TorqStor units are based on a 200 kJ energy storage capacity with a peak power rating of 101 kW and internal flywheel speed of approximately 44,000 rev/min (subject to a total gear ratio of 22:1). The unit is compact, with a package volume of only 221 liters, and lightweight, at less than 100 kg excluding the interfacing hydraulic pump/motor.

At CONEXPO 2014, Ricardo will be displaying a full 200 kJ capacity TorqStor unit comprising genuine machined parts fitted in a transparent casing to enable delegates to see the internal workings of the system. This unit is identical to the pre-production prototypes currently being prepared by Ricardo for delivery to key OEM and Tier 1 customers; these units are intended both for detailed evaluation and product integration, paving the way for rapid market introduction.

While Ricardo has comprehensive technical and integration experience of a wide range of energy storage systems—from super-capacitors and electrical hybrids to accumulator based systems—we believe that the high speed flywheel offers a highly pragmatic and low cost approach to achieving real-world fuel savings in construction equipment operations.

—Ricardo VP of Innovation David Rollafson

HFX. Click to enlarge.

At the Bauma 2013 show Ricardo had unveiled its High Efficiency Excavator (HFX) concept which was based on the previous generation of Ricardo high speed flywheel technology to TorqStor. This 17-tonne production excavator was installed with the flywheel unit and tested over a repeated materials handling cycle at a range of different engine speeds.

Integration with the machine’s hydraulic systems was of a limited nature but sufficient to demonstrate the benefits that could be expected of a production implementation. While fuel savings were measured across all engine speeds, the results indicated that with the improvements of the new TorqStor device in this application, fuel savings of in the region of 10% would be expected for a well-integrated excavator application of this technology, when used at typical operating speeds.

To put this into perspective, this means that approximately half of the total potential energy that is currently wasted in arm/bucket descent is available for storage and re-use, reducing the amount of fuel burned in the engine. Coupled with further improvements to the base machine such as engine downsizing, hydraulic system improvements and ancillary load optimization, the fuel saved could be substantially greater than this.

Moreover, while TorqStor integration would be potentially more challenging in a wheeled-loader application, the fuel saving benefits would be expected to be considerably higher than for an excavator application.