[Homestead] Ethanol and Corn
Don Bowen
don.bowen at earthlink.net
Fri Apr 11 00:20:40 EDT 2008
Some interesting information from
http://www.eere.energy.gov/afdc/pdfs/fueltable.pdf
BTU and stoichametric ratings
Gasoline 116090 14.7
Diesel 129050 14.7
Methanol 57250 6.45
Ethanol 76330 9.00
Propane 84500 15.7
Natural gas. 19800 17.2
I forgot to add one more important piece of information. Stoichametric
ratio or the Fuel / Air ratio. For spark ignition engines, this ratio is
when you have enough oxygen molecules to create complete combustion of the
fuel molecules. If you have more oxygen that fuel it is a lean condition,
more fuel than oxygen is a rich condition. Running rich means wasted
unburnt fuel. Running lean leads to more misfires and again wasted fuel.
As you can see from above both ethanol and methanol require significantly
more fuel per charge of air.
The small extra BTUs in Diesel are not entirely why Diesel gets better
mileage. Higher compression ratios, lower pumping losses, and controlled
injection under stoich ratios gets more of the available BTUs out.
Don Bowen KI6DIU
http://www.braingarage.com/Dons/Travels/journal/Journal.html
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