Oshkosh Truck Corp. demonstrated its first heavy-payload HEMTT-LHS tactical defense truck, featuring the ProPulse electric hybrid-drive propulsion system with an electric hybrid drive, for the U.S. Army. Although initially designed for military trucks, the company expects the system will also be used in commercial vehicle applications. Oshkosh said the ProPulse system design uses a unique, modular series-hybrid arrangement to simplify the transmission of power to the wheels. The diesel engine controls a large electric generator, which provides direct power to the wheels, eliminating the torque converter, transmission, transfer case and drive shafts. Oshkosh said it believes this technology can increase the fuel economy by up to 40% over conventional powertrain designs. The diesel engine is optimized for operation at a constant rpm, the company said, which eliminates the inefficiency associated with changing rpm levels during acceleration and deceleration. The constant speed also slashes emissions, the truck maker said. According to Oshkosh president & CEO Robert G. Bohn, the generator is powerful enough that, when not driving the vehicle, it can produce sufficient AC electrical output to power an airfield, hospital, command center, or up to 300 homes.