Acetone instead of methanol?
08-27-2007, 04:48 AM
#1
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Acetone instead of methanol?
I've seen a quite a few mentions of using Acetone to break the surface tension of gasoline so it "sprays" better. Has anyone tried this with WI? I'm guessing that most people don't have as good a source of Acetone as they do Methanol so it would never be popular even if it worked better. I've got access to 1,000's of gallons of each so it makes no difference to me. Comments?
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08-27-2007, 10:21 AM
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my dad uses it in his turbo diesel motorhome and claims it's the ****.
apparently the place to buy it in qty is beauty supply stores. NOT home depot or the drugstore.
apparently the place to buy it in qty is beauty supply stores. NOT home depot or the drugstore.
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09-01-2007, 11:18 PM
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I work in a chemical plant. We have TONS (as in 10,000 gallon tanks) of Acetone around here. I threw some in the gas tank of my JRSC'd Miata the other day for the hell of it. I think it has a pretty high octane rating but I haven't looked at the actual number recently. I know the boiling point is 56C while Meoh is 65C.
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09-04-2007, 01:35 AM
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It raises the octane of your fuel but I don't think either one will have the intercooling effect of methanol, and especially not water, which is the point of water/alcohol injection. The latent heat of evaporation of acetone is about half of what methanol is and benzole, which is very similar to xylene, is about 35% of meth. And for what it's worth, I personally wouldn't waste my time with water either, I'd run straight methanol maybe with an additive like Top Lube or Upper Lube.
Last edited by jwarriner; 09-04-2007 at 01:50 AM.
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09-04-2007, 09:35 PM
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It raises the octane of your fuel but I don't think either one will have the intercooling effect of methanol, and especially not water, which is the point of water/alcohol injection. The latent heat of evaporation of acetone is about half of what methanol is and benzole, which is very similar to xylene, is about 35% of meth. And for what it's worth, I personally wouldn't waste my time with water either, I'd run straight methanol maybe with an additive like Top Lube or Upper Lube.
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09-05-2007, 01:11 AM
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Acetone is miscible in water but I think you'd need to ask a chemist how the properties of the water will change, I would not assume that water and acetone would be the same as gasoline and acetone. That being said, it probably will be similar to mixing methanol with the water, but shittier.
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09-05-2007, 08:17 AM
#14
And i tell you J the sheer calorie holding power of water makes up for it's slow movement the methanol helps this by bleeding off the excess heat un a hurry while the water stores it as kenetic enerdy ie steam that, acts as a buffer to the flame frobt in the Combustion chamber and balast to spool in the post combustion world. Clean motivates portects h20 does alot. I think you need to do abit more research before you tout the meth alone is better than meth and watter. + Even by the 55 gallon barrel meth is expensive. Withthe mix i run it is like 75 cents a gallon with pure meth it would be 3 some odd a gallon easy. Not to mention the problem of storing pure meth in the car that **** likes to evaporate very quickly trust me out side of the barrel or diluting it i have yet ot find a way to store it for more than a day with out a loss of atleast 1/3 pure methanol gone from evaporation. It just isn't practical at all. Unless you have a specialy sealed fuel cell etc by then you might as well convert the whole car to methanol and run some 1000 cc/min injectors to make 350 or so whp. Meth is a great helper but running it alone/pure is silly expensive and hard.
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09-05-2007, 05:42 PM
#16
go ahead J i wanna hear your real opinion. show me some numbers etc. PM it or email what ever i am always willing to learn. I stand by what i alraedy know until someone shows me where it is wrong. This debate is very healthy. So hit me up with your arguments, in private if need be and we can see about learning me something. It wouldn't be the first time.
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09-05-2007, 07:12 PM
#17
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Argument: Water doesn't burn. It is taking up space in your combustion chamber that could be used by something that will produce energy. Methanol is almost as good as water when it comes to intercooling and will produce energy during combustion. More combustion energy = more power. That's my argument right there.
Also a lot of hearsay. In other communities people have stopped using water altogether, they don't even discuss it, everyone has switched to methanol. That being said, most stupid people should not be touching methanol. Water is easier (hydrolocking is your only concern, blowing up yourself or your motor is not) and will still allow you to keep your timing, which is the main point of injecting water/alcohol.
