Engineers showcase prototype flywheel hybrid for Jaguar XF

A group of UK engineers has showcased the first prototype flywheel hybrid system to be included in a Jaguar XF as part of a Technology Strategy Board-funded project.

Flywheel hybrids are thought to improve efficiency by reducing the number of energy conversions on board a vehicle. The system, which was showcased at the Millbrook Low Carbon Vehicle event, is claimed to provide up to 82PS (60kW) of recovered energy and is predicted to demonstrate fuel economy gains of 20 per cent.

Dick Elsy, chief executive of Torotrak, believes that flywheel hybrids are well suited for high-performance vehicles. ‘If you want a vehicle that is fairly quick, then the system is absolutely perfect. It gives all the credentials of a hybrid, saving fuel and energy, but it also gives the potential for a performance boost.’

Most hybrid systems convert kinetic energy into electricity for storage in a battery. However, the flywheel hybrid uses continuously variable transmission (CVT) to transfer energy directly into a compact, high-speed flywheel during braking. When the driver reapplies the accelerator, the CVT transfers the energy back to the wheels.

‘The beauty of this system is its commercial strength,’ said Elsy. ‘The indications so far are that we’re targeting half the cost of an equivalent electric hybrid system. So there is real commercial logic behind it; we wouldn’t be doing it otherwise. This is a mechanical engineer’s solution to the electric hybrid world, which is going to be a lot cheaper.’

The consortium, which includes Jaguar Land Rover, Prodrive, Ricardo, Xtrac, Flybrid Systems, Ford and Torotrak, has just finished an extensive programme of rig testing and will be conducting track testing in the coming months. By the end of the project, it hopes to have demonstrated the viability of flywheel hybrids for large-scale production.