Here is the original article: http://www.technologyreview.com/energy/21442 http://www.technologyreview.com/energy/21442 Caption: Piston power: In an unconvent

Here is the original article: http://www.technologyreview.com/energy/21442 http://www.technologyreview.com/energy/21442 Caption: Piston power: In an unconventional engine design, a rod with a piston at either end shuttles between two combustion chambers. Magnets at the center of the rod move past metal coils (orange) to create an electrical current. I usually call these crankless engines. . Free-piston engines aren't new: they were invented in the 1920s. But the increased recent focus on hybrid cars has led a growing number of research groups and automakers to start research programs to develop the technology. Unlike in conventional engines, there is no mechanical connection between the piston and a crankshaft (hence the name free-piston). Since the design allows for improved combustion and less friction, the engines could be far more efficient in generating electricity than either conventional generators or newer fuel-cell technology.