汽车无级变速器传动性能评价系统研究

根据无级变速器电子控制单元的控制算法,结合试验数据,建立了无级变速器(CVT)性能评价系统中的驾驶员模型、发动机模型、无级变速器模型与整车动力学模型。同时给出了各个模型在Simulink中具体的建模方法。最后,针对具体车型,建立了该车型的CVT传动性能的评价系统。     

Frequency-domain method for evaluating the ride comfort of a motorcycle

In many European towns, the demand for fast and efficient mobility is frequently satisfied by means of two-wheeled vehicles. The improvement of comfort of two-wheeled vehicles used by tired and busy workers can increase safety in ground transport. Nowadays, multibody codes make it possible to predict the ride comfort of two-wheeled vehicles by means of time-domain or frequency-domain simulations. Comfort indices can be developed by post-processing the results of numerical simulations. This task is difficult, because the indices should depend on vehicle characteristics and should be independent of road quality and vehicle speed. Poor quality roads may generate nonlinear effects. Speed influences the trim of the vehicle and the wheelbase filtering, which takes place because the same road unevenness excites the front and rear wheel with a time delay which depends on the vehicle's speed.

In this paper, the comfort of two-wheeled vehicles is studied by means of a frequency-domain approach. The wheelbase filtering is averaged considering typical missions of the vehicle. The missions are journeys with a forward speed that assumes different values according to a probability density function. Indices of comfort are calculated taking into account the human sensitivity. The examples show that the proposed comfort indices depend on suspensions' characteristics and, hence, are useful design tools. Finally, some time-domain calculations are carried out to give emphasis to nonlinear effects and to show the limits of the frequency-domain analysis.     

Frequency-domain method for evaluating the ride comfort of a motorcycle

In many European towns, the demand for fast and efficient mobility is frequently satisfied by means of two-wheeled vehicles. The improvement of comfort of two-wheeled vehicles used by tired and busy workers can increase safety in ground transport. Nowadays, multibody codes make it possible to predict the ride comfort of two-wheeled vehicles by means of time-domain or frequency-domain simulations. Comfort indices can be developed by post-processing the results of numerical simulations. This task is difficult, because the indices should depend on vehicle characteristics and should be independent of road quality and vehicle speed. Poor quality roads may generate nonlinear effects. Speed influences the trim of the vehicle and the wheelbase filtering, which takes place because the same road unevenness excites the front and rear wheel with a time delay which depends on the vehicle’s speed.

In this paper, the comfort of two-wheeled vehicles is studied by means of a frequency-domain approach. The wheelbase filtering is averaged considering typical missions of the vehicle. The missions are journeys with a forward speed that assumes different values according to a probability density function. Indices of comfort are calculated taking into account the human sensitivity. The examples show that the proposed comfort indices depend on suspensions’ characteristics and, hence, are useful design tools. Finally, some time-domain calculations are carried out to give emphasis to nonlinear effects and to show the limits of the frequency-domain analysis.     

无极变速器在轿车中的应用与发展动向

研究了无级变速器的发展历程,并分析了几种典型无极变速器的结构。从专业的角度阐述了它目前所存在的优点与缺点以及目前国内市场上的应用现状。通过分析与预测说明无极变速器在未来中国市场上将起着重要的作用。无级变速器必将是未来中国变速器市场上的"主力军"。     

某车金属带式CVT钢球滑道的设计

在国内某车金属带式无级变速器开发中,介绍如何进行钢球滑道截面形状的选取和应力计算,以及钢球的安装尺寸确定。通过运用有限元法,计算出钢球滑道在转矩和金属带夹紧引起的载荷共同作用下的最大挤压应力;指出钢球在变速过程中的移动仅是与之相接触可动轮移动距离的一半,钢球应满足最大速比状态和最小速比状态时的几何安装要求。     

Performance analysis of a CVT clutch system for a hybrid electric vehicle

In this study, the performance of a CVT clutch system for a hybrid electric vehicle was investigated. To analyzed the vehicle performance at restart, the restart delay and driveshaft torque was investigated by simulations and experiments. It was found from the simulation results that the vehicle restart response depends on the clutch pressure buildup time to the point where the clutch torque begins to overcome the vehicle road load, and driving comfort at restart is directly related to the rate change of the clutch pressure.     

