Modelling of dual clutch transmission equipped powertrains for shift transient simulations

Popular methods for simulation of shift control in dual clutch transmissions rely on two assumptions, (1) the application of minimal degrees of freedom for the powertrain model, and (2) the use of mean torque engine models to describe engine torque. Such assumptions will impact on both the observed powertrain response and control of lightly damped powertrains. In this paper these two assumptions are tested through a comparative numerical study of shift transient control through the application of alternate powertrain and engine models. To study the influence of engine torque harmonics, model degrees of freedom, and dual mass flywheels on the transient response of a vehicle powertrain equipped with a dual clutch transmission two powertrain models are presented. Four degree of freedom and 15 degree of freedom models are compared using free vibration analysis and shift transient simulations. Models are then extended to include an engine model with torque harmonics resulting from piston-by-piston firing of the engine with and without the addition of a dual mass flywheel to study the impact on powertrain response. Results indicate that degrees of freedom, engine model, and flywheel model all contribute significantly to variance in powertrain response under each configuration.