新型电控机械式自动变速器参数优化及性能研究

Parameter Optimization and Analysis of a Novel Automated Manual Transmission with Planetary Gear Train

为解决传统电控机械式自动变速器(AMT)换挡过程中的动力中断问题,同时提高整车动力性与经济性,提出一种将行星机构安装在AMT输入端构成的新型自动变速器(N-AMT),并对N-AMT基本结构进行详细介绍,同时就驻车、起步和换挡过程中行星机构工作模式进行详细分析。首先根据最大、最小传动比、挡位数和相邻速比的设计要求对N-AMT进行速比初步设计,然后结合AMT换挡和双离合(DCT)换挡各自特点,以动力性为约束,NEDC工况最佳燃油经济性为目标进行遗传算法速比优化设计。利用速比优化设计方法进行不同挡位N-AMT方案设计,并根据动力学关系建立整车模型,对N-AMT进行动力性与经济性分析。综合考虑不同挡位数方案的分析结果和变速器结构成本等因素,确定8挡N-AMT为最终设计方案。最后对8挡N-AMT进行台架、起步和顺序换挡试验。研究结果表明:8挡N-AMT的NEDC循环工况油耗为6.38 L·(100 km)^(-1),较5挡AMT原型车工况油耗6.95 L·(100 km)^(-1)减少了8.86%;N-AMT可以有效消除部分挡位间动力中断的问题,在30%加速踏板开度下,8挡N-AMT的起步时间为1.55 s,较5挡AMT起步时间1.61 s减少了3.7%,整车动力性得到提高;N-AMT换挡时间保持在1.05 s以内,且换挡平顺性较好。

To solve the power interruption problem during the gear shifting process in a conventional automated mechanical transmission (AMT)system,a novel AMT (N-AMT) characterized by a planetary gear train installed on the conventional AMT was built.The basic structure was evaluated,and the working modes of the planetary gear train during parking, startup,and shifting conditions were analyzed.First,the initial speed ratio was designed based on the maximum ratio,minimum ratio,gear number,and adjacent speed ratio.Then,through combining the characteristics of "AMT shift"and "dual clutch transmission (DCT)shift,"the speed ratios of the AMT with planetary gear train were optimized by using genetic algorithm to minimize the fuel cost over New European Driving Cycle (NEDC)drive cycle under the condition of ensuring dynamic performance.Different gear number plans were designed by using this speed ratio design method.Based on the simulation of an 8-gear N-AMT and analysis of the dynamic and economic performance,the results indicate that the N-AMT with eight gears has the most optimal performance considering the overall structure,which is intended to be the final design. The simulation results indicate that the NEDC cycle fuel consumption of the 8-gear N-AMT is 6.38L per 100km,which is 8.86%less than the fuel consumption of a 5-gear AMT (6.95L per 100km).Finally,the startup and successive shifting bench tests of the 8-gear N-AMT were conducted,and the test results show that the dynamic interrupt in partial gears is eliminated and the dynamic performance is improved;the startup time of the 8-gear N-AMT is 1.55s,which is 3.7% less than the 1.61s of the 5-gear AMT.In addition,the shift time is maintained within 1.05s,which ensures a better shift-feel.