Analysis on the gear-shifting schedule of hydraulic automatic transmission

With an advanced foreign hydraulic automatic transmission as the objective,an analytical method for the gear-shifting schedule is proposed.First the demanded maximum gradient of test is estimated.Then a test scheme and analytical procedure is formulated by initial test and hypothetical shift parameters.Finally through gear-shifting tests under different road conditions,load,accelerator pedal position limitation,throttle opening and output shaft speed are found to be the gear-shifting parameters.Under a common road condition,the gear-shifting schedule is a double-parameter schedule.Based on the driver＇s demands on braking and dynamic performance,different shift schedules are made under downhill,uphill and quick releasing acceleration pedal conditions.The operation criteria of down-shift schedule on abrupt grade are proposed.

STUDY ON SHIFT SCHEDULE AND SIMULATION OF AUTOMATIC TRANSMISSION

From the point of view of saving energy, a new shift schedule and auto-controlling strategy for automatic transmission are proposed. In order to verify this shift schedule, a simulation program using a software package of Matlab/ Simulink is developed. The simulation results show the shift schedule is correct. This shift schedule has enriched the theory of vehicle automatic maneuvering and will improve the efficiency of hydrodynanic drive system of the vehicle.

STUDY ON SHIFT SCHEDULE OF AUTOMATIC TRANSMISSION TO IMPROVE ENGINEERING VEHICULAR EFFICIENCY

New shift schedule for automatic transmission is proposed from the point ofview of saving energy. The bench-test of automatic shift adopting this shift schedule is done onautomatic transmission's test-bed. The experimental results show the shift schedule is correct. Thisshift schedule has enriched the theory of vehicle automatic maneuvering and will improve theefficiency of hydrodynamic drive system of the vehicle.

Optimal tracking control for automatic transmission shift process

In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrange method. And a powertrain model is built in the Matlab/Simulink and veri- fied by the measurements. Considering the shift jerk and friction loss during the shift process, the tracking trajectories of the turbine speed and output shaft speed are defined. Furthermore, the linear quadratic optimal tracking control performance index is proposed. Based on the Pontryagin＇ s mini- mum principle, the optimal control law of the shift process is presented. Finally, the simulation study of the 1 - 2 upshift process under different load conditions is carried out with the powertrain model. The simulation results demonstrate that the shift jerk and friction loss can be significantly re- duced by applying the proposed optimal tracking control method.

Desktop calibration of automatic transmission for passenger vehicle

Desktop calibration of automatic transmission(AT) is a method which can reduce cost, enhance efficiency and shorten the development periods of a vehicle effectively. We primary introduced the principle and approach of desktop calibration of AT based on the condition of coupling characteristics between engine and torque converter and obtained right point exactly. It is shown to agree with experimental measurements reasonably well. It was used in different applications abroad based on AT technology and achieved a good performance of the vehicle compared with traditional AT technology which primary focuses on the drivability, performance and fuel consumption.

Study on shift schedule saving energy of automatic transmission of ground vehicles

To improve ground vehicle efficiency, shift schedule energy saving was proposed for the ground vehicle automatic transmission by studying the function of the torque converter and transmission in the vehicular drivetrain. The shift schedule can keep the torque converter working in the high efficiency range under all the working conditions except in the low efficiency range on the left when the transmission worked at the lowest shift, and in the low efficiency range on the right when the transmission worked at the highest shift. The shift quality key factors were analysed. The automatic trans-mission's bench-test adopting this shift schedule was made on the automatic transmission's test-bed. The experimental results showed that the shift schedule was correct and that the shift quality was controllable.

Application of clutch to clutch gear shift technology for a new automatic transmission

For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Aiming at four different shift types,the ideal characteristics of shift clutch and engine control were set up.By using torque estimation method,PI slip control algorithm and engine coordinated control principle,the control model and transmission controller were well developed for three shift phases which included rapid-fill phase,torque phase and inertia phase.The testing environment on the rig and prototype vehicle level was built and the testing results obtained in ultimate condition could verify the accuracy and feasibility of this shift control strategy.The peak jerk during shift process was controlled within ±2 g/s where the smooth gearshift was obtained.The development proposal and algorithm have a high value for engineering application.

