Still not sure electric power is the wave of the future? Here's a way to keep yourself squarely on the fence, batteries powered by gasoline. Set your coffee down and think about that one. When I saw this story the other day I wasn't sure what the breakthrough was. Clarian Labs designed this small rotary engine/generator, but except for size, why is it different than rotary engines we've seen before in Mazda cars or motorcycles like the Hercules or Suzuki RE5?
The difference is there's no output driveshaft. The rotary piston does not mechanically drive any external transmission, instead, the piston rotates around the components that make up the generator itself. The only output of this engine is electricity. Electricity stored in capacitors starts the engine rotating, like a starter normally would, then the gasoline or other fuel takes over. The capacitors can also be used as a power booster if needed, but all of the rotating mechanical energy is used to generate electricity to run electric motors or whatever else you want. Think about this, there are no external storage batteries, generators, flywheels, alternators, fan belts, pulleys or gears to bolt on and take up space. Even the starter is internal.
Another interesting difference between this unit and a normal rotary engine is extra pistons operate asynchronously. In other words, you can add more rotary pistons to scale up for more power but they are not connected to any common crankshaft so each piston can operate independently, at a different speed or not at all, depending on the requirements for power or efficiency with all of this controlled by the Energy Management System (EMS).
The rotary engine/generator/battery can run on many different fuels from gasoline to propane, natural gas, ethanol, methanol or hydrogen. It's an electric battery you can refill at the gas pump.
Clarian originally designed this for the Department of Defense for their humanoid robot program so it was fairly small, but it can be scaled down or up very easily. They say a typical unit would be about the size of a standard car battery.
You have to think about this for a bit to really get it and after you do, it seems like a pretty neat setup. You can use a small one to power electronics or a bigger one to run an electric vehicle. It would seem to shrink the actual power unit necessary in most applications but it would be an interesting and complex calculation to know if it was any more efficient. I'm still thinking about this one but it's definitely worth a look.
Previously on The Kneeslider: Free Piston Engine which also directly produces electricity from mechanical motion
Of course, we might end up with this: Video below