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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.

42 of 324 comments (clear)

  1. stirling engine is a no-go by Ancient_Hacker · · 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.

    1. Re:stirling engine is a no-go by OrangeTide · · Score: 4, 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.

      --
      “Common sense is not so common.” — Voltaire
    2. Re:stirling engine is a no-go by raynet · · Score: 4, 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.

      --
      - Raynet --> .
    3. Re:stirling engine is a no-go by shbazjinkens · · Score: 5, Interesting

      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.

      Citation Needed

      20 years ago NASA had an automotive Stirling program. Read it and stuff it.

      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.

    4. Re:stirling engine is a no-go by CubicleView · · Score: 3, Insightful
      From TFA

      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.

    5. Re:stirling engine is a no-go by rolfwind · · Score: 4, 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

      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).

    6. Re:stirling engine is a no-go by Anonymous Coward · · 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.

    7. Re:stirling engine is a no-go by MechaStreisand · · Score: 5, Insightful

      Nothing is free. There is a cost in weight and a dollar cost to the vehicle itself. 3% efficient doesn't look very good when it's not free at all.

      --
      Disclaimer: IANAL. This post is, however, legal advice, and creates an attorney-client relationship.
    8. Re:stirling engine is a no-go by JoeMerchant · · Score: 4, Insightful

      Too bad that it's being produced by someone who thinks a $20K wheelchair and a $5K scooter are "practical." Maybe he's learned his lesson, but I bet this econobox will come in over $30K to the public.

    9. Re:stirling engine is a no-go by JanneM · · Score: 3, 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

      --
      Trust the Computer. The Computer is your friend.
    10. Re:stirling engine is a no-go by fyrewulff · · Score: 3, Insightful

      I counted it out myself while riding in a car, and 6.5 seconds seems like the normal amount of time to get up to 30mph on city roads, unless you're flooring it every time the light turns green.

      --
      "We need to get over this notion, that, for Apple to win... Microsoft must lose." - Steve Jobs, 1997
    11. Re:stirling engine is a no-go by EaglemanBSA · · Score: 4, Interesting

      It is indeed the most efficient thermal engine we know of. Whoever said they're terrible in terms of efficiency is, for the most part, incorrect. They're difficult to implement because of the extremely tight tolerances needed to maintain such high efficiency, but you can achieve efficiencies at least as good as or better than a typical car engine (28% is usual for the car, 35-40% is easily achieved with a stirling engine, depending on the operating points).

      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.

      --
      Quiz: True or False -- On a scale of 1 to 10, what is your middle name?
    12. Re:stirling engine is a no-go by OrangeTide · · Score: 3, 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 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.

      --
      “Common sense is not so common.” — Voltaire
    13. Re:stirling engine is a no-go by shbazjinkens · · Score: 4, Informative

      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.

    14. Re:stirling engine is a no-go by Anonymous Coward · · Score: 4, Funny

      And if you run it in reverse you have a great heat pump, often used in cryocooling etc.

      So instead of backing into a parking space you freeze solid in the middle of the road??? No thanks!!!

    15. Re:stirling engine is a no-go by ppanon · · Score: 3, Informative

      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).

      --
      Laissez lire, et laissez danser; ces deux amusements ne feront jamais de mal au monde. - Voltaire
  2. Disruptive technology by Chairboy · · Score: 4, 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

    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.

  3. Think CITY?? by caffeinemessiah · · Score: 3, Funny

    0-30, 6.5 second

    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.

    --
    An old-timer with old-timey ideas.
    1. Re:Think CITY?? by Rei · · Score: 4, 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 :)

      --
      Mr. Wizard... why is this place called the Cave of Hopelessness?
    2. Re:Think CITY?? by smart.id · · Score: 3, 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.

      --
      blog & fiction: jd87
  4. Wondering what a Stirling engine is? by mgkimsal2 · · Score: 4, Informative

    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.

