Gasoline VAPOR?

[Ecky]

Originally Posted by redneck

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As usual people here fail to look outside the box. Unfortunately (sadly), this place has become a echo chamber of what is acceptable and what is not when it comes to pushing the frontier.


In 1973 a small group of engineers entered a 1959 Opel P1 in a mpg contest.

Shell Opel

The contest required a minimum of 30 mph speed.
They achieved 376 miles per gallon in their record run.
They eliminated the radiator and super insulated the engine. A tiny Tillotson lawnmower carburetor with a 3/4” bore was used. It used a direct drive chain from the clutch to a live axle. No suspension. The rear wheels were pushed closely together. It was stripped, chopped and lowered.

In the video of the Maverick with a 302. The guy used a carburetor from a lawnmower engine. It looks almost identical to the carburetor on my 35 hp Briggs V Twin (Daihatsu) zero turn. So, loosely it is capable of producing at a minimum 35 hp. Highway speeds usually require approximately 20 hp or less depending on the vehicle. He is using modern sensors to monitor engine parameters and control AFR at 14.5 to 1. The Opel ran 15 to 1.

While I’m dubious of short fills. His results are entirely possible. However, I would like to know more about his controls. He apparently uses a vacuum bleed to control AFR. At a minimum, he’s using a wide band O2 sensor, a custom controller for vacuum and probably a custom ignition advance also.




Lately, there has been a few new threads coming out pushing the boundaries of accepted knowledge.

I welcome this...

There’s more than one way to skin a cat...

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I just get skeptical when I start seeing claims where the amount of energy needed to push a car down the road greatly exceeds the energy content of the fuel. There is an upper limit to how much useful work you can extract from the chemical bonds in a gallon of gasoline.

[Isaac Zachary]

Originally Posted by redneck

Lately, there has been a few new threads coming out pushing the boundaries of accepted knowledge.

I welcome this...

There’s more than one way to skin a cat...

��

>

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True, and I appoligize for having done this.

It can happen that something out there that we know-it-alls think has been done and tried and beaten to death with a dead horse on a stick to the point it's not worth looking at that in reality is the key to something perfectly practical and beneficial.

Originally Posted by racprops

A change of state, from a liquid takes a fair amount of energy, and to condense a vapor takes the removal of a fair amount of energy, in other words to get vapor you need to really heat if up and to turn it back into a liquid you need to do a lot of cooling.


Stuff has a tenancy to stay in the state it is in. My understanding gasoline once vaporized will stay as a vapor for some time unless acted apron by a drastic temperature drop.

And again, once in a vapor state there will be NO liquid droplets to cool the mix, and they do that because of their absorbing heat as they are changing state into vapor and it will all BE VAPOR.

Dew point.

Stuff does not really have a "tendency to stay in the state it is in." There are many variables here, such as the temperature of the air and how saturated it already is (e.g. humid vs. dry air). But just feeding a hot gas into a cooler one does not mean the hot gas will have a tendency to stay a gas.

If you look at a tea kettle with boiling water you see white "smoke" coming out of the top. Steam is completely transparent just like air. What you see are water droplets formed from the steam cooling in air.

The same will apply to gasoline, especially since some of gasoline's contents need to reach about 200° C in order to boil, which is 100° C more than water. The question is what is the dew point of gasoine in air. Surely it varies, but I don't see air holding nearly 7% of it's mass in liquids that boil up to 200° C at ambient temperatures.

Originally Posted by racprops

Timing will indeed need to cut back, to zero most likely as unlike gasoline droplets which need time to be vaporized BY the early start of combustion, vapor will flash burn producing more pure power to drive the piston and in correctly metered be completely consumed at the end of the combustion cycle and there will be no farther burn, thus much less engine heat. Also as there is no early start of combustion they will not be expanding gassed for the piston to fight as it tries to compress them. This could also add to the power output.

That all sounds good and all but I feel is overly optomistic. We already have engines that run on completely vaporized fuels such as hydrogen, propane and natural gas, and none of those work at zero timing advance since they run better with advanced timing. There is no reason vaporized gasoline would work any differently. I would think gasoline would be even worse because it has a lower octane which, long story short, means you end up with a slower burn or it will detonate, and detonation means ¡adiós motor!

Originally Posted by racprops

And here you thinking of the other vapor fuels which contain less BTUs that gasoline, all the power gasoline make is from its vapor state, liquid does not burn.

"liquid does not burn." Well duh! I fully understand that. But that's not what I'm talking about.

