My apologies if this was covered earlier in the post. I read so much stuff..!
I NB that we are not talking about heating fuel to the point where it breaks down into smaller fractions pre compression stroke here, as is the case with Geet etc.
Quote:
Originally Posted by pgfpro
I think Smokey was on to something due to the mere fact that fuel was completely in a vapor form. This does help with burning most of the fuel in every power stroke, but there is more to it than just heating the fuel/air. The fuel has to do more than just light load, and this is why there are light medium and heavy fractions that make up todays fuel and the fuel that Smokey used during his testing.
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???
My understanding of things is that while the heavy fractions do get you more calories per gallon in your tank, they don't evaporate or burn as well, which is why heating them up helps?
ie: Up to a certain temperature (as you are doing) you make them evaporate better/faster, then above that they start to break down into smaller, more volatile fractions..?
This would only begin to really happen during compression in your case.
(It's at higher, gas carb reqd, type temperatures that one might get a tiny bit of Hydrogen with the judicious use of steam and catalysts like Zinc.
There's a bit to be had elsewhere, pertinent to your setup, too...
But mostly we are heading into gas carb territory here and away from the quick, easy, precise metering and timing of liquid fuel injection)
So; same amount of energy in the tank and going to the engine, but more evaporation and lighter fractions pre use, from waste heat and compression.
As far as
the hot air goes what I think happens is:
With air at 200F say, the molecules are further apart, so compressing the gas is easier and compression only starts to add heat after the point where compression alone would have gotten the air up to 200F..?
ie: You end up with something of a Miller Cycle as the initial part of the compression cycle is easier..?
Then
during all that or on top of it;
there is less cooling of the combustion chamber due to a smaller delta T between the intake charge and the combustion chamber walls.
That gives you an efficiency gain as less heat is lost and helps give you the higher temperatures useful for igniting/burning very lean mixtures.
(Also the hot air and fuel may lead to a tiny bit of partial oxidation during the compression stroke
?? An exothermic reaction at the wrong time, but adds to the heat and temperature reqd for super lean burn)
Quote:
Originally Posted by pgfpro
...I'm also heating the fuel by using a fuel heating coil that gets its heat next to the exhaust manifold.
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I assume this heating is after the high pressure fuel pump, so that the pump has liquid, not vapour (lock) to pump, and so that the high pressure then keeps the fuel liquid?
How hot do you make it and how do you control that temperature?
I'm guessing this has to be pretty precise?
Quote:
Originally Posted by pgfpro
Another thing I found was when burning automotive waste paint solvent that is made up of very light solvents is I don't need as much heat via intercooler and a heated fuel coil. So, this why I started about few years ago testing different solvents as a fuel.
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This goes to my 1st point..??
And to that point I like to add that any Ozone one can add to the mixture will help.
In the old days of distributors, a small (filtered) vent and a (vacuum) line to the intake would give you some
free Ozone and make the distributor work better and last longer to boot.
Nowadays; I see no reason why the spark-plug spark couldn't be made to jump an extra gap in the air filter box!? (slower air) Compacting a bit of O2 to O3 pre filter restriction..?
On pre chamber cooling:
As I understand things you are already injecting fuel during valve overlap, pre TDC to get a rich mixture into the prechamber while the piston is moving very slowly.
You also have a water injection system fitted IIRC.
Is it perhaps possible to
add a tiny squirt of water during this pre chamber filling stage, then cut it off for the main intake stroke?
That may just be enough to prevent pre-chamber pre-ignition and perhaps even work well with the copper? to add a bit of Hydrogen.
The only other option,is sub ambient cooling of the chamber using the aircon or evaporative cooling and complex 3D metal printing of a pre chamber with cooling channels, plus a ceramic coating on the nozzle and threads
That tiny squirt of water might be cooled sub ambient as above.
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