http://www.greencarcongress.com/2009/04/ford-e85di-gasolinepfi-20090426.html Using a separate E85 direct injection boosting system combined with gasoline port fuel injection (PFI) makes the engine more efficient in its use of gasoline, and can be viewed as a more cost-effective alternative to a modern diesel, according to a Ford study presented by Robert Stein, currently of AVL, formerly of Ford, at the SAE 2009 World Congress.
Proposed by John Heywood and colleagues at MIT in 2005, the basic premise of E85 boosting is that ethanol (or other lower alcohols) suppresses knock due to the large evaporative cooling effect it has on the air-fuel mixture when injected directly into the cylinder, supplemented by ethanol’s inherent high octane number.
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With knock suppressed, the compression ratio (CR) can be increased; in a turbocharged or supercharged engine, even higher boost pressure can be used. The resulting higher BMEP levels allow downsizing of the engine at equivalent vehicle performance. The MIT team spun off a startup—Ethanol Boosting Systems, LLC (EBS)—in 2006 to commercialize the concept. (Earlier post.) EBS has a collaborative R&D agreement with Ford, and participated in the study reported at the World Congress.
The vehicle owner will realize high fuel economy because gasoline, with its greater eating value per volume, is the fuel that is primarily used for most driving modes. Furthermore, by enabling higher CR, downsizing and downspeeding, E85 DI + gasoline PFI makes the engine more efficient in itsusee of gasoline.
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In the study, Ford applied the E85 boosting approach to two engines: an early prototype 3.5-liter EcoBoost direct injection, turbocharged engine outfitted with PFI, and a 5.0L PFI engine in a Ford F-150 pickup truck.
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I added the Ecoboost engine to the spreadsheet that calculates payback periods for three hybrid cars see link:
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=193994&mesg_id=195119. ... the payback for the Ecoboost engine? 4 years.