Enterprising hybrid owners tinker to get better mileage

Hybrid vehicles have been touted as the Next Big Thing in efficient transportation. So what’s the Next Next Big Thing? Maybe hybrids with a twist. A handful of engineering students at the University of California at Davis and other mechanically inclined greens have been tinkering with existing hybrids to boost their mileage by giving them increased battery capacity and a plug. The result is cars and SUVs that are still powered by a gasoline/electricity mix but whose internal-combustion engines switch on later and less often than those of unmodified hybrids — and on short trips, often not at all. Toyota insists that “plug-in hybrids” would be impractical due to the weight of additional batteries. But Andrew Frank of UC-Davis disagrees: “We’re just a bunch of students,” he said. “If we can build this with off-the-shelf technology, they can too — and do things better than what we do.”