The first examples of ‘Gyrodrive’ flywheel hybrid buses have been delivered to operator Oxford Bus for use on its Brookesbus network.
The vehicles are a variant of the new ADL Enviro400 and feature the Gyrodrive energy recovery system developed by component engineering firm GKN. This technology harvests energy that is normally wasted when braking and stores it in a flywheel, which runs at up to 36,000rpm. When the driver accelerates the system works in reverse, feeding the energy into a traction motor. The buses will also be fitted with a Euro-6 compliant drivetrain.
Oxford Bus predicts that the fuel saving will be in the region of 20% – comparable with a conventional battery-electric hybrid drivetrain, but with a much lower unit price.
Although the system is being trialled by Transport for London, the Oxford Bus Enviro400s will be the first to go into regular service.
Phil Southall, Operations Director for Oxford Bus said, “It achieves the benefits of electric hybrids at a fraction of the cost”.
GKN believes it will be possible to retrofit many existing vehicles with the Gyrodrive flywheel.