Cummins Westport Inc. announced that an independent study on the Cummins Westport ISX12N 400 hp natural gas engine demonstrated that the engine meets and exceeds California Air Resources Board’s (“CARB”) optional Low NO_x standard of 0.02 g/bhp-hr.

The study was prepared by the University of California, Riverside College of Engineering Center for Environmental Research and Technology, with funding provided by the South Coast Air Quality Management District, the California Energy Commission, and Southern California Gas Co. (“SoCalGas”).

The study also found that other gaseous and particulate matter were below the standards and/or similar to previous levels. However, particle number, ammonia emissions, and methane emissions were higher than current 2010 certified diesel engines on similar drive cycles. These higher emissions should be considered for health and environmental impact studies, the UC Riverside team said.

In general, they concluded that it is expected that natural gas vehicles could play a significant role in achieving the NO_x inventory goals given the near-zero-emission factors demonstrated.

Engine testing was performed on a chassis dynamometer. The cycles selected for the study were representative of operation in the South Coast Air Basin and included drayage port cycles (near dock, local, and regional), the urban dynamometer driving schedule, and three cycles designed by CARB (called HHDDT cycles).

Results showed that the ISX12N 400 hp engine met and exceeded the target NO_x emissions throughout a range of duty cycles.

When the engine operates on renewable natural gas, there are significant reductions in greenhouse gas emissions. In addition to providing air quality and greenhouse gas benefits, the ISX12N can also take advantage of low natural gas prices and available incentive funds.

The ISX12N, in production since February 2018, was the first Class 8 truck engine for larger heavy-duty vehicles to certify to CARB’s optional Low NO_x standard. Today, more than 1,000 ISX12N engines have been produced for North American customers. The ISX12N is produced at the Cummins Jamestown, NY engine plant, and is available from a wide variety of vehicle manufacturers. It’s designed for regional haul, refuse, and vocational trucks, as well as motorcoach and commuter buses. Cummins Westport natural gas engines can operate on compressed natural gas, liquefied natural gas, or renewable natural gas.