金属带式无级变速器带轮变形分析

基于为某国产金属带式无级变速器建立的从动带轮三维模型,利用有限元方法,分析了轴向力和速比对带轮变形的影响,并据此拟合出带轮最大变形量和最大变形位置分布的数学公式,再利用文献中现有的试验数据,验证了有限元分析的有效性.结果表明,速比是影响最大变形量位置的主要因素,而轴向力和速比同时影响变形量的大小.     

金属带式无级变速器控制任务的分解

将无级变速器的控制任务按执行顺序分解为工况识别、控制策略设计和系统执行3个层次,并将工况识别再细分为驾驶员意图识别、车辆环境识别和传动系统状态识别3类.以电液控制系统为例的分析表明,控制任务的分解,减少了需要处理的工况数量.文中提出的方法大大减少了控制系统设计的工作量,缩短了控制系统分析调试时间.     

无级变速器多片湿式离合器起步分析

将多片湿式离合器作为无级变速器(CVT)的起步离合器,以油门开度和变化率作为输入,通过模糊推理和实践经验综合分析得到起步时间,再通过最优算法根据起步时间得到离合器目标压力来控制车辆起步。试验结果表明,该方法起步时间较短,冲击也较小,具有较大的实用价值。     

汽车自动变速器原理与发展趋势

自动变速器是现代汽车的关键总成之一。本文对液力自动变速器、机械式无级自动变速器、双离合自动变速器以及机械式自动变速器的原理进行了简单介绍,分析了这四种自动变速器目前存在的优势和劣势,并在此基础上对这四种类型自动变速器的技术发展趋势进行了展望。     

压力钢带式CVT滑转率理论分析与精确测算方法研究

针对滑转率现有的测量方法和汁算方法的不足,分析了产生测量和计算偏差的原因,将金属带回转中心的偏移理论引入到滑转毕的计算模型中,提出了一种新的滑转率测量与计算模型.并以该模型为基础设计了滑转率测量试验装置.试验结果表明,新的测箅模型达到了纠正原有方法偏差、实现高精度测算CVT滑转率的目标.     

Elaboration and quantitative assessment of manoeuvrability for motorcycle lane change

The desire to quantitatively assess vehicle manoeuvrability and handling has led to the development of various expressions, or metrics, which typically relate system input to system output. With regard to motorcycle manoeuvrability, a notable example of such a measure, or metric, is the Koch index [Koch, J., 1978, Experimentelle und Analytische Untersuchungen des Motorraad-Fahrer Systems. Dissertation, Berlin.]. This article describes the development of a new metric applied to lane change (LC) tests and coined ‘LC roll index’. This metric takes into account the peak-to-peak values of the rider-input steering torque divided by the peak-to-peak roll rate response of the vehicle and normalizes this quantity by the forward velocity. In addition to this new metric, an analytical expression is developed, which in many cases summarizes a motorcycle’s LC performance in a single, terse, analytical term. Experimental results are presented for three vastly different motorcycles: a scooter, a street, and a touring motorcycle performing variations of the LC manoeuvre. Numerous test runs for each vehicle are analysed and the results are summarized along with those presented in the recent literature. Finally, simulation results are presented to highlight the correlation between the proposed indices and handling.     

