【作者】 刘永刚；

【导师】 秦大同； 张毅；

【作者基本信息】 重庆大学 ， 车辆工程， 2010， 博士

【摘要】 双离合器自动变速器(DCT-Dual Clutch Transmissions)是汽车自动变速器领域的一种新型自动变速器。DCT结合了手动变速器(MT-Manual Transmission)和传统液力机械自动变速器(AT-Automatic Transmission)的优点,使得DCT车辆具备与AT车辆一样的驾驶方便性和舒适性,同时拥有比AT车辆好得多的燃油经济性。另外,由于DCT与MT拥有相似的结构和零部件,具有MT变速器生产条件的继承性,从而使DCT的制造成本降低。因此,近年来DCT已经成为了汽车业界研究开发的新热点。本论文针对干式DCT的关键技术问题,对轿车DCT自动变速系统的综合匹配控制技术进行了深入的理论和试验研究,主要研究工作如下:1)在发动机测试数据基础上,建立了发动机的数值模型;根据离合器均匀磨损原理,推导出离合器静态转矩模型。搭建了基于DCT的整车动力传动系统模型,并对DCT起步、换挡过程进行了深入的动力学分析。2)在离合器执行机构力学及参数分析的基础上,建立了离合器转矩控制模型。根据DCT动力学系统模型,提出了DCT离合器转矩标定方法,在Matlab/Simulink软件平台上建立了离合器转矩标定的离线模型。通过对搭载DCT的样车进行试验测试,建立了离合器转矩与离合器执行机构控制参数之间的关系,达到了离合器转矩实际控制的要求。3)在发动机局部恒转速控制原则的基础上,提出了DCT两离合器起步的控制策略。在起步过程中的各个阶段,制定了两个离合器各自接合速度的控制策略。在Matlab/Simulink仿真平台上,建立了DCT两离合器起步控制的仿真模型,并进行了不同油门开度下的仿真分析。结果表明,通过该策略可以分散起步过程中离合器产生的热量,平衡两个离合器的滑磨功,从而延长离合器的使用寿命。4)根据实车测试发动机数据和整车参数,设计了DCT最佳动力性换挡规律和最佳经济性换挡规律。研究了驾驶意图和行驶工况统一识别的规则和策略,在此基础上对常规的标准换挡规律进行了修正,并通过仿真分析证明了修正后换挡规律能更好地满足驾驶意图和行驶工况的要求。建立了DCT智能换挡体系结构,分析了在综合行驶条件下的挡位决策问题,制定了智能挡位决策规则,为开发DCT智能换挡系统打下了基础。5)深入分析了DCT换挡过程的动力学特性,建立了DCT换挡过程动力学模型。针对目前DCT换挡控制方法的缺陷,提出了考虑驾驶意图和车辆状况的DCT换挡控制策略。分别设计了发动机节气门开度控制器和两离合器控制器,在Matlab/Simulink软件平台进行了建模仿真分析,并在装备DCT的试验样车上进行了升、降挡过程的试验对比,验证了DCT换挡控制策略的有效性。本文通过理论分析与试验研究相结合的方法,对轿车DCT自动变速系统的综合匹配控制技术进行了深入研究。理论分析和试验结果取得了较好的一致性,为研究开发DCT车辆提供了理论和试验基础。更多还原

【Abstract】 Dual clutch transmissions (DCT) are a new and fastly developing technology in automatic transmission field. DCT combines the advantages of manual transmission (MT) and conventional automatic transmission (AT). DCT vehicles feature the convenience and comfort of AT vehicles and the fuel economy better than AT vehicles. In addition, dual clutch transmissions is less costly to manufacture since it shares similar structure and components with MT. Due to its advantages, DCT has attacted extensive development interests in the automotive industry in recent years.In this paper, the key technical problems and integrated control of DCT-powertrain systems have been investigated deeply through both theoretical and experimental means. The main research work is as follows:(1) The engine model has been established based on the test data. According to the principle of uniform wear of clutch, the static clutch torque has been formulated. The powetrain system model for DCT vehicles has been established and the dynamics of DCT launch and shift have been analyzed in detail.(2) According to the dynamic analysis of clutch actuator, the model of clutch torque control has been established. The calibration method for DCT clutch torque has been proposed based on the DCT vehicle dynamic model. The off-line calibration model of clutch torque has been built up using Matlab/Simulink software. This method has been applied to a test vehicle equipped with DCT. The correlation between clutch torque and control parameters has been validated on testing vehicle. This correlation realizes the requirement of actual control of clutch torque.(3) Based on the principle of partly constant engine speed, the control strategy of launch with two clutches has been proposed. During the each phase of launch, the clutch engaged speeds of both clutches have been designed. The launch model with two clutches has been established based on Matlab/Simulink software and the simulation have been carried out. The results show that this strategy can share the friction work between two clutches during launch and extend the clutch life.(4) The shift schedules for both the dynamic performance and fuel economy have been designed based on engine map data and vehicle parameters. The uniform recognition of both driver intention and driving conditions has been carried out and then the standard shift schedules have been amended. The simulation results show that the amended shift schedules are better satisfied the driver intention and driving conditions. The DCT intelligent shift system has been established and the algorithms of shift decision have also been proposed. It provides foundation for intelligent control of DCT.(5) The dymamic models of DCT shift have been built based on the analysis of the DCT shift characteristics. Considering the weakness of existing DCT shift control strategy, a shift control strategy based on driver intention and vehicle condition has been proposed. The controllers of engine throttle opening and two clutches have been designed. DCT shift modeling and simulation are carried out using Matlab/Simulink software. The effective of this strategy have been validated by a test vehicle during the process of both upshift and downshift.In this paper, Simulation and testing methods are both used for integrated control of DCT powertrain system. Testing results are highly agreeable with the research results of this work. It provides a theoretical and experimental foundation for the development of DCT vehicles.更多还原