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I didn't bother to check the calculator on the web site, but stoichiometric mass air to fuel ratio for neat ethanol is 9.0...not 11.

Yes, it is well known that methanol has laudable anti-knock properties. Its higher chemical octane and superior charge cooling benefits allow for higher compression, closer to MBT timing, and/or higher boost pressures, which of course all served to increase power. In addition, methanol also...

Just to add, using elemental heating values published at Wiki, (http://en.wikipedia.org/wiki/Heat_of_combustion), here is what I got earlier. Using Qlhv = 32.808 and 120.971 MJ/kg for carbon and hydrogen, respectively, I came up with 44.79 and 19.91 MJ/kg for gasoline (approx as C8H15) and...

Ah, I see what you were getting at. My apologies. I was the one confused! Heywood lists sAFR = 14.6 and 6.47 for gasoline and methanol, respectively. So using those along with his values of lower-heating values per kg of fuel, (for consistency), one gets 2.821 and 2.677 MJ per kg of mix...

Perhaps just some confusion. Yes, you are correct that there will be a larger mass of fuel in the case of alcohol due to its higher stoichiometric fuel-to-air mass ratio. But again, that effect is already taken into account in the first set of numbers. The first set is basically MJ per kg of...

The lower, first set of numbers are for a stoichiometric mix, so the difference in air-to-fuel ratio is already taken into account. Although alcohol contains oxygen, it is not really the way we want it. In general, the higher the oxygen content, the lower the energy content.

By calculating the heating values and stoichiometric ratios from the fuel compositions and the elemental heating values, I get different results myself, Pat. Nonetheless, those are indeed the values he has listed. Personally, I would tend to doubt they are typos. He does list sources, but I...

The fuel properties table in back of Heywood give the lower-heating values of a stoichiometric mix, for gasoline and methanol to be 2.83 and 2.68 MJ/kg, respectively. Per kg of fuel, the lower-heating values are 44 and 20 MJ/kg, respectively.

Thanks. I will look into it. A quick Google search turned up multiple volumes. Do you happen to know which one? In the mean time, perhaps someone else out there has a copy?

I have a question regarding this now defunct test standard, and wondered if anyone here had a copy. (It is no longer available through SAE.) Thanks in advance.

bob102939, Snake oil aside, I thought I would answer this one question you posed: "I fail to see how accelerating the combustion rate would offer any benefit" A faster burn speed, (i.e., shorter burn duration), does actually increase thermal-conversion efficiency. The shorter the duration, the...

Tony, It has been reported that use of gasoline (instead of diesel) in HCCI mode helps further reduce NOx emissions and smoke via an increase in engine ignition delay (time between start of injection and 50% burn), which tends to help with the (high) load problem. Do you find this to be the...

Tony, Thanks for posting the additional information, and link. Regarding the similarities to HCCI, I wondered if you could comment on how this system compares to some of the general advantages/disadvantage of HCCI. For example, with HCCI the homogeneous lean mixture leads to advantages of...

I hadn't considered injection timing, thanks Mike. (And OP...please scratch my comments regarding figure referenced. I misread it!)

OK. I endured through some of the video, too, and they are just as bad. Egregious, as was said. That alone should give one reason not to believe. As one simple example...He says a compression ratio of 20:1 increases pressure from 14.7 psi to 294 psi. That's wrong. The compression ratio is...

Go figure. Interesting. A couple possible reasons that came to my mind for improved efficiency were, 1) more air for a given amount of fuel means cp/cv of the mix gets higher and closer to that of just air, and 2) lower starting temps mean lower temps throughout the cycle, which would reduce...

Don't see why it would matter. Diesels run lean and without a throttle. Lots of extra air, and just add fuel to meet needed torque output. So fuel consumption just depends on how much is required to meet torque/power demand.

"This blog lists a bunch of details from the video: http://dreamer3000.wordpress.com/80-thermally-efficient-opposed-pistons-engine/ " Wow! I think that wins the prize for the most poorly written article I have ever read. (Well...OK...just part of it, because I couldn't stomach it any more.)

Hi Steve – What the OP is referring to is the correction factor as described in SAE J1394. (Please refer to his other thread in the Thermo forum). Actually, the coefficient and constant that appear in that expression are not determined empirically, either. They come about by assuming a...

P.S. Regarding the duplicate thread, it has been recommended by other long timers here, (patprimer) that one red flags those themselves. Personally, I think this is the more appropriate forum for your thread. Cheers!