As I have said before, there are certain people whose activity, taken as a whole and per realizations, surpasses many bigger companies and many universities – Dean Kamen is one of them. The inventor of Segway (you know, those 2-wheeled self-balancing personal transporters you see in touristic cities – I saw one in Rome) is now specializing in Stirling engines – the grandfather of the steam engine and more efficient than current gasoline engines.
You can build a Stirling engine at home, out of a Cola can and some parts you can take from old toys. Stirling engines are based on a temperature difference between two cylinders. This difference moves the cold air from one to another and makes the pistons spin a crankshaft. Stirling engines have no gaseous output from their pistons, all the pollution they can cause can be controlled in the burner. Thus, you can burn virtually anything that burns, create heat and move the engine. The problem with Stirling engines is that they are harder to start and don’t respond as quickly to throttle-like action (if you ever drove a pure diesel you know what I mean) as gasoline engines do. That is one of the reasons they haven’t been mounted on vehicles.
Still, Dean Kamen comes with an interesting idea (I’m not sure if it’s really his, but he’s the one who applies it, anyway) and puts besides a stirling engine, an electric motor and a battery. What do you get from these three? A Stirling-electric hybrid, planned in the form of a scooter, that uses the power in the battery to drive the electric motor, responds promptly and torquefully to any throttle change, and is very efficient. The battery, on the other hand, is topped up by the Stirling engine, that creates electricity from its pistons’ movement. The Stirling engine can work even after the scooter has been parked somewhere and rests, because all it must do is burn what it has inside, and then… you know will create some ash and that’s all it can happen.
One beautiful and environmentally-friendly part of this invention is that the burning can be much more efficiently monitored with high-quality burners, that incinerate the fuel entirely and don’t leave hydrocarbons in the atmosphere, like petrol engines do. Anyway, you can even fuel this thing with petrol or biodiesel, and still have much higher efficiency than you classic car has.
Of course, the tutorial from the post I linked to above only shows how to make a rudimentary stirling engine, but it shows the minimum you have to know. If you’re a passioned DIYer, I see no reason why you shouldn’t build one for yourself or your kids.
One other interesting application of Stirling engines is a robot powered entirelly by one (of course, with an electric buffer), and that can feed itself with burnable stuff for years (or forever, if it can). Good job, mr. Kamen! Let’s see it for real! By the way, Dean Kamen is not at his first attempt to build a Stirling-electric hybrid. He already did that with an electric Th!nk. He named the car DEKA Revolt!