Carbon fiber pistons
- Thread starter Tom Dunlap
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Lawn Masters
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I dunno. probably pretty pricey though.
Crofter
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Tom, I have had my hands on some carbon fibre composites for model air craft and the strength and rigidity is simply amazing. I wasn't aware the had a matrix that would stand piston kind of temperatures but I guess its here. I think even crankshafts and cylinders could one day be composites too.
The pistons in the link are not carbon fiber, but rather carbon carbon. Big differance. The Army did a big research project on carbon/carbon pistons diesel engines. Carbon/carbon will take massive amounts of heat so they are perfect for applications like diesels and two strokes where piston heat is always a problem.
The only problem with them was that the tended to fail after relativly short periods and when the did it was total failure.
The only problem with them was that the tended to fail after relativly short periods and when the did it was total failure.
NevadaWalrus
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Toyota may be getting into NASCAR for sales purposes but Honda never will. Push rod engines aren't in their future. Honda only gets involved with high tech or racing if they think they may be able to use it to advance producton engines. If they're interested they must think there's something to it.
Al Smith
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There are many innovations ,taking place,in engine designs.Several Ford engines,have Teflon,impregnated on the piston skirts.The use of ceramic composites ,have been discussed,for years .The days of the internal [sometimes infernal] combustion engine,are not over .
njforestfire
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that is the same carbon/carbon that they use on the space shuttle wings.
Blowdown1
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I woule expect ceramics to be used before carbon, but maybe not.
klickitatsacket
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stihl used a ceramic piston and cylinder in a preasure washer pump. I do not believed they had good success with it and that was in a water enviornment.
Crofter
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njforest, that stuff didnt seem to like impact did it. A piston has a difficult job, accelleration and decellerations of up to 120,000 G's a couple hundred times a second. They will continue to work on it. The inventions in synthetics during the forties really advanced anything to do with hydraulics. previous to that, leather seals were used in a lot of things and the natural rubbers wouldnt work with the mineral oils. Temperature was a serious limitation. Cylinders were huge because pressures were limited to 12 or 1500 psi. Now pressures on construction equipment run up around 5000 psi. Technology!
jimbo1490
ArboristSite Guru
Back when I was associated with some racing people, we got a 'preview' of the various composite technologies being toyed with over in Stuttgart. Normal organic polymer matrix composites can't stand up to combustion temps, but there are a few ways around this problem. One is to use a super high-temp matrix. Carbon matrix (hence the term carbon/carbon) is the most widely recognized. They make it basically by partially burning out the matrix of an organic polymer matrix part. Of course this is done under very well-controlled conditions. It matters a lot just exactly what polymer matrix you start with, too. These details are still carfefully guarded secrets.
Another way around the problem is to shield the part so it never really gets that hot. Ceramics are one way. Also, several companies make a coating (I've used the one from Sterling) that has amazing heat shielding properties. Something like this could be put on the top of the piston and in and above the ring land(s) where it normally runs really hot. You would probably still need a really HP resin system like bismaleamide rather than epoxy, but it's still doable.
Once you get away from thermoset type resins, there are even more possibilities. Amoco plastics has several thermoform resins that can and have been used(with the right fiber reinforcements, of course) to make any engine part, including pistons. These have been around since the early 80's. They used metal shielding for the piston crowns on their test engines, IIRC. Of course this type of plastic needs to be melted and injected into the mold which implies a pretty big capital investment. Those German boys were playing with all of these options.
The last barrier now is only cost. Can any of these materials compete with aluminum on cost? I doubt it. So they will remain for now the toys of the race car crowd, NASA, aerospace and the military.
Jimbo
Another way around the problem is to shield the part so it never really gets that hot. Ceramics are one way. Also, several companies make a coating (I've used the one from Sterling) that has amazing heat shielding properties. Something like this could be put on the top of the piston and in and above the ring land(s) where it normally runs really hot. You would probably still need a really HP resin system like bismaleamide rather than epoxy, but it's still doable.
Once you get away from thermoset type resins, there are even more possibilities. Amoco plastics has several thermoform resins that can and have been used(with the right fiber reinforcements, of course) to make any engine part, including pistons. These have been around since the early 80's. They used metal shielding for the piston crowns on their test engines, IIRC. Of course this type of plastic needs to be melted and injected into the mold which implies a pretty big capital investment. Those German boys were playing with all of these options.
The last barrier now is only cost. Can any of these materials compete with aluminum on cost? I doubt it. So they will remain for now the toys of the race car crowd, NASA, aerospace and the military.
Jimbo
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