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Future Engines and etc.

  1. Mar 11, 2008 #1
    What do people think of the developments and future of Waste Exhaust Heat Recovery? Thermoelectric Conversion of exhaust heat into electric power to drive auxiliaries.

    Thermodynamic Conversion of waste exhaust ( + radiator + Charge air cooler + EGR cooler) heat into additional crankshaft power: Hybrids + Regenerative Energy Recovery ( Batteries , Hydraulic , etc ) , Renewable Energy + Biofuels.

    This is a paraphrased question for my girlfriends father :smile:
     
  2. jcsd
  3. Mar 11, 2008 #2

    Danger

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    I'm a firm beliver in the use of heat-pipes, thermionic converters, etc. to extract every possible bit of energy from the combustion process. I guess that the trade-off would be when the weight of the equipment would offset the amount of energy it can provide (assuming no purchase cost issues).
     
  4. Mar 11, 2008 #3

    wolram

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    I think we are waiting for a material that can keep the heat of the combustion in and not melt, along with other properties needed for a ice.
     
  5. Mar 11, 2008 #4

    russ_watters

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    Those ideas sound neat, but they have extremely poor efficiency. Thermoelectric is something like 5% for generating electricity. I'm a fan of waste heat recovery, but by far the best way to do it (if the goal is mechanical or electrical energy) is via some conventional combined-cycle or boosted thermodynamic cycle. Ie, you use an aft-end boiler to run a steam turbine or you use the exhaust itself to spin a turbocharger.
     
  6. Mar 11, 2008 #5

    Danger

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    I didn't mean to imply that thermionic converstion would be a major stage. I'm thinking more of just something to line the ass end of the exhaust pipe with after there isn't enough heat left to power a mechanical conversion. It might serve to provide onboard clock or radio functions.
     
  7. Mar 12, 2008 #6
    Are they're any cars/vehicles that use this waste recovery technology? Anything in development?
     
  8. Mar 12, 2008 #7

    brewnog

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    I know that a few German automotive OEMs are looking at using exhaust heat exchangers to drive a turbine for supercharging, but nothing electrical. The juice isn't worth the squeeze.
     
  9. Mar 15, 2008 #8
    i just posted a new topic kind of in this genre. the title is "turbo alternator" but to add to this convo, I know that bmw has a steam turbine supplement in development, it uses waste heat to turn a turbine that turns the alternator thus removing the parasitic loss off the engine. if you feel like it, check out my idea, posted in the mech engineering section.
     
  10. Mar 15, 2009 #9

    OmCheeto

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    I think the secret to future engines is to go beyond the fact that heat is required in the first place. Once you overcome that barrier, you will no longer be constrained by the laws of thermodynamics.
     
  11. Mar 15, 2009 #10

    russ_watters

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    Year-old thread, but....
    Sorry, but the laws of thermodynamics are more general than that. They cover every situation where there is energy transfter, so anything that ever powers a car will have to adhere to them.
     
  12. Mar 15, 2009 #11

    OmCheeto

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    Interesting. I'll have to check that out. I've never thought about a marble rolling down an incline and the laws of thermodynamics in the same way. Might be old preconceptions.

    BTW, I was researching something yesterday and ran across this thread. I thought it was an interesting topic that I thought would have been fun to discuss. But alas, in the myriad of posts, I missed it. Today someone told me it was Greg's birthday. I thought it would be fun to do a necropost for the occasion.
     
  13. Mar 15, 2009 #12

    russ_watters

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    Yep - you're converting gravitational potential energy (PE) to kinetic energy (KE) and you're losing it to friction (FE) and air resistance (AE). So your conservation of energy (first law of thermodynamics) statement is:

    PE - FE - AE = KE

    And your efficiency statement is:

    KE/PE * 100 = Eff (< 100%)
     
  14. Mar 16, 2009 #13
    research turbo compound. its a miracle no large company has brought this wwii technology back in to modern context. its basically a huge exducer that is connected to the crankshaft. if my research is correct and not false some test planes have shown an increase in torque production in the order of 30% with obviously 0% increase in fuel consumption. should result in a 25% decrease in BSFC. what do you guys think?
     
  15. Mar 16, 2009 #14

    Ranger Mike

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    Smokey Yunick..my idle and know genius in racing.. did some work on the extended tip spark plug, reverse flow cooling systems, a high efficiency vapor carburetor, a high-efficiency adiabatic engine, Hot Vapor Cylce Engine and various engine testing devices. Check out HVC engine and adiabatgic engine

    He took air fuel mixture and heated to 190° F by the coolant, then it goes through the turbo/atomiser, which heats it to 280° F then is heated further by the exhaust to 450° F

    Then it is compressed in the cylinder to 1500° F, at which point the spark fires.

    Then it goes through the exhaust valve, heats the incoming mixture, and then into the expansion side of the turbo. He got a Plymouth Horizon 4 cyl to go over 50 mpg
     
  16. Mar 16, 2009 #15
    generally at 536 degrees F gasoline auto ignites. before the air fuel mixture could even come close that 1500F it would auto ignite. and if i understand correctly the auto ignition temp could be artificially raised by lowering oxygen concentration mainly by diluting the mixture with water injection or exhaust gases of high amounts but then there would be considerably less air fuel mixture to burn per expansion phase hence severely reduced power production. it might work but then it wouldnt make any power, at least not nearly enough to keep the consumers of today happy.
    it shouldnt be any different than just using a 1 litre regular piston. that'll get you 50mpg too with similar power production. as long as it doesnt have to be fast getting 80mpg is a piece of cake.
     
  17. Mar 16, 2009 #16

    Ranger Mike

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    you are correct reagrding the statements about normal gasoline and normal exposure to hi temps..but Smokey solved all of these through hard work and much innovation..in fact the Detroit gang flew in several times to see his hi temp engine working..
    i suggest anyone interested ..research this...i got no dog in this fight..just tellin ya what has been done...
     
  18. Mar 16, 2009 #17
    I believe the future of energy production on a utility scale will be fusion. I base this on the fact that it has relatively no waste. (I know the question was on waste heat but I wanted to add this post). Check out the iter. www.iter.org
     
  19. Mar 16, 2009 #18
    Being a turbo guy, I believ the direct future is combined cycle or co-generation. the first can reach cycle efficiencies up to 65% and the later around 80%. This will also be a way to burn gasified coal and reduce NOx, CO, Soot and mercury emissions. The main problem today is to have a single engine capable of operating on several different fuels (liquid, gas, high hydrogen, etc).

    For car engines, I expect more hybrids and eventually electric cars depending on the battery technology. With the fuel prices being low again the incentive for these technologies has diminished significantly, regretfully.
     
  20. Mar 16, 2009 #19
    jaap de vries, the cost of fuel plays such an impact on alternative technology progression. It is a shame.
     
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