AUSTIN, Texas—A prototype hybrid bus that uses a high-speed, high-power flywheel levitated on magnetic bearings has produced a significantly smoother ride and fuel savings of about 30 percent on a typical urban route, according to researchers at The University of Texas at Austin.
“As the bus is stopping, motors on the bus wheels convert the energy of the bus into electricity that is stored in the flywheel,” said Dr. Bob Hebner, director of the Center for Electromechanics at the university’s J.J. Pickle Research Center. “As the bus starts, energy needed to get it back up to speed is taken from both the flywheel and the motor. Thus, less energy is wasted in starting and stopping, reducing fuel use and reducing emissions.”
An additional improvement in the bus’ technology was made replacing the springs and shock absorbers with electrical actuators, he said.
“Not only do these improve ride and handling, but rather than wasting the energy in the up-and-down motion of the wheels as heat, the motion is converted into electrical energy that can also be stored, further increasing fuel efficiency,” Hebner said.
Richard Hayes, a research engineer on the project, said the improvements in fuel efficiency and air quality do not require a reduction in performance.
“The acceleration, handling and ride smoothness can all be better than in today’s buses, ” he said.
Hayes said that the most efficient hybrid buses in the United States use batteries to store energy. In Europe, where fuel tends to be more expensive and environmental issues are viewed differently, some flywheel buses are in operation. The technological breakthrough at The University of Texas at Austin is the demonstration of a high-speed, high-power flywheel levitated on magnetic bearings. This advance permits flywheels to be smaller, last longer and be more efficient, which makes them more practical. In addition, it is anticipated that flywheels will become more important on future fuel cell powered vehicles.
Note: The researchers will be available 10 a.m. to noon, Friday (Sept. 13) at the Center for Electromechanics at J.J. “Jake” Pickle Research Center, 10100 Burnet Rd., for interviews and to provide test rides on the bus for news media reporters and photographers.