An independent, third-party study on the Cummins Westport ISX12N 400 hp natural gas engine recently demonstrated that the engine meets and exceeds California Air Resources Board’s (CARB) optional Low NOx standard of 0.02 g/bhp-hr.

The study was carried out 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. It confirms that natural gas engine technology provides one of the cleanest available options for on-highway transportation, according to Cummins.

Engine testing was performed on a chassis dynamometer, with test cycles representative of operation in California’s South Coast Air Basin. Results showed that the ISX12N 400 hp engine met and exceeded the target NOx 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.

In production since February 2018, the ISX12N was the first Class 8 truck engine for larger heavy-duty vehicles to certify to CARB’s optional Low NOx standard. Currently, more than 1,000 ISX12N engines have been produced for North American customers. 

The ISX12N is produced at the Cummins Jamestown, N.Y., 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.