Dean Kamen Combines Stirling Engine With Electric Car

Colin Smith writes "Dean Kamen, (inventor of the Segway) has combined a Stirling engine with a battery-powered electric vehicle based on the Ford Think to provide a fully decoupled electric hybrid car which can run on any fuel which can provide enough heat to run the Stirling generator. Think are also producing a purely battery 'Think City' car which is capable of 62mph and with a range of 126miles." Some stats on the Ford Think: Top speed, 55mph; 0-30, 6.5 seconds; Range, 60 miles on battery.

Comments

Disruptive technology

[Chairboy]

When he mentions it being 'disruptive', he's referring to the concept of disruptive technology as written about in The Innovator's Dilemma by Christensen:
http://www.amazon.com/Innovators-Dilemma-Revolutionary-National-Bestseller/dp/0066620694

Great read, and the concepts are laid out here:

http://en.wikipedia.org/wiki/Disruptive_technology

If you're not familiar with the concept, it's worth checking out.

Wondering what a Stirling engine is?

[mgkimsal2]

Wonder no more

"A Stirling engine is a closed-cycle regenerative heat engine with a gaseous working fluid."

As with many of these hybrid and electric car announcements, it'd be great if I could really go buy one, and have it be inexpensive. We're always just "2-3 years" away from these things reaching market, and "eventually" being affordable by regular folks.

Perhaps some Indian or Chinese company will make these and sell them here for under $10k. That would spark a huge revolution. Hybrids at $24k don't change people's buying habits enough to cause a huge shift in demand.

For better or worse, I think we'll see an alt-energy evolution in the US, rather than a revolution.

Re:stirling engine is a no-go

[rolfwind]

I'm no engines expert, but I thought the good part of a stirling engine was that they often are just a few percentage points from theoretical maximum efficiency of a heat engine, about 50%???

http://en.wikipedia.org/wiki/Stirling_engine

I thought the downside is that they take a while to get up to speed. Ford in the 1970s tested a small vehicle with such an engine and they could get it up to speed after 13 seconds. So it should be a natural fit as a battery charger in an electrical car...

At least, that's what I thought when I looked into this a few years back (just as a curiosity, nothing professional mind you).

Stirling not connected, not enough to power car.

[guidryp]

http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/27/sv_deankamen.xml

I read several articles on this when news first broke. The above indicates the Stirlin isn't even connected. When it is, it doesn't produce enough power to actually move the car. Kamen has a 1KW Stirling that is about the same size as what is pictured and other articles mentioned it as a "trickle charger".

In this case the Stirling is essentially a novelty, it doesn't drive the car when the battery is run down.

Re:The Uri Geller of industry

[abigor]

Well, I'd say his inventions such as the portable dialysis machine, the auto-syringe technology for people who require round the clock injections, and the wheelchair that can climb stairs made a tremendous difference. These medical inventions restored a reasonable standard of living to a great number of people, and are the foundation of his current fortune.

Re:stirling engine is a no-go

[JanneM]

Stirling engines can be fairly efficient if you have the (space and weight) budget to make them big and heavy. For cars they're certainly not a very good idea.

But the main point of Stirling engines isn't efficiency but the fact that they are not only fuel-agnostic; unlike combustion engines or steam engines they don't need any kind of combustion or medium phase-change to operate. Anything that can generate a temperature differential will do. They're also quiet and very reliable (few moving parts).

That makes them well suited for things like backup generators, where you can store them for years on end, then run them on whatever fuel you can get hold of. They're used in submarines too, due to their silent operation and no need for actual combustion to generate enough heat. You could set up a Stirling engine to run on the waste heat from other processes. And they're reversible, so they're used as coolers for certain temperature ranges (overkill for a normal freezer but if you want much colder it's one way to go). Heat pumps are essentially Stirling engines.

Shameless plug ahead: a blog post of mine on Stirling engines here: Stirling Engine

Re:stirling engine is a no-go

[shbazjinkens]

According to wikipedia, Stirlings have efficiency equivalent to conventional auto engines, but for the same power they're more expensive and heavier.

According to NASA, there was no weight change. Read it. More expensive is a matter of mass production, no auto engine is exactly simple nowadays anyway.

Re:stirling engine is a no-go

[ppanon]

It powers the features that would normally drain huge power from the battery, notably the defroster and heater.

Not much point being efficient at generating electricity etc. if its primary function is to generate heat.

A Stirling engine is an external combustion engine. It generates waste heat as a byproduct of operation just like an internal combustion engine does. That allows the heat to be used for the defroster and heater. But it's primary function is no more to generate heat than it is with the engine in your car. However, unlike an internal combustion engine that requires fuel that can undergo controlled explosion, the stirling engine just requires a source of sufficiently high heat (efficiency of the stirling cycle is related to the difference in temperature between heat source and sink).