Rich: Ethanol in two and four strokes?
- Thread starter Dirthead
- Start date
Are you talking about E85 or 10-20% ethanol added to regular gasoline?
- Thread starter
- #3
It just says "ethanol". I would assume that they couldn't advertise the blend as ethanol. But I can pass by there today and check for sure.
Assuming it is the E85 (this place has biodiesel and some other stuff I have never heard of) what are your thoughts?
Assuming it is the E85 (this place has biodiesel and some other stuff I have never heard of) what are your thoughts?
- Jun 15, 2001
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Biodiesel is probably made out of Sunflower seeds. I'm assuming this, as I've personally planted and cultivated more than my share of Sunflowers, and knew where it went for processing. The crap seed gets rejected to fuel production. I'm not sure of the exact compound, but know that the lower quality diesel fuels are directly distilled from crude, and are comprised of a product just above the distillation temperature of heavy ends. The better diesels are created from hydrocracking (catalyst in a fully H2 environment) of heavy components (bottom/heavy ends).
As regards the Kali fuel, I'd doubt it's E85. I think that's only made it as far as the great lakes region, where Ford has contracted to make a number of vehicles capable of running it. It's probably a 10% Etoh mix, like everything else. E85 requires special tank liners, tubing, carburetor parts, and different ring end-gap specs than standard vehicles.
As regards the Kali fuel, I'd doubt it's E85. I think that's only made it as far as the great lakes region, where Ford has contracted to make a number of vehicles capable of running it. It's probably a 10% Etoh mix, like everything else. E85 requires special tank liners, tubing, carburetor parts, and different ring end-gap specs than standard vehicles.
It won't work without major modifications and a bunch of trashed parts along the way. Even if you did get the bike to run it would never run worth a damn.
As Nephron pointed out it's probably just a percentage added to the fuel, so it will just make your bike run like crap and and make it hard to jet.
Here's a link that goes into more detail on alcohol as a fuel.
http://www.dirtrider.net/forums3/showthread.php?s=&threadid=5262&highlight=ethanol+single+boiling
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Apparently some people are having some trouble with the link I posted, so I'll just cat and paste my long boring thoughts on alcohol for anyone who is interested. ;)
There are a couple of things to consider here. Alcohols are single boiling point fuels with a hydroxyl-radical (OH) attached while hydrocarbon based race fuels are made up of hundreds of hydrogen and carbon based components with a wide range of boiling points and technically yes alcohol has a lower flame temperature than typical gasoline . As fuels they couldn't be much MORE different but what’s interesting is if you compare the heat of combustion of 1 cu. Ft of chemically correct mixture at 14.7 psia @ 60F you get the following values:
Methanol (neat methyl alcohol) = 94.5
Gasoline (SG 0.739 @ 60f) = 94.8
Benzene (aromatic hydrocarbon) = 95.7
The second thing is you seem to be equating latent heat of vaporization with heat of combustion. While the two are ultimately inter-connected in the end, it's not in the way that you seem to be leaning. We have to step into science mode for a second to (hopefully) make this clear.
We all know fuel has to be a vapor for combustion to occur, and the process of changing a liquid to a vapor is sort of a two-part phase change. The temperature that a fuel's components will boil at is varied, and the temps are dependent on the pressure exerted on them. Lower the pressure (like at high altitude) and it boils at a lower temp, raise the pressure (below sea level or supercharging) and the fuel will boil at a higher temp. BUT even at the boiling point temperature, for the phase change from liquid to vapor (technically gas) to occur additional latent heat is required. The heat is obtained from the surrounding air and the fuel that remains in the liquid state. In the case of methanol we have a fuel that has a relatively low boiling point, but a high latent heat of vaporization, so lots of heat is removed from the surrounding air which leads to a denser mixture reaching the combustion chamber, which is good for power (higher volumetric efficiency), but the fuel that remains in the liquid state enters the combustion chamber at a much lower temperature and will ultimately need to leech additional heat from the combustion chamber to change to a vapor that can be burned, which isn’t good for power. Some good some bad, but on the whole in the case of methanol the end result is higher volumetric efficiency, more power, higher overall cylinder temperatures but a similar heat of combustion. A common rule of thumb is for every 11 degree F drop in temperature you have the potential to make an additional 1% more horsepower due to increased air density.
To make this more understandable, keep in mind you can have two liquids with the SAME boiling temperature but DIFFERENT latent heat requirements. The liquid with the higher latent heat will steal more thermal energy from the surrounding air and liquid.
