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SoCal Funds Westport HPDI CNG Work

The California South Coast Air Quality Management District (AQMD) made a $1.95 million award to Westport Innovations to advance further the development of Westport’s proprietary High Pressure Direct Injection (HPDI) natural gas fuel systems (earlier post) for heavy-duty truck engines.

Under the program, Westport will continue developing its HPDI natural gas fuel systems for 450 hp Cummins ISX engines to meet approaching emissions regulations for NOx and PM emissions set by the EPA and California Air Resources Board (CARB).

The AQMD contribution is part of a larger heavy-duty truck program undertaken by Westport and its partners. Westport recently announced a US $1.5 million cost-sharing subcontract with the U.S. Department of Energy's National Renewable Energy Laboratory.

Current medium- and heavy-duty natural gas engines use lean-burn spark ignition technology to achieve low emissions with full-load efficiencies slightly lower than those of conventional diesel engines. Part-load efficiencies for the natural gas engines, however, are much lower than those of diesel engines.

The Westport HPDI system directly injects a small quantity of pilot diesel fuel into the engine cylinder to provide diesel-like compression ignition for natural gas. This gives the engine the efficiency and low-speed torque advantages of compression ignition while using natural gas as the primary fuel.

With HPDI engines, approximately 95% of diesel consumed in a diesel heavy-duty truck is displaced with natural gas. HPDI natural gas engines can produce approximately 50% less NOx, 90% less PM, and 15%-25% less carbon dioxide emissions than equivalent diesel engines, according to Westport.

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