Ducati develops auto clutch system
By Ben Purvis
The sudden influx of semi-automatic motorcycles over the last couple of years, and the broad variety of systems being developed to make gear-shifting easier has been remarkable - particularly given that, for decades, buyers shunned any attempt at shoehorning an auto transmission into a bike. However, even Ducati is now preparing to get in on the action with its own, sports-oriented take on the auto-clutch.
While going to a fully-automatic transmission would be a step too far for a superbike brand like Ducati (at the moment), the company has filed a patent application for an automated clutch system that's similar in concept to the E-Clutch that Honda introduced on the latest CB650R and CBR650R models, which it has since expanded to the Rebel 300 and CL300 in some markets.
The Honda system aims to be the best of all worlds. It's much cheaper than an automated transmission, but lets the computer take control of the clutch - perhaps the element of motorcycling that new riders are most likely to struggle with - to make gearchanges, starts and stops much easier. What's more, it retains the conventional clutch lever so anyone who wants to have full, manual control can simply override the computer at any time.
Ducati's proposed system works the same way, but where Honda uses a cable-operated clutch and attaches the electro-mechanical actuator that automates the clutch control to the clutch housing on the transmission, Ducati uses a hydraulic clutch and adds an extra, computer-controlled master cylinder to the system to automate it.
In fact, Ducati's patent shows two variations on the idea. One retains the standard clutch on the bar but extends the hydraulic system to the additional master cylinder, which is operated via an actuator that spins a threaded bar through a ball-screw to push or pull a rod attached to the piston in the second master cylinder. That design gives the rider a mechanical override via the bar-mounted lever, rather like Honda's system.
The second version of Ducati's design simplifies the system by removing the bar-mounted master cylinder, relying purely on the computer-controlled one, but retains a clutch lever connected, via a potentiometer, to the bike's ECU - again allowing the rider to operate the clutch manually, albeit in a clutch-by-wire fashion rather than using a real mechanical connection.
In both instances, the actual gearshifts are still completed conventionally, using a foot lever, but the bike can automatically intervene to prevent misjudged clutch operation. That means it can dip the clutch to make sure you don't stall when coming to a halt, or release it more slowly to prevent stalls when pulling away.
It can also act as a launch control system, combining with the ride-by-wire throttle to perfectly balance the clutch and the throttle opening to maximise acceleration while ensuring the bike doesn't flip.
Importantly for Ducati, the current WSBK technical regulations wouldn't prevent an auto clutch from being used in competition, on the proviso that the same system is fitted as standard to the homologated street model that the race is based on.
