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Angled jets form a water vortex on the combustion chamber walls of a slightly oversized inverted cylinder, fast enough that there's a dry spot at the very bottom where the centrally located valves & stuff are. The whirlpool reaches up to the point of maximum incursion of the piston (possibly a bit higher).
A reservoir tank surrounding the head replenishes the water lost to steam (and is itself replenished by cooling and denaturing the exhaust).
- the cylinder is now variable displacement by adding or subtracting to the volume of water in the cylinder
- on the spot conversion of water to steam
- little or no engine cooling required; in fact you'd probably want to insulate it
- the piston/cylinder assembly could be water-lubricated
(variations on this idea include using a magnetically induced stirrer to swirl the water around instead of pressurized jets, and making the entire cylinder head the reservoir)
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Annotation:
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You can't do this on a multi-cylinder engine running
at a thousand cycles per second. Water isn't that
fast, or precise. Even if you could get the water to
form a vortex, the temperature inside would
vapourize the water and extinguish all possibilities
of combustion. |
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well, I've had lots of ideas concerning trying to shoehorn steam generation into a 2stroke IC engine. This is the latest and with the exception of the quite similar "Water Sump Cylinder" (same thing minus the vortex: less complex but the water doesn't cover the cylinder walls, only the head) possibly the most likely to work or at least understand... it seems to be as well received as the others so far :( |
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First of all the cylinder is upside down: the piston comes in from above. The whirlpool is limited to the combustion chamber area: the part of the cylinder bounded by the head and the piston at maximum incursion. Bear in mind that this isn't a retrofit; the cylinder is made with this in mind: perhaps it's bulb shaped at the very end. |
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This means the vortex will cover the cylinder sides and most of the bottom during combustion. We're talking much more water than will be flash evaporated by the combustion. More water is squirted in in between combustion strokes to replace water lost to evaporation, and keep the vortex spinning. You might need a drain at the bottom: depends on how much steam-replacement water is needed vs. what flow is required to shape the whirpool properly. |
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There's 3 distinct advantages to this: |
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- extra power from steam
- lower external cooling requirements
- variable CR (by varying the amount of water in the cylinder) |
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//engine running at thousands of cycles per second// umm what ? |
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//water isn't that fast// It doesn't have to be, it's not going anywhere except 'round and 'round; just part of it gets evaporated off with each combustion, but that part's replaced by the same mechanism that does the spinning thing. The vortex makes a water-walled combustion chamber. |
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//the temperature inside would vapourize the water// YES: instead of wasting energy heating the cylinder wall then wasting more energy cooling it from outside, we flash a layer of water into steam. |
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It's not perfect, coverage is limited to 9-10% of the cylinder wall(but it's the % that gets the hottest) and maybe 70-80% of the head, and there doesn't seam to be an easy way to cover the piston-head in water at all (at least none that are probably more bother than they're worth). |
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//and extinguish all possibilities of combustion.// The thing with the vortex is to keep the water *away* from the combustion... you might get some stray HC's perhaps. |
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Sorry, my math. A four-cycle engine running at 2000 RPM is running at 1000 4-stroke cycles per minute per cylinder, or about 32 compressions per second. So the intake stroke is about 1/64th of a second long. Can you create a vortex around the outer perimeter of a cylinder without creating water vapour that would prevent the ignition of the gasoline in this length of time? |
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The vortex is a permanent thing, not one vortex per cycle, but a spinning mass of water of which a small portion gets vapourized at each combustion. The speed of the whirlpool needs to be fast enough such that water isn't bounced around too much. |
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To make coverage complete, a few short radial fins extrude from the piston head: these intersect the top edge of the whirlpool when the piston comes up to TDC and divert some water across the piston head. |
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Using mercury rather than water would have the following advantages: |
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-Easier flow over surfaces due to lack of wetting
-Lower heat capacity so turns into vapour more easily
-Higher boiling point makes it easier to get out of exhaust
-Good anti-detonation properties, effectively upping the octane rating of the fuel |
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//mercury// that would be pretty neat up to the point where you end up with mercuric oxide in the exhaust... couldn't use aluminum anywhere in there either. |
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