When you boil a liquid it can expand well over a thousand times it's original volume, and many times even far more. A voluminous gaseous fuel displaces a lot more of air that can get into the engine than a liquid fuel does. You can't just make gasoline 1,600 times or more it's original volume and expect to get the same amount of air into the engine without adding super or turbocharging. Simply put, gaseous fuel means less air and fuel will get into the engine.

This also doesn't take into account that feeding 200° C boiled gasoline vapors into the air is going to increase the air's own temperature causing it to expand before getting into the cylinder, which means even less air will enter the engine.

Originally Posted by racprops

You’re talking the current state of thinking….finer and finer atomization. ALL to TRY to help those droplets vaporized more…none the less there is still left over fuel otherwise they would remove the cats as they would no longer be needed to clean up the unburned fuel.

Rich

There will always be left over fuel in the exhaust even if you vaporized all the gasoline. The same happens with other gaseous fuel engines.

Why? Because of quench.

The flame stops burning when it gets to a certain distance near the combustion chamber, the valves, the piston and the cylinder walls. At this point the flame is too close to the metal which, even at temperatures of up to 200° C or more is too cold to let it burn. It ends up sucking the heat out of the flame where the flame gets close enough and leaves a thin layer of unburned air and fuel vapor along the edges of all the metal parts.

The reason small droplets can burn is that the flame that propagates throughout the combustion chamber is around 1,500° C, plenty hot to vaporize any liquid fuel droplets that are small enough. Not that there isn't some potential benefit of reducing them to the point they are completely vaporize, but modern gasoline engines already burn up to 90% of the fuel (or more) in the combustion process. And most of that 10% (or less) of fuel that isn't burned up in the combustion chamber is from quench which is still a problem in gaseous fuel engines.

It would seem that reducing or eliminating quench would be more important if you want to burn up 100% of the fuel in the combustion chamber. One way is using a stratified engine.

But anyhow, you could still be onto something. I wonder what combining a gaseous fueled engine with a stratified charge or some other idea would lead to in terms of thermodynamic efficiency.

[pgfpro]

As far as the Maverick guy goes. The A/F ratio the vacuum inch/hg and the cars Cd tells the story. Put these values into an engine sim and things look a little weird?
The thing that drives me crazy about crazy claims without making big changes to the engine is well the engine. Each engine has a BSFC and BSAC fingerprint.
You can change the fuel to vapor put a smaller then normal carb on it but the facts are you did nothing to improve on the engine BSFC numbers. The ICE is the biggest problem. You can only squeeze so much out of it.

I'm not doubting that the lawn mower carb did better then his other one. Major gains can be made from one carb to another. The fuel test he did didn't sit well with me. I even showed a friend the same test in my 97 stock eclipse. Doing the same test "short fill" my cars fuel mileage went up from 30mpg to 65mpg. The Maverick guy was always about getting more hits and subscribers and man did it pay off for him. Hope he sleeps well at night.

[freebeard]

I have resisted the lawnmower carb videos, despite Youtube's insistence.

[racprops]

In 1973 a small group of engineers entered a 1959 Opel P1 in a mpg contest.

Shell Opel

The contest required a minimum of 30 mph speed.
They achieved 376 miles per gallon in their record run.
They eliminated the radiator and super insulated the engine. A tiny Tillotson lawnmower carburetor with a 3/4” bore was used. It used a direct drive chain from the clutch to a live axle. No suspension. The rear wheels were pushed closely together. It was stripped, chopped and lowered.


I know about that Opel, and they allowed hypemiling as well.

It was just a little game with Shell engineers amount themselves.

And like my testing and on the Bonneville Flats the testing is done with a flying run.

Rich

[racprops]

Dew point.

Stuff does not really have a "tendency to stay in the state it is in." There are many variables here, such as the temperature of the air and how saturated it already is (e.g. humid vs. dry air). But just feeding a hot gas into a cooler one does not mean the hot gas will have a tendency to stay a gas.

True to a point…none the less once in a vapor state some action is needed to cause a change into another state.


If you look at a tea kettle with boiling water you see white "smoke" coming out of the top. Steam is completely transparent just like air. What you see are water droplets formed from the steam cooling in air.


Steam IS the “smoke” true fully vapor would be transparent, fully in a full vapor state. My idea of a system would be feeding hot vapor directly into the intake allowing very little time to cool down.


The same will apply to gasoline, especially since some of gasoline's contents need to reach about 200° C in order to boil, which is 100° C more than water. The question is what is the dew point of gasoine in air. Surely it varies, but I don't see air holding nearly 7% of it's mass in liquids that boil up to 200° C at ambient temperatures.