Defect Analysis and Innovation Design of Synchronizer for Clutchless Automatic Mechanical Transmission

The synchronizer is a key component of automatic mechanical transmission(AMT)equipped in electric vehicles,but the inertial lock-ring synchronizer(ILRS)commonly used there is not suitable especially for pure electric vehicles without a clutch because of big shift impact.To make the shifting process rapid and smooth,a new synchronizer named pressure-controllable friction ring synchronizer(PCFRS)was designed.Initially,the inevitable shortcoming of ILRS was verified by simulation and test.Furthermore,the mechanical characteristics and advantages of the new synchronizer over ILRS were analyzed.Then,the formulations describing the dynamic transmission based on the working mechanism of the PCFRS were established.Finally,the shifting simulation results with PCFRS and ILRS based on the same operating conditions were compared and analyzed.The research shows that the PCFRS can meet the main shifting evaluation index of an AMT without complex control methods,as well as it takes only 0.2406 s to finish the comfortable and zero-speed-difference shifting.The shifting quality of PCFRS is better than that of the ILRS.It lays a foundation for using the new synchronizer as a part of clutchless AMTs equipped in pure electric vehicles.

Scheme optimization of AT shifting element based on genetic algorithm

In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio sequence as an optimization objective and simple shifting logic between adjacent gears through operating only one shifting element as a constraint condition, a fitness function of shifting element schemes was proposed. ZF-8AT shifting element schemes were optimized based on GA work-box of MATLAB, and the feasibility of the optimization algorithm was verified.

重型车辆电控机械式自动变速系统的设计与实现

针对重型车辆在驾驶过程中变速难、控制能力滞后等问题,该文设计一种基于重型车辆电控机械式自动变速系统。该系统采用电控自动变速控制技术(transmissioncontrol unit,TCU),引入巡航模式(adaptive cruise control,ACC)和防滑模式(traction control system,TCS),以全面提升重型车辆的安全性和性能。此外,该系统还将档位转换与人工智能相结合,创建了挡位智能转换模块,根据车速、平衡度、加速度和环境等因素进行智能换挡,从而降低了驾驶员的操作难度。通过对该系统技术核算的数据,发现误差率在可接受范围内,表明该研究系统在解决该文中提到的问题上具有实用性和卓越性。

汽车自动变速器换挡控制自动校准算法研究

为改善自动变速器的换挡特性,提出了一种基于模型的自动变速器离合器液压自动校准方法,实现离合器换挡参数的自动调整。该校准方法包括自动变速器仿真模型、车辆仿真分析算法和基于优化过程的自动校准算法,并在优化过程中进行迭代仿真和分析。以通电换挡为研究对象,仿真结果表明无论是通电升挡,还是通电降挡,该方法均能够有效地执行离合器液压曲线的基本映射,通过所提出的校准方法能够缩短实际车辆试验前的校准时间,提高自动变速器开发过程的效率。

VEHICLE SIMULATION MODEL FOR DEVELOPING AN INTELLIGENT SLOPE SHIFT STRATEGY

With the rapid development of electronics and the growing demand for highervehicle performance, intelligent shift technology is becoming increasingly important, and itpromises to be a developing trend in vehicle automatic transmissions, A new simulation model ispresented, which includes engine, powertrain, tire and vehicle dynamics models. Based on the model,simulation experiments are conducted to investigate the slope shift strategy. The data andconclusions obtained from the simulations are valuable contributions to the development of anintelligent slope shift strategy.

匹配CVT的乘用车回挡抖动问题研究

当前,越来越多的汽车匹配无级变速器(CVT)。在换挡过程中,自动变速器的控制策略无法通过算法完全识别和覆盖部件自身存在的尺寸和性能误差,导致部分车辆在控制其动力耦合或分离的过程中不平稳,使车体晃动。例如,驾驶员在从D到N或从N到D进行换挡操作时,可能会感受到座椅和方向盘的晃动。主要从振动机制分析入手,针对驾驶员从R到N或D到N(释放动力)的操作,分析了车身振动问题,并给出了解决方案。

2012款上汽大众途观SUV车换挡杆不能移动

文章主要通过对某2012款上汽大众SVW6451JFD途观SUV车换挡杆不能移动的案例进行诊断仪检测,发现自动变速器控制模块与诊断仪无法通信,故进入发动机系统检测,读取相关数据流,无异常,进入09系统检测,发现多个电子控制单元(包含变速器控制模块)无信号/无通信-间断,因此依据自动变速器控制模块电路图,对其供电电源进行检测,发现控制模块的15供电熔断丝异常。更换熔断丝后,故障顺利排除。

