Heavy-Duty Natural Gas Near-Zero NOx Engine Development, Cummins ISX15-G Engine

In the South Coast Air Basin, onroad heavy-duty diesel vehicles are currently the largest source of oxides of nitrogen (NOx) emissions — precursors to ozone formation and a human health risk factor. The development and commercialization of a new generation of on-road heavy-duty engines that achieve NOx emission levels far below regulated standards is a critical component for achieving the federal ambient air quality standards in the South Coast Air Basin, improving air quality throughout California, and safeguarding the health of Californians.

Cummins Inc. is a global leader in the design, development and sales of diesel and natural gas engines. Through a joint venture with Westport, Cummins manufactured and marketed state-of-the-art on-road 9-liter and 12-liter natural gas engines in increasing numbers and are rounding out the lower end of the power range with the development of a 6.7-liter engine. The development of these products was accomplished through funding support of the South Coast Air Quality Management District, the California Energy Commission, and the Southern California Gas Company.

Cummins is now undertaking a research effort to develop a heavy-duty natural gas engine designed specifically for natural gas operation. The research captured in this report has demonstrated that a well-designed heavy-duty natural gas engine can match a diesel engine in performance and has the capability to deliver extremely low emissions with a cost effective after treatment system. This report summarizes the results of that development effort with ambitious targets for emissions, efficiency, performance, and robustness. With technology additions, a heavy-duty natural gas engine can be nearly as efficient as a modern diesel engine, but with the advantage of near-zero tailpipe emissions and significantly lower greenhouse gas emissions.