Quote:
Originally Posted by racprops
You getting close, Consider this: Gas burns SO SLOWLY that they have to start it burning some 30 degrees (or More) BEFORE top dead center...and as even the finest droplets are NOT vapor but converting TO vapor only 30% is able to produce the power stroke, the rest do burn but make no power as they are still burning though the rest of the rotation of the crank and the final piston moving though bottom dead center and back up in the exhaust stroke and still are burning on its way out of the exhaust valve and out the exhaust manifold and tail pipe, which is IF you were running straight pipe a like a dragster you see flames.
The power stroke is some 10 degrees after top dead center and down to about 70/80 degrees to bottom dead center, after bottom dead center that burning fuel is a waste of fuel as it can make no power..do no work.
IF you are running vapor you then need timing of ZERO DEGREES or a couple of degrees AFTER top dead center because vapor explodes so nearly 100% can produce the power stroke and THAT means all of the 20 to30% of the fuel makes more power with no waste and give more power an more MPG.
It is used up during just the few degrees of crank turning after top dead center and can be all gone before bottom dead center, and there is no (or very little) waste of fuel.
At least that is the theory... as I under stand it.
Knocking is when fuel burns or explodes BEFORE top dead center...
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As OilPan4 has pointed out, vapor fuels do not have any advantage. Why is propane fuel no more economical to use per BTU than any other fuel? Why does it need to have an ignition lead of pretty much the same range as gasoline? I think you need to answer that before we move forward.
I think you need to study up on detonation more intimately as this is where heated fuels and air mixes end up. This will lead you to the study of HCCI ( homogeneous charge compression ignition ) engines. But, they only test out to an increase of 50% thermal efficiency gain.
There are no magical 200 mpg carbs. I've built a few, and some have merit in reducing ignition lead time or extending effective lean limits, but there is no getting 10x the fuel efficiency from a heat engine that is already 25% efficient. If it ran at 100% efficiency, it can only go 4x the distance. ChazInMT and Frank Lee did very similar math. It is good math. How would you reconcile that?