Regenerative braking system for railcars relies on composites

A new flywheel-based regenerative braking system, the Digital Displacement hydraulic pump-motor transmission system from Artemis Intelligent Power (Loanhead, UK), has demonstrated that it can reduce the carbon footprint of trains. It stores and then reuses energy, by means of Ricardo’s (Shoreham-by-Sea, West Sussex, UK) TorqStor high speed flywheels, which spin at 45,000 rpm. Artemia, Ricardo and rail technology firm Bombardier Transportation (Berlin, Germany) have formed the DDflyTrain consortium to demonstrate that this technology could work on diesel-driven commuter trains.

In an article at theengineer.co.uk by Julia Pierce, David Rollafson, VP global innovation at Ricardo, points out, “Every train journey involves a lot of stopping and starting, and so also a lot of braking and acceleration. If we can harvest some of the energy from braking and use this when the vehicle is gathering speed again, we can save a lot of diesel and, so, a lot of money for train operators.” Pollution also would be reduced. “Pulling out of a station, diesel engines  pump out a lot of pollution,” he notes. “Adding stored energy to help acceleration would reduce this.” The DDflyTrain system is reportedly easy to retrofit and it’s modular — operators could scale up energy storage as finances permit. The consortium is now discussing application of its technology with a number of UK train operators.

Ricardo’s TorqStor technology combines a modular, high efficiency, carbon fiber composite flywheel with a magnetic coupling and gearing system that enables a scalable range of energy storage capacities for different equipment applications.

Rollafson adds that the technology also could reduce costs and save fuel in commercial trucks and in mining and construction equipment: “We are actively seeking further opportunities to realize the benefits of TorqStor in new sectors.”