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Duke students make Guinness record for world’s most efficient vehicle

Update: The Duke students broke the world record on their second attempt on July 21, reaching 14,573 miles per gallon with their vehicle. You can watch a video about the record-setting here.

This Saturday, a group of Duke students will use a prototype hydrogen fuel-cell vehicle to attempt to break the Guinness record for “world’s most fuel-efficient,” which was set in 2005.

In April, 17 members of the Duke Electric Vehicles student organization won three awards at the Shell Eco-Marathon Americas competition in Sonoma, Calif. For the second year in a row, they took first for most efficient electric battery vehicle in the American branch of the global efficiency competition, which has existed since 1939.

“After we won the competition last year, we asked ourselves, ‘where do we go from here?’” said Patrick Grady, president of the club. “The answer was hydrogen. Tomorrow we’re trying the world record, and next year they’re going for the electric [vehicle efficiency] world record.”

This year, the team decided to build a second vehicle and enter the field of hydrogen fuel cell cars. The resulting car was more than twice as efficient as the second place winner. After that victory, the students set their sights on the world record.

What is a hydrogen fuel cell vehicle?

Hydrogen fuel cells take the place of a combustion engine in a vehicle and run off of hydrogen gas. Instead of burning the fuel like a combustion engine, a fuel cell chemically converts hydrogen gas and air into water vapor and electricity.

“It’s a combination of a combustion engine and a battery,” said Nico Hotz, a professor at Duke’s Pratt School of Engineering, which houses the team. “It works more like a battery because there’s no combustion, but it’s like an engine because you have a fuel tank and you don’t have to charge it.

“It has two big advantages — no toxic climate-changing emissions, and it’s very efficient so you need less fuel than a combustion engine.”

A team of 70 Swiss students, professors and industry professionals built the record-setting 2005 car and won the Shell Eco-Marathon that year. The Duke team hopes to beat that record by 5 percent in front of a panel of three unaffiliated judges, who will measure how much fuel they use and verify how far they travel.

After their April win, the team fine-tuned every aspect of the car, which weighs just over 50 pounds.

“We made it lighter, we took out unnecessary components, we improved the wheel hubs, we used tubeless tires, we improved electronics,” said team member Shomik Verma. “We removed a converter, which means we can’t regulate the power directly.”

Converters let a driver decide how much electricity they want to use from the fuel cell. Without it, the driver can only oscillate between two speeds.

“I have to concentrate because it’s not like normal driving,” said recent graduate Anna Li, who will drive the car Saturday. “It’s like riding a bicycle and a go-kart. … The max speed is only 20 miles per hour, but it’s kind of scary when you go over bumps because there’s no suspension.”

Since the team maximized the aerodynamics of the vehicle, Li doesn’t get any ventilation. After she lies down in the car, they tape the top on and seal her in.

“Usually I’m so focused on the driving that I don’t notice the heat,” Li said. “The tires have a little bit of wind that passes through them. But it’s black, and you know how it is if you’ve ever been in a hot car on a sunny day.”

The path to the world record

During the fall semester, the team members design their cars. Over winter break they order parts and they put together their vehicles in the spring, preparing for the Eco-Marathon.

“I’m almost embarrassed they got the fuel cell-based car to work so well in less than a year,” said Hotz, the faculty adviser. “I have worked for more than 10 years on fuel cells, so I think I know a bit about them, but I did not do anything besides some brainstorming and ideas.”

The technology the students developed, which won an innovation award at the Eco-Marathon, will hopefully lead to leaps in the automobile industry.

“What I find really fascinating about this competition and the team is that we’re very open,” Hotz said. “All the construction plans, schematics and diagrams are publicly available. There’s no patents and no secrecy, so all the other teams can learn from us and do similar things next year as well. You could try to reproduce our technology tomorrow and build it.”

Right now the team is focused on Saturday’s attempt, when Li will take around half an hour to drive seven laps at Galot Motorsports in Dunn.

“We had two things go wrong when we tested on Wednesday — the fuel cell operated poorly and the tires were leaking,” Grady, the club president, said. “If everything goes perfectly, I’m very confident we can break the world record, but you can never guarantee that. I’m nervous but I’m hopeful.”

Grady stuck around after graduating this spring for the attempt. The team began seven years ago to compete in the Eco-Marathon. Some of the alumni now work at Tesla, said Braden Welborn from the Duke University Energy Initiative, which supports the team.

“This is an incredible learning experience for the students as they prepare to be innovators in the energy industry,” Welborn said. “We hope they achieve their goal tomorrow, but we recognize that the risk taking and experimentation they’re doing is worth celebrating in and of itself.”

world record duke team car
The Duke team with their cars and awards in Sonoma, Calif. at the Shell Eco-Marathon in April 2018. Ismail Iberkak
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