Double Clutch Transmission for Motorcycles 2007-32-0006

Until now automatic or automated transmissions are not common in motorcycles whereas in passenger cars a clear trend towards various types of automatic shifting transmissions could be observed during the recent years. For 2-wheelers CVT drives are well known for 50 cc scooters and in the scooter class a trend towards CVTs for bigger displacement vehicles is obvious. Evidence for this is the introduction of scooters with a displacement up to 800 cc which use CVT drives. Reflecting the overall CO₂ targets and their impact on individual transportation and the demand for sportiveness in the area of motorcycles dual clutch transmissions (DCT) are certainly a valid alternative.

Meanwhile automated manual transmissions (AMT, clutch actuation and gear shifting by actuators) are available in series production. Other than in the most passenger car applications the shifts are initiated by the rider. As in the car area a full “by-wire” interface is utilized.

From its driving performance a double clutch transmission (DCT) would fit very well into motorcycle applications. Compared to an automated manual transmission (AMT) a double clutch transmission does not have any interruption of the tractive force during the shifting and a DCT features instantaneous acceleration and the feeling of a “direct” connection of the engine with the rear wheel which is highly appreciated by motorcycle riders. Using a DCT for the motorcycle application it has to be guaranteed that the driver has the same or even better control abilities compared to the manual transmission (MT). To fulfill the driver's demand of direct response and control of gear shift and clutch operation the motorcycle DCT needs to have driver controlled overrule functionalities of the automation system.

Although there are several reasons which make it worth using a DCT for motorcycles there is currently no DCT for motorcycles in production. An investigation to apply passenger car DCT technology to motorcycles is the focus of this paper. The main objective is the study of the installation space requirements and the packaging of the double clutch into a motorcycle. Special attention is paid to find an arrangement which ensures that there is no negative effect on the riding performance (e.g. no reduction of the achievable lean angle) but also on the visual appearance of the motorcycle.