  5. Diagram by russoc4 · · Score: 5, Funny

    For those of you who do not know what a Stirling engine looks like, Wikipedia has a very detailed diagram.

    1. Re:Diagram by Anonymous Coward · · Score: 3, Funny

      I can't find the vas deferens, is there another diagram?

    2. Re:Diagram by ScrewMaster · · Score: 4, 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.

      --
      The higher the technology, the sharper that two-edged sword.
  6. Wow. More of the same. by schnikies79 · · Score: 3, 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.

    --
    Gone!
  7. Not fast enough by MMC+Monster · · Score: 3, 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).

    --
    Help! I'm a slashdot refugee.
    1. Re:Not fast enough by OrangeTide · · Score: 3, 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).

      --
      “Common sense is not so common.” — Voltaire
  8. Re:*yawn* by OrangeTide · · Score: 3, 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.

    --
    “Common sense is not so common.” — Voltaire
  9. Thermodynamics 101 by GrahamCox · · Score: 4, Insightful

    Why don't the inventors of these various electric cars do some basic sums? If you're going to have any sort of hydrocarbon fuel involved then use the most efficient conversion possible to electric power given the space constraint of a practical vehicle. Right now that's a fixed-speed diesel engine at approaching 50%. All these 'exotic' heat engines like Stirling etc. are dead in the water when it comes to basic thermodynamic efficiency. If you don't start with a reasonably efficient conversion you are not going to end up with a vehicle that is even slightly practical.

    1. Re:Thermodynamics 101 by theapeman · · Score: 3, Interesting

      But the engine in a truck or bus is not fixed speed. It varies according to driving conditions, and there is a loss in efficiency due to the need to allow for the flexible load. If you use an engine merely for charging the battery then it can be a fixed speed, fixed load engine - I.e. it can run at peak efficiency whenever it is running, and the efficiency can be higher than a more flexible engine.

  10. Re:*yawn* by zappepcs · · Score: 3, 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.

  11. Stirling not connected, not enough to power car. by guidryp · · Score: 4, Informative

    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.

  12. Re:*yawn* by Rei · · Score: 3, 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.

    --
    Mr. Wizard... why is this place called the Cave of Hopelessness?
  13. Re:Couple of things bother me... by MartinSchou · · Score: 5, Insightful

    60 miles for some is less than their daily commute to work.

    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.

  14. Re:The Uri Geller of industry by abigor · · Score: 4, 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.

  15. Re:Couple of things bother me... by Rei · · 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?

    --
    Mr. Wizard... why is this place called the Cave of Hopelessness?
  16. Re:Too Slow by Miseph · · Score: 4, 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.

    --
    Try not to take me more seriously than I take myself.
  17. He just likes building neat stuff by zogger · · 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 research scientist and practical engineer, he figures out how to make sci fi stuff actually work. Our society *demands* marketing and short term megaprofits though, so he's stuck sometimes. He's the kind of guy just needs some billionaire to adopt him as a pet project and turn him loose, so he doesn't need to worry about funding ever again. If even one out of ten things he makes really takes off, I mean to the general public and outside of medical specialties, yes, it will be worth it.

  18. Stirling Engine by cwsulliv · · Score: 3, 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.

  19. Re:Couple of things bother me... by apoc.famine · · Score: 3, Insightful

    Because if they don't have one, it makes them dependent on others when they need one. And there are many people who can't handle that.

    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?

    --
    Velociraptor = Distiraptor / Timeraptor
  20. Re:The Uri Geller of industry by bennomatic · · Score: 4, Interesting

    Don't forget the water purifier. Kamen went on Colbert and showed off a system that can extract pure water out of essentially any stew, and is robust and cheap enough to use reliably and distribute throughout the the third world. His demonstration was pulling good water out of, I don't know, raw sewage or something, and he was drinking it.

    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.

    --
    The CB App. What's your 20?
  21. Re:Air Submarines And The Hunky Men Who Love Them by Nefarious+Wheel · · Score: 4, 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.

    --
    Do not mock my vision of impractical footwear