| That is the specific modified SAAB vs. US averages. Apples to Oranges.
No, the link says US flex fleet averaged 3% better in the gasoline equivalent ratio, the ethanol European stock Saab was 4% city and 7% highway. - Saab BioPower fuel economy is very good compared to the US FFV fleet, as it is among higher fuel economy FFVs available in the U.S. The Saab’s gasoline equivalent fuel economy on E85 is on par with the U.S. fleet on the highway test (about 3% better than on gasoline). The gasoline equivalent fuel economy on E85 is slightly better on the city test (about 7% better than on gasoline, versus 3% for U.S. Fleet).
And that is not the EPA but a contractor for Oak Ridge national labs, part of the dept. of energy.
Thanks for the correction.
I guess what they are saying is that by modifying the engine to perform optimally on ethanol you can eliminate the drag on MPG. I suspect that is going to add some cost for building it. The Saab had variable rate turbo and a knock sensor and they sold a version of it here even in a non flex I do believe.
The main thing that optimizes ethanol to not only eliminate the drag in MPG, but to even do better is the use of an engine high in compression, which does require a more robustly built engine very similar to a diesel, but some costs can be offset by the smaller sized engine needed to produce the same power as seen in my previous examples from Cummins and Ricardo.
This quote did come from the EPA and there no fuel that is as efficient as ethanol, the +40% ranges of efficiency is getting into the realm of fuel cells.
An important step toward increasing alcohol fuel demand, then, may lie in providing economical engine technology options that utilize such fuels more efficiently, to compensate for the lower fuel energy density. The FFVs produced today, however, use fairly typical gasoline engines, which, because they must retain dual-fuel capability, are not able to take full advantage of the favorable combustion characteristics of alcohols. Engines optimized for alcohol fuel use, on the other hand, may yield efficiencies that exceed that of state-of-the-art diesel engines—or, about one third higher than that of FFV engines. In earlier engine research at EPA with neat methanol and ethanol [1], for example, over 40% brake thermal efficiency was achieved over a relatively broad range of loads and speeds, with peak levels reaching over 42%. http://www3.epa.gov/otaq/presentations/epa-fev-isaf-no55.pdf |
WOW!! E-85
