The ISL G Near Zero (NZ) NOx natural gas engine was the first MidRange engine in North America to receive emission certifications from both the U.S. Environmental Protection Agency (EPA) and Air Resources Board (ARB) in California for meeting the 0.02 g/bhp-hr optional Near Zero NOx Emissions standards for medium-duty truck, urban bus, school bus, and refuse applications.

The Cummins Westport ISL G NZ exhaust emissions are 90% lower than the current EPA NOx limit of 0.2 g/bhp-hr. Like the industry leading ISL G engine, the ISL G Near Zero operates on 100% natural gas which can be carried on the vehicle in either compressed (CNG) or liquefied (LNG) form. The ISL G NZ can also run on renewable natural gas (RNG).

The ISL G Near Zero is no longer available. It has been replaced by the L9N near-zero emissions engine. Learn more at cumminswestport.com.

Features & Benefits

Factory-Built, Dedicated Natural Gas Engine – Manufactured on the same assembly line as Cummins diesels, the ISL G Near Zero, like the ISL G, shares many components and parts with Cummins L Series diesels.

• Electronic Control Module: Provides full monitoring and control of engine sensors, fuel system and ignition system, with full interface capability to Cummins INSITE and diagnostic service tools.
• Three-Way Catalyst: Simple passive device, highly effective hydrocarbon, CO and NOx control with no maintenance costs. No Diesel Particulate Filter (DPF) or Selective Catalytic Reduction (SCR) systems are required.  The ISL G Near Zero catalyst includes a mid-catalyst temperature sensor connected to the ECM.
• Closed Crankcase Ventilation (CCV):  The ISL G Near Zero features a chassis mounted CCV system that prevents crankcase emissions that are generated by the engine during normal operation from escaping into the atmosphere.  This reduces engine related Methane emissions by 70%,  by capturing crankcase emissions and redirecting them through the CCV filter where any oil is removed before sending crankcase gases back to the intake manifold to be reintroduced to the combustion chamber.
• Low installed weight: Highest power:weight ratio in its class.
• High-Energy Ignition System – Improved Ignition Control Module (ICM) provides better performance and improved spark plug and coil durability, plus self-diagnostics.
• Fuel Capability - Natural gas can be stored on the vehicle in either compressed (CNG) or liquefied (LNG) form. The ISL G can also operate on renewable natural gas or biomethane that meets fuel-quality specifications.