混合级联多端直流暂态过电压机理及抑制措施

混合级联多端直流采用常规直流与柔性直流混合级联的新型拓扑结构,为我国远距离、大容量、多落点的能源传输提供了新模式,但常规直流与柔性直流之间的交互作用也引发了新问题。该文首先揭示实际受端电网交流电压恢复特性导致混合级联多端直流暂态过电压机理以及低端模块化多电平换流器(modular multilevel converter,MMC)闭锁风险;然后分别从送受端两个方面,提出降功率运行、改进送端移相策略和提升MMC有功功率传输极限等暂态过电压抑制措施。最后,基于PSD-PSModel软件,搭建送受端电网机电暂态和混合级联多端直流电磁暂态的混合仿真模型,仿真验证理论分析的准确性和抑制措施的有效性。

纯电动汽车三参数换挡控制策略研究

为了提高纯电动汽车的动力性和经济性,开发了某两挡自动变速器(AMT)的三参数换挡策略,以改善电动机的运行工况,提高驱动电动机工作效率。基于Matlab-Simulink建立了整车仿真模型。将电池荷电状态(SOC)参数引入换挡策略判断模块,并制定了动力性优先和经济性优先的换挡策略。仿真结果表明,采用三参数换挡策略的纯电动汽车具有更好的动力性和经济性:百公里加速时间和能耗都得到改善。通过新欧洲测试(NEDC)、城市道路循环(UDDS)工况仿真发现,三参数换挡策略比两参数换挡策略经济性均有提升。

电控汽车自动变速器换挡系统设计

为了提升电控汽车在换挡过程中的顺畅度及舒适性,实现自动变速的换挡控制功能,分析了换挡质量的衡量指标,构建车辆传动系统中核心部件发动机、离合器、变速器的动力学模型以及车辆阻力模型,详细设计了自动变速换挡控制系统的转速控制模块、变速执行模块以及动态抗扰动模块。利用PID控制实现发动机的转速调整,利用选换挡电机实现变速控制,采用动态滑膜算法提升系统抗扰动能力。经过实车验证,系统在升档过程中换挡耗时1.15 s,车辆冲击度在4 m/s3以内,耗时短、冲击小,达到了良好的换挡控制效果。

纯电动装载机自动变速箱换挡策略研究

针对纯电动装载机传动系统,取消了传统柴油动力装载机的液力变矩器,采用电液换挡系统控制两挡离合器工作。基于电机控制器返回的转速、转矩信息及变速箱输出轴转速信息制定换挡策略,由整车控制器切换电机控制模式,控制挡位执行机构电磁阀动作,实现纯电动装载机挡位的平滑切换。基于Simulink搭建纯电动装载机换挡控制算法模型,使用Simulink自动代码生成技术生成可应用于整车控制器的程序并进行试验,结果表明,所提出控制策略能明显缩短换挡时间并提升换挡平顺性,换挡时间可达到0.66 s,由一挡切换至二挡时,车速波动值为1.4 km/h。

重型液力自动变速器换挡控制系统仿真及其油道设计与分析

为了明确重型液力变速器液压系统的主要工作原理,完成对其印刷油路板油道的设计与优化。从液压系统中的换挡控制系统着手,通过AMESim液压仿真软件模拟液力变速器换挡控制系统,观察液力变速器不同离合器油压的变化并进行分析,得出(0.7~2.5)MPa的油压区间。通过三维软件UG设计部分印刷油路板中油路,运用AMESim软件的仿真结果在Fluent软件中对所设计的油道进行的仿真,分析油道性能,得出油液进入阀体的进口速度方向与管道入口方向夹角为15°时,油道有较佳的物理性能,为印刷油路板的设计与优化提供理论依据。

基于模型预测控制的换挡规律优化研究

车辆传动系统特性是复杂、时变且非线性的,传统换挡规律通过发动机和车辆简化数学模型制定,难以保证实际控制效果的鲁棒性和一致性。文章提出一种根据当前车辆状态预测未来时域内车辆行驶状态并且实现车辆行驶状态优化挡位决策的方法。首先通过对车速信号的预测以及动态规划算法构建基准规律,作为挡位滚动优化的控制策略,然后通过软件仿真平台对比传统两参数换挡规律与滚动优化换挡规律。结果表明:相比两参数换挡规律,模型预测控制的换挡规律在油耗和挡位切换有更好的表现。