Methanol has a boiling point of 149 F and a latent heat of vaporization of 1.17 MJ/kg
Ethanol has a boiling point of 172 F and a latent heat of vaporization of 0.93 MJ/kg
Typical gasoline has boiling points in 85 - 410 F range and a latent heat of vaporization of approximately 0.18 MJ/kg
When you start getting into hydrocarbon combinations with varying latent heat requirements, you have the potential to influence the cylinder filling in similar ways with the right combinations of fuel components.
The end result is the heat of combustion changes very little, while the overall combustion temperatures will rise pretty much in direct proportion to the increase in cylinder pressure that comes with a denser mixture in the combustion chamber. Filling the cylinder more completely whether it’s done with fuel or, porting wave tuning has the same overall effect. Make more power and you get heat, increase the load and the same things happens.
I hope this made some sense. This is way too much thinking for a Sunday morning. :)
For what it's worth I wouldn't put too much stock in anything in Dirt Rider or any of the dirt bike mags unless it was written by a known industry expert. The editors and writers of Dirt Rider are journalists (poor ones at that) and haven't the FIRST CLUE about anything even remotely technical.
There are a couple of things to consider here. Alcohols are single boiling point fuels with a hydroxyl-radical (OH) attached while hydrocarbon based race fuels are made up of hundreds of hydrogen and carbon based components with a wide range of boiling points and technically yes alcohol has a lower flame temperature than typical gasoline . As fuels they couldn't be much MORE different but what’s interesting is if you compare the heat of combustion of 1 cu. Ft of chemically correct mixture at 14.7 psia @ 60F you get the following values:
Methanol (neat methyl alcohol) = 94.5
Gasoline (SG 0.739 @ 60f) = 94.8
Benzene (aromatic hydrocarbon) = 95.7
The second thing is you seem to be equating latent heat of vaporization with heat of combustion. While the two are ultimately inter-connected in the end, it's not in the way that you seem to be leaning. We have to step into science mode for a second to (hopefully) make this clear.
We all know fuel has to be a vapor for combustion to occur, and the process of changing a liquid to a vapor is sort of a two-part phase change. The temperature that a fuel's components will boil at is varied, and the temps are dependent on the pressure exerted on them. Lower the pressure (like at high altitude) and it boils at a lower temp, raise the pressure (below sea level or supercharging) and the fuel will boil at a higher temp. BUT even at the boiling point temperature, for the phase change from liquid to vapor (technically gas) to occur additional latent heat is required. The heat is obtained from the surrounding air and the fuel that remains in the liquid state. In the case of methanol we have a fuel that has a relatively low boiling point, but a high latent heat of vaporization, so lots of heat is removed from the surrounding air which leads to a denser mixture reaching the combustion chamber, which is good for power (higher volumetric efficiency), but the fuel that remains in the liquid state enters the combustion chamber at a much lower temperature and will ultimately need to leech additional heat from the combustion chamber to change to a vapor that can be burned, which isn’t good for power. Some good some bad, but on the whole in the case of methanol the end result is higher volumetric efficiency, more power, higher overall cylinder temperatures but a similar heat of combustion. A common rule of thumb is for every 11 degree F drop in temperature you have the potential to make an additional 1% more horsepower due to increased air density.
To make this more understandable, keep in mind you can have two liquids with the SAME boiling temperature but DIFFERENT latent heat requirements. The liquid with the higher latent heat will steal more thermal energy from the surrounding air and liquid.
Methanol has a boiling point of 149 F and a latent heat of vaporization of 1.17 MJ/kg
Ethanol has a boiling point of 172 F and a latent heat of vaporization of 0.93 MJ/kg
Typical gasoline has boiling points in 85 - 410 F range and a latent heat of vaporization of approximately 0.18 MJ/kg
When you start getting into hydrocarbon combinations with varying latent heat requirements, you have the potential to influence the cylinder filling in similar ways with the right combinations of fuel components.
The end result is the heat of combustion changes very little, while the overall combustion temperatures will rise pretty much in direct proportion to the increase in cylinder pressure that comes with a denser mixture in the combustion chamber. Filling the cylinder more completely whether it’s done with fuel or, porting wave tuning has the same overall effect. Make more power and you get heat, increase the load and the same things happens.
I hope this made some sense. This is way too much thinking for a Sunday morning. :)
For what it's worth I wouldn't put too much stock in anything in Dirt Rider or any of the dirt bike mags unless it was written by a known industry expert. The editors and writers of Dirt Rider are journalists (poor ones at that) and haven't the FIRST CLUE about anything even remotely technical.
