Looking for help building a Gas Vapor system

[Frank Lee]

OK so there's heat at the intake but racprops sez we're throwing away most of the fuel.

WHAT DOES HE WANT FROM US???

[ChazInMT]

I always love how people are smart enough to know the 30% utilization thing but not smart enough to figure out where it comes from and what it means. Never mind 99% + is burned in the combustion chamber of any modern vehicle...that number is of no value when when 70% is wasted. By using a fuel vapor system, you can burn up to 99% + instead of 30%!! Oh Heck Yea!!!

So if a car is getting 33MPG burning 99% of the fuel 99% of the time, and it's only using 30%....Then....It should get 100MPG if it burns 90% cause 90 ÷ 30 = 3 and 3 X 33 is almost 100!!! See, the math does work.

[Hersbird]

IF a motor is getting much better MPG with some kind of vapor setup it is only because it is way outside emissions requirements and making a fraction of the power. Probably only enough to idle or drive a few mph in first gear. IF you applied a similar lean condition to an emissions stripped motor you might pick up quite a few MPG. I have long wanted to see testing done by an actual manufacturer at what would be possible mpg wise, emissions be dammed.
There just isn't that much wasted energy in a modern fuel injected motor cracking gasoline. Yes there is heat and pumping losses, but you would still have these losses if you were using vapor, especially if you were making a motor that was operational over a range of power. The vapor has to be compressed, then ignited, which causes it to get really, really hot, expanding the air and driving the piston. That heat doesn't just disappear because you ignited vapor rather then tiny droplets (AKA also a vapor).
Basically no matter how you say it, every car runs on gasoline vapors and seeing as how there is not a stream of liquid gas flowing out the exhaust it is burning all of it. If that much gas was being wasted in the exhaust it would be much, much hotter then it already is.
I have seen articles where a Mazda 626 vapor car was put to the test. It went 45 miles on a gallon at 65. The article tried to say it's only rated for 30 mpg so that was a big improvement (but nowhere near the claimed 100 mpg the builder made). The problem is they didn't test the car in normal gas mode to see if that 626 wouldn't have gotten the same 45 mpg just running a constant 65 mph down a Florida highway, the EPA rating is far from the best mpg possible as proven here 1000 times over. Then what if you were to remove the catalytic converter and run a lean burn tune on the standard fuel injection. A modern motor doesn't run as rich as it does for best mpg or power, it does it to keep the converter working and emissions low. Also every one of those 100 mpg cars out there always seem to keep a normal fuel system in place that has some kind of supposed shutoff. I just don't believe any of them are really not tapping into that gas at anything above idle.

IDK, build one I guess, and then make a clear video showing proof. These guys in the videos are getting 200 mpg without any of the fancy heat and pressure setups supposedly. You should be able to get 400-500 mpg no problem with a 800 degree gas vapor cooker. Then the big oil execs will come to your door and kill your whole family. Probably try and make it look like a gas explosion accident too.

[racprops]

done

[davelobi]

CAFE wouldn't be an issue if there was any way in the world an automotive V-8 could obtain 100 mpg! The car manufacturers would be all over it. The internal combustion engine is rapidly losing opportunities for big gains in fuel economy. It is pretty well engineered in the modern engines. AFM (active fuel management, ie dropping cylinders under light loads) and start/stop technology are a couple of the latest gains after going to lighter lubricants. Concentration has been on lighter and slippery cars as well as less and less displacement. We are still buying V8 vehilcles because we want/like em and gas is cheap.

You can pick up a couple thousand BTUs/gallon in the winter by storing some summer formulation gasoline.

just my 2 cents

[davelobi]

Originally Posted by racprops

... Gas burns SO SLOWLY that they have to start it burning some 30 degrees (or More) BEFORE top dead center...
....Knocking is when fuel burns or explodes BEFORE top dead center...

huh? how are "they" starting the burning 30 degrees btdc? Engine would stop, almost like a hydro lock, if you set ignition to spark (burn the gas) at 30 deg btdc. Imagine the power of the starter motor that would be needed to crank that puppy up. Ever advance timing a little too far? = bucking the starter motor.

[oil pan 4]

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...

Then you want a diesel engine. Fuel is injected no more than 4 degreed before top dead center and is burned up well before 45 degrees after top dead center.
Gasoline has to burn slow, fuel that just all explodes at once will blow cylinder head gaskets, crack pistons and bend connecting rods.
Diesel explodes as soon as it hits the inside of the cylinder but there is only a tiny amount exploding, then the rest burns as fast as it gets injected.
Heat still needs to be rejected at the end of the cycle to produce work. You can try to build a superheat engine that produces work with no heat rejection.
Many have tried, all have failed.

[RustyLugNut]

Originally Posted by davelobi

huh? how are "they" starting the burning 30 degrees btdc? Engine would stop, almost like a hydro lock, if you set ignition to spark (burn the gas) at 30 deg btdc. Imagine the power of the starter motor that would be needed to crank that puppy up. Ever advance timing a little too far? = bucking the starter motor.

You are trying to correct erroneous points and yet have no knowledge of such a basic principle as ignition lead time? It undermines your position.

[RustyLugNut]

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...

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?

[davelobi]

Originally Posted by RustyLugNut

You are trying to correct erroneous points and yet have no knowledge of such a basic principle as ignition lead time? It undermines your position.

How could you possibly know what level of knowledge I have on such a basic principal as ignition lead time? I understand that preferred maximum combustion pressure would be just after top dead center to maximize the power stroke. With that in mind and the rate of fuel burn in a gasoline engine the spark will be before tdc, yes, but 30 degrees before tdc would break things. Timing in a modern car is much more fine tuned by the engines computer than the old mechanical advanced distributers. Slight operating condition changes will call for slight lead time changes to constantly strive for max fuel economy at any given speed-load.

the op would probably have more fun changing individual parameters in the ecm to play with fuel economy but will likely fall out of emissions regulations that the manufacturers can't do.