【作者】 刘振杰；

【导师】 雷雨龙；

【作者基本信息】 吉林大学 ， 车辆工程， 2013， 博士

【摘要】 液力机械式自动变速器（Automatic Transmission，简称AT）以其成熟的技术和优良的换档平顺性而在自动变速器家族中占居主导地位，但由于液力变矩器的存在，使得传动效率低成为其主要缺点。为了提高液力变矩器的传动效率，在泵轮和涡轮间加装闭锁离合器，在一定工况下通过控制闭锁离合器，使液力变矩器由液力传动过渡到机械传动，从而有效提高传动效率。本文在系统研究起步工况特征的基础上，提出起步工况下液力变矩器闭锁离合器滑差控制，重点解决起步工况下实施闭锁离合器滑差控制的可行性、工作区域划分、控制目标优化及控制算法等四个问题。主要研究内容如下：1)整车动力学建模。基于Matlab/Simulink和AMEsim联合仿真平台，建立装有6档AT车型的整车动力学仿真模型，尤其是液力变矩器和闭锁离合器的耦合动力传递模型以及闭锁离合器的扭转振动模型。2)液力变矩器动态特性预测。基于Hrovat和Tobler提出的液力变矩器的动态特性描述方程，对起步工况液力变矩器传递转矩特性进行预测，为进行闭锁滑差控制时转矩特性预测提供依据。3)闭锁离合器摩擦片温度特性分析。仿真分析闭锁离合器摩擦片温度随滑差控制转速变化规律，验证进行起步闭锁离合器滑差控制摩擦片承受温度的可行性。基于仿真结果，建立基于温度预测的闭锁离合器修正模型。4)传动系统扭振特性分析。建立传动系统扭转振动模型，研究现有扭转减振器下车辆扭转振动特性；应用回归分析法建立传动系统固有频率的递归方程，并对扭转减震器刚度进行优化，使其满足滑差控制要求。5)滑差控制区域选择及滑差转速优化。针对起步时不同动力需求，对液力变矩器起步转矩特性进行分析，确定闭锁离合器起步滑差控制区域；对闭锁离合器滑差转速过零进行检测，并提出相应的滑差转速恢复策略；以发动机转矩波动水平、传动系统转矩波动水平、传动效率为控制指标，对闭锁离合器滑差控制转速进行优化。6)闭锁离合器滑差控制算法研究。对闭锁离合器滑差控制不同阶段进行控制油压的模糊优化；特别针对第一阶段，分析不同充油压力时闭锁离合器由空行程阶段到达滑摩阶段响应特性及振动冲击特性；实车对标及验证起步工况液力变矩器闭锁离合器滑差控制效果。更多还原

【Abstract】 With the advantages of mature technology and smooth shifting, Automatic Transmissionoccupies a dominant position in the transmission family, but the low transmission efficiencyis its main drawback because of torque converter. In order to improve the transmissionefficiency, torque converter clutch is installed between the pump and turbine of torqueconverter, and then the transmission efficiency was improved effectively through thechanging power transmission mode. Slipping control of torque converter clutch at launchingconditions was proposed based on the characteristics of launching conditions, and problemsof feasibility, working zone division, control objectives optimization and control algorithmswere solved. The main contents are as follows:1) Vehicle dynamics model: The vehicle dynamics model of POLO car with AT wasestablished, especially the torque converter and lockup clutch coupling power transmissionmodels and lockup clutch torsional vibration model were built.2) Predictions of torque converter dynamics characteristic: Based on Hrovat andTobler’s description equations of the torque converter, the dynamic characteristic of torqueconverter was predicted at launching conditions. The perdition results provided a basis fortorque prediction when the implementation of slip control.3) The temperature characteristic of torque converter clutch friction plate: Variation ofthe temperature characteristic of torque converter clutch friction plate was simulated withchanges of slipping speed; the feasibility of torque converter clutch slip control because offriction plate bearing temperature was verified. Based on temperature prediction model, thetorque converter clutch model was amended.4) Torsional vibration of transmission system: The torsional vibration modelof transmission system was established and the torsional vibration characteristicof vehicle under the existing torsion damper was researched. Using regression toestablish natural frequency recursive equation of transmission system and make slipping control demand of torque converter clutch through the optimization of torsional vibrationdamper stiffness.5) Slipping control region selection and slipping speed optimization: According tothe different power requirements when starting, the slipping control region was determined.The zero slipping speed was detected and the corresponding slipping speed recovery strategywas proposed. The slipping speed was optimized taking the Torque fluctuation andtransmission efficiency as evaluation target.6) Research on slipping control algorithm: The control oil pressure at different stages ofslipping control was optimized based on fuzzy control. The characteristics of shock responseand vibration was analyzed at the first stage, also called oil filling stage. In order to validatethe effect of slipping control of torque converter clutch at launching conditions, realcar benchmarking was done.更多还原