I'm wondering does ethanol burn faster or slower than gasoline, and by how much? (Flame speed not quantity)

Also assuming the engine could handle it, does anyone know roughly at what rpm these fuels could no longer burn fast enough to keep up?

  • Flamespeed is a thing, but there are ways to cheat that. But F1 won't uncover their secrets about their techniques. Maybe they use HCCI or another sophisticated form of ignition. Ethanol contains less energy though, which means more weight or refilling the tank more often. None of these will put a smile on a F1 driver's face. – Bart Jan 31 '17 at 8:36
  • Does this answer part of your question? As @SteveMatthews aludes to, getting the rpm limit is going to be depenent upon the engine design (cam, ignition timing, combustion chamber shape, etc). I don't think there's any way to quantitatively put an accurate number on this. – Pᴀᴜʟsᴛᴇʀ2 Jan 31 '17 at 12:14

Surely it's impossible to say at what RPM the speed of the flame-front means that the burn isn't complete at the end of the combustion stroke without knowing the diameter of the piston, volume of the combustion chamber and stoke of the engine.

A small diameter bore with a long stroke will mean that the flame-front has less distance to travel and more time to do it in. A large bore with a short stroke is a combination which will be more susceptible to hitting a flame-front speed RPM limit.

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