Elaboration and quantitative assessment of manoeuvrability for motorcycle lane change

The desire to quantitatively assess vehicle manoeuvrability and handling has led to the development of various expressions, or metrics, which typically relate system input to system output. With regard to motorcycle manoeuvrability, a notable example of such a measure, or metric, is the Koch index [Koch, J., 1978, Experimentelle und Analytische Untersuchungen des Motorraad-Fahrer Systems. Dissertation, Berlin.]. This article describes the development of a new metric applied to lane change (LC) tests and coined 'LC roll index'. This metric takes into account the peak-to-peak values of the rider-input steering torque divided by the peak-to-peak roll rate response of the vehicle and normalizes this quantity by the forward velocity. In addition to this new metric, an analytical expression is developed, which in many cases summarizes a motorcycle's LC performance in a single, terse, analytical term. Experimental results are presented for three vastly different motorcycles: a scooter, a street, and a touring motorcycle performing variations of the LC manoeuvre. Numerous test runs for each vehicle are analysed and the results are summarized along with those presented in the recent literature. Finally, simulation results are presented to highlight the correlation between the proposed indices and handling.     

自动离合无级变速器动力性能试验研究

分析了踏板车自动离合无级变速器(CVT)的测试方法及原理,并以GY6-125型CVT为试件设计了一个试验台架,以测试啮合转速、变速特性等动力性能,并得出了该试件各项力学特性的详细数据和曲线图,较全面地了解了自动变速离合器工作过程中性能特性的状态。该试验平台对自动离合器的调整精准便利,可对CVT进行合理选型或对CVT各部件进行优化设计,以实现CVT与发动机的最佳匹配。     

环面型CVT凸轮加载机构迟滞特性的研究

为研究环面型CVT凸轮加载机构轴向力迟滞的影响因素,在离心力和由自旋产生的摩擦力作用下,对传统的圆柱滚子和新型的圆锥滚子两种自动加载机构进行受力分析,分别在自动加载机构静止和高速旋转时分析其轴向力迟滞特性.数值计算结果表明,在输入转矩增加和减小过程中,静止的圆柱滚子实际轴向力分别为理想轴向力的80％和120％,在高转速下,离心力使圆柱滚子产生的轴向力迟滞现象更为严重,最严重时实际轴向力只有理想轴向力的50％;而圆锥滚子静止时的轴向力分别为理想轴向力的98％和102％.高速时实际轴向力与理想轴向力的偏差在7％以内,轴向力迟滞现象显著减弱.     

五测功机多功能传动系半消声室的设想与实践

随着汽车的普及与发展,人们对汽车的驾乘体验、声音品质的要求越来越高,传动系NVH性能是其重要影响因素之一,主要体现为齿轮的啸叫噪声。文章介绍了乘用车传动系半消声室结构布局、技术指标与试验能力,五测功机布局通用性好、覆盖面全,能够满足前驱、后驱、四驱传动系台架NVH测试需求,为传动系NVH目标定义、NVH性能验证与优化提供支撑。     

摩托车变速器加工和测量方法的改进

摩托车变速器的传统加工方式是在立式铣床或工具铣床上人工手摇靠模加工,不仅加工效率低、劳动强度大、成本高,而且加工质量难以保证。通过对传统加工设备的技术改造,实现数控加工和通过增设测量点在微机型万能工具显微镜上实现曲线槽几何形状的精密测量,不仅保证了加工质量,提高了加工效率,还实现了对变速器的整体质量正确评定。     

带高低挡电动汽车变速装置的设计与开发

多数电动汽车采用固定速比的1挡减速器,存在电机效率低,续驶里程短等问题.基于此,改用2挡变速传动方案,设计了一种新型高低挡变速电动汽车驱动系统.对传动系统的速比进行了优化设计,2挡传动比分别为6.7和10.5;将高低挡位变速器与驱动系统集成于一体.研发了一种体积小、强度高、功能性强且性能稳定的差速器.经实际道路试验,该新型电动汽车能耗降低了6.8％,续驶里程延长了7.2％.     

CVT夹紧力控制系统动态性能及其影响因素分析

在对某型无级变速器夹紧力控制系统结构原理进行分析的基础上,采用键合图理论建立其数学模型,对该系统动态性能进行仿真。分析结构参数对系统阶跃响应时压力上升时间和超调量的影响,找出了对系统动态性能影响较大的结构参数,为系统动态性能的优化奠定基础。台架试验结果表明,所建立的夹紧力控制系统模型具有较高精度,仿真结果可信。