共查询到20条相似文献,搜索用时 93 毫秒
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在双轮加压模型的基础上,结合发动机特性,建立了整车模型。利用软件绘制出目标速比和油门开度和路面坡度的关系图,从而分析了冰、雪面上的整车调速特性。 相似文献
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本文通过对行星齿轮无级变速器演化过程的分析,着重研究了其运动学和传动效率,以及输出速度的波动和控制方法。 相似文献
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液压机械无级变速器对车辆实现无级变速具有重要的作用。本文先对液压机械无级变速器进行了简单的介绍,再重点分析了液压机械无级传动变速器的传动特性。 相似文献
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In this paper, an algorithm to increase the shift speed is suggested by increasing the line pressure for a metal belt CVT.
In order to control the shift speed, an algorithm to calculate the target shift speed is presented from the modified CVT shift
dynamics. In applying the shift speed control algorithm, a criterion is proposed to prevent the excessive hydraulic loss due
to the increased line pressure. Simulations are performed based on the dynamic models of the hydraulic control valves, powertrain
and the vehicle. It is found from the simulation results that performance of the engine operation can be improved by the faster
shift speed, which results in the improved fuel economy by 2% compared with that of the conventional electronic control CVT
in spite of the increased hydraulic loss due to the increased line pressure. 相似文献
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A high level CVT ratio control algorithm is proposed to improve the engine performance by considering the powertrain response
lag. In this algorithm, the desired CVT speed ratio is modified from the vehicle velocity, which is estimated after the time
delay due to the powertrain response lag. In addition, the acceleration map is constructed to estimate the vehicle acceleration
from the throttle pedal position and the CVT ratio. Using the CVT ratio control algorithm and the acceleration map, vehicle
performance simulations are performed to evaluate the engine performance and fuel economy. It is found that the fuel economy
can be improved about 3.6% for FUDS by the ratio control algorithm for the target vehicle. In selecting the appropriate time
delay, compromise between the fuel economy and the acceleration performance is required. 相似文献
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金属带式无级变速器的力学分析 总被引:3,自引:1,他引:3
论述了金属带式无级变速器的力学分析模型,建立了金属环、金属块的力学分析模型。运用相关工具就金属环张力和金属块挤推力进行计算分析,得出了重要的结果,可直接用于金属带CVT的设计分析。 相似文献
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燃油经济性和较少的有害气体排放和日益增大的舒适性等要求是现代汽车十分重要的研究课题,CVT已经从理论上回答现代汽车设计所需迫切解决的很多问题,其主要优点是改善了汽车性能,燃油消耗和排污。 相似文献
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从确定目标夹紧力、设计控制算法和验证传动可靠性三个方面,对无级变速器夹紧力控制中的可靠性问题进行了研究。澄清了绝对安全系数与相对安全系数在概念上的混淆,指出错误地采用相对安全系数法不能保证夹紧力的可靠性。分析了惯性力矩和计算流程对主动轮扭矩计算误差的影响,给出了主动轮扭矩的正确计算方法。提出了夹紧力控制算法的模块化和通用化,设计了夹紧力通用复合控制算法。实验分析了速比控制对夹紧力的耦合作用,指出低速重载工况下为防止金属带打滑必须限制速比变化率。分析了最容易引起金属带打滑的工况,对车辆从冰面打滑状态突然进入水泥路面的行驶过程进行了仿真,验证了夹紧力控制方法的可靠性。 相似文献
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对国内外某些有关金属带无级变速传动装置的金属块受力分析图及力平衡方程式进行了对比研究,指出文献[2]及文献[4]的受力图在i>1,传递大转矩时应加以修正. 相似文献
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CVT轻度混合动力系统电动机和发动机联合工作模式下的系统效率优化 总被引:1,自引:0,他引:1
进行无级变速器(Continuously variable transmission, CVT)轻度混合动力电动汽车关键部件效率的试验数值建模,基于效率数值模型和系统的纵向动力学方程,分析推导出混合动力电动汽车驱动工况不同工作模式下的系统效率计算公式,得到了系统效率优化模型,利用序列二次规划算法对CVT轻度混合动力电动汽车驱动工况的系统效率进行优化计算,从而确定了驱动工况不同工作模式下的最佳电动机/发电机输出功率和最佳CVT速比,为驱动工况下CVT轻度混合动力汽车系统效率的提高和控制策略的优化提供了方法和依据。 相似文献
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金属带式无级变速器壳体的强度和刚度分析 总被引:2,自引:0,他引:2
通过对一种自行研制的车用金属带式无级变速器(continuously variable transmission,CVT)壳体的应力和变形情况进行ANSYS有限元分析,表明CVT壳体结构设计不仅对自身的强度而且对变速器的传动性能都十分重要。解决了由于传统设计时无法估算箱体变形而造成的传动隐患,使曲母线锥盘和摩擦片真正啮合,从而使轴向无偏的金属带传动成为可能,也为实现整个CVT系统的进一步优化和改进提供了必要的依据。利用Pro/Engineer平台构筑了复杂的CVT箱体模型,利用ANSYS有限元分析软件对该模型进行了较准确的强度和刚度分析。 相似文献
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Dynamic characteristics analysis and vibration experiment of Upper-time of Flight Counter (U-ToFC) 总被引:1,自引:0,他引:1
The dynamic characteristic parameters of Up-time of Flight Counter (U-ToFC) are important for research of structure optimization and reliability. However, the current simulation is performed based on homogenous material and simplified constraint model, the correct and reliability of results are difficult to be guaranteed. The finite element method based on identification of material parameters is proposed for this investigation on dynamic analysis, simulation and vibration experiment of the U-ToFC. The structure of the U-ToFC is complicated. Its’ outside is made of aluminum alloy and inside contains electronic components such as capacitors, resistors, inductors, and integrated circuits. The accurate material parameters of model are identified difficultly. Hence, the parameters identification tests are performed to obtain the material parameters of this structure. On the basis of the above parameters, the experiment and FEA are conducted to the U-ToFC. In terms of the flight acceptance test level, and two kinds of joints condition between the U-ToFC and fixture are considered. The natural frequencies, vibration shapes and the response of the power spectral density of the U-ToFC are obtained. The results show simulation which is based on parameters identification is similar with vibration experiment in natural frequencies and responses. The errors are less than 10% . The vibration modes of simulation and experiment are consistent. The paper provides a more reliable computing method for the dynamic characteristic analysis of large complicated structure. 相似文献