High efficiency flywheel system reduces fuel costs in two ways: recovers energy that would otherwise be wasted and enables smaller, more economical engines to deliver high power when required
Low carbon vehicle technology innovator, Torotrak Group, is working with some of the leading off-highway equipment manufacturers to achieve significant fuel savings on future generations of off-highway vehicles. The company’s Flybrid flywheel energy recovery system (ERS) features in two programs currently underway; one with JCB and another recently announced with Turner Powertrain Systems Ltd (a wholly owned subsidiary of Caterpillar Inc.). Though quite separate, both programs are part government-funded by Innovate UK through the Advanced Propulsion Centre.
Torotrak Group research estimates that fuel savings of between 15 and 30% could be achieved by off-highway machine operators opting to specify Flybrid ERS, significantly reducing operating cost. The system achieves the improvement by capturing and re-using energy that is normally wasted during repetitive cycles and operations such as raising and lowering the boom of an excavator or the mast on a fork lift truck; slewing on an excavator; or shuttling between forward and reverse with a loader.
By pre-charging the flywheel, Flybrid ERS can also provide load-levelling, meeting surges in power demand by providing a boost in peak power of between 10 kW and 1000 kW, depending on application. This means that smaller engines and those de-rated to below 56 kW to meet emissions legislation, can match the performance of more powerful units without incurring the fuel consumption penalty resulting from a bigger engine.
“A mechanical flywheel is a compact, well proven and highly efficient way to capture and release large amounts of energy very quickly,” commented Steve Hughes, Chief Operating Officer, Torotrak Group. “The low cost of Flybrid ERS provides fuel savings that pay for the technology within the first year of operation.”
Torotrak Group’s Flybrid ERS is self-contained and designed for minimal maintenance. It can be connected to the vehicle via the hydraulic system, engine, transmission or driveline. It can be easily designed into many machine types without disrupting the basic vehicle architecture, according to Hughes. “Flybrid ERS is very compact; we can transfer up to 1,400 kJ at up to 900 kW using just a space-efficient, 10 kg flywheel,” he said. “The typical installation envelope is smaller significantly than a DPF exhaust after-treatment system.”
Flybrid ERS is market-ready using a hydraulic interface through a pump/motor and valve block; alternatives which interface via the engine or transmission are at an advanced stage of development. The system is currently being presented at a series of prestigious technical conferences and events, most recently on 9th November at the Electric & Hybrid Industrial Vehicle Technology symposium in Cologne, Germany. A further presentation will be take place next week (6th December) at the 15th International CTI Symposium, in Berlin.