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BMW turbosteamer concept

  1. Mar 3, 2006 #1
    http://www.gizmag.com/go/4936/

    theres the link in case anyone hasnt seen it already. pretty simple concept, and it sounds like a great idea to me, but I dont quite understand 2 areas of the specific design, maybe somone can help.

    Firstly, is the heat from the exhaust gasses really enough to instantaniouslly boil water? and in that same light, how is the water not pumped through the turbine? in other words, how can they make sure that only steam is used to spin the turbine? do they use gravity in their setup so that the turbine just sits higher?

    secondly, in the article they say that the turbine will be connected directly to the crankshaft. I do not understand how this would be possible, wont the turbine be spinning at a variety of different speeds and be somewhat unpredictable in RPM because of the dramatic lag that the heat transfer and spin up in the turbine would cause? so even if it was geared down, you wouldnt know what ratio to have put inbetween the turbine shaft and the crank. the only solution i could think of (since i have been researching them recently) is to put a type of CVT (continuously variable transmission) between the two so that the gear could be selected depending on what speed the crank was turning at.

    thanks for any help guys
     
  2. jcsd
  3. Mar 3, 2006 #2

    FredGarvin

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    Well, take a feel of a catalytic converter next time you've been driving for a while. I would venture a guess that there is, but not instantaneously. As far as the liquid/stem goes, what you're thinking is exactly what I would expect them to do. There is most likely a liquid trap somewhere in line to prevent liquid phase ingestion into the turbine.

    Or they plan on somehow regulating steam flow based on crank speed/turbine speed. I am sure that this would be one of the big issues that would be worked out on the test rig.
     
  4. Mar 3, 2006 #3
    ya i thought about a steam regulator, but maybe a cvt could do 2 things at once, that way you wouldnt need seperate valves and a teperature switch etc etc. (in terms of what i could replicate at home at least haha) what do you think would be more efficent for heating water by exhaust for a teat at home? wrapping some copper tubes around the exhaust pipe? a radiator?, and also for the turbine, would half a turbocharger work well?
     
  5. Mar 3, 2006 #4

    FredGarvin

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    I would think that the radiator would be the better bet since it would maximize the surface area that is responsible for the heat transfer. You could try the coil, but there would definitely gaps, etc that would reduce the effectiveness. It would be very easy to make a coil though. So I would, if I were to try to replicate this, try the coil first.

    The turbo is the basis for many a home made turbines. You have to get them turning at very high speeds though. That may be an issue. I'm not quite sure of the size they're using on the BMW. I only skimmed the article.
     
  6. Mar 3, 2006 #5
    ya, i would have to give some thought to it as well, the size i mean. obviously i should use the exhaust turbine part of the turbo right? so its good for high temperatures etc. and also (ive never worked with a turbo beofre) is it possible to take off the other turbine blade? or seperate the housing halfs? because i wouldnt need it to pump air, only have one turbine wheel spin on an extended axis
     
  7. Mar 4, 2006 #6
    What are they using for makeup water? There are always leaks.

    Basically looks to be a waste heat boiler powering a turbine. Look up some of the marine engine/turbine sites.
     
  8. Mar 4, 2006 #7
    i have no idea, thats why i put it to everyone here, the details on this thing are missing ha. maybe they routed the condensation of the A/C unit into the lines, thats the only place i could think of where you could get some extra water without thinking about refilling it. why are there always leaks? plumbing isnt that hard is it?
     
  9. Mar 4, 2006 #8
    Generally leaks a little around the shaft seals on the turbine, not much but does add up. Also, eventually, through valve spindles and so on. Plumbing does eventually wear out, breakdown. For steam systems usually by erosion, scale and expansion contraction. In a vehicle vibration/shock would be an issue as well.

    If you're interested, Lee Valley has some good reprints of old tech from about the 1890s. Or you could check out Lindsey(Lindsay?) books, the build your own smelter/lathe people. The catalog is a hoot.
     
