clare at snyder dot ontario dot canada wrote in message
...
On Sun, 13 Apr 2008 19:04:55 -0400, "Ed Huntress"
wrote:



More to do with the actual fuel composition than the actual octane
rating, wouldn't you agree?

No, they're talking about octane ratings, and you'll find the same pattern
for gasoline and other high-octane fuels versus diesel fuel, throughout
the
literature. The issue here is the differences in performance relative to
different octane rating systems.


You will admit, will you not, that propane, ethanol, and leaded racing
fuel will have 3 very widely varying burn speeds, very different
flamability ranges, extremely differing autoignition specs, widely
disparate energy densities,just as widely disparate specific gravities
and reid vapour pressures, yet very close to the same octane?

I have no idea. Where's the data?


SO.
Octane has NOTHING to do with flame front speed, nothing to do with
autoignition temperatures, nothing to do with vapour pressure, power
density,specific gravity, or ANY other property except the resistance
to detonation in a spark ignition internal combustion engine.

Where's the data?


It MAY have an effect on the operation of a compression ignition
engine as well - I would say there is little chance that any fuel with
high octane would run successfully in a standard CI engine - but
octane, by it's definition has little if any to do with compression
ignition engine operation.

Well, it's commonly said in the literature that cetane and octane have an
inverse relationship.


The big MYTHS out there are several, including but not limited to the
following:

Clare, I don't think I've heard most of those myths, and we've departed
pretty far from the question of what gasoline does in a diesel engine.

--
Ed Huntress