Kenworth recently delivered two prototype Kenworth T680 tractors equipped with a hybrid electric propulsion system to Total Transportation Systems Inc. (TTSI) in Southern California. TTSI is a drayage, storage, and transportation company based in Rancho Dominguez, California.

The two T680 day tractors are Kenworth’s second generation electric trucks with extended range. According to Kenworth, they can run on batteries for 30 miles in zero-emission mode and charge those batteries while driving with a generator powered by a zero-emission natural gas engine. The trucks were built under a project funded by California Climate Investments and the Greenhouse Gas Reduction Fund (GGRF) and managed by the California Air Resources Board and the South Coast Air Quality Management District.

The two Kenworth T680 hybrid electric vehicles use the Cummins Westport L9N Near Zero (NZ) emissions engine, which runs on compressed natural gas (CNG) and powers a generator to extend the truck’s battery range. The truck uses lithium-ion batteries to reach its zero-emission range and to supplement the power of the generator as it climbs, says Kenworth.

The system’s energy management and control functions ensure that the energy generated by the engine and regenerative braking system is appropriately applied by the electric motor, resulting in lower fuel consumption, says Kenworth. The company says recent tests comparing the range of an electric truck with a truck using traditional natural gas propulsion showed a 23% improvement in fuel consumption and an 18% reduction in CO2 emissions.