Slashdot Log In
Dean Kamen Combines Stirling Engine With Electric Car
Posted by
timothy
on Sun Nov 09, 2008 05:16 PM
from the is-there-anything-kamen-can't-do? dept.
from the is-there-anything-kamen-can't-do? dept.
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.
Related Stories
[+]
News: Inside Dean Kamen's Seceded Island of Geekery 187 comments
mattnyc99 writes "The new issue of Esquire has a long, in-depth, intricate profile of Dean Kamen and his quest to invent a better world. Earlier this month, we discussed Kamen's Sterling-electric car, but this piece goes into much more detail about how that engine works — he got the original idea from the upmodded Henry Ford artifact in the basement of his insane island lab — and about how his inventions often go overlooked, including the Slingshot water purifier that Stephen Colbert made famous but that no one has actually bought yet. Quoting: 'To get the Slingshot to the 20 percent of the world that doesn't have electricity, Kamen came up with the idea of splitting it in half. Leaving the Stirling aside, he would try to develop a market for his distiller in parts of the developing world that have electricity but not reliable clean water. "There are five hundred thousand little stores in Mexico," he says. "If we can put one of these in 10 percent of them, that's enough to put it in production." That may be the killer app for the distiller.' So, is this guy all hype with overpriced devices, or is time for someone to take his genius (Segway aside) to the mass market?"
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Full
Abbreviated
Hidden
Loading... please wait.
stirling engine is a no-go (Score:5, Insightful)
It's been refined for 160 years plus change. So it ought to be really spiffy, right? Well, no. There are definite upper limits to the efficiency of such a device. Most Stirling sites are very cagey when it comes to mentioning the efficiency of what they're selling. For good reason, it's terrible. Like 3 to 6 percent. That kinda explains why it's not in use everywhere, more like nowhere.
Re:stirling engine is a no-go (Score:5, Interesting)
I've seen simple steam boiler engines that are more efficient and more versatile than a stirling engine. And something like the Green Steam engine can be small, compact and cheap and operate in a closed loop system. (I've only seen the Green built up to 10hp, but I think theoretically it should scale to a fairly large size due to the short stroke)
I think the important thing to realize is that people are out there trying new ideas and experimenting with old ideas.
Parent
Re: (Score:3, Interesting)
I've seen simple steam boiler engines that are more efficient and more versatile than a stirling engine.
You mean like this one [wikipedia.org]?
Re:stirling engine is a no-go (Score:4, Interesting)
Well those aren't very modern. there are far more modern designs that can reclaim heat in a closed loop system. Of course if I would love to own a Stanley Steamer, just from the pure novelty (and history!) of it.
Green Stream Engine [greensteamengine.com] is a newer design and with the right condensers is very practical and can be built compact enough to fit inside an electric vehicle to complement the electric drive train. One could just run the steam engine at a fixed rate to constantly recharge a battery system, so that overall the generators will produce enough power to maintain a constant charge on the system. But short bursts of power that deplete the system more quickly can be used for acceleration. I believe that is the point of a hybrid electric.
Parent
Re:stirling engine is a no-go (Score:5, Interesting)
Actually stirling engine in theory has almost perfect efficiency, unfortunately in practice this is difficult to do. A large, as in huge compared to car engine, stirling engine is easier to make efficient and there are several applications where these are used. And if you run it in reverse you have a great heat pump, often used in cryocooling etc.
Parent
Re:stirling engine is a no-go (Score:4, Funny)
So instead of backing into a parking space you freeze solid in the middle of the road??? No thanks!!!
Parent
Re:stirling engine is a no-go (Score:5, Interesting)
Citation Needed
20 years ago NASA had an automotive Stirling program. Read it and stuff it. [nasa.gov]
They converted a Chevy Celebrity and the results show that the highway gas mileage was increased from 40 to 58 mpg and the urban mileage from 26 to 33 mpg with no change in gross weight of the vehicle. This is NOT a hybrid - it is Stirling only.
By combining the efficiency of the Stirling with the get-up-and go of an electric this is a pretty good thing coming, and I've been waiting a while to see someone to produce it.
Parent
Re:stirling engine is a no-go (Score:5, Insightful)
Parent
Re:stirling engine is a no-go (Score:4, Insightful)
Parent
Re:stirling engine is a no-go (Score:5, Informative)
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.
Parent
Re:stirling engine is a no-go (Score:4, Insightful)
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.
Parent
Re:stirling engine is a no-go (Score:4, Informative)
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).
Parent
Re:stirling engine is a no-go (Score:5, Informative)
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 [wikipedia.org]
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).
