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Have ceramics come of age for use in ic engines?

  1. Oct 21, 2006 #1

    wolram

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    Have ceramics come of age for use in ic engines? from what i can make out they do not improve performance by much, but do make the engine more reliable, coating the piston crown and cylinder head seem to be the favorite use, or components that require little or no lubrication..
     
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  3. Oct 21, 2006 #2

    turbo

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    One thing that ceramics can do (especially if you used a Wankle design instead of reciprocating cylinders) is make the engine WAY more efficient. IC engines are made of metal, and metal is thermally conductive, so a lot of the energy of the combustion process is lost to the environment as waste heat. If you could fashion your combustion chamber and rotor from ceramic materials, you could operate at much higher temperatures and get cleaner burns with less waste heat. Certainly there are lots of smart people who have already thought of this, so I imagine that there are some severe engineering and/or fabrication problems preventing such an advance. Years ago at a regional drag racing track, I saw a Harley that was a pretty impressive performer. I was in the pits with a friend and went to look at it between runs. There were no cooling fins on the jugs, and the exhaust pipes were wrapped in insulating tape. I asked the owner about these features and he said that keeping the combustion chambers hot increased horsepower, and keeping the exhaust flow as hot as possible increased scavanging, with an additional power increase.
     
  4. Oct 21, 2006 #3

    Danger

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    Really now, to a pervert like me, if I didn't know that you were talking about a bike...

    Seriously, though (:rolleyes: ); you obviously can't disconnect the radiator on a street vehicle, but would insulating the exhaust increase performance? I've always just stuck to headers with a cross-over pipe for increased scavenging, but I'll grab an extra couple of horsepower whenever I can find them.
     
  5. Oct 22, 2006 #4

    PerennialII

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    Don't know if I'm off with this, but on the basis of different applications have seen etc. have thought the durability & reliability aspects are 'easier' to utilize with coatings and so forth using basic properties of ceramics, but going after performance is more difficult since ceramics don't give you that "leeway" traditional materials do (with respect to failure - but well, coatings for one do provide possibilities for performance gain immediately). Would think some interesting composite & smart materials applications might reach (or have?) ic engines as well.
     
  6. Oct 22, 2006 #5

    brewnog

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    Exhaust insulation will increase horsepower, but with potential reduced durability due to extra thermal loading on in-cylinder components.
     
  7. Oct 22, 2006 #6

    Danger

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    Thanks, Brewski. That gives me an idea, but I don't know how worth-while it would be. I could insulate the entire exhaust system, but tap into the engine coolant flow and run lines inside the insulation to keep things cool. Come race time, hit a cut-off valve to halt circulation. I suspect that it might result in a decrease in horsepower and fuel economy during regular driving due to the increased load on the water pump.
     
  8. Oct 22, 2006 #7

    marcusl

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    I think you'd overheat in a hurry. Considering what a tiny leak in the head gasket does to your coolant, trying to cool the whole exhaust system 24/7 would be a disaster.

    If you want to increase chamber temperature, why not drain your radiator on race day? If you're at the drags, you can probably make it down the 1/4 mile without cracking the block.
     
  9. Oct 22, 2006 #8

    Danger

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    Not practical; I'm a street racer. Quarter-mile only, none of this insanity of blasting all over town in rice-rockets, and with full safety measures in place.
     
  10. Oct 22, 2006 #9

    wolram

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    I have been keeping an eye on ceramics for ic engines, this site seems to be one of the leading coating companies,

    http://www.swaintech.com/store.asp?pid=10539&catid=19694

    But as Turbo said ,that major breakthrough to hold a" lot" more heat in still
    seems to be beyond production methods to date.
     
  11. Oct 22, 2006 #10

    wolram

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    I did read of a guy who built an eight stroke engine, the thing only fired every two cycles, he injected water into the non firing cylinder, the resulting
    steam pressure took the place of combustion, the engine ran quite well AFAIK, and was cool to the touch, maybe just a novelty but who knows.
     
  12. Oct 22, 2006 #11

    turbo

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    I would be impressed if the engine had any kind of longevity. Thermal cycling causes stresses, cracks, scaling, and mechanical failures. Efficiency and longevity are enhanced when you can keep an engine performing consistently. An engine that is started up from cold, run until warm or hot and shut down is not going to be good for as many miles as one that is started up, warmed, and run at a stable and consistent temperature for many miles. I would rather buy a used vehicle with 75K miles that was used by a salesperson with a large, sparse, sales region (lots of miles on every trip) than buy a used vehicle with 75K miles from someone who had a daily commute of just a few miles.
     
  13. Oct 22, 2006 #12

    marcusl

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    Can you translate for me, Danger? Best I can figure from this is you're a street racer who races 1/4 miles (is that on streets?) but not all over town, and not in an imported car (how's that for being PC?) that is safe?
     
  14. Oct 23, 2006 #13

    brewnog

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    Using jacket water to cool your exhaust would be asking for trouble unless you uprated the whole cooling system to cope with the heat rejection.
     
  15. Oct 23, 2006 #14

    wolram

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    Has any one information on the DAR rotary engine? it is supposedly all ceramic, i will google some more, no luck to date.
     
  16. Oct 23, 2006 #15

    wolram

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