It largely comes down to personal preference. Some people run band-aids because it's easier. Some people think a standalone is easier. In my opinion the people are following two different schools of thought and the statements should be "band-aids are easier to get results" and "standalones are easier to get exceptional results". I think the same is true of water and methanol.
Also a lot of hearsay. In other communities people have stopped using water altogether, they don't even discuss it, everyone has switched to methanol. That being said, most stupid people should not be touching methanol. Water is easier (hydrolocking is your only concern, blowing up yourself or your motor is not) and will still allow you to keep your timing, which is the main point of injecting water/alcohol.
It largely comes down to personal preference. Some people run band-aids because it's easier. Some people think a standalone is easier. In my opinion the people are following two different schools of thought and the statements should be "band-aids are easier to get results" and "standalones are easier to get exceptional results". I think the same is true of water and methanol.
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09-05-2007, 07:43 PM
#18
While i don't wholely agree with LS1 he has some valid points as well. I see the mix as the best of both worlds. Storeable and effective.
I dunno if i posted this over here yet, but some good info.
You are rigth though, if you have the means to run straight methanol then that is awesome. But as i said before it is quite abit harder to do than gong from bandaids to a standalone. The evaporation issues alone kill the idea for me. + The real reason of calories absorbed helps out alot. I already hit 100+% VE so running out of room is not a problem for me. The water vapor does help spool the turbo a good bit though as has been evidenced by others. More mass and velocity in the exhaust is always a good thing. right.
Originally Posted by LS1 Bound
I want to address the issue of knock and what causes it.
Consider the following liquids and their heats of vaporizations.
Water 40.655 KJ / mole or about 2259 KJ/Kg water
Methanol 35.2 KJ /Mole or about 1102 KJ/Kg Methanol
Pentane 25.77 KJ/mole or about 357 KJ/Kg Pentane
Octane 38.8 KJ/mole or about 339 KJ/Kg Gasoline.
As you can see, the cooling effect of Methanol is significantly higher than the cooling effect of Octane. Different fuels have different heats of evaporization. Look at water however. For cooling - no contest.
Knock is more complex than this however. Temperature certainly plays a role, but it is not the only parameter that plays a role.
Knock is caused by the rate of reaction (more specifically, the speed of the flame front) exceeding the speed of sound.
As temperature goes up. Molecules move faster. If they move fast enough you may knock (faster flame front). You can reduce the velocity of the molecules by cooling them. In fact, temperature is really just a measure of the mollecular velocity. Cold air has slower moving molecules. If a fuel molecule is moving faster, it will find an oxygen molecule faster.
Adding methanol molecules to compete with gasoline (octane molecules) will certainly reduced knock. Methanol is a slower burning fuel. Why???
Methanol works not by lowering the temperature, but by reducing the rate of reaction statistically.
If we look at a specific volume of methane, it will contain more molecules (lower atomic mass) than a high atomic mass fuel like Octane. This means that during the combustion reaction, a Methane molecule is more likely to hit a nother methane molecule than it is likely to hit an oxygen molecule. If it hits another methane or an Octane molecule, it does NOTHING. It bounces and maybe it hits an oxygen next time, maybe it hits a Nitrogen or another methane, or an octane or one of the products of combustion, water and CO2.
In any case, the more methanol you add, the slower the reaction proceeds because of statistics/kinetics.
It takes longer to burn and will produce lower pressures and will thus yield lower power. Even though the reaction will proceed to completion. The torque developed during the power stroke will be reduced.
The idea is NOT just to burn as much fuel as possible! It is to make the most power with the least amount of fuel and to get the maximum torque from your power stroke.
Using high mollecular weight fuels decreases the number of fuel molecules per mass. This means that there are fewer fuel molecules "searching" for oxygen molecules before some sort of reaction takes place. The reaction is quite complex and will produce many intermediate products until all fuel product has been oxidized. Having said this, we start out with a faster reaction because there are fewer fuel molecules (although they are large) - before the spark provides sufficient activation energy to start the reaction. There are plenty of oxygen molecules and very few few molecules.