Granted most modern ICEs are running dry intake manifolds so perhaps some testing may be needed to insure no liquid drop out happens.

I believe we would be talking a conversion temperatures of around 500/600C. With a cool down system to lower it to 200C.

That all sounds good and all but I feel is overly optomistic. We already have engines that run on completely vaporized fuels such as hydrogen, propane and natural gas, and none of those work at zero timing advance since they run better with advanced timing. There is no reason vaporized gasoline would work any differently. I would think gasoline would be even worse because it has a lower octane which, long story short, means you end up with a slower burn or it will detonate, and detonation means ¡adiós motor!

[B]Well: Gasoline Gallon Equivalents
Fuel Type Unit of Measure BTUs/Unit Gallon Equivalent
Gasoline (regular) gallon 114,100 1.00 gallon
Diesel #2 gallon 129,500 0.88 gallons
Biodiesel (B100) gallon 118,300 0.96 gallons
Biodiesel (B20) gallon 127,250 0.90 gallons
Compressed Natural Gas (CNG) cubic foot 900 126.67 cu. ft.
Liquid Natural Gas (LNG) gallon 75,000 1.52 gallons
Propane (LPG) gallon 84,300 1.35 gallons
Ethanol (E100) gallon 76,100 1.50 gallons
Ethanol (E85) gallon 81,800 1.39 gallons
Methanol (M100) gallon 56,800 2.01 gallons
Methanol (M85) gallon 65,400 1.74 gallons

Gasoline has the most bang for your buck. Vapor gasoline It also has a high vapor density, which means it produces a lot of vapor compared to other combustible liquids.

The flash point of a volatile material is the lowest temperature needed to evaporate enough fluid to form a combustible concentration of gas. Gasoline has a flash point of -45°F and an auto-ignition temperature of 536°F.

Burning gasoline vapor can cause an explosion.

When you boil a liquid it can expand well over a thousand times it's original volume, and many times even far more. A voluminous gaseous fuel displaces a lot more of air that can get into the engine than a liquid fuel does. You can't just make gasoline 1,600 times or more it's original volume and expect to get the same amount of air into the engine without adding super or turbocharging. Simply put, gaseous fuel means less air and fuel will get into the engine.

This also doesn't take into account that feeding 200° C boiled gasoline vapors into the air is going to increase the air's own temperature causing it to expand before getting into the cylinder, which means even less air will enter the engine.

A ICE is a fairly effect air pump, there is a large amount of air being drawn in, gasoline vapor at say 200C is already working in a 100C engine compartment. I don’t think it will cause any problem in a few seconds as it is fed into the engine.


There will always be left over fuel in the exhaust even if you vaporized all the gasoline. The same happens with other gaseous fuel engines.

Why? Because of quench.

The flame stops burning when it gets to a certain distance near the combustion chamber, the valves, the piston and the cylinder walls. At this point the flame is too close to the metal which, even at temperatures of up to 200° C or more is too cold to let it burn. It ends up sucking the heat out of the flame where the flame gets close enough and leaves a thin layer of unburned air and fuel vapor along the edges of all the metal parts.

The reason small droplets can burn is that the flame that propagates throughout the combustion chamber is around 1,500° C, plenty hot to vaporize any liquid fuel droplets that are small enough. Not that there isn't some potential benefit of reducing them to the point they are completely vaporize, but modern gasoline engines already burn up to 90% of the fuel (or more) in the combustion process. And most of that 10% (or less) of fuel that isn't burned up in the combustion chamber is from quench which is still a problem in gaseous fuel engines.

On the other hand IF the claims are true and gasoline vapor explodes then it “burn” cycle may be too short to allow quenching…it might combust too fast for that action.

Interesting talk.

All things to be looked into.

Rich

[racprops]

Each engine has a BSFC and BSAC fingerprint.

BSFC can only be measured on a dyno. The formula is: BSFC = lbs. of fuel used per hour ÷ horsepower For example, a 300hp engine using 150 lbs./hr. of fuel would have a BSFC of 0.5. Different engines using different fuel types will have different BSFC values.

Well how much fuel is my 03 Ford Explorer 4.6 in 5th gear (overdrive) into a 3.73 rear end using when I drive it at 49MPH which is 1500RPMs and it shows it is getting 30MPG?? Steady running…how much HP and torque is it making?

Also same question for a 2000 Mercury Grand Marques, Well how much fuel is 4.6 in 4th gear (overdrive) into a 3.27 rear end using when I drive it at 65MPH which is 1700RPMs and it shows it is getting 30MPG?? Steady running…how much HP and torque is it making?