Parent
Re: (Score:3, Informative)
I'd like to add I like Aptera's approach of putting a small engine in an electrical car and letting it charge the batteries. Many vehicles only use a tiny fraction of their horsepower to maintain speed and the rest is for acceleration, so in an car driven by electrical motors - the gasoline recharging engines can be significantly smaller; 5-20hp (? - my civic has 140hp in comparison); probably just a little more than what's needed to maintain targetted top speed (or up-hill considerations).
And a gasoline o
Re:stirling engine is a no-go (Score:5, Interesting)
The problem isn't that they're difficult to get up tospeed, but rather that they tend to operate at a constant speed. This is related to the pressure inside the engine, so the only way to vary its natural operating speed is to add or remove pressure from the chamber. It was this added system that drove the Ford's engine to failure because of the extreme complexity needed to control the speed.
This engine does make an ideal charger. I'm excited to see the results in production.
Parent
Re:stirling engine is a no-go (Score:4, Insightful)
The efficiency of a stirling cycle engine is a complete NON-ISSUE! for one simple reason.
most stirling engine setups use WASTE heat. And that is the most intelligent use of the stirling cycle. turning waste into power.
so efficient or not. you're getting energy for FREE from something that is complete waste.
even 3% efficient is still 3% you got for FREE and worth it.
Parent
Re:stirling engine is a no-go (Score:5, Insightful)
Parent
Re:stirling engine is a no-go (Score:4, Informative)
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 [blogspot.com]
Parent
Re:Air Submarines And The Hunky Men Who Love Them (Score:5, Insightful)
space has a cold side? what would that be - the vacuum? like what you have for a fucking brain?
Ignoring your manners for a moment, yes it can be said that space has a cold side. If you have an object facing a source of heat (the Sun, for example) then you will have roughly half the object in shadow. The shadow-side surface will be receiving no incident heat from radiation, yet will be able to exhibit cooling by thermal radiation. Thus, a "cold side".
Now, go back to your day job, which no doubt involves waiting under a bridge and shaking down travellers for coins.
Parent
Disruptive technology (Score:5, Informative)
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 [amazon.com]
Great read, and the concepts are laid out here:
http://en.wikipedia.org/wiki/Disruptive_technology [wikipedia.org]
If you're not familiar with the concept, it's worth checking out.
Think CITY?? (Score:4, Funny)
This should have been called a "Think Village", because I doubt any large enough city will have traffic that is forgiving enough to allow a small electric car to reach 30 (either kph or mph) in 6.5 seconds. Seriously, just start counting off 6.5 seconds right now.
Re:Think CITY?? (Score:5, Insightful)
I seriously don't know how Th!nk plans to stay in business with the City versus some of its competitors. Say, the Aptera, for example.
Seating: 2 or 2+2 (Th!nk City); 2+1 (Aptera)
Trunk: 6 cubic feet (Th!nk City); 15.9 cubic feet (Aptera)
Top speed: 60-65mph (Th!nk City); 85-90mph (Aptera)
Accel: 0-30 in 6.5 seconds (Th!nk City); 0-60 in less than 10 seconds (Aptera)
Range: 110 miles (Th!nk City); 120 miles (Aptera)
Charge time: 10 hours at 230V/14A (Th!nk City); 8-10 hours at 120V/15A or 2-3 hours at 240V/30A (Aptera)
Construction: Plastic, aluminum, steel (Th!nk City); Layered composite monocoque (Aptera)
Insurance category: Car (Th!nk City); Motorcycle (Aptera)
Purchase price: $20-25k + $150-$200 per month battery rental (Th!nk City); $27k (Aptera)
Seems a no-brainer to me unless you're one of those people who don't like the Aptera's looks (I think it's one of the most beautiful cars I've ever seen). I'm getting an Aptera :)
Parent
Re:Think CITY?? (Score:4, Insightful)
Offtopic, but related to your sig: AC comments aren't anonymous when logged in. Try posting as AC while logged out, then moderating your comment.
Parent
Wondering what a Stirling engine is? (Score:5, Informative)
Wonder no more [wikipedia.org]
"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.
Diagram (Score:5, Funny)
Re: (Score:3, Funny)
I can't find the vas deferens, is there another diagram?
Re:Diagram (Score:5, Funny)
I can't find the vas deferens, is there another diagram?
Well, there is a vas deferens between a Stirling Cycle engine and a conventional internal combustion engine.
Parent
Wow. More of the same. (Score:4, Insightful)
Great acceleration and no range. I don't care if it takes me 12 or 20 seconds to reach 60mph if I can go 300mi/charge, with the heat, headlights and windsheild wipers on.
Like I just did yesterday.
