Jaguar is testing a British-engineered flywheel hybrid that promises an 81hp power boost and up to a 20 per cent fuel economy improvement.
Packaged into the rear axle of an XF test prototype, the hybrid features components from British engineering specialists. The £3m project is dubbed the FHSPV — Flywheel Hybrid System for Premium Vehicles — and is funded to the tune of around £2.2m by the government’s Technology Strategy Board.
Project’s engineer Daniel Loftus said. “We need to look at mechanical flywheels and see how they compare with electric hybrids. And then see if they have a production future.”
There are weight, cost and engineering advantages. The complete system weighs in at 65kg, half the weight of a comparative hybrid, the costs are “significantly lower” and the package size smaller.
The composite flywheel is driven through a Torotrak/Xtrac CVT gearbox and spins at up to 60,000rpm to store a peak of 60kW, equivalent to 81hp but there’s only enough energy to deliver the peak 81hp for around seven seconds.
Jaguar is currently testing it in stop-start city mode, which means the flywheel gathers energy lost in braking and then delivers ‘free’ power at start-up to save fuel. Jaguar is already recording significant fuel savings of 20 per cent.
The FHSPV is also easily scalable to bigger and heavier cars than the XF, which would include Land Rovers. However, its production future is still unclear, particularly as the cost of battery hybrids is falling and electrical energy saving is becoming the industry standard.