GM Adds B-20 Biofuel Capability to Heavy-Duty Lineup
GRAPEVINE, TX - General Motors' new lineup of heavy-duty diesel pickups will have B-20 biodiesel capability, the automaker announced Feb. 8 at the National Biodiesel Conference.
GM's new Duramax 6.6L turbo diesel engine has been substantially revised to include B-20 capability, as well as meet strict new emissions standards effective this year. Extensive testing and validation was performed on the Duramax 6.6L using B-20 that meets ASTM International's standard D7467, which covers biodiesel blends between B-6 and B-20.
The new Duramax will power the redesigned 2011 Chevy Silverado and GMC Sierra heavy-duty pickups, as well as the Chevrolet Express and GMC Savana full-size vans. Chevrolet will unveil the 2011 Silverado heavy-duty trucks at the Chicago Auto Show on Feb. 10.
"We are seeking different paths to fuel solutions in order to maximize efficiency, reduce emissions, and minimize the dependence on petroleum," said Mike Robinson, vice president, Environment, Energy and Safety Policy. "The 2007 federal energy bill mandates increased biodiesel production and more states and municipalities are requiring it."
To make the Duramax 6.6L and its fuel system compatible with B-20, 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 that could plug filters.
The Duramax 6.6L's diesel particulate regeneration system features a downstream injector that supplies fuel for the regeneration process to help reduce potential oil dilution. Downstream injection saves fuel and works better with B-20 than in-cylinder post injection, according to the automaker.