【作者】 屠海峰；

【导师】 廖林清；

【作者基本信息】 重庆理工大学 ， 车辆工程， 2010， 硕士

【摘要】 DCT(Dual Clutch Transmission,双离合器自动变速器)是一种新型自动变速器,综合了AMT(Automatic Manual Transmission,电控机械式变速器)的传动效率高、机构简单、生产继承性好、制造成本低等众多优势和AT(Automatic Transmission,液力自动变速器)动力换挡的优点,具有良好的换挡品质和车辆动力性、经济性,所以非常适合于诸如我国这样以手动变速器为主导的国家。对双离合器自动变速器接合控制过程和换挡控制策略进行深入研究,有利于提高我国汽车零部件的研发水平,同时对促进我国自动变速器的发展具有重要意义。本文在重庆市教委科技项目(项目编号:KJ080619)资助下,应用AMESim软件和Matlab软件建立了仿真分析模型,对DCT的动力换挡相关内容进行研究,获得了换挡重叠的离合器油压控制特性,得到了DCT换挡规律的制定方法。本文主要研究内容包括:(1)在分析DCT动力学模型基础上,运用AMESim建立了DCT动力换挡仿真模型,此模型不仅为分析DCT换挡过程,深入研究两离合器与发动机匹配的综合控制策略搭建仿真平台,而且为缩短DCT控制系统开发周期奠定了基础。(2)利用已建立的AMESim仿真模型,对DCT换挡过程进行了仿真,通过仿真结果,分析了滞后时间、终始压力、正压力变化率对离合器油压换挡重叠的影响,得到了一些有用的结论。在上述基础上,对三个参数进行了正交实验设计,通过分析正交实验结果,得到了正压力变化率是影响车辆换挡重叠的主要因素这一结论,并提出了通过控制正压力变化率来减小滑磨时间和滑磨功的方法。(3)在分析现有万有特性曲线的基础上,利用Matlab计算软件对其进行了变换,通过变换后的万有特性曲线,可以直接得到等速百公里燃油消耗量,简化了百公里燃油消耗量的计算过程,不仅使发动机万有特性曲线变得直观、易读,而且对最佳燃油经济性换挡规律的理论研究及实际应用具有重要意义。(4)提出了制定燃油经济换挡规律曲线的新方法,即是利用Matlab在变换后的万有特性曲面上绘制阻力功率曲面,得到了两曲面的交线,该交线就是燃油经济性换挡规律曲线。(5)在原有经济车速的基础上,提出了汽车综合经济车速的概念。综合经济车速可以更全面地平衡油耗与车速之间的关系,在兼顾油耗的同时,引入行车时间来评价经济车速,具有一定的实际应用价值。本文还在分析综合经济车速概念的基础上,提出了两种它们的求解方法:作图法和解析法。(6)在综合经济车速的基础上,提出了发动机综合经济转速范围的概念。综合经济转速范围可以清楚地知道发动机的经济转速区间,一方面为技术工程人员制定合理的燃油经济换挡规律提供了参考依据,另一方面为追求燃油经济性的驾驶员特别是新驾驶员进行合理换挡提供了换挡依据。更多还原

【Abstract】 As a new type transmission, DCT(Dual Clutch Transmission) combines the advantages of AMT and AT. As the abbreviation of Automatic Manual Transmission, AMT has the traits of high efficiency , simple structure, excellent technology inheritance, low manufacture cost. Whereas as the abbreviation of Automatic Transmission, AT has the traits of power-shift. For these reasons, DCT has high quality of shift, fantastic power performance and fuel-economy, which is especially available for the markets in which manual transmission takes the dominant role. It can improve our R&D ability on the automobile components and promote the development of automatic transmission industry for us to study the process of engagement as well as the control strategy of shift.Funded by Chongqing Municipal Education Commission(project NO:KJ080619), in this paper, an AMESim model for the simulation is established and the power shift of DCT is studied, the hydraulic pressure traits of the clutch during the process of shift overlap are obtained, and shift schedule of DCT is worked out. The main research includes:(1)Based on the analysis of dynamic model of DCT, power shift simulation model has been set up using AMESim. This simulation model not only establishes a simulation platform for further researching comprehensive control strategy between two clutches and engine during shifting process, but also lays a foundation for cutting down control system development cycle of DCT.(2)The shift process of DCT is simulated based on the AMESim simulation model. Some valuable conclusions are obtained by analyzing the relationship between the hydraulic pressure of clutch during the shift process and three parameter (lag time, start and end pressure and slope of positive pressure) by using the simulation results . Based on the above results, the conclusion that the slope of positive pressure is the key factor influencing the jerk and slipping work through Orthogonal Distributing Design of Experiments(DOE). Finally the method of controlling the slope of positive pressure is presented by reducing slipping time and work.(3)Based on the analysis of a car’s engine map, the fuel consumption of constant speed 100 kilometers was obtained directly through the transformation of car’s engine map by MATLAB. Through this method, the computing process is simplified, a car’s engine map is directly perceived and readable, an important significance is developed for theoretical research and practical application of fuel-economic shift profile. (4)According to transformed engine map, fuel-economic shift profile is acquired by drawing resistance power surface and external characteristic power surface on the engine map.(5)Based on the concept of economic speed, the concept of comprehensive economic speed of a motor vehicle are put forward. The relationship between fuel consumption and travel speed is balanced, fuel consumption is saved as well as time. The solution methods are also introduced.(6)Based on the concept of comprehensive economic speed of a motor vehicle, comprehensive economic rotational speed of engine is put forward. The fuel-economic range of engine is easily knew, which provides a reference basis for engineers during process of establishing reasonable fuel-economic shift profile, which also provides a reason of shifting for drivers who chose fuel-economy especially the fresh ones.更多还原