Papers by Keyword: CVT

Abstract: In order to deal with Hertz contact problem of friction drive in continuously variable transmission (CVT), two methods were proposed in this paper. One is a numerical computation method by MATLAB to solve the elliptic integral equations of Hertz contact, while the other is a finite element method (FEM) which uses the ANSYS Workbench to calculate the point contact between two elastic bodies. The computation results of Hertz contact problem of friction drive in a new CVT proposed by our research group show that, compared with a look-up table method, the numerical solution of MATLAB has many advantages such as high precision and less computational cost, while the finite element method has more simplicity and better visibility. The present methods can provide a reference for the solution of Hertz contact problem of common friction drive.

Abstract: The system considered in this paper is a half toroidal Continuously Variable Transmission (CVT) system for cars. The existing CVT controllers most adopt to PID to design the controller, but the precision and reliability do not meet the requirements of the CVT well. The ADRC (Auto Disturbances Rejection Controller) technology is able to solve the nonlinear systems whose model is difficult to get and has many uncertain external disturbances. The ADRC in this paper is used to combine with the half toroidal CVT to design a robust, reliable, anti-jamming and feasible controller.

Abstract: In this paper, the CVT shifting control system based on vehicle operating conditions is modeled and simulated using MATLAB/SIMULINK. The modeling stage begins with the derivation of required mathematical model to illustrate the CVT shifting control system. Then, Linear Quadratic Gaussian (LQG), Proportional- Integrated-Derivative (PID) and Pole Placement are applied for controlling the shifting speed ratio of the modeled CVT shifting system. Simulation results of shifting controllers are presented in time domain and the results obtained with LQG are compared with the results of PID and Pole placement technique. Finally, the performances of shifting speed ratio controller systems are analyzed in order to choose which control method offers the better performance with respect to the desired speed ratio. According to simulation results, the LQG controller delivers better performance than PID and Pole Placement controller.

Abstract: Automatic Variable Transmission (AVT) is composed of a metal belt CVT unit and a step speed changing transmission component. According to the needs of automotive conditions, AVT can realize continuously variable transmission and gear transmission, which not only play the advantage of gear transmission efficiency, but also overcome the deficiency of CVT when it is in high-speed. In the paper, the transmission matching rule is introduced, and engine model is established using engine test data. Based on SimulationX software, a vehicle that equips AVT is used for modeling and simulation. Finally the power matching is researched.

Abstract: According to the issue of CVT torque converter internal flow field such as the complexity and not easy to calculate, the channel model of torque converter is established by UG, the grid of channel model is generated by GAMBIT, the internal flow field of torque converter is simulated based on FLUENT while the pressure and velocity distribution of flow field are calculated under three different conditions. The results show that analyzing the flow field of torque converter by FLUENT has certain guiding significance for the design and optimization of torque converter.

Abstract: This paper examines wide V-belt operational behaviour operated continuously variable transmission (CVT). Important for the prediction of an optimum driving performance it is necessary to understand the motion principle of the belt in the pulley during operation. First, the design of a test rig is described, where both the driving and driven pulleys are programmable controlled, giving details of the capabilities. Second, to describe the efficiency of the drive, losses due to slip and the mechanical properties of belt material are determined. To conduct the mechanical properties of the steel-reinforced belt an experimental method is introduced. Finally, emphasis is placed on determination of circumferential motion of the belt due to various drive operating parameters. Through the study, it is found that mechanical wear at both sides of the V-belt caused by the belt’s motion is the most serious problem that affects the CVT performance.

Abstract: Adaptive-mechanical CVT differs from existing CVT by absence of the hydraulic converter. The transfer mechanism contains the toothed wheels closed contour which provides definability of motion at presence only one entry. Such transfer possesses effect of power adaptation. Change of a moment of resistance leads to change of target angular speed. Dynamics problem consists in definition of parameters of transition from one power regime to another. The work purpose consists in definition of dynamic parameters adaptive-mechanical CVT and in definition of parameters of transition from start power regime to operation regime.

Abstract: In this paper,a novel CVT with electronic control and a motor as actuator (EM-CVT) is presented, whose speed ratio can be adjusted by driving the two movable discs of the primary and secondary pulley at the same time. Firstly, the EM-CVT transmission dynamics mode was established based on the analysis of EM-CVT working principle and ratio change characteristics. Secondly, the speed ratio control strategy and control method for EM-CVT was designed according to the EM-CVT features and functional requirements of the control system; Finally, the simulation was carried out to verify the validity of the control strategy and meth

Abstract: In order to improve ride comfort and reduce the sense of frustration generated by the car when shifting, H robust control algorithm is proposed to optimize the design of CVT electro-hydraulic servo system. The CVT electro-hydraulic servo system is optimized by the development of system control model and the design of H∞ robust controller. The simulation result indicates that the systems uncertainties can be optimized effectively by the H∞ controller, while the systems anti-interference ability and robustness is improved obviously.

Abstract: It will cause the drop of the acceleration performance and driving comfort if the continuously variable transmission shift too quickly. So Aiming at the shifting problem of continuously variable transmission system, This thesis put forward the method to control shift speed of the continuously variable transmission based on driving intention. By the dynamics analysis of continuously variable transmission system, it does a research on the influence on the motor automobiles acceleration performance and driving comfort, when the ratio changes too fast. According to working practice, analyzing shift way of continuously variable transmission system. Through the above analysis and findings, the method to control shift speed based on driving intention will be designed to make acceleration and driving comfort unified. And by limiting the maximum CVT ratio change rate, the automobile acceleration performance can be further improved.