[AT] Carburetor Icing (Off Topic)

[George Willer]

Dudley,

Thanks for the clarification.  It may help some of the misinformed gain a
better understanding.  I haven't looked any of it up since I think I learned
the basic principles nearly 60 years ago when I paid attention in school.

The metric system is fine for some, but some of us prefer to think in terms
of BTUs so I'll discuss degrees F and Lbs.  In general, the heat
content/temperature rise is nearly linear, but not quite 1 degree F./Lb.
The figures I pull from the deep recesses of my memory are very different
for the phase change of water to steam compared to the change to ice.  The
latent heat of vaporization is approximately 941 BTU/LB while the latent
heat of freezing is only 144 BTU/Lb.  The point here is that it takes adding
much more heat to vaporize water than it requires removing to freeze it.
Freezing is what is important to this discussion, which is MUCH easier to
do.

It would be easy to look up the latent heat of vaporization of gasoline and
I'm certain the curve is much different from water (I've never seen solid
gasoline due to temperature).  My guess is that the heat required for fuel
vaporization is within one order of magnitude of the energy removal to
change condensed water to ice.

The fuel vaporizing in the carburetor acts exactly the same as Freon
vaporizing in a refrigeration unit.

George



> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com [mailto:at-
> bounces at lists.antique-tractor.com] On Behalf Of Dudley Rupert
> Sent: Sunday, December 09, 2007 4:33 AM
> To: Antique tractor email discussion group
> Subject: [AT] Carburetor Icing (Off Topic)
> 
> Several of the recent posts on wind chill and oil change veered into
> carburetor icing which I found to be an interesting subject in and of
> itself.  For my own enlightenment I summarized/paraphrased some of those
> posts, added input from my own rusty background and checked a few web
> sites.
> You're welcome to read if you feel so inclined.
> Dudley
> Snohomish, Washington