TECHNOLOGY - KERS
Slipped discs
The Swiss Hy-Tech ORECA, run by Hope Racing at Le Mans this year, features the latest in hybrid technology from Flybrid Systems
BY SAM COLLINS
Clutched Flywheel Transmission, or CFT KERS. The core principle of the kinetic energy recovery system is essentially the same as previous offerings from the company, in that a fl ywheel is used as the storage medium. However, where the CFT system differs is in the way it transmits the drive from the fl ywheel to the rear wheels.
F The CFT uses a number of
discrete gears and high-speed clutches that perform a controlled slip to transmit the drive. When connected to an engine- speed shaft within the vehicle transmission, the three gears in the CFT KERS are multiplied by the number of gears in the main vehicle transmission to provide a large number of available overall ratios between fl ywheel and wheels. ‘The idea came from Doug Cross, our technical director,’ reveals Jon Hilton, managing director of Flybrid. ‘It actually came from a proposed road car solution, and I asked Doug to see
www.racecar-engineering.com • Le Mans
itted to the Hope car is the latest innovation from English fi rm Flybrid Systems, which it has dubbed the
if he could make it for £10 and fi t it to every Tata Nano. The next day he came back with this idea for transmitting drive through a slipping clutch. He thought it would be cheap, but rubbish. We did a quick analysis and almost straight away realised it was not rubbish at all!’ Hilton and Cross then set about taking the idea from vague concept to reality and, in a short period of time, patents had been applied for and motorsport applications were under discussion. ‘There are a number of good
reasons for it not being as bad as you think,’ Hilton continues. ‘Everyone imagines that clutches suffer with a lot of losses. This is because people are used to using them in the condition when you have the car stationary with the engine revving and you slip the clutch to pull away until you can close it and stop losing energy through the clutch. But that is an extreme case, where one side is not moving and the other is moving quickly. The moment you let the clutch out, the losses are 100 per cent – all of the energy turns into heat until the car starts to move. In fact, when you look
the
transmission essentially gains an extra three ratios…
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