Study Of Basic Characteristics On Power-cycling Variable Transmission System

Supported by National Natural Science Foundation(No. 51375505), this paper discussed ‘ design theory and methods of new type of power-cycling variable transmission.In this paper, A novel method for design of Power-cycling Variable Transmission(PCVT) is proposed. As the core device of PCVT, power-cycling device is structured by torque converter and the planetary gear train. The main contents are as follows.① To ensure the typicality and the convenience of the following study, this article studied the construction of PCVT whose gear transmission is set to direct mechanical connection. The calculation formulas of some basic characteristics are also derived in this paper, such as speed ratio characteristics, efficiency characteristics, torque characteristics and capacity characteristics. The parameters that influence those characteristics are also proposed.② The construction of PCVT whose gear transmission is set to direct mechanical connection is regarded as a new kind of torque converter. The paper compared it with prototype torque converter and analyzed the change tends of those characteristics such as the law of the speed ratio, the level of efficiency, the ability of torque changing and the distribution of load characteristic. Certain request of torque converter is presented in this paper.③ The influencing factors of the various properties of PCVT not only include the characteristic of torque converter itself but also the parameter of planetary gear train and the speed ratio of speed changing device. Through analysis of the change of the parameter of planetary gear train and speed ratio of speed changing device, the multi-gear transmission is presented to optimize the performance and then the design principle of PCVT is proposed. Two kinds of power-cycling variable transmission are designed in this article, which applies fixed axis transmission.④ The PCVT with axis-fixed gearbox is applied in Chang-an car, and the speed ratio characteristics, efficiency and torque characteristic are analyzed and subsection variable speed changing will be realized. Full vehicle model was established and simulation analysis was carried out on the system, the changing of actual speed, ratio of torque converter, ratio of PCVT system and the efficiency are shown in this article and fuel consumption is calculated in ECE driving profile and ECE+EUDC driving profile.