The Kinergy flywheel stores energy that would otherwise be wasted when the vehicle slows down, returning it to the wheels as it pulls away, lightening the load on the engine. Unlike outgoing systems, it transmits the rotational energy magnetically, not mechanically.

Ricardo said it has managed to improve efficiency of the unit so that it betters conventionally geared drive setups, with the added advantage of reduced size and weight by comparison. The Kinergy high-speed flywheel is also sealed for life, saving on maintenance, and designed to be more cost-effective than conventional units.

Early testing has been carried out on the Flybus hybrid bus, and Ricardo said it aims to find ways to integrate the unit with a continually variable transmission (CVT) and power take-off to recharge batteries. Recent developments have cut magnetic losses in its coupling to the transmission.

‘The efficiency improvements announced today represent a significant milestone in the development of this highly promising Ricardo patented energy storage technology,’ commented Nick Owen, project director for research and collaboration at Ricardo UK.

‘This next-generation, cost-effective, high energy density flywheel system technology genuinely moves the state of the art forward, offering the prospect of effective mechanical hybridization of low-carbon powertrain applications in all types of vehicles from passenger cars to high speed railway rolling stock.’

The Kinergy unit was developed as part of KineStor project, led by Ricardo with partners including CTG, JCB, Land Rover, SKF, Torotrak, Williams Hybrid Power. Once production-ready, it could be retro-fitted to existing models to reduce fuel consumption and emissions.