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Do ceramic pistons make sense?

Discussion in 'Technical Q&A' started by Pikemann Urge, May 28, 2009.

  1. Pikemann Urge

    Pikemann Urge Rookie

    May 23, 2009
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    Melbourne, Australia
    I'm not up with the latest in materials technology but I do believe that back in the day, 500cc motorbikes had ceramic pistons. Now, the obvious problem with that is the different expansion rates between ceramics and metals. Not to mention the fact that there exist some very strong and very light metals.

    So anyway - where road going Ferraris are concerned, would they make sense?

    Come to think of it, why not the block and heads?
     
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  3. miketuason

    miketuason F1 World Champ
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    Sounds like a ceramic would crack.
     
  4. Challengehauler

    Challengehauler Formula 3

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    If ceramic pistons were worth anything in performance, savings, or reliability they would be in production.
     
  5. 2000YELLOW360

    2000YELLOW360 F1 World Champ

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    I believe that motogp bikes and the forumla1 cars both have these types of pistons. The expansion problem has been resolved, but the cost of making these work is huge. I believe that the oval piston Hondas of the 80s started the trend.

    Art
     
  6. James_Woods

    James_Woods F1 World Champ

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    I don't think I have heard any solid evidence that F1 cars are using ceramic pistons. The oval piston Honda parts that I saw pictured at the time looked as if they were aluminum.
     
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  8. James_Woods

    James_Woods F1 World Champ

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    OH - is that what we are talking about? A coating on a metal piston? I assumed he meant all ceramic...

    That might actually make some sense, but how long would it go before it got all carboned up like a conventional piston?

    Remember the teflon coating for drag engines? It was said to reflect heat back into the combustion gasses, but was pretty much all gone by the 1/4 mile.
     
  9. Far Out

    Far Out F1 Veteran

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    Nearly every F1 team has their pistons (and engine internals) coated by one company. "Diamond Coating" or something like that, they have a very special technology, but the parts you want to coat have to be designed for their coating in the first place.
     
  10. James_Woods

    James_Woods F1 World Champ

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    I was thinking that the thread meant total ceramic construction when it first came up.

    So what would be the technical reason? Heat reflection, heat tolerance for leaner and hotter burn mixtures?
     
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  12. Far Out

    Far Out F1 Veteran

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    No, just reduced friction. By a ridiculously large amount, but the coating is, of course, extremly expensive, and as I said, you can't just coat every part you like, the materials have to be specially designed.
     
  13. finnerty

    finnerty F1 World Champ

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    #11 finnerty, May 28, 2009
    Last edited: May 28, 2009
    There is a friction improvement, but it is not tremendous, and it is not why the coatings are used. There is also a large gain in wear resistance (ceramics are much harder than metals), but it also is not why the coatings are used.

    The purpose of coating the piston crown (face) with ceramic is to reduce surface temps. Ceramics are refractory materials, so they don't absorb / retain heat and don't become as hot as most metals. The advantage of this in an internal combustion engine is that it prevents pre-detonation in engines running with high compression ratios, high RPM's, turbo / super charging, very advanced (early) ignition timing, or unusually volatile fuel.

    Data from testing has shown this to be quite effective, and really, it's the only way to reduce piston temp. There is no need to coat the cylinder wall, combustion chamber, or valve heads as they are adequately cooled by exposure to the coolant (and / or air). Tests have been done with coating on these surfaces as well, and they have shown no significant change in lowering temps.

    A buddy of mine works at Ford in their Engine Design R & D Department, and they have studied ceramic coatings and components in test engines for some time ----- According to him, the results are interesting, but seem to have little or no meaningful application to the typical passenger car engine.
     
  14. James_Woods

    James_Woods F1 World Champ

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    By that I would guess you mean reduced friction from piston scuff against the bore? They have rings, don't they? Or is that just a compression ring and they let the base end make a near interference fit to avoid slapping around in there?

    BTW - is the "diamond" just a marketing name? Surely you would not want real diamonds grinding away in your cylinders!
     