Since there are many more molecules of Methane per specific mass, there is a greater chance of a fuel molecule hitting another fuel molecule and doing nothing instead of adding to the rate of reaction.
Now you have to ask yourself what you are after. Are you trying to get maximum power from a low energy fuel or decrease the power of your high energy fuel. Pick one and go with it. In the end, if you do both, you lower efficiency and maximum yield.
Higher Temperatures, produce the highest pressures. Faster flame fronts give the maximum efficiency. As long as the flame front does not exceed the speed of sound (in a combustion chamber) you will get the best power. If they exceed the speed of sound, you will make the most power, but it is unlikely that a gasoline engine will survive for long.
Those adding Methanol are lowering the rate of reaction statiscally. Those adding water are lower the rate of reaction Thermodynamically. There is a cost to using Methanol. There is none in not. The results are same. The efficiency is what changes. Adding methanol is expensive and yields the same thing. Add water to bring the temperature down to where there is a comfortable safety margin and stop there.
Sam
Consider the following liquids and their heats of vaporizations.
Water 40.655 KJ / mole or about 2259 KJ/Kg water
Methanol 35.2 KJ /Mole or about 1102 KJ/Kg Methanol
Pentane 25.77 KJ/mole or about 357 KJ/Kg Pentane
Octane 38.8 KJ/mole or about 339 KJ/Kg Gasoline.
As you can see, the cooling effect of Methanol is significantly higher than the cooling effect of Octane. Different fuels have different heats of evaporization. Look at water however. For cooling - no contest.
Knock is more complex than this however. Temperature certainly plays a role, but it is not the only parameter that plays a role.
Knock is caused by the rate of reaction (more specifically, the speed of the flame front) exceeding the speed of sound.
As temperature goes up. Molecules move faster. If they move fast enough you may knock (faster flame front). You can reduce the velocity of the molecules by cooling them. In fact, temperature is really just a measure of the mollecular velocity. Cold air has slower moving molecules. If a fuel molecule is moving faster, it will find an oxygen molecule faster.
Adding methanol molecules to compete with gasoline (octane molecules) will certainly reduced knock. Methanol is a slower burning fuel. Why???
Methanol works not by lowering the temperature, but by reducing the rate of reaction statistically.
If we look at a specific volume of methane, it will contain more molecules (lower atomic mass) than a high atomic mass fuel like Octane. This means that during the combustion reaction, a Methane molecule is more likely to hit a nother methane molecule than it is likely to hit an oxygen molecule. If it hits another methane or an Octane molecule, it does NOTHING. It bounces and maybe it hits an oxygen next time, maybe it hits a Nitrogen or another methane, or an octane or one of the products of combustion, water and CO2.
In any case, the more methanol you add, the slower the reaction proceeds because of statistics/kinetics.
It takes longer to burn and will produce lower pressures and will thus yield lower power. Even though the reaction will proceed to completion. The torque developed during the power stroke will be reduced.
The idea is NOT just to burn as much fuel as possible! It is to make the most power with the least amount of fuel and to get the maximum torque from your power stroke.
Using high mollecular weight fuels decreases the number of fuel molecules per mass. This means that there are fewer fuel molecules "searching" for oxygen molecules before some sort of reaction takes place. The reaction is quite complex and will produce many intermediate products until all fuel product has been oxidized. Having said this, we start out with a faster reaction because there are fewer fuel molecules (although they are large) - before the spark provides sufficient activation energy to start the reaction. There are plenty of oxygen molecules and very few few molecules.
Since there are many more molecules of Methane per specific mass, there is a greater chance of a fuel molecule hitting another fuel molecule and doing nothing instead of adding to the rate of reaction.
Now you have to ask yourself what you are after. Are you trying to get maximum power from a low energy fuel or decrease the power of your high energy fuel. Pick one and go with it. In the end, if you do both, you lower efficiency and maximum yield.
Higher Temperatures, produce the highest pressures. Faster flame fronts give the maximum efficiency. As long as the flame front does not exceed the speed of sound (in a combustion chamber) you will get the best power. If they exceed the speed of sound, you will make the most power, but it is unlikely that a gasoline engine will survive for long.
