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Superefficient vehicle
The lean and efficient Bear, with creators (standing, left to right) James Jenkins, Kevin Ciocia, Matthew Rogge, Benjamin Chui, Suzy Park, Jane Chen, and (kneeling) Rui Lam and Kenneth Hsu

UC Berkeley students take top honors in fuel-economy competition at 1,068 miles per gallon
27 June 2002

By Bonnie Azab Powell, Public Affairs

Imagine driving from Los Angeles to Seattle — on a single gallon of gas. That's roughly equivalent to what a team of UC Berkeley engineering undergraduates achieved on June 8, when their vehicle won the Society of Automotive Engineers (SAE) Student Design Supermileage Competition held in Marshall, Michigan.

Berkeley's 2002 entry, "The Bear" (apparently the team saved its creativity for the design), beat out 20 other colleges by squeezing an efficiency of 1,068.69 miles per gallon from its standard-issue fuel bottle. Fortunately for the driver, the Bear did not have to travel quite that far: the performance segment of the contest required only six laps around a 1.6-mile test track at a minimum average speed of 15 miles per hour.

 
Driver Ken Hsu climbs in the "carbon coffin" so that supermileage competition judges can evaluate the vehicle's technical and safety compliance
 

Energy-conscious Californians won't be rushing out to test-drive this supermileage vehicle anytime soon. Yes, it's 15 times more fuel efficient than the Honda Insight hybrid car, but the Bear is definitely not for the claustrophobic.

"We call it the 'carbon coffin,'" says Ben Chui, the Bear's main designer and a May 2002 graduate in mechanical and materials science engineering. "With temperatures around 90 degrees in the June heat, the inside of the car can get up to 110."

Black, therefore, was probably not the most desirable color for the vehicle's fairing (its aerodynamic external shell). True, says Chui, but "the shiny weave effect of the carbon fiber looked cool, and we didn't want any extra weight." Without driver, the Bear tips the scales at 93 pounds. SAE rules specify that drivers can weigh no less than 130 pounds, and the Berkeley team's two drivers, Rui Lam and Kenneth Hsu, are as lean as jockeys in that regard.

The competition rules emphasize driver safety, setting strict guidelines for type of helmets, firewall placement between the cockpit and engine, fire extinguisher location, and how long it can take for the driver to exit the car unassisted. The contest leaves the vehicle dimensions up to the student teams: anything goes, as long as it has at least three wheels, uses a standard-issue Briggs & Stratton four-cycle engine, and runs solely on fuel, with no human or battery assistance.

Founded in 1995, Cal's supermileage team didn't crack the top 10 until the 2000 competition, when it came in third among the college teams. Because several high schools compete alongside the universities, that year Cal actually placed fifth overall. Then in 2000, one high school, St. Thomas Academy, set the contest's mileage record of 1,130.74 mpg. This year, Homestead High School of Fort Wayne, Indiana, squeaked ahead of Berkeley into overall first place with 1,071.83 mpg. "They had a professional fairing on their chassis," says Chui. "I guess it's a very good high school."

Compared to last year, the Berkeley team more than doubled its efficiency. While the near-perfect conditions — clear, calm weather and a recently resurfaced track — no doubt contributed, Chui also points to a major design change from previous vehicles. "We went with a fully enclosed vehicle, with the wheels inboard," he says, "and that gave us a significant aerodynamic advantage." Chui designed the fairing without any aerodynamic analysis software, using common-sense principles and design guidelines that he learned in a mechanical engineering fluid dynamics course. "The shape was really hard to fabricate, because it's all fully compound curves," he says.

For more information:
 
     
Development of the Berkeley supermileage vehicle
 

Other Berkeley student vehicle teams: CalSol, the solar-powered car; Human-Powered Vehicle; the newly formed Berkeley Formula SAE
 

The Society of Automotive Engineers' Supermileage Competition home page

         

A custom, reverse-ratcheted rear wheel, made by sponsor Phil Wood & Company, maximized performance of the drive train, while racing-bike front tires with a secret lubrication made coasting as frictionless as possible. Most of the teams use the "burn and kill" racing method, in which the drivers open the throttle and push the cars up to around 30 mph, before killing the engine and coasting to save fuel. An on-board bicycle computer keeps track of average speed and distance covered so as not to be penalized by falling below the average speed requirement.

Next year, the team plans to modify the stock engine, which is permitted with certain restrictions, to eke out a few more fuel-efficiency miles. Chui, who will be attending graduate school at Berkeley, says the undergraduates will be taking charge while he concentrates on raising the $15,000 it takes to field a vehicle. "Most of that money goes toward getting us and the vehicle to Michigan, which is quite an expensive trip," says Chui. For the 2002 vehicle, Chevron and the chip company Rambus each contributed $5,000, while Tap Plastics chipped in a 40 percent discount on materials.

With a top prize of only $500 at the Supermileage Vehicle competition, these students clearly are motivated by something more than NASCAR envy. "In mechanical engineering you usually get just one hands-on course, ME 102B," Chui explains. "This way, we get to apply what we learn in the classroom. It's a big project, but it can be done in a year. Plus it's just fun."



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