Some interesting reading on methanol & ethanol

[BDC]

Found this little blurb earlier when I was looking for information on effective octane rating of methanol. Have a peek.

http://www.hpt-sport.com/gasclass.htm

B

 

[BDC]

Found a little bit more on the physical properties of methanol... check out that flash point and autoignition temperature!

http://www.engineeringtoolbox.com/methanol-water-d_987.html

B

 

[MrMNTTA]

One quick note in reading the first article, it states that ethanol and/or methanol is about 140 to 160 octane. This is dead wrong. I'm not certain about methanol, but ethanol is about 105-110 octane. Just FYI.

 

[BDC]

One quick note in reading the first article, it states that ethanol and/or methanol is about 140 to 160 octane. This is dead wrong. I'm not certain about methanol, but ethanol is about 105-110 octane. Just FYI.

I've kept that in the back of my mind as well. The octane ratings quoted are admittedly on the higher range. It seems to me however that it can vary due to its ability to lower charge temperatures so much. The way I like to think of 'octane' rating of alcohol is 'effective octane' in that (arguably) it can't be truly measured. What do you think?

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[MrMNTTA]

I've kept that in the back of my mind as well. The octane ratings quoted are admittedly on the higher range. It seems to me however that it can vary due to its ability to lower charge temperatures so much. The way I like to think of 'octane' rating of alcohol is 'effective octane' in that (arguably) it can't be truly measured. What do you think?

B

I agree with what you are saying about its ability to lower charge temperatures.......I believe this is due to it's lower boiling point, and also a lower vapor pressure.

I'm not certain about the measurability, I guess I hadn't put any thought to it that way!

 

[BDC]

I agree with what you are saying about its ability to lower charge temperatures.......I believe this is due to it's lower boiling point, and also a lower vapor pressure.

I'm not certain about the measurability, I guess I hadn't put any thought to it that way!

I need to learn more about it but from what I understand "octane" is a specific kind of hydrocarbon that exists in gasoline fuels but not in alcohol. So, I'm not sure if there's a real way to measure the 'octane' rating of alcohol, hence perhaps the varying numbers that some writes project (110 to 140, etc). Maybe the term 'octane' itself doesn't fit. I don't know. What's the exact process for measuring the knock resistance of a fuel? It's basically in a labratory engine where they increase compression ratio, right?

B