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  1. schwee

    PM or solenoid?

    I'm building a linear motor employing two coils, arranged axially, about 1" apart, with a hollow rod passing through the coils. I'm planning on embedding a soft iron slug or permanent magnet in the center of this hollow rod, and then energizing each coil alternately to pull the rod back and...
  2. schwee

    Differential Driven Turbine

    You might want to check out avonaero.com for used surplus aircraft APU power turbines. Many (most?) include an integral gearbox to get about a 10:1 gear reduction. I'm told a used Allied Signal JFS-100 runs about $4,000 - $5,000. It sounds like what you are proposing is a 2-spool turbine where...
  3. schwee

    The future of the engine as we know it

    I'm not sure I understand how this engine has advantages over existing clean-burning two-strokes incorporating direct in-cylinder injection. I can see the argument for eliminating piston rocking, but it seems there are sharp, square corners that need to be sealed. I think that's one of the...
  4. schwee

    The future of the engine as we know it

    sorry - that last query was for turbocohen, not PJGD.
  5. schwee

    The future of the engine as we know it

    PJGD: Do you have more information on plasma ignition? I don't fully understand its purpose, but it could be useful to me to know. Of even more immediate relevance is lean direct-inject gasoline, which is exactly what I propose doing, I think. That is, what I really need is any information...
  6. schwee

    The future of the engine as we know it

    globi5- Sure, gas turbines are terrible in regard to rapid load changes. They also simply eat fuel at idle. Gas turbines are totally inappropriate for automotive use, as Chrysler found out in the 1960s. They have their limitations in other applications as well, which are not limited to their...
  7. schwee

    The future of the engine as we know it

    On this of Franz: >>>>Is the answer recovering the waste heat and totally transforming the thermodynamic capabilities of the fuel to usable energy? What about cutting down on the waste heat in the first place? Who said that is a given? My take is that waste heat comes from combustion gases at...
  8. schwee

    The future of the engine as we know it

    globi5- Well, sort of.. You can try http://www.turbokart.com Look under Projects, Project X. That gives a general overview. The free-piston compressor/combustor (X combustor, is I think what my partner calls it) is the innovation. You have a good point on the possibly diminishing retuns of...
  9. schwee

    The future of the engine as we know it

    globi5 -- I'm with you on the idea of making the engine efficient at low throttle settings. That is the crux of the issue, because you are right, 90% of most driving cycles is done at partial throttle. In automobiles, engines are in general hugely oversized to get acceleration, leading to...
  10. schwee

    The future of the engine as we know it

    Terry - Congratulations on the patent! That's exciting news. What about just hauling your test engine to their location? No substitute for the real thing to generate interest. Or to a manufacturer? globi5 - Very interesting article. I haven't had time to look through it completely, but they...
  11. schwee

    The future of the engine as we know it

    Nope -- I've been working with a partner for the last two and a half years, who knows more about adapting APU-type gas turbines to novel purposes than about anyone I've found. He owns about ten of them, and has donated one to the project. He'll also handle all integration of the free-piston...
  12. schwee

    The future of the engine as we know it

    franzh/Terry: It is coming. I should get my compressor/combustor by next week, and send it off for starting and ignition work thereafter. Variable nozzles, etc., reserved for phase 2 testing. The free power turbine and turbocharger are purchased and waiting. The answers are, in order, HCCI...
  13. schwee

    optimal sfc, rpm, apparent CR, const vol combustion

    Greg - Well, I don't think the graphs really answer my questions, but perhaps I haven't expressed them, or formulated them, well enough. I am of course never asking about what is already known - I'm trying to take known observations apart in light of a novel proposition, which in this case is...
  14. schwee

    HCCI, hi/low octane fuels

    obanion -- I haven't been folowing your project. Looks like you're experimenting with an HCCI engine?
  15. schwee

    optimal sfc, rpm, apparent CR, const vol combustion

    In SBBlue's thread "Value of Engine Efficiency? (thread71-105903), SBBlue said: "The smaller the engine, the better the engine efficiency, because the smaller engine operates at a higher rpm to produce the same amount of power as a larger engine." In considering this, I think I don't at all...
  16. schwee

    Running Lean and "Melting Pistons"

    crystal clear wrote: "Is it going to rev three times as fast making the total fuel burnt about the same?" Yes. It is, in fact, going to "rev" at least four times as fast as a standard crank piston engine, and it is going to fire at every stroke. At stoich it could conceivably deliver 16 times...
  17. schwee

    The Bourke Engine

    From the original link: http://www.constant-pressure.com/RD.htm "As the piston reaches the bottom of it's [sic] stroke, the exhaust port is uncovered and the remaining gases are exhausted into the atmosphere. The exhaust gas temperature is much lower than normal engines, due to the fact that...
  18. schwee

    The Bourke Engine

    Thanks for the explanation, Pat -- that makes a lot of sense to me. I can't see the advantage of a scotch yoke arrangement, either, unless it does in fact let the piston spend a longer time at TDC. And if it does, what advantage would this provide -- better approximation of constant volume...
  19. schwee

    Running Lean and "Melting Pistons"

    Hmmm. I hope this is related. I want to run an engine very lean (AFR~40:1 or so). I think I can get away with this in a pure detonation (HCCI) engine in a free piston configuration. Let's see, other conditions: Burn rate should be very fast, maybe ten times as fast as spark ignition -- so...
  20. schwee

    The Bourke Engine

    I have some questions about NOx emissions, if I can backtrack a bit. per patprimmer 8/31: >>>>Re NOx emissions. I have been taught that lean mixture, high compression and too much advance all lead to NOx emissions. The high compression and/or excessive advance generates more peak pressure, and...

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