Sayan Biswas is inventing an unusual kind of green car: one that burns gas…

Squeezing more efficiency out of internal combustion engines is a difficult challenge. Engineers have been designing and redesigning car engines for more than a century, and in recent years progress has slowed. To Biswas, the problem came down to one thing: a better spark plug…

Cars equipped with plasma spark plugs could have a big impact on efforts to tame climate change. But trucks, boats, planes and helicopters may be a bigger opportunity. Unlike cars, all-electric versions of heavier, higher-powered vehicles can’t yet match the range of gas or diesel engines at a reasonable cost.

“Moving heavy vehicles like school buses. construction equipment and big trucks to electrification will definitely be slower,” says Kate Whitefoot, an associate professor of mechanical engineering and public policy at Carnegie Mellon University who studies transportation. “That’s where improving the efficiency of internal combustion engines will be important.”