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Old 02-09-2011, 12:40 AM   #70 (permalink)
FourBinLabs
Confused, as usual
 
Join Date: Feb 2011
Location: SW Michigan
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Quote:
Originally Posted by Old Tele man View Post
...lookup the "auto-ignition" temperatures for gasoline (495ºF) and diesel (~600ºF).

octane-rating is for gasoline...resistance to detonation
cetane-number is for diesel...ignition delay or quality of combustion
Being that a combustion chamber must be ~100°F hotter to "auto ignite" diesel, it would require more compression to achieve the necessary temperature to auto ignite diesel than gasoline.

about.com defines detonation as: "Definition: An unwanted explosion of the air/fuel mixture in the combustion chamber caused by excess heat and compression, advanced timing, or an overly lean mixture."

How can diesel fuel have a lower octane rating then regular gasoline then?

I hope I'm not pestering anyone, I really am trying to wrap my head around this.
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