Physicist Daniel Cohn's invention doesn't look like much--it's just a small metal cylinder about the size of a soup can. But if some forthcoming experiments pan out, the little can might one day become a standard feature in automobiles. The device is called a plasmatron, and Cohn and his colleagues at MIT are using it to turn gasoline and other fuels into a mix of hydrogen-rich gases that are far less polluting than regular gasoline.
The MIT team has not yet installed a plasmatron in a car, but they have injected various fuels (even canola oil) into the device and measured what comes out. In a car, says Cohn, "the plasmatron would be like a carburetor--it's a fuel preparation unit." Instead of 100 percent fuel being pumped into the engine, about a quarter of the fuel would be diverted into the plasmatron, where it would be mixed with air.
Inside the plasmatron, an arc of electricity ignites the air-and-fuel mix into a plasma--a hot collection of molecules, atoms, and electrons. Gasoline, for example, breaks down into hydrogen and carbon monoxide. The whole process takes less than a second, after which the hydrogen-rich gas joins the rest of the gasoline going to the engine.
The mix of hydrogen gas and gasoline is more readily combustible than ordinary gasoline, which allows the engine to run on much less fuel. This increased fuel efficiency reduces pollution emitted from the engine by about 90 percent. And unlike a catalytic converter, a plasmatron doesn't need to warm up--it begins working as soon as the engine starts, when a car emits much of its pollutants.