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2ndGenGuy
10-17-2007, 12:17 PM
I'm curious if there's a connection between stoichiometric AFR 14.7 and Atmospheric Pressure at sea level 14.7?

Any link between those two?
POS carb
10-17-2007, 02:13 PM
coincidence
if you run alcohol or other fuels the ratio would be different for the same pressure
:b
cygnus x-1
10-17-2007, 04:12 PM
None whatsoever. The stoich ratio is a ratio of air mass to fuel mass. And that assumes a given type of fuel and a given concentration of oxygen in the air. And in fact most pump gas is not exactly 14.7 since they dilute it with ethanol. I want to say it's like 14.5:1 for 10% ethanol.

C|
Hauntd ca3
10-17-2007, 10:31 PM
as below.
14.7:1 stoich is just the ratio of air to fuel that allows it to burn best.
At full power it'll drop to 12:1 or there bouts.
2oodoor
10-18-2007, 04:24 AM
I'm curious if there's a connection between stoichiometric AFR 14.7 and Atmospheric Pressure at sea level 14.7?

Any link between those two?

interesting
which one of those would be be used as a factor in estimating BTU
cygnus x-1
10-18-2007, 10:33 AM
Energy output in any form (including BTU) would have to assume complete combustion, so it's based on the type of fuel only.

1 gallon of gasoline ~= 114,000 Btu

from:

http://www.epa.gov/orcdizux/rfgecon.htm

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2oodoor
10-19-2007, 12:56 PM
gotta love the internet :cheers:

It still seems btu is applicable to an air and fuel mixture, also now I am wondering about furnaces that use the same fuel but have diff btu rating.
Also in the formula is the amount of energy any particular type of fuel can produce at different sea level. I don't see how they can say 1:114,000 unless that is just an average for nominal complete combustion for generic gas engines.
What are you getting at 2ndGenGuy?
2ndGenGuy
10-19-2007, 03:19 PM
gotta love the internet :cheers:

It still seems btu is applicable to an air and fuel mixture, also now I am wondering about furnaces that use the same fuel but have diff btu rating.
Also in the formula is the amount of energy any particular type of fuel can produce at different sea level. I don't see how they can say 1:114,000 unless that is just an average for nominal complete combustion for generic gas engines.
What are you getting at 2ndGenGuy?

:dunno: I was just curious... I saw 14.7 in two different places, both related to air, and couldn't think of a logical link. I just wondered if there was some scientific explanation or if it was just a co-inky-dink. :wave: Guess it was the latter.