Development Of CVT HIL Simulation Platform And Ratio Control Strategy

CVT(Continuous Variable Transmission) has been paid more and more attention in AT(Automatic Transmission) domain because its advantage of changing gear ratio continuously, shifting smoothly and better fuel economy. However domestic researchers are lack of experience for their stepping late into this domain, the validation of CVT control system normally relies on expensive road tests and some extreme working conditions are hard to achieve. Applying widely-used HIL(Hardware In the Loop) simulation technology into TCU(Transmission Control Unit) software development, testing and calibration may reduce the cost and time for development. In addition, it could minimize the potential risk of dangerous test cases. Hence, building CVT model and developing HIL system are of great significance to TCU development.Based on comprehensive literature review on CVT’s structure and working principles of CVT, this dissertation develops a CVT model with multi-domain modeling and simulation software AMESim and carries out offline simulation and co-simulation with Matlab/Simulink. Based on the simulation results, it is optimized to fulfil requirements of real-time simulation. Accordingly, the control strategy on gear ratio control is proposed and simulation is carried out.Finally, the CVT model is integrated with GEVM(Gasoline Engine Vehicle Model) in Matlab/Simulink to make a whole powertrain simulation model. Then the whole vehicle model was integrated with ETAS LAB CAR. After all the configurations of hardware and software are accomplished, simulations are carried out to test the TCU. The results show that the TCU control strategy is feasible and which in turn proves the HIL system effective.