum average speed of 25 mph (40 km/h). Drivers must maintain an average minimum vehicle speed of 15 mph (24 km/h) during six laps.
Other than the driver weight requirement dropping from a minimum 150 lb (68 kg) to 130 lb (59.0 kg) with ballast if needed, the competition was virtually unchanged. Even the single-cylinder, 3.5-hp (2.6-kW) Briggs & Stratton engine, typically used for rototillers and snowblowers, remains an equipment staple.
“The competition rules haven’t fundamentally changed in 35 years," Jim Gluys, Supermileage’s event manager and a product design engineer for Eaton Vehicle Group, said in an SAE Magazines interview. "This year we’re starting the transition to another Briggs & Stratton engine, so a couple of teams are using that Junior 206 model. But the basic engine used by all teams has been the same since the competition’s inception.
What has changed over the years is technology has evolved, so it’s possible for teams to find low-friction tires, better oil for the engine, high-performance bearings, even carbon fiber.”
Lightweight materials are overwhelmingly favored by teams. Popular shell materials included fiberglass, clear plastics, and fabric. But carbon-fiber “was by far the most utilized [shell] material,” said Philip Wetzel, an engineer in Eaton’s supercharger division and Supermileage’s coordinator for written and verbal team design reports. (Teams score points for mileage and for quality of their design report).
The hands-on experience of building a vehicle from scratch is an excitement-generator.
Standing next to their brightly colored yellow, blue, and red vehicle, the 16 Universidad Simon Bolivar (USB) teammates flash big smiles. “Our university has been at other SAE competitions—Formula SAE and Baja SAE—but this is the first time for Supermileage,” Gustavo Santamaria, a USB production engineering student at the Venezuelan, school told SAE Magazines.
To make the vehicle’s fiberglass body that surrounds a stainless-steel chassis designed in Dassault Systèmes’ SolidWorks, the team talked with a sculptor after realizing a preferred fiberglass mold-making method would be too expensive.
Explained USB electronic engineering student Andreína Parés: “First, we boiled the [laundry] soap so it would be kind of thick, and then we added the floor wax and ‘cooked’ the mixture for a few minutes. When it was still hot, we poured it over the styrofoam mold to fill up the holes and shape it. The mixture stayed over the styrofoam, [forming] our mold. Upon that, we made the fiberglass. Because the mixture is oily, that allowed us to remove the fiberglass easily.”
The Venezuelan team completed the technical inspection process but did not achieve a qualifying fuel-economy run.
Five mechanical engineering students from The College of New Jersey (TCNJ) designed and built their supermileage vehicle as a senior project. The three-wheeler had a 6061-T6 aluminum frame covered by a transparent polycarbonate fairing. A two-stage chain drive converted the engine power to rear-wheel-drive rotation.
Engine rpm was controlled by a mechanical speed limiter. “We made a throttle plate that just has two slots in it. The first slot is the idle slot, so you can have the full range of the engine and it will return to idle,” said team member Matt Southard, adding, “The second slot will stop at whatever rpm the engine is at when you let go of the throttle handle.”
The team’s pre-competition fuel-economy strategy centered on having a consistent rpm range, he explained: “This approach gives us a lot of versatility. We have a screw that makes the throttle system adjustable so we can set a different depth on the slot. If on race day we determine that the car is not going fast enough or the fuel economy isn’t where we want it, we can adjust that very easily right from the field.”
TCNJ team’s vehicle achieved 245 mpg.
From start-to-finish, Southard relished the teamwork experience. “Our advisor [professor emeritus Dr. Norman Asper] shared a lot of knowledge with us," he said. "He’s been at this school for more than 40 years, so that really helped with project development. Now, I’m looking forward to enjoying another team experience that works well to achieve a well-oiled machine.”
Freudenberg-NOK Sealing Technologies sponsored a team at the 2013 competition. “But this year we wanted to take a bigger role, so we’re an event sponsor,” said Mike Rowe, the firm’s Strategic Product Development Manager. In advance of the 2014 event, the company offered Supermileage teams custom-designed Energy Saving Seals for the Briggs & Stratton engines used by teams.
Beyond getting engineering students familiar with Freudenberg-NOK’s lower emissions/lower fuel economy product line, Rowe views Supermileage as a venue for introducing the students to the company.
“We’re always looking for young engineers to come join the company, and these are some of the best and brightest," he said. "These are the students going above and beyond to get such a wide, broad education. They’re learning in the classroom, but they’re also learning the real-world lessons out here through the school of hard knocks,” Rowe said, adding, “For us, recruiting here is so much more valuable than just going to the university.”
Cory Newton’s participation on Brigham Young University’s SAE Supermileage team supports his next educational journey. “Working with carbon fiber and other composites and metals for the BYU Supermileage vehicle helped develop my skills in designing and fabricating structures,” he said, noting that he’ll return to BYU this fall in pursuit of master’s degree in mechanical engineering while researching the field of nano-composites.
The BYU vehicle featured an integrated carbon-fiber frame that transitioned to an aluminum rear fork and aluminum front-wheel attachments. Explained Newton: “Our chassis was simultaneously laid up with the bottom half of the shell, and this assembly was vacuum-bagged. The engine plate, which is a carbon-fiber honeycomb-sheet steel sandwich, was subsequently integrated into the frame. The bottom and top halves of the shell were then fused together with carbon fiber.”
BYU’s vehicle tallied 1211 mpg, the highest fuel economy of the 19 competing university team vehicles. The next highest mpg numbers were by Université Laval of Quebec, Canada (1145 mpg); University of Massachusetts-Amherst (1142); École de Technologie Supérieure (ETS) of Quebec, Canada (1134); and Penn State University-Behrend College (1020).
Université Laval of Quebec, Canada, was the overall winner with the highest score (1533) for combined mpg and design report, and for its efforts receives $1500. Following Laval, in order, were École de Technologie Supérieure (1517), BYU (1514), University of Massachusetts-Amherst (1485), and Penn State University-Behrend College (1410).
A team from the University of California-Los Angeles won the Design Report portion of the competition with a score of 408. The University of Illinois-Urbana Champaign team won the Best Newcomer Award. The City College of New York was chosen by the event organizing committee to have the Best Design Execution; Ryerson University received the Best Demonstrated Overall Team Attitude Award; and Concordia University of Montreal won the 35th Anniversary Endurance Award (minimum of five successful fuel-economy runs).
“It is truly amazing what these student teams were able to accomplish,” said Tom Stover, Chief Technology Officer for Eaton’s Vehicle Group in Galesburg, MI. “The Supermileage competition helps them develop practical engineering, team building, and leadership skills that they can use to succeed in their careers, including making tomorrow’s cars and trucks more fuel-efficient.”Continue reading »