  10. Mar 4, 2006 #9
    haha sounds interesting, i love that old technology stuff.
     
  11. Mar 5, 2006 #10

    FredGarvin

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    Old technology doesn't equal bad. You can learn a lot from that. I know I have. Plumbing does eventually leak, that's true, but a properly designed system can go for a whole lot of years before that happens. That usually get's hot to hell when someone decides to take something apart.

    I would imagine that they'd have to have another tank, similar to the windshield wiper fluid tank that you'd have to refill every so often. A low level on that tank prohibits that system's usage. You will get a small amount from the exhaust products as well. But I don't know how much the system would require.
     
  12. Mar 10, 2006 #11
    I think it would be more logical to use power produced by steam turbine to recharge battery and to provide energy to other components. This way all the power produced by ICE can be dedicated to providing torque to the wheels. Using this design problem of torque synchronization can be avoided.
    Also this hybrid is not practical in countries where temperature falls below 0C in a winter time. Unless they are planning to use some kind of water substitute.
     
  13. Mar 10, 2006 #12

    brewnog

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    As it stands, not all the power produced by the engine is dedicated to providing torque to the wheels. A good 65-70% is just wasted. A fair proportion is used to drive ancilliary systems, - oil, water and power steering pumps, fans, ignition, lighting, and then all the driver comforts. This is just a way of utilising more of the wasted energy.

    This logic holds for conventional cars too, - what goes in your cooling system? :smile:
     
  14. Mar 10, 2006 #13
    Does not portion of engine's torque has to be used to generate power for these systems? All I am saying is why not to use thermal energy to provide power for this systems. So engine itself does not have to lose some of its power.

    Can you really use antifreeze in steam engines?
     
  15. Mar 11, 2006 #14

    FredGarvin

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    Sure, but it raises the boiling point and would, most likely, leave a residue over all of the components. Plus, that stuff just smells bad when it's vaporized. Pretty nasty smell.
     
  16. Mar 11, 2006 #15

    russ_watters

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    Yeah, if they can keep the leakage to a few pints per thousand miles, then it isn't a big deal to just refill it at the same time as your windshield washer fluid every time you get an oil change.

    I'm a big fan of trying to recover and use waste heat for other purposes. It's easy money.
     
  17. Mar 11, 2006 #16

    russ_watters

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    Sure, but one way or another, the system produces some total amount of power and the accessories use some total amount of power. It doesn't matter where exactly you take off the accessory power, you get the same amount at the wheels.

    One good reason to not tie the turbine to the accessories is that the accessory power varies widely and the turbine power varies widely - and the two don't correlate. But the turbine power varies with engine output, so the turbine puts power down to your wheels exactly when you want it.
     
  18. Nov 23, 2011 #17
    The system is under really high pressure and temperature (about 40bar and 400 degrees) the pressure is dropped in the turbine to atmospheric, which causes the pressurised hot water to change into steam, thus no water. Also steam engines have purge valves for any condensation build up.

    The pressure supplied to the system will be controlled under load dependent criteria. The problem with this system is it is only good on long runs, and when the vehicle is turned off all that heat energy is lost.

    The steam needs to generate electricity which can be stored, also this way even when the vehicle is stationary or switched off it still can reclaim the lost heat energy.
     
  19. Feb 14, 2012 #18
    guys ,i'm working on this project for my senior project , the tempreture is high enough to generate steam , however i'm facing a problem :
    according to my design , the water flow rate is very low (0.54 l/min) and the pressure is up to 7 bars , so i'm finding it hard to allow water to be distributed equally in the 250 tubes tube side of the shell and tube heat exchanger , and i don't know how to do that or if it's possible or not can anyone help ? thank you :)
     
  20. Feb 14, 2012 #19
    I'm doing a similar kind of project, why does the water not distribute evenly? Could you turn the exchanger 90 degrees so the water fills the tubes and flows up, the water level will be equal in each tube . Why can you not increase the water flow rate?
     
  21. Feb 14, 2012 #20

    russ_watters

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    Is the pressure drop high? Then you have too few/too small tubes.
     
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