Those adding Methanol are lowering the rate of reaction statiscally. Those adding water are lower the rate of reaction Thermodynamically. There is a cost to using Methanol. There is none in not. The results are same. The efficiency is what changes. Adding methanol is expensive and yields the same thing. Add water to bring the temperature down to where there is a comfortable safety margin and stop there.
Sam
You are rigth though, if you have the means to run straight methanol then that is awesome. But as i said before it is quite abit harder to do than gong from bandaids to a standalone. The evaporation issues alone kill the idea for me. + The real reason of calories absorbed helps out alot. I already hit 100+% VE so running out of room is not a problem for me. The water vapor does help spool the turbo a good bit though as has been evidenced by others. More mass and velocity in the exhaust is always a good thing. right.
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09-05-2007, 07:50 PM
#19
Originally Posted by J_Man
Here is a paper directly from NASA, from their Aircraft Engine Research Lab. It shows comparison between just water and water/methyl alcohol, etc. mixes for water injection:
http://naca.larc.nasa.gov/reports/19...report-812.pdf
Their summary:
1. In all cases the use of methyl alcohol-water, monomethylamine-water, and dimethylamine-water mixtures as internal coolants raised the knock-limited performance of AN-F-28 fuel more than did water alone.
2. The addition of ammonia to the methyl alcohol-water solution as an internal coolant lowered the knock-inhibiting effects of the solution and also promoted surface ignition.
3. The commercial trimethylamine-water solution lowered the knock-limited performance of the AN-F-28 fuel except in the very rich mixture region
4. At fuel ratios of 0.05 or less, extremly high knock-limited powers could be obtained by using internal coolants.
5. At fuel-ratios lower than the stoichiometric-mixture ratio, addition of each of the internal coolants except water lowered the indicated specific fuel consumption, in some cases to an amount greater than can be explained by considering the contributions of the internal coolant to the heat of combustion.
6. Internal cooling at extremly low fuel-air ratios allowed high knock-limited powers at much lower indicated specific liquid consumptions than were obtained when operating at high fuel-air ratios either with or without internal cooling. (Lean mixture operation, of course, implies high indicated specific air consumptions)
7. The use of monomethylamine-water mixture at an inlet-air temperature of 150F and a fuel ratio of 0.049 allowed a knock limited power of 1.96 horsepower per cubic inch of cylinder displacement (imep of 620 lbs/sq in). The corresponding indicated specific fuel and liquid consumptions wer 0.37 and 0.55 pound per horsepower-hour, respectively.
http://naca.larc.nasa.gov/reports/19...report-812.pdf
Their summary:
1. In all cases the use of methyl alcohol-water, monomethylamine-water, and dimethylamine-water mixtures as internal coolants raised the knock-limited performance of AN-F-28 fuel more than did water alone.
2. The addition of ammonia to the methyl alcohol-water solution as an internal coolant lowered the knock-inhibiting effects of the solution and also promoted surface ignition.
3. The commercial trimethylamine-water solution lowered the knock-limited performance of the AN-F-28 fuel except in the very rich mixture region
4. At fuel ratios of 0.05 or less, extremly high knock-limited powers could be obtained by using internal coolants.
5. At fuel-ratios lower than the stoichiometric-mixture ratio, addition of each of the internal coolants except water lowered the indicated specific fuel consumption, in some cases to an amount greater than can be explained by considering the contributions of the internal coolant to the heat of combustion.
6. Internal cooling at extremly low fuel-air ratios allowed high knock-limited powers at much lower indicated specific liquid consumptions than were obtained when operating at high fuel-air ratios either with or without internal cooling. (Lean mixture operation, of course, implies high indicated specific air consumptions)
7. The use of monomethylamine-water mixture at an inlet-air temperature of 150F and a fuel ratio of 0.049 allowed a knock limited power of 1.96 horsepower per cubic inch of cylinder displacement (imep of 620 lbs/sq in). The corresponding indicated specific fuel and liquid consumptions wer 0.37 and 0.55 pound per horsepower-hour, respectively.
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