Nonlinear dynamic modeling and analysis of shift quality of vehicle powertrain

It is commonplace to develop a precise model to predict dynamic characteristics to achieve the best possible responses during shifting in vehicle powertrain. The objective of this paper is to present a systematic model for shift analysis and the simulation of an integrated powertrain. The research work is concentrated on modeling the powertrain transient dynamics during shifting and analyzing the influencing factors on shift quality. Dynamic models of all the subsystems or components in the driveline from the engine to the wheels are obtained according to LAGRANGE’S EQUATION and then integrated into an integrated powertrain model. Finally, the integrated model is developed by using VISUAL FORTRAN as the simulation platform. In the paper, the dynamic behavior of the powertrain in shift process is simulated by the model under various powertrain operation conditions. Simulation data such as maximum output torque, shift time, etc., are quantitatively analyzed for the assessment of shift quality. The main finding is the Influencing rules on shift quality, including internal factors (friction characteristic and backlash) and external factors (engine torque, road resistance coefficient and applied oil pressure characteristic). The results provide the foundation of optimization and matching of system parameters.