Ricardo yesterday announced that its research conducted with Artemis Intelligent Power and Bombardier Transportation has confirmed the potential for 10% real-life fuel savings for integrating its TorqStor high-speed flywheel onto a Bombardier Turbostar diesel multiple unit (DMU).
With the 28 month Digital Displacement Rail Transmission with Flywheel Energy Storage project now complete the company announced it is now in position to demonstrate the technology to potential rail industry customers.
Regenerative energy recovery system for a commuter rail-car
The Artemis led project, funded under the first Innovate UK Accelerating Innovation in Rail competition, concluded with confirmation at the bottom end of an initially projected potential fuel saving of around 10% for the use of high speed flywheel brake recovery technology retrofitted to DMU rolling stock.
This £492,873 project, than ran from January 2013 to the end of March this year, combined, for the first time, the Ricardo’s Kinergy flywheel and Artemis Digital Displacement hydraulic pump/motors in a regenerative energy recovery system for a commuter rail-car demonstrated in a test rig commissioned in Ricardo’s Edinburgh lab.
Bombardier Transportion provided system-integration expertise to ensure that the system can be packaged into existing rolling stock.
£11,000 per vehicle per annum savings claimed at kick-off of the project
Last October, ahead of the third Accelerating Innovation in Rail competition, we reviewed the status of the live or completed projects in the first competition: A head of steam for Accelerating Innovation in Rail - competition roundup.
The project stated at the proposal stage to set out to demonstrate fuel savings in the range of 10% to greater than 20% on commuter routes.
At the start of the project Artemis claimed that at 100 mph, the energy in a 133 tonne three-car Class 170 DMU is 133 Megajoules (MJ), and a study of the stopping service between Edinburgh and Dunblane (ten stops over 42 miles) showed that braking losses accounted for 52% of the energy use. A further 16% was lost due to transmission slippage during initial acceleration, a significant factor for stopping services.
Ricardo estimated then a typical fuel saving of around 10-20% on services such as Edinburgh to Dunblane. This gives around £11,000 per vehicle per annum savings with a 4.5 year payback period for an estimated system costs of £50,000 at low volume production costs.
Last April, TorqStor was recognized with a ‘Tech Award’, as one of the top five technologies at the SAE (Society of Automobile Engineers) World Congress.
This was followed in late November by the award to the DDflyTrain project for its application of TorqStor on diesel powered rolling stock, of 'The Most Interesting initiative in safety and sustainability' category at The Rail Exec Club Awards in Leicester on 29 November 2014.
Field service data and test rig
The research project, co-funded by Innovate UK and the Rail Safety and Standards Board, included extensive simulation work based on field service data, which was used in the optimal sizing and design of a practical installation high speed flywheel brake energy system for rail-based application, and the construction and commissioning of a test rig for demonstration purposes.
The project has also completed an initial integration exercise to incorporate the hardware and software onto a Turbostar DMU.
How the DDFlyTrain hybrid system works
Ricardo’s TorqStor was connected to the DMU driveline via Artemis’s Digital Displacement hydraulic pump-motors in which computer-controlled solenoid valves coordinate the responses of individual pistons to the overall power and torque requirements. Compared with conventional hydraulics, Digital Displacement pump-motors have inherently high part-load efficiencies and controllability and this makes it economically feasible to use hydraulics in energy sensitive applications such as DMU regenerative braking.
In the DDFlyTrain project, the optimal configuration for a DMU was found to be two 4.5MJ capacity TorqStor units with a maximum speed of 45,000 rev/min.
The proof of concept demonstration test rig was a scaled-down version of the DMU architecture, based on a single 220kJ TorqStor, that has a permanent vacuum. This is made possible by its advanced magnetic gear system that enables the transmission of torque across a vacuum without the limitation of rotating seals or necessity for vacuum pumps.
In the DDFlyTrain project, the optimal configuration for a DMU was found to be two 4.5MJ capacity TorqStor units with a maximum speed of 45,000 rev/min. The proof of concept demonstration test rig was a scaled-down version of the DMU architecture, based on a single 220kJ TorqStor.
Improving legacy diesel fleets
Rob Cowling, Ricardo’s Head of Value Added Services said his company is actively discussing the potential application of the TorqStor technology as a means of improving the environmental performance and operational viability of legacy diesel fleets.
Accelerating Innovation in Rail competition 2 and 3
The second Accelerating Innovation in Rail competition Enabling the Digital Railway involving ten projects is currently live with projects running until next year.
The third Accelerating Innovation in Rail competition Enabling the Digital Customer closed for applicantions on 22 April 2015.