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AZEqualizer
10-28-2008, 07:22 PM
Dean Kamen working on Stirling engine-assisted electric car (http://www.autobloggreen.com/2008/10/28/dean-kamen-working-on-stirling-engine-assisted-electric-car/)This was inan article on Autobloggreen today (Oct 28,2008)

http://www.blogcdn.com/www.autobloggreen.com/media/2008/10/618px-betastirlingtg4web.jpg

The internal combustion engine, as we've known it for over a century, is what's known as an open cycle device. That is, the so-called working fluid flows into and out of the engine and is constantly circulated. A closed cycle engine keeps the same working fluid contained within the device and heat is generated externally rather than from combustion inside the cylinder. The best known example of the latter is the stirling cycle engine. The advantage of the stirling cycle is that the heat source can be anything since the combustion (or non-combustion) occurs outside of the mechanism. The theoretical thermodynamic efficiency of the stirling cycle is 100 percent although creating a 100 percent efficient mechanism has proved elusive. Nonetheless, the flexibility of the stirling engine has made it a popular choice among those researching alternative powertrains.

When it comes to alternative anything, few people rank with Dean Kamen. Kamen is best known to most people as the creator of the oft-derided, but certainly innovative Segway scooter. For some time now, Kamen and his staff have been working on a extended range electric vehicle. As with most other EVs of late, energy storage comes in the form of the usual array of lithium ion batteries. The stirling engine will be used to recharge the battery pack making the car useful for more than just urban commuting. If anyone can make the stirling engine work in a car, Kamen might be the one. We'll have to wait and see.

[Source: The Telegraph (http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/27/sv_deankamen.xml)]

Derwin
10-28-2008, 08:10 PM
Very cool! But please tell me that I don't have a dirty mind. :shup:

Miracleman89
10-28-2008, 08:29 PM
Rotflmao!!!!!! r:o:f:l:2:2:1

It is not just you, or we are both in trouble!

Miracleman89
10-28-2008, 08:45 PM
Something tells me that this style engine will be found in vehicle that look like someone is trying to compensate for something!

r:o:f:l:2:2:1

ziggy951
10-29-2008, 12:03 AM
Did you see two piercings or just one piercing gone bad?



Z

Mark Tomlinson
10-29-2008, 12:56 AM
Children! Please, behave!

Meanwhile, perhaps a better article about Dean Kamen and his Sterling Engine ambitions - http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/27/sv_deankamen.xml

Mark Tomlinson
10-29-2008, 12:58 AM
(Okay, I got to admit my first impression was that we'd have to ban AZE for posting ****).

Miracleman89
10-29-2008, 03:29 AM
I have to say this has really been good for a laugh!!!!

westonlgray
10-29-2008, 08:57 AM
Hopefully the article was also honest enough to explain that the 100% efficiency they are talking about is not 100%. For stirling engines, in theory, they could approach Carnot efficiency which is not 100% efficient. A realistic Carnot efficiency is 75%.

Therefore, if you could make a perfect stirling engine, it would be around 75% efficient at most. In practice, like other types of engines, you never quite get to the theoretical limit. That means that if you could make a very good stirling engine, it would be as efficient as a very good diesel engine plus or minus a couple of percent.

miraclewoman89
10-29-2008, 10:12 AM
Something tells me that this style engine will be found in vehicle that look like someone is trying to compensate for something!

r:o:f:l:2:2:1


I think you'd find it in a woman's vehicle myself.=y:

Mark Tomlinson
10-29-2008, 11:45 PM
Hopefully the article was also honest enough to explain that the 100% efficiency they are talking about is not 100%. For stirling engines, in theory, they could approach Carnot efficiency which is not 100% efficient. A realistic Carnot efficiency is 75%.

Therefore, if you could make a perfect stirling engine, it would be around 75% efficient at most. In practice, like other types of engines, you never quite get to the theoretical limit. That means that if you could make a very good stirling engine, it would be as efficient as a very good diesel engine plus or minus a couple of percent.
Yeah. I saw that figure in two different articles about Kamen and the Sterling as well. I'm no engineer, but I know the laws of thermodynamics make 100% impossible. 75%. however, is damn good if they can reach it.

I wrote it off as a journalistic blunder. It would have really irked me if a science writer had made the claim. What bugs me, though, is that I saw it in two articles about Kamen's Sterling. I hope that one article is just repeating the claims of the other and that neither are quoting Kamen. DEKA, itself, claims (http://www.dekaresearch.com/coreTech.html#) "an inherently high potential for thermodynamic efficiency", but doesn't make any claims about being impossibly perfect.

By the way, Kamen's site has a much less suggestive photo (http://www.dekaresearch.com/popUps/popImages/StirlingEngineLG.jpg).

Mark Tomlinson
10-30-2008, 12:08 AM
Another point that is made with the Sterling, and proven out by Kamen's work, is that the Sterling really is "flex fuel" compatible. Or at least more so than any internal combustion engine.

AZE makes a good point in another thread that to be multi-fuel compatible, an internal combustion engine must change out everything from the fuel pump to the injectors and more, as well as adapt it's fuel/air mixture accordingly. For even my favorite vaporware engine, the Starrotor, this means significant changes to the engine itself.

Since a Sterling uses any source of heat, theoretically, all you need to change is the heat generator. In fact, a device to combust gasoline could probably be designed to also combust diesel, bio-diesel, ethanol or vegetable oil without modification.

In practice, however, I bet the DEKA Sterling version 1.0 has a combustor built into it that will be optimized for one (or a couple) of type(s) of fuel. But if this thing comes to market, it leaves the door open to someday filling your tank with whatever is available - or cheapest.