Study on shift dynamics and shift quality of dual clutch transmissions

Dual clutch transmissions (DCTs) offer full shift comfort, and significantly improved fuel efficiency and performance. This paper presents a model for the simulation and analysis of shift dynamics for DCT vehicles. A DCT structure for heavy duty trucks was proposed and the simulation model was built with the software Matlab/Simulink. System dynamic equations were derived according to the detailed analysis of upshifts and downshifts. The importance of engine throttle control, clutch apply timing and clutch pressure characteristics were quantitatively analysed and explained. Simulation results show that better shift quality can be achieved with proper throttle control. The release signal of off-going clutch should be initiated at the same time as the engaging signal of on-coming clutch in upshifts. Optimised clutch pressure canbe achieved for smooth shifts by modifying the clutch pressure characteristics interactively based on the simulation results.