Mack Trucks Inc. today displayed on Capitol Hill a prototype hybrid electric powertrain for Class 8 trucks mounted on an Air Force R-11 6,000 gallon refueler truck built on a Mack RD 6x4 chassis.

The powerplant combines the power of an electric motor with that of a diesel engine. The electrical motor runs on regenerative energy stored during braking.

The refueler was developed largely in Hagerstown, MD thanks to a $1.2 million Dept. of Defense contract. Enova Systems supplied the motor, motor control, and battery system used in the vehicle. Kovatch Industries manufactured the refueler tank and pumping station.

Congressional supporters of the project aim to ultimately see the development of a full hybrid system capable of launching a heavy-duty truck on electrical power alone. Full hybrids would significant reduce fuel consumption and noise, especially for refuse trucks, Mack said.

Such an application is of particular interest to Mack, which holds over 70% of the refuse vehicle market in North America.