REALITY CHECK; Challenge X strives for extreme fuel economy and real-world driveability.

Byline: GEORGE P. BLUMBERG

Although the venue was New York City's posh Tavern on the Green, the engineering students from 17 universities who were assembled on May 16 at the Central Park restaurant seemed oblivious to their upscale surroundings.

Instead, the teams were tightly focused on their accomplishments as part of Challenge X, a competition sponsored by the U.S. Department of Energy and General Motors that asked teams to reengineer a 2005-model Chevrolet Equinox. The teams were challenged to use advanced powertrain technologies to create vehicles with improved fuel economy and lower emissions, all while maintaining driver comfort and vehicle performance. Argonne National Laboratory gave technical support, and more than 30 industry sponsors provided fuel cells, software, propulsion systems and control technologies.

Vehicles underwent a wide range of performance testing, the final stage being an economy run from New York to Washington, D.C., where the winners were announced on May 20.

To modify the Chevy, the University of Tulsa team replaced the Equinox's standard 3.4-liter, 185-hp V6 with a biofuel 1.9-liter direct-injection turbodiesel pushing about 150 hp to the front wheels. A 67-kilowatt rear transaxle sends another 80 hp to the rear wheels. Energy is stored in a 288-volt nickel-metal-hydride battery. Particulate filters and urea injection function to scrub emissions

In the measured events, Andrew Harmon, who auto-crosses a 250-hp Honda ...