Skip to content

Cummins Westport Unveils ISB 6.7 G Natural Gas Engine

Last week at the ACT Expo, Cummins Westport unveiled the ISB6.7 G, a 6.7L medium-duty, factory built dedicated natural gas engine for school bus, shuttle bus, medium-duty truck and vocational applications.  The new ISB6.7 G is currently in field trials with full production expected to commence in mid-2016.

The ISB6.7 G natural gas engine is based on the Cummins ISB6.7 diesel engine platform.  The ISB6.7 G will operate exclusively on natural gas (CNG or LNG) using Cummins Westport’s proprietary spark-ignited, stoichiometric combustion with cooled exhaust gas recirculation (SEGR)  technology, first introduced with the 8.9L ISL G.

The ISB6.7 G features three-way catalyst after-treatment, which is packaged as a muffler and is maintenance-free. No diesel particulate filter or selective catalytic reduction after-treatment will be required.  Preliminary specifications include a range of ratings to 260 hp and 660 lb-ft torque and automatic transmission capability to meet customer and original equipment manufacturer requirements.  The ISB6.7 G will be manufactured in Cummins’ medium-duty engine plant in Rocky Mount, North Carolina.

Partial funding in support of the ISB6.7 G engine development has been received from California Energy Commission through its Public Interest Energy Research (PIER) Program in conjunction with the Gas Technology Institute. The ISB6.7 G is expected to be certified at launch to meet the U.S. EPA and CARB emission standards and fuel economy regulations.