Dean Kamen working on hybrid scooter with Stirling engine
Dean Kamen's Stirling-powered hybrid scooter patents - Click above for image gallery
We've known about Dean Kamen's work on the Stirling engine for hybrid vehicle use since the inventor introduced the DEKA Revolt late last year. According to some recently-filed patent applications, though, it would seem that Kamen has lots more up his sleeve for the good 'ol Stirling engine, including a possible hybrid scooter.
According to Gizmag, Kamen is thought to be using a prototype scooter featuring the Stirling hybrid powertrain at his personal residence on an island a mile off the coast of Connecticut. From the patent drawings, we can see a that the Stirling engine is mounted at the rear of the bike while a rechargeable battery pack for the electric motor sits under the scooter's floor.
According to the report, Kamen has invested some $50 million into the development of the Stirling engine, though it's unclear whether there are any possible production plans for this particular hybrid scooter.
[Source: Gizmag]
Reader Comments (Page 1 of 1)
bvz 8:20PM (7/01/2009)
Sorry for being a bit dense... but what is the advantage of a sterling engine hybrid over a regular ICE hybrid? Not being snarky. I'm genuinely curious.
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Chris M 9:23PM (7/01/2009)
The stirling, being external combustion, can use any fuel or heat source, and the continuous combustion makes it easier to control emissions.. Stirling engines tend to be smooth and quiet running. If there is a sufficient temperature difference between "heat in" and "heat out", it can be more efficient than a high efficiency IC engine.
Stirling engines work best at a constant power and speed, and respond rather slowly to changes in burner output. That would be a major problem if used as the only engine in a car, but is no real problem for a series hybrid setup like this.
Now for the downsides. Stirling engines tend to be larger and heavier than IC engines of equivalent power, though careful design and use of lightweight materials like aluminum can help. To obtain high efficiency, it needs a very large heat sink to dispose of waste heat - for land vehicles, that means huge radiators. Cooling the engine might prove to be a major problem for this scooter.
By the way, there have been proposals to use stirling engines to power private aircraft, using the wings as radiators. The large wing surface insures low "heat out" temperatures fir high efficiency, while the heat keeps them clear of ice.
kert 2:42AM (7/02/2009)
If he has a working small-scale stirling generator, producing a working scooter prototype should be really easy : high power electric scooters like XTreme XM-5000Li and Vectrix are readily available, purchase one and add your generator through regular battery charge port without even breaking warranty.
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