Same car running a 16.4 A/F ratio gets 35MPG same specs.

[racprops]

How much vapor can one gallon of gasoline make if converted to vapor?

Briefly, the saturated vapor volume of an average gallon of liquid gasoline when fully evaporated is 160.4 gallons of vapor at 60° F and sea level.

Vapor volume of a liquid is the number of cubic feet of vapor resulting from the complete evaporation of the liquid. The vapor volume depends on parameters of density, temperature, pressure and molecular weight which is affected by the variety of formulas for gasoline that is comprised of a wide range of hydrocarbons.

Several approaches are available to solve this problem. One is shown below.

Using a common industrial formula:

one liquid gallon = [(8.31) x (SG) x (387 cu ft)] / (MW)

Where:

8.31 = pounds in gallon of water

SG = specific gravity of liquid being vaporized

387 = At standard conditions, one pound-molecular weight of a material will evaporate to fill 387 cubic feet of space.

MW= molecular weight of liquid being vaporized

Then using the approximate gasoline constants:

one liquid gallon of gasoline = [(8.31 pounds in a gallon of water) x (.70 approx. specific gravity of gasoline) x (387 cu ft)] / (105 molecular weight of average gasoline)

= 21.4 cubic feet of vapor volume

There is 7.481 U.S. gallons in one cubic foot.

So:

one liquid gallon of gasoline = (21.4 cubic feet) x (7.481)

= 160.4 gallons of saturated gasoline vapor

The vapor volume will vary based on the specific formulation of gasoline, pressure, and temperature.

D. Hollatz

Two questions I cannot find answers to:

How much energy in gasoline vapor?

I believe IF I can meter the same amount energy in gasoline vapor like 30% of what normally would be fed into the ICE it would product the same power as it does on its normal system.

And

Is gasoline still burning in the exhaust manifold?

I believe it is as I have read it does in the past.

Also if combustion is completed within the chamber that there would be no need of the cats.

Gas ICEs are still rated at on 30/35% effectent.

Rich

[pgfpro]

Originally Posted by racprops

Each engine has a BSFC and BSAC fingerprint.

BSFC can only be measured on a dyno. The formula is: BSFC = lbs. of fuel used per hour ÷ horsepower For example, a 300hp engine using 150 lbs./hr. of fuel would have a BSFC of 0.5. Different engines using different fuel types will have different BSFC values.

Well how much fuel is my 03 Ford Explorer 4.6 in 5th gear (overdrive) into a 3.73 rear end using when I drive it at 49MPH which is 1500RPMs and it shows it is getting 30MPG?? Steady running…how much HP and torque is it making?

Also same question for a 2000 Mercury Grand Marques, Well how much fuel is 4.6 in 4th gear (overdrive) into a 3.27 rear end using when I drive it at 65MPH which is 1700RPMs and it shows it is getting 30MPG?? Steady running…how much HP and torque is it making?

Same car running a 16.4 A/F ratio gets 35MPG same specs.

Trust me I know what BSFC is.

I'm not going to play this game. Been here and have done it 100 times, probably 20 times on this forum. If I we're to play your game you left something major out... "engine load" I would need to know what it is and it can be measured in kPa, inch/hg or psi I just need one of them to solve for it.

As far as the Mavrick guy. I had the inputs I needed.
Fuel type
Load inch/hg
IAT's
DA
AFR
BSFC load Map for a 302 Ford
Bore
Stroke
Compression Ratio
RPM
Rod length
Ignition timing BTDC
Cd
Transmission type


Anyway, I hope you find what you're looking for and prove me wrong. Like I said I already tested a vapor carburetor on my lawn mower engine. My results were no improvement in fuel consumption. Same EGT's and cylinder temps with the same AFR.

Good Luck

[Isaac Zachary]

Originally Posted by racprops

True to a point…none the less once in a vapor state some action is needed to cause a change into another state.

Steam IS the “smoke” true fully vapor would be transparent, fully in a full vapor state. My idea of a system would be feeding hot vapor directly into the intake allowing very little time to cool down.

Extremely wishful thinking. Taking two mixes of gases at extremely different temperatures and mixing them enough for them to burn at all in a combustion chamber and doing so without giving them enough time to settle to a similar temperature is... for lack of a better word and with all due respect, impossible.

Intakes aren't instant transportation devices. Air and fuel stops and starts, stops and starts as each intake valve opens and closes. It then has to go through the intake cycle and then the compression cycle. At what point are you injecting the fuel so fast it doesn't have time to condensate? Is this direct gas injection that you're thinking of? Maybe only then could gasoline stay in a gaseous state if injected exactly as combustion starts. Other than that, its and the air's temperatures are going to quickly find an equilibrium.

