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Warning - no real engine knowledge .
Design the piston head as a cup rather than plug .
The cup would slide on a protrusion down from the head .
The cup could have balanced lugs on outside to open and close valves .
Holes /channels in head protrusion could supply fuel / spark .
A solid
open frame could hold crank shaft and head in respective positions .
Exaust headers could be piped to seal against moving piston cup which has a hole that is open when inline with
header .
The open room could be used for technology to trap and use excess heat .
Thought inspiration
Stationary_20piston_20ICE
amazing what misreading can do . [wjt, Dec 08 2007]
[link]
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Read your title and thought you meant an engine with normal piston/cylinder arrangement, however "skeletonised" without the bulk of the engine block. Which, I think, would be a better idea than this one, - maybe. I still think you'd have problems with thermal mass, hotspots, etc. |
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or maybe not. I think the moving "cup" part of your idea would add too much mass to your pistons. Generally, one of the limitations to modern engine design is fatigue loading on the conrod - which is directly related to piston moving mass and engine speed. Increasing this mass would result in lower permissable rev range. |
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I imagined a conventional head block arrangement with a "cylinder" sliding up and down around each piston . |
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=> => which mental twisted into the inside out cupped piston . |
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Ahh, I see. My design is flawed though, because I have put no thought into how to cool the engine. I imagine encloseing everything with a stainless steel container and then spraying water on the walls of the cylinders. |
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you idea seams very similar [+] |
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If you were to have an explosion inside a 'cup' you would tend to try and push the walls of the cup outward, which would need to be resisted by the the cup walls themselves. Sounds like it would be a very heavy reciprocating mass. |
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Then again, cylinder pressure in a car engine isn't particularly high - I don't think the walls need be enormously thick. |
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Remembering that hydraulic cylinders withstand 1000's of psi, and most aren't all that thick. I'm looking at an enerpac 10kpsi aluminium cylinder, I'm guessing maybe 15mm wall over a 100mm bore? |
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It's still a lot more weight than a conventional piston. |
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With a remarkable propensity to turn into shrapnel as soon as it develops any fatigue cracking. |
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yes, but it'd be interesting to work out the s-n curve. |
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I can't think of a more stress-releived arrangement than that of a cylinder undergoing internal presurisation. |
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Other than, perhaps a sphere. |
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Relatively thin-walled tubes can withstand enormous constant stresses. A pop (soda) can will support the weight of a fully grown human. However, try stepping up and down a few times and see what happens. It is the reversal of stress that does for a material. |
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Hydraulic cylinders don't see anything like the enormous number of pressure pulses that an IC engine experiences. |
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There is no stating of the possiblity of shaping the charge . The chamber could be more in the head protrusion with a pipe to the cup . |
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The explosion expansion would be focused to the centre of the cup and as the force moved the cup down the volume increases and the pressure on the sides of the cup is less . The expansion could even vent out the top of the cup . |
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//There is no stating of the possiblity of shaping the charge . The chamber could be more in the protrusion with a barrel to the cup // |
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Pressure is pressure. The nature of pressure is that it's the same all over. |
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It's a nice idea, but unfortunately it's not as good an idea as the current technology which has been in use everywhere for a very long time. |
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sound is a changing pressure wave and can be manipulated with materials . Shape and hardness can deflect and contour pressure waves . |
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Lucky we have people in the world willing to give the inefficient a go just because they want to . |
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