, Farm Journal Seeds & Production Editor
Purchasers of GM's 2011 heavy-duty diesel pickups can look forward to putting B20 in their tank. B20 fuel is a blend of 20% biodiesel and 80% conventional diesel.
GM's new Duramax 6.6L turbo diesel engine has been substantially revised to include B20 capability and meet strict new emissions standards that become effective this year. The new Duramax engine will power the redesigned 2011 Chevy Silverado and GMC Sierra heavy-duty pickups.
"B20 capability in our new heavy-duty trucks is the latest addition to a growing number of alternate fuel options offered by General Motors,” says Mike Robinson, vice president for environmental, energy and safety policy. "We are seeking different paths to fuel solutions in order to maximize efficiency, reduce emissions and minimize the dependence on petroleum.”
To make the Duramax 6.6L and its fuel system compatible with B20, GM upgraded some seals and gasket materials to withstand the ester content of biodiesel and included an upgraded fuel filter that includes a coalescing element. It improves the separation of water that may be present in the fuel, because biodiesel can attract and absorb water. Also, additional heating of the fuel circuit was added to reduce the chance of fuel gelling or waxing, which can plug filters.
The Duramax 6.6L diesel particulate regeneration system features a downstream injector that supplies fuel for the regeneration process. This reduces potential oil dilution, important with using biodiesel. Downstream injection saves fuel and works better with B20 than in-cyclinder post injection.
The National Biodiesel Board estimates about 700 million gallons of the fuel were produced in 2008, up from about 500,000 gal. in 1999.
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