Among on-road motor vehicles, diesel-fueled heavy-duty trucks emit disproportionately high amounts of oxides of nitrogen (NOx) and particulate matter (PM). The trucking industry has taken an active interest in the use of engines powered by liquefied natural gas (LNG) to reduce NOx and PM emissions. However, major barriers exist to widespread use of LNG in trucking applications, including reduced performance and higher initial capital costs compared to diesel-fueled vehicles, as well as a limited fueling infrastructure.
To help address these barriers, the California Energy Commission (Commission) joined with the South Coast Air Quality Management District (SCAQMD) and the U.S. Department of Energy's National Renewable Energy Laboratory (DOE/NREL) in cost sharing a program led by the West Coast Transportation Technology Group of Arthur D. Little, Inc. (ADLittle). The objective of the program was to upgrade three LNG-fueled semi-tractors with new-generation Detroit Diesel Corporation (DDC) Series 60G (S60G) engines that can deliver high horsepower and torque, and demonstrate these LNG tractors in revenue service in a Southern California trucking fleet. A specific goal was to enhance the commercial viability of this low-emission, high-horsepower, high-torque LNG engine for use in Class 8 semi-tractors. Successful commercialization in this high-fuel-use sector can ultimately lead to the displacement of large and significant diesel fuel volumes.