Cummins Reveals Near-Zero Natural Gas Engine for Transit, Shuttle Buses


Cummins Inc. has unveiled the SmartEfficiency initiative for transit buses, which focuses on improved uptime and reliability. As part of the initiative, the company revealed the ISL G Near Zero (NZ) NOx natural gas engine and the isolated engine coolant loop system for the ISL G.

According to Cummins, the ISL G NZ engine offers transit authorities an alternative product that is certified to optional near-zero emissions standards. The ISL G NZ is built off the current ISL G platform, but requires Closed Crankcase Ventilation that prevents crankcase emissions, a larger maintenance-free Three-Way Catalyst, and a unique engine calibration.

Together, the company says these improvements will allow the ISL G NZ to certify to 0.02g/bhp-hr, or 90% below the current U.S. Environmental Protection Agency NOx standards, and provide up to a 15% reduction in CO2 emissions. The ISL G NZ can power transit and shuttle buses each weighing up to a gross vehicle weight of 66,000 lbs.

Cummins asserts that the ISL G Near Zero will operate on 100% natural gas, which can be carried on the vehicle in either compressed natural gas or liquefied natural gas form. The ISL G Near Zero can also run on renewable natural gas.

Another SmartEfficiency-driven improvement is the isolated coolant loop for transit buses using an ISL G powertrain, which improves reliability and reduces downtime. This approach reduces potential coolant leakage or air infiltration for better Exhaust Gas Recirculation cooler reliability and durability. Installation of the isolated coolant loop becomes standard in transit buses beginning January 2017.

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