There are electric cars and minivans, so why not a heavy-duty Class 8 truck?
Volvo Trucks North America Inc. is helping to build a hybrid Class 8 tractor that will be powered by electric motors at low speeds and a diesel engine at high speeds.
The project is expected to be done by December for a U.S. Army program that promotes joint military and commercial development. Some or all of the technologies on the truck could be ready for commercial use within seven years.
Volvo's partners are Lockheed Martin Control Systems and Radian Inc.
A 460-hp diesel engine will be combined with two 250-hp electric motors. Lead acid batteries charged by an on-board generator will power the electric motors. The hybrid highway tractor will be tested at several military sites in the United States. Data from the test sites will be transmitted from the vehicle to government research labs and facilities at the University of Michigan's Transportation Research Institute.
Combining diesel and electric power could reduce emissions significantly and increase fuel efficiency without sacrificing performance, said Keith Brandis, Volvo Trucks vice president of business development.
'We expect this truck to demonstrate unprecedented acceleration,' Brandis said. 'The theory behind the system suggests that the combination of diesel and electric propulsion could give drivers more power than today's high-torque, high-horsepower engines.'
The prototype propulsion system is expected to reduce operating costs. Another goal of the program is to investigate methods to make battery technology more practical for use in commercial applications.
The electric motors also will be used to increase braking efficiency. When the brakes are applied, the magnetic field of each motor will be reversed to provide increased stopping ability. This effect also will be used to recharge the batteries.