Abstract
Vehicles with dual clutch transmissions (DCT) offer many advantages in terms of reduction of fuel consumption and improvement of driving comfort and shift quality. A detailed description of a driveline model with electro-hydraulic actuators demands complexity, nonlinearity and high order dynamics of the DCT.
The paper describes the concepts of nonlinear modelling of the electro-hydraulically actuated dual clutch transmission. Wet clutches are used in this model for high torque applications where there is more energy to handle, longer life, less noise and smoother operation to be achieved. The aim of this model is to determine a nonlinear complex model that can be used for control during shifting operation, in order to minimize the jerk and increase the shifting speed. Experiments performed on a test vehicle, confirm that the proposed model is able to describe the actuators behaviour characterizing the system dynamics during a shifting process.
The derived model can be useful for an early and accelerated start of the application process in the development phase especially as a simulation tool for gear shift control by means of Software in the Loop (SiL). A detailed dual clutch transmission model made up of sub-models is used for the virtual calibration to simulate clutch torques in order to analyse the longitudinal vehicle dynamics during gear changes based on the hydraulic pressures, controlled by electromagnetic valves on both clutches. The optimal control parameter adjustment for each shifting process is determined in an optimisation calculation by means of an empirical model of the shift behaviour.
Keywords: dual clutch transmission, electro-hydraulic system, gear shift operation, shifting comfort, nonlinear modelling.