A consortium of UK automotive companies is showcasing a prototype flywheel hybrid system for premium vehicles (FHSPV) at the Low Carbon Vehicle event at Millbrook (UK) on 15 September. The system adds up to 82PS (60kW) of recovered energy and is predicted to demonstrate fuel economy gains of 20% relative to the current production model. Testing work is already underway.
Part-funded by the UK’s Technology Strategy Board, FHSPV’s industrial partners include: Jaguar Land Rover, Flybrid Systems, Ford, engineering consultancies Prodrive and Ricardo, and transmission experts Torotrak and Xtrac.
Compared to conventional hybrid systems, flywheel hybrids reduce the number of energy conversions onboard the vehicle, improving the efficiency of the regenerative braking system, according to the partners.
Instead of converting kinetic energy into electricity for storage in a battery, a small continuously variable transmission (CVT) connected to the car’s rear differential transfers the energy directly into a compact, high-speed flywheel. When the driver reapplies the accelerator, the CVT smoothly transfers the energy back to the wheels.
This research project explores the potential for more efficient and cost-competitive hybrid drivetrains that improve fuel economy while enhancing standards of vehicle refinement and performance. We have investigated the base technology, built the prototype and will be testing it in the next few months to see if it lives up to its potential.—Pete Richings, Chief Engineer at lead partner Jaguar Land Rover
The flywheel-CVT system uses a flywheel developed by Flybrid Systems. Spinning at speeds of up to 60,000 rpm enables the flywheel to achieve a high energy density, making it smaller and easier to package. The CVT, which manages the flywheel’s speed and the flow of kinetic energy, has been built by motorsport firm Xtrac using Torotrak’s traction drive technology.
Automotive consultancy Prodrive is responsible for the system’s configuration and integration into the vehicle. The company is also developing the system’s sophisticated control software and electronics.
Ricardo is providing independent analysis on the potential for alternative technologies within the system. Ford Motor Company is examining the potential for secondary applications for flywheel-CVT systems.