Peterbilt Motors is offering the Cummins Westport ISL G Near Zero NOx emissions natural gas engine for its Model 567, 520, and 320 trucks.

The new engine’s performance and efficiency matches the current ISL G with 320 horsepower and 1,000 lb.-ft. of torque available. The engine option is aimed at customers with linehaul, vocational, and refuse applications.

The ISL G Near Zero engine’s emissions are 90% lower than the current EPA NOx limit, made possible with a three-way catalyst in the aftertreatment, advanced engine calibration and a closed crankcase ventilation system.

Like the current ISL G engine, the new model will operate on 100% natural gas, which can be carried on the vehicle in either compressed or liquefied form. The ISL-G Near Zero can also run on renewable natural gas.

The ISL G NZ is the first mid-range engine to meet the 0.02 g/bhp-hr optional Near Zero NOx Emissions standards for medium-duty truck, urban bus, school bus, and refuse applications, according to Cummins Westport. It meets California Air Resources Board certification eight years in advance of the 2023 California Near Zero NOx schedule.

The engine will be available for production in Models 520 and 320 by year's end and in the Model 567 early next year.