Honda to launch motorcycle DCT
World motorcycle market leader Honda has developed a dual clutch transmission for large displacement sports bikes. The system, which has yet to be given a commercial name, is the first to have been designed specifically for motorcycle use, the company claiming that the transmission "provides riders with a sporty riding experience combined with easy operation and superior transmission efficiency."
The transmission is light and compact in design, allowing it to be combined with existing engines without substantial layout modification, says the company. Honda's first official illustration of the transmission shows it integrated into a V4 engine block, and the compact nature of the system is evident from the fact that the gearbox is contained within the width of the cylinders, with only the clutch unit projecting to the right hand side - just as it does on many other large motorcycles. The cutaway model also shows what appears to be a splined output shaft on the left hand side, indicating that the dual clutch system is also likely to be applied to a large touring or luxury motorcycle with shaft (rather than chain) drive to the rear wheel.
Three operating modes will, says Honda, allow the rider to respond to the demands of a wide variety of situations. Two fully automatic modes - D and S - cater for cruising or more enthusiastic riding, while the six-speed manual mode is claimed to deliver "the same shift feel as a manual transmission".
Honda does not state how the system is controlled or how the rider initiates manual gearchanges.
Helping the transmission achieve its compact format are the use of dual input shafts, the inline positioning of the clutch, and the packaging of the hydraulic circuitry beneath the engine cover. Aiding lightness and simplicity is a shift mechanism design based on that of a conventional motorcycle shift drum.
Honda has not stated any performance claims for the new transmission other than that optimized shift scheduling will contribute to "efficient fuel economy" and that the DCT will deliver environmental benefits as well as smooth riding performance.
The company intends to introduce the DCT to some of its sportier, larger-displacement models from 2010. In parallel, Honda is introducing a new generation of belt CVTs for its popular commuter bikes, again offering advantages in efficiency and durability.