Originally Posted by racprops

Gasoline has the most bang for your buck. Vapor gasoline It also has a high vapor density, which means it produces a lot of vapor compared to other combustible liquids.

Um, I still don't get your point. Forget any other types of fuel and focus only on liquid gasoline vs. vaporized gasoline. How much energy is stored in a gallon of liquid gasoline? How much is stored in a gallon of gasoline vapor? How much air and fuel can a cylinder with a displacement of half a liter inhale every intake stroke? How much of that is air and how much is fuel?

Originally Posted by racprops

The flash point of a volatile material is the lowest temperature needed to evaporate enough fluid to form a combustible concentration of gas. Gasoline has a flash point of -45°F and an auto-ignition temperature of 536°F.

But you can't have every last drop of gasoline in a container vaporized at -45° F. It needs to be at around 200° C or 395° F at atmospheric pressure to completely boil it. Then you start compressing it and its boiling/condensing temperature will also go up meaning some of it will condense if you get it to just 200° C or 395° F before compressing it, so it has to be even hotter in order to not condense.

What's the point of boiling gasoline if some of it is going to just condense right back into a liquid?

Originally Posted by racprops

Burning gasoline vapor can cause an explosion.

On the other hand IF the claims are true and gasoline vapor explodes then it “burn” cycle may be too short to allow quenching…it might combust too fast for that action.

Please research what detonation is.

There are three ways you could potentially burn fuel in a combustion chamber. The conventional way is to do so with a flame front. Flame starts at spark plug and works it's way out like an inflating balloon. This is why we need advanced spark ignition of course.

Another way is to make it all burn up at once, preferably at top dead center. But that needs to be done very precisely, evenly and at exactly the same time and is extremely difficult to pull off. Only Mazda, that I know of, has a spark controlled compression ignition engine that basically does this under certain circumstances. Note that it's the compression that ignites all the fuel quickly, not the spark plug itself.

The third way is to end up with a pocket of fuel and air exploding out of sync with the rest of the combustion chamber. This is mainly caused from lean pockets with less fuel droplets that can absorb the heat as compression from the expanding flame front pushes in on the rest of the unburnt mix. When this happens you get detonation, a sonic pressure wave that results from that small pocket rapidly expanding instead of either gradually, with a flame front, or in sync with the rest of the combustion chamber, as in the case of homogenous compression ignition. The result is the sonic pressure wave pushes hot combustion gases into the metal which causes them to exchange heat very quickly. You lose power because a lot of heat gets into the metal and you also quickly start liquifying metal. This is what causes you to punch holes right through your pistons and causes you to bend rods.

Note that detonation is also something that can be a problem in propane and natural gas engines. These also like having a flame front move from the spark plug out to the edges of the combustion chamber over the course of several, if not dozens of degrees of crankshaft rotation. Just because it's a gas does not mean it's easy to make it all explode instantly at a precise moment.

Originally Posted by racprops

A ICE is a fairly effect air pump, there is a large amount of air being drawn in, gasoline vapor at say 200C is already working in a 100C engine compartment. I don’t think it will cause any problem in a few seconds as it is fed into the engine.

I don't see what that has to do with what I was saying, but I think I can agree to a point on that.

Originally Posted by racprops

Two questions I cannot find answers to:

How much energy in gasoline vapor?

I believe IF I can meter the same amount energy in gasoline vapor like 30% of what normally would be fed into the ICE it would product the same power as it does on its normal system.

And

Is gasoline still burning in the exhaust manifold?

I believe it is as I have read it does in the past.

Also if combustion is completed within the chamber that there would be no need of the cats.

Gas ICEs are still rated at on 30/35% effectent.

Rich

How much energy is in gasoline vapor?
At 200° C my rough calculations tell me it's about 2,000 times less dense than in liquid state. So 2,000 times less energy. In other words, you need about 2,000 times more gas vapor to get the same power as liquid gasoline.

Does fuel still burn in the exhaust? No. Yes. it depends.

With most modern engines the answer is no. Engineers are getting better and better at getting the fuel to burn up quickly, long before the exhaust stroke. Nearly all the fuel left over that burns up in the catalytic converter is from quench, not flame speed.

Of course if you can make it burn up even faster then it can be better. It's best to have it all burnt up as close to TDC as possible, as the top part of the stroke is the part where most of the energy from the already burnt fuel is extracted.