Not fast enough (Score:4, Interesting)
Ford Think: Top speed, 55mph; 0-30, 6.5 seconds; Range, 60 miles on battery.
0-60, never. :-(
The problem isn't the top speed being less than 60 mph. The problem is that as vehicles get close to top speed they tend to be less responsive to the accelerator.
With a top speed of 55 mph, this is relegated to situations where you know you will never end up on a highway... Heck, most cities have some highways in them (I know that Manhattan, New York, has a couple where you can legally go 50mph and sometimes see people hit 75mph).
Re:Not fast enough (Score:4, Interesting)
If you want to go less than 60mph, excluding yourself from highway travel in the US (and most other countries). Then it seems like it would be easier to just get a scooter, a gasoline one can get over 150mpg these days. Electric ones exist too, but so far I have been unimpressed. But scooter might only cost you $3000 new, and one that is less efficient might only cost $300 used (but in good shape).
Parent
Re: (Score:3, Interesting)
Scooters are the most unsafe road vehicles. It's damn too easy to get yourself into a road accident. Most cities are just not planned for scooters or bicycles.
I used a scooter for about two months and then sold it, because I value my health too much.
Thermodynamics 101 (Score:5, Insightful)
Re: (Score:3, Informative)
Sterling engines in theory approach the Carnot limit. In practice, they do very very well compared to other engines, especially on a weight basis. However, they also have problems that normally make them inappropriate for cars. They don't do well with variable outputs, and they don't start up rapidly. Over the normal operating range of a car engine, diesels do much better. If, however, you could run it at a fixed speed and not care about startup time, then the Sterling engine starts to look good. And,
Re: (Score:3, Interesting)
Stirling not connected, not enough to power car. (Score:5, Informative)
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/27/sv_deankamen.xml [telegraph.co.uk]
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.
Too Slow (Score:3, Insightful)
Just by looking around on the road you can tell people are chomping at the bit to drive a tiny tin can looking car, especially if that car is also slow as hell. In fact, the less likely (real or perceived) someone with boobs will give it a second look, the better.
Wait, scratch that, the exact opposite is true.
How about something between the Tesla Roadster and the Smart car. A mid-sized sedan style vehicle that is a plug-in hybrid with a constant RPM diesel generator when needed. Or fuel cells whenever Hydrogen refueling becomes a reality.
0-30 in 6.5 seconds? Sheesh. Better buy a dorky bumper sticker right off the showroom floor. This will give the people waiting behind you at the green light something to laugh at while they try furiously to pass you.
Re:Too Slow (Score:5, Funny)
Just by looking around on the road you can tell people are chomping at the bit to drive a tiny tin can looking car, especially if that car is also slow as hell. In fact, the less likely (real or perceived) someone with boobs *and shaved armpits* will give it a second look, the better.
Fixed that for you.
Parent
Wood burning car? (Score:3, Funny)
I'm looking forward to being able to toss a couple armfuls of firewood in the trunk of my car and running errands.
Stirling Engine (Score:4, Funny)
The Stirling engine is pretty neat. It'll run on hot air.
If we install a bunch of them in Washington DC, the energy problem of the US will be solved for good.
Re:*yawn* (Score:4, Insightful)
stirling engines are ridiculously safe. And if you mass produced them on the scale that typical car engines are mass produced they would have to be a fraction of the price. I don't agree that it's a good design to go with, but I can't argue with the price for the components.
Parent
Re:*yawn* (Score:4, Interesting)
But here is the deal... this is a START. Better things are coming. There are other ways to hybridize a power train. Several really good ideas for recovering energy that is typically wasted in current vehicles will help, _more_ efficient engines help, better battery technology helps, more efficient solar cell technology helps, more efficient electric motors helps, and most of all a populace willing to accept smaller more efficient vehicles will help. It will take time to put it altogether and make it usable.
You should not be expecting a revolutionary vehicle or power train technology to come along next Tuesday at 2:37 p.m. It will take time. If instant success at the end goal of technology were possible we would not be following Moore's Law at all. We would simply have leap-frogged to the end-game technology. Let's not even go to that thought that alien technology would help if the government would release the information from Area 51. I'm quite happy that there are folk working diffidently to create things that will help us arrive at the end goal - very efficient modes of travel. Note that automobiles are not the only place that improvements can be made.
Safe and ridiculously cheap is what you will not have for a while yet. They will get there. There are private groups working on electric and hybrid cars as well as very cheap cars. The no one you speak of are the same people that think driving a hummer or huge pickup is ok since it only costs a few dollars more. Not everyone has those 'few dollars more' to waste.
