Touting 90% improvement on current nitrogen oxide (NOx) standards, Cummins Westport Inc. (CWI) on Monday said its new ISL G natural gas engine is the first mid-range engine in North America to gain both U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CARB) certification.

That means the engine meets the 0.02 grams/brake horsepower-hour (g/bhp-hr) optional near-zero (NZ) NOx emissions standards for medium-duty trucks, urban buses, school buses and refuse trucks.

Production of the ISL G NZ is slated to begin in April, according to CWI, with the engine being made available as a first fit engine with transit and refuse OEMs, and as an engine replacement for existing ISL G vehicles. For California, this means NOx emissions reductions immediately that meet 2023 state NZ NOx emission goals.

A spokesperson with Sempra Energy’s Southern California Gas Co. (SoCalGas) called the engine a “game-changer,” particularly for companies like SoCalGas that are trying to accelerate fleet conversions to natural gas among the medium- and heavy-duty vehicles.

In response to last week’s EPA announcement on more stringent ozone standards, natural gas vehicle (NGV) advocates pointed to the nine- and 12-liter Cummins Westport engines as easily meeting the newest ozone standards (see Daily GPI, Oct. 5).

The ISL G NZ exhaust emissions will be 90% lower than the current EPA NOx limit of 0.2 g/bph-hr, and it also meets the 2017 EPA greenhouse gas emission requirements, a Cummins Westport spokesperson said. CWI natural gas engines also have met the EPA 2010 standard for particulate matter (0.01 g/bhp-hr) since 2001, he added.

With more than 40,000 NGV trucks and buses now operating in North America, CWI touts its new ISL G NZ engine as being capable of providing NZ emission trucks and buses “a significant discount to the cost of electric powered vehicles.” And in addition to the 90% NOx reduction, the ISL G NZ will feature “closed crankcase ventilation” (CCV), which reduces engine-related methane emissions by 70%.

CWI said it was assisted in funding for the development of the NZ engine by support from the South Coast Air Quality Management District, SoCalGas and the California Energy Commission alternative transportation fuel technology grant program. The engine’s performance, efficiency, base warranties, extended coverage options, maintenance, procedures and service intervals will all be the same as the current ISL G engines, CWI said.

Since its introduction in 2007, the CWI ISL G 8.9-liter engine has become the leading natural gas engine for transit buses, refuse trucks and urban delivery trucks, according to CWI. It added that CARB has defined the new engine’s certified NZ emission level as equivalent to a 100% battery truck using electricity from a modern combined-cycle natural gas power plant.