  15. Far Out

    Far Out F1 Veteran

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    They coat all engine internals, not just the pistons. Did you see my thread in the F1 section about the lecture I recently visited? It was there where I heard about that stuff.

    I'm not sure if it was "diamond", but something like that. And yes, it obviously is a marketing name.
     
  16. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Ceramic coating has been around for decades. I had some done back in the mid 70's and it was not all that new then.

    All ceramic pistons have been talked about for a long time and I think it is pretty well accepted that the advantages would be huge but since we haven't seen any I assume the technology to to make them and make them work has not yet come along.
     
  17. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Ceramic pistons would be pretty light and thats a good thing but the real benefit comes from it's tolerance to heat. A very real limiting factor in how much power a motor can make is how much heat can it take and aluminum pistons give it up too soon.
     
  18. solofast

    solofast Formula 3

    Oct 8, 2007
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    There are a number of coatings that are routinely used on very high performance engines to control heat transfer. In particular, coating of the exhaust port and back side of the exhaust valve is particularly productive. Almost half of the heat that goes into the coolant via the cylinder head is transferred though the exhaust port walls. Remember that the exhaust ports only see hot gasses and never get a shot of cool air at any other time (like what happens to the combustion chamber and the pistion). The exhaust valve transfers heat thru the seat and the stem, but a thermal barrier coating (TBC) can make a big difference in valve life. At the temperatures that exhaust valves run, a 25 degree F change in temperature can double the life of a highly loaded valve.

    Virtually all NASCAR engines use some type of thermal barrier coating or other means to reduce the heat transfer from the port and exhaust valve. This reduces the amount of cooling required from the radiator, so the radiator gets smaller and the amount of air needed is lowered so the aerodynamics of the car can be improved. There are some new thermal barrier coatings that have been developed for turbine engines that are about twice as effective as older coatings, so there is a real gain in doing this. Old 944 turbos had a cast in ceramic liner in this area to reduce the heat transfer, not sure what the F1 guys do, but I am sure that they do everything they can, and wouldn't doubt that they use some type of cast in place liner in this area.

    Coatings in some cases are applied to cylinder heads and pistion tops. The problem with that is that the surface of the coating, since it doesn't conduct heat well, gets hotter. This can lead to detonation issues, so the type of coating and the thickness is not as good an insulator as it is in some of the other coatings. Coatings can increase the amount of heat kept in the combustion chamber, and therefore make more power, so there is a balance there between detonation and power gain.
     
  19. James_Woods

    James_Woods F1 World Champ

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    Thanks for all the information on this thread...very interesting stuff.
     
  20. synchro

    synchro F1 Veteran

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    http://www.performancecoatings.com/index2.html
    Click on "Internal Coatings"

    Horsepower and increased life are achieved 3 ways:

    First by impregnation of the skirts, pin bores and ring area with a dry film coating, reducing the effects of piston scuffing, piston rock and other friction induced problems.

    Next, the piston dome is coated with a Ceramic thermal barrier to distribute heat evenly across the piston dome and increase combustion temperatures.

    Finally, the underside of the piston is coated with a thermal barrier. This process evenly distributes heat in the chamber, thereby greatly diminishing or eliminating the chance of detonation, while reducing oil cling.



    Scroll down that webpage to see what they can do to other parts of your car, such as the trans.
     
  21. JCR

    JCR F1 Veteran
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    Usually referred to as DLC "diamond like carbon". Typically used on valvetrain components. http://www.bekaert.com/en/Product%20Catalog/Products/C/Cavidur%20DLC%20on%20Race%20Engine%20Components.aspx

    See the pdf. at the bottom of the page.
     
  22. senna21

    senna21 F1 Rookie

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    Ceramic coatings work very well when paired with turbo charging. The reduced temps on the piston top reduce the chance of knock and allow the use of higher boost pressure with added safety. The later generation of MR2 Turbos came with a ceramic exhaust wheel turbo that was very light weight when compared to a steel impeller, allowed quicker spool and higher boost pressure than the stock ct26. But those could also be rather fragile. They don't bend or chip if debris hits them, they explode.
     

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