Jason Cammisa:

Let’s get one thing straight: The variable-valve-timing, direct-injection, turbo-wonderful powerplant in your new car is not cutting-edge. Despite the complexity of the modern engine, the fundamentals haven’t changed since Grover Cleveland was in office. Pistons turn a crankshaft that eventually spins your car’s wheels.
 
 Yawn.
 
 Electrically driven cars are the future. But until we have cheap, 1000-mile batteries, we still need range-extending fossil-fuel engines. Those devices don’t need to turn wheels, just generate juice. The simple solution is to strap a generator to a piston engine, as BMW did with the two-cylinder range extender in its i3 EV. But if the engine never turns a wheel, there’s no need for it to rotate anything. Why not cut out the middleman and use the piston’s reciprocating motion to generate electricity? That obviates camshafts and most other rotating parts, too.