Cummins Westport’s ISL G Near Zero NOx natural gas engine is the first MidRange engine in North America to receive emission certifications from both the EPA and the California Air Resources Board that meet the 0.02 g/bhp-hr optional Near Zero NOx Emissions standards for medium-duty truck, urban bus, school bus and refuse applications.
Cummins Westport ISL G NZ exhaust emissions will be 90 percent lower than the current EPA NOx limit of 0.2 g/bhp-hr and also meet the 2017 EPA greenhouse gas emission requirements, the company says. CWI natural gas engines have met the 2010 EPA standard for particulate matter (0.01 g/bhp-hr) since 2001.
The new ISL G NZ meets the CARB certification eight years in advance of the 2023 California Near Zero NOx schedule contributing to California Clean Air initiatives. CARB has defined this certified Near Zero emission level as equivalent to a 100 percent battery truck using electricity from a modern combined cycle natural gas power plant.
In addition to the 90 percent reduction in NOx, the ISL G NZ will feature Closed Crankcase Ventilation (CCV) reducing engine related methane emissions by 70 percent, Cummins Westport says.
The ISL G NZ will continue to offer customers the benefit of performance with the lowest emissions utilizing maintenance-free Three Way Catalyst (TWC) aftertreatment, the company says. TWCs are passive devices, packaged as part of the muffler.
Cummins Westport natural gas engines do not require active aftertreatment such as a Diesel Particulate Filter (DPF) or Selective Catalytic Reduction (SCR).
Production of the ISL G NZ is expected to begin in April 2016 and the engine will be made available as a first fit engine with transit and refuse OEMs, and as an engine replacement for existing ISL G vehicles, resulting in an immediate NOx emission reduction well before the 2023 Near Zero NOx goals set in California.
CWI proprietary Stoichiometric EGR Spark Ignited (SESI) natural gas engine technology with TWC as released on the ISL G NZ is also applicable to CWI ISB6.7 G and ISX12 G engines, with Near Zero product plans for these engines being assessed.