Quote:
Originally Posted by garys_1k
Not quite, ethanol blends' effects on FE are not in line with its energy content. That's because FE drive cycles can actually improve volumetric efficiency with lower heating content fuel.
Some data:
http://www.ethanol.org/pdf/contentmg...yStudy_001.pdf
http://www.ethanol.org/pdf/contentmg...inal_12507.pdf
You can bet that the max. torque line fell in pretty much proportion to the lower heat content (unless the ECU allowed more spark with the ethanol, then the torque loss would be at least partially offset). But FE is a different issue -- lower heat content can improve things even if spark advance is constant. |
EPA mileage ratings of flex-fuel vehicles appear to be pretty consistent with the lower heat content: (Change year to 2008 for the complete list.)
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Perhaps if you built an engine to run on E85 only you could optimize all conditions and do better.