Electric Bus Propulsion with a High-Capacity Composite Flywheel

The development of a flywheel propulsion system for a full-size transit bus is currently in progress at Garrett under a U.S. Department of Transportation contracted program sponsored by the Urban Mass Transportation Administration (UMTA) and managed by the Transportation Systems Center (TSC). A determination of requirements for the flywheel coach based on contacts with the transit industry has shown that the maximum possible range between recharges is desired. Thus, consideration has been directed toward a composite flywheel rotor since this technology can provide a high-capacity flywheel package (including containment) which has an energy density which is several times that of a metallic flywheel unit. The composite flywheel under development will provide more than 12 kwh of usable energy which will provide an urban operating range for the bus of nearly six kilometers between charges. The demonstration of flywheel propulsion in transit buses is expected to establish new alternatives in energy-efficient, ecologically acceptable urban transit vehicles.