Safety? Are motorcycles safe? If there were far fewer SUV's and other big vehicles on the road, safety issues change a bit. No vehicle is safe enough to drive head first into a concrete bridge upright at 70 MPH. Safety is a subjective word and ideal. If you want to drive around in a tank, I'm pretty sure that more than 50% of the populace is okay with you having to pay quite a bit extra for the privilege. Good luck with that.
Parent
Re:*yawn* (Score:4, Insightful)
Small and light doesn't have to mean unsafe. Example: rollovers. Not only are big, topheavy vehicles like SUVs more likely to roll over, but they're also more likely to crush their occupants. Big and heavy means more weight trying to crush the roof. Furthermore, more modern materials can reduce weight while *increasing* strength./ I am legally prohibited from stating what I've seen in regards to the Aptera, but I'll just point out that there's a video on YouTube of an Aptera employee slamming a large hammer into the vehicle's shell with absolutely no damage. Go try that with your car sometime and see if you get the same results. Lastly, big and heavy often means less maneuverable which means more likely to get into an accident. There's this strange notion in this country that accidents are inevitable, so you better armour up; however, greater maneuverability and lower stopping distances means lower odds of getting into an accident in the first place.
Parent
Re: (Score:3, Insightful)
Absolutely right on! Safety is not common sense in many cases. Look at F1 racing vehicles. They move at incredible speeds and consequently, when they crash it is a sight to behold, yet because their cockpit is designed with lightweight and very strong materials, drivers survive all but the most devastating of crashes. Those materials push up the cost of the vehicle, but if there are several million vehicles made every year with such materials, the cost of manufacturing with those materials will go down. Not
Re:Couple of things bother me... (Score:5, Insightful)
Ah, yes, the horrors of a car that won't fulfill EVERYONES needs. How about this - the people who drive more than 60 miles in a day can get another car. Maybe one with a bigger range.
People who need to drive 150 mph can get a powerfull sportscar - maybe even one that'll only do 2 mpg flat out.
People who need to haul a ton of stuff could get a different kind of car. Maybe one with a nice big flat section where you'd have the rear seats. Maybe a "flat bed" of sorts.
The people who have a need to drive 6 kids and their dogs every day could get something like a bus, but smaller. Miniature bus of sorts.
And maybe people like you could start to consider that there is no car in the world, that fulfills EVERYONES needs at once.
Parent
Re:Couple of things bother me... (Score:5, Insightful)
Exactly. On the one or two times per year that I need a truck, *I Rent One*. I don't keep a truck around at all times for the offchance that I might perchance need one. Why do people feel the need that they must have a vehicle that can do everything when they'll mainly just use it for their daily commute?
Parent
Re:Couple of things bother me... (Score:4, Insightful)
A fair number of my co-workers are amazed that I'll drive a small car for my daily commute. When I ask they why they use a massive pickup truck as their commuter vehicle, it's "in case I need it", or some BS about not being able to afford a smaller commuter car while keeping their large truck. For them, knowing that they have a massive four-wheel drive truck at their disposal at all times is worth the cost.
For me, I make them feel good about themselves by asking to borrow it when I need a truck. Nothing is more manly than being able to help someone with your massive truck. It's the reason you bought it, right?
Parent
Re:The Uri Geller of industry (Score:5, Informative)
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.
Parent
Re:The Uri Geller of industry (Score:5, Interesting)
When Colbert made his characteristic sarcastic remarks about not being able to see the point, Kamen responded that 50% of the deaths in the third world could be traced back to water-borne diseases. With this machine, he said, we could save the lives of millions of people per day.
Until that moment, I had thought that he was the self-promoter-yadda-yadda of the GP poster, but his concern and contemplation of the possibilities seemed genuine and sincere. I'm not going to buy a Segway any time soon, but man, but hats off to him if his inventions really do save lives.
FWIW, Colbert had a sip, too.
Parent
He just likes building neat stuff (Score:3, Insightful)
I met the guy and talked to him for awhile at a medical tradeshow when he had a really cheap 10 foot backwall booth and the most amazing piece of gear on the whole show, beat the snot out of all the big blinkenlights booths and their stuff, the go most anyplace crawling, climbing wheelchair thing. He's opposite of marketing, just thinks 18 miles away from some box all the time..then builds it and it works. Whether or not it sells marvelously or not, the dude is a rare man, a combination far out pure researc
Re: (Score:3, Informative)
It's not. "Minutes" isn't a problem at all for ER-EVs. Gas turbines integrate quite nicely. They take the time that they need to to start up and can run for a dozen minutes or two, then they shut off. DesignLine busses use Capstone microturbines for this very purpose. The Capstones use an air suspension so that the shaft encounters nearly no friction. As a consequence, they have very long lifespans.