Jun 5, 2008

6 Fuel-Efficient SUV Mods by College Kids: 2008 GM Challenge X Test Drive

For the second year in a row, Mississippi State University (MSU) took home top honors in the Challenge X, a competition sponsored by General Motors and the U.S. Department of Energy that invites teams from colleges across the United States and Canada to mod an SUV and make it go green. GM supplied each of the 17 teams a with a 2006 Chevy Equinox, then let them employ any technology at their disposal to achieve better fuel economy and lower emissions while maintaining driver comfort and vehicle performance. Team MSU bested the other 16 entrants with a 38-percent boost in efficiency.

Team MSU’s Equinox uses a through-the-road parallel hybrid architecture, which is powered by both a direct-injected 1.9-liter turbo diesel engine running on B20 biofuel and a 45-kW Ballard Integrated Power Transaxle electric motor. It gets 23 mpg around town and 33 mpg on the highway. While these numbers might not seem very impressive, they are a dramatic improvement over the sport-ute’s stock 18-hp, 3.4-liter V6’s measly mileage rating of 17 city and 24 highway.

The contest follows the typical timeframe for bringing a vehicle from planning through production—approximately 72 months. The first year of the Challenge was dedicated entirely to simulation, modeling and projection. “Students used tools to simulate and predict emission and fuel-economy goals,” explains Ed Wall, program manager for vehicle technology at the Department of Energy. The physical work began in Year Two, after the vehicles were distributed. Each team had a functioning mule vehicle by the end of the second year, and then refined and tweaked it during the third go-around. By Year Four, these one-off Equinoxes were ready to meet production standards of fit, finish and reliability.

Students employed everything from regenerative braking and engine stop/start technology to ultracapacitors and plug-in hybrid setups to take home the prize. Each vehicle was judged for drive quality, consumer acceptability, technical presentation, technical progress, on-road safety, acceleration, auto-cross, on-road-emissions and well-to-wheel greenhouse gas emissions. Judges subtracted points from mules that strayed too far from the original plans. In the end, the panel felt MSU brought forth the best compromise. Here’s how five other teams modded their Equinoxes. ... —Basem Wasef

University of Waterloo

Sporting the only powertrain running solely on hydrogen, the University of Waterloo’s ambitious fuel cell entry incorporates two electric motors driving all four wheels, hybridized with a 300-volt nickel metal hydride battery pack. A massive hydrogen tank constructed of carbon fiber was not only rigorously tested for leaks, it also had to be secure enough to maintain its integrity in the event of an accident.

When we drove it, the vehicle buzzed, vibrated and hummed, illustrating some of the inherent challenges of building your own alternative-fuel vehicle. Nonetheless, team co-captain Charles Hua says he’s proud of the team’s work, especially the copious amounts of carbon-fiber parts that were custom-made in order to keep it within the Challenge X weight limit.

Texas Tech University This parallel hybrid system incorporates an E85-burning, 2.4-liter Ecotec engine mated to a hydrogen injection system for cold starts and cruising, and a 36-volt COBASYS nickel metal hydride battery for its GM Belt-Alternator-Starter.

Though hydrogen is one of the sexier alternative power sources available, team member Tim Maxwell remembers a moment in which the technology’s dangers became imminently visible. “In Michigan we had an event where somebody took too many fittings out, messed up the check valve, and we couldn’t find the leak. It was an exciting few minutes,” he recalls.

University of Tennessee
This direct injected 1.9-liter turbo burns B20 biodiesel, and gets supplemental power from a 67 kW Ballard AC Induction Transaxle motor drawing juice from 288-volt nickel metal hydride batteries. “Having access to the 1.9-liter turbodiesel alone was worth coming to the competition,” says team member Scott Curran.

One of Tennessee’s biggest challenges was using computer-aided design to model the vehicle’s subframe so it could handle the stress of the 90-hp electric motor.

Ohio State University
Like many Challenge X vehicles, the Ohio State Equinox incorporates a through-the-road parallel configuration using a B20-burning 1.9-liter turbo diesel, nickel metal-hydride batteries and a rear-mounted electric motor that can propel the car up to 10 mph.

“Our car has excellent drivability,” boasts Craig Pablich. “We use an automatic engine stop/start strategy. Our Equinox matches the stock version from 0-60 mph, and is faster from 50-70 mph.”

San Diego State University
The unabashed hot rod of the group, SDSU’s Equinox utilized some inventive construction techniques in order to produce 400 hp and achieve a combined fuel economy figure of 32 mpg. “We tracked down nickel metal hydride batteries from Toyota Priuses that were damaged in Hurricane Katrina,” explains team leader Frank Falcone. By doubling the battery’s capacity and using a 200-hp AC induction motor at the back wheels, SD State was able to offer more grins per mile than other more sensible designs.

While its fan-cooled hood scoop and copious engine venting suggest that this car plays on the outer boundaries of the contest’s rules, SDSU’s so-called “Freaquinox” proves there’s no reason why sustainable mobility can’t be fun.

1 comment: