Cummins B6.7 Stop/Start Ready; Westport Has Near-Zero-Emissions ILSL-G

By Tom Berg, Truck Editor | March 15, 2017

Cummins’ fuel-saving Stop/Start feature for the B6.7 diesel is ready for the market, and it’s waiting for truck builders to begin offering it. So far none has, and Mario Sanchez, Cummins’ marketing manager, said it will probably take “competition” for the feature to become an option.

 “What will probably happen is one OEM (original equipment manufacturer) will offer it, then the others will get in line,” he said. He and other Cummins executives spoke on the eve of the opening of the National Truck Equipment Association’s Work Truck Show in Indianapolis.

Start/Stop, announced last year, is among the 2017 B6.7’s improvements, which also include enhanced combustion, a more efficient turbocharger, and tweaked electronic controls that make the series an average of 6 percent more fuel efficient than previous models. It’s offered in Performance and Efficiency versions for midrange trucks and buses.

Start/Stop is a function of electronic controls and an additional sensor, explained Jeff Caldwell, a Cummins vice president. . It shuts off the engine when a truck comes to a halt and restarts it within a half-second. A stronger cranking motor and higher capacity batteries are part of the package. The feature improves fuel economy by 8 percent and makes the engine more “sociable” because noise and exhaust emissions are reduced,

The cost of a Stop/Start upgrade will be set by OEMs, but Sanchez said that, depending on the operation, it would be paid for in fuel savings within three years.

Th 6.7-liter B series, formerly called ISB6.7, is offered by several truck makers. It is the only medium-duty diesel used by Navistar International after it dropped its MaxxForce series midrange engines. Kenworth and Peterbilt sell it as the Paccar PX-7.

Meanwhile, Cummins Westport has developed a Near Zero-emissions version of its natural gas-burning ISL-G, and it is now in production, according to Rob Neitzke, president of the joint venture owned by Cummins and Westport Innovations. The engine emits 90 percent fewer nitrogen oxides than the 0.2 gram per horsepower-hour allowed by government standards.

Near-Zero is an official designation important to vehicle operators because they help California and other non-attainment areas in their quest to meet federal Air Quality standards, Neitzke said. California’s Air Resources Board classifies N-Z engines as equivalent to electric powertrains whose batteries are recharged by typical stationary power plants.

The 8.9-liter ISL-G uses a Cummins L series diesel’s block and a Westport spark-ignition cylinder head. To meet the stricter N-Z standards, engineers added a closed crankcase ventilation system to capture oil fumes and loop them to cylinders to burn them, and a slightly larger three-way catalyst to cleanse exhaust of residual pollutants, he explained.

“It meets fleets’ needs at a reasonable cost, and fits in existing chassis with little modification,” Neitzke said.