Generic control flow for the four types of clutch-to-clutch shifts

It is known that the clutch-to-clutch shifts in both planetary-type automatic transmission and dual clutch transmission can be divided into four types, which are power-on upshift, power-on downshift, power-off upshift, and power-off downshift. In previous studies, many control methods of clutch-to-clutch shifts are analyzed, but the control flows of the four types are different. In this article, the principle of these shifts is analyzed in detail. The concept of oncoming clutch's torque ability is proposed. A generic control flow is designed, which divides the shift processes of the four types into the same three phases, and the control algorithm in transmission control unit and the calibration process can be simplified. The powertrain system model and the shift controller are established on MATLAB/Simulink platform. The generic control flow is verified by software-in-the-loop simulations. The simulation results show that the proposed generic control flow can control the four types of shifts properly.