考虑动力系功率损失和CVT响应滞后集成发动机-CVT控制的性能

本文考虑由于CVT速比变化引起动力系功率损失和惯性转矩推荐了一种集成发动机一无级变速器(CVT)控制算法。此外还提出了减少CVT速比响应滞后对驱动转矩影响的补偿算法。实验结果表明，最佳发动机速度补偿算法给出最佳发动机工作点在最佳工作线附近。当加速度响应接近相等时和最佳转矩补偿比较。建议把集成发动机-CVT控制算法的特点和传统CVT相比较，加速时采用集成控制来实现在最佳工作线上找到最佳发动机工作点。     

Integrated engine-CVT control considering powertrain response lag in acceleration

In this paper, an engine-CVT integrated control algorithm is suggested by considering the inertia torque and the CVT ratio change response lag in acceleration. In order to compensate for drive torque time delay due to CVT response lag, two algorithms are presented: (1) an optimal engine torque compensation algorithm, and (2) an optimal engine speed compensation algorithm. Simulation results show that the optimal engine speed compensation algorithm gives better engine operation around the optimal operation point compared to the optimal torque compensation while showing nearly the same acceleration response. The performance of the proposed engine-CVT integrated control algorithms are compared with those of conventional CVT control, and It is found that optimal engine operation can be achieved by using integrated control during acceleration, and improved fuel economy can be expected while also satisfying the driver’s demands.     

CVT ratio control for improvement of fuel economy by considering powertrain response lag

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.     

并联混合电动车辆采用无级变速器速比控制对燃油经济性的改进

考虑到并联混合电动车辆(HEV)动力系响应滞后,建议采用无级变速器(CVT)速比控制方法来实现HEV的燃油经济性的改进.在该方法内,由估算于动力系响应滞后之后根据车辆速度来修正目标CVT速比,并推荐一个加速图谱来估算响应滞后的车辆速度.该CVT速比控制方法采用HEV台架试验机试验证实.根据试验结果,可以看到用修正速比控制方法发动机工作迹线比用常规CVT速比控制对于适度加速模式可以有更有效换档范围,故能给出最佳的燃油经济性.此外,还采用HEV动力系模型对联邦城市驱动计划性能仿真进行估算响应滞后对燃油经济性的影响.仿真结果表明作为响应滞后采用修正CVT速比增大可以实现最佳的燃油经济性.但在实际应用中,要求最佳燃油经济性和加速性能之间进行折衷.     

基于模糊自适应滑模方法的混联式混合动力客车模式切换协调控制

在混联式混合动力汽车纯电动至并联驱动模式切换过程中,由于发动机、电动机及离合器瞬态特性的影响,可能导致动力系统输出转矩的突变从而使车辆产生较大的纵向冲击。以混联式混合动力客车为研究对象,考虑发动机和电动机瞬态响应特性的显著不同,针对离合器在结合过程中的运行状态,以提高驾驶性能为目标设计出混合动力客车纯电动至并联驱动模式切换协调控制策略。协调控制采用模糊自适应滑模方法,其中模糊自适应系统用于估计系统参数不确定性引起的偏差以及发动机实际输出转矩与目标转矩的偏差,估计出的偏差值用于调整滑模控制器的控制量,从而提高控制系统的控制精度和鲁棒性。通过仿真及实车试验验证控制策略的有效性。结果表明,设计的控制策略在模式切换过程中满足驾驶员动力需求的前提下使动力系统输出转矩的波动范围和最大冲击度分别下降85%和78%,从而显著提高了混合动力客车的驾驶性能。     

PERFORMANCE SIMULATION OF VEHICLES EQUIPPED WITH TRACTION DRIVE CVTS

0 INTRODUCTIONVehicles equipped with continuously variable transmission(CVT) have the potential of better fuel economy than vehicleswith conventional stepped ratio transmissions. Although the mar-ket penetration of CVT vehicles today is still insignifican…     

基于改进PID算法的EM-CVT速比控制研究

机电控制CVT(EM-CVT)是一种新型无级变速传动装置,其速比跟随误差是作为评价车辆操纵性能的重要指标之一。为了对车辆行驶过程中EM-CVT与发动机动态匹配技术进行研究,通过实验获取了发动机的两种工作模式的外特性;并根据EM-CVT传动机理,理论分析车速与速比间的关系。以PID为基础,提出一种改进PID控制算法实现速比控制,并进行实验验证。实验结果表明,采用改进PID控制算法能获得较好的速比控制,具有实际应用价值。     

四轮轮毂电机驱动电动汽车纵侧向稳定性协调控制策略研究

结合四轮轮毂电机驱动电动汽车四轮转矩独立可控的特点,针对加速同时转向时地面附着力不足的情况,研究车辆纵向和侧向稳定性协调控制策略。针对未知和复杂多变的路面附着情况,设计对路面附着变化具有良好鲁棒性的滑转率自寻优驱动防滑控制策略,采用滑模控制方法实现了对路面最优滑转率的自适应追踪。在此基础上,构建稳定性协调控制策略,通过对车辆纵、侧向动力学目标进行优先级判断和多目标协调控制,有效提升了车辆纵向和侧向稳定性。通过CarSim-Simulink联合仿真验证了驱动防滑控制策略在未知路面附着情况下的有效性,提出的纵侧向稳定性协调控制策略能够有效提升车辆的纵向和侧向稳定性,控制效果优于直接横摆力矩控制。     

基于无级变速器的并联式混合动力汽车能量管理策略

针对一种采用金属带式无级变速器(CVT)的并联式混合动力汽车(PHEV),以发动机稳态效率图和电池的充放电内阻曲线为依据,提出基于逻辑门限方法的PHEV能量管理策略,实现混合动力系统不同工作模式间的动态切换。并通过确定不同工作模式中混合动力系统的最佳工作曲线,合理控制发动机和电动机的转矩分配以及CVT的速比。基于ADVISOR仿真平台的仿真研究表明,所提出的能量管理策略能够在满足车辆动力性能指标的前提下有效地降低混合动力汽车的燃油消耗,并能将电池组电池荷电状态(SOC)维持在合理的范围内。     

Development of TCS slip control logic based on engine throttle control

Slip control systems are used to prevent wheel slipping and to improve acceleration performance, stability and steerability on slippery roads through the engine torque and/or brake torque control. This paper mainly deals with the engine control algorithm via adjustment of the engine throttle angle. The slip control algorithm developed in this research includes a control gain scheduling part and a road estimating part to enhance control performance. Various actual vehicle tests have been carried out on low friction roads in order to verify the developed slip control algorithm. The test results show that the controlled vehicle is superior to the non-controlled vehicle in acceleration performance and stability.     

A study on regenerative braking for a parallel hybrid electric vehicle

In this paper, a regenerative braking algorithm is presented and performance of a hybrid electric vehicle (HEV) is investigated. The regenerative braking algorithm calculates the available regenerative braking torque by considering the motor characteristics, the battery SOC and the CVT speed ratio. When the regenerative braking and the friction braking are applied simultaneously, the friction braking torque corresponding to the regenerative braking should be reduced by decreasing the hydraulic pressure at the front wheel. To implement the regenerative braking algorithm, a hydraulic braking module is designed. In addition, the HEV powertrain models including the internal combustion engine, electric motor, battery, CVT and the regenerative braking system are obtained using AMESim, and the regenerative braking performance is investigated by the simulation. Simulation results show that the proposed regenerative braking algorithm contributes to increasing the battery SOC which results in the improved fuel economy. To verify the regenerative braking algorithm, an experimental study is performed. It is found from the experimental results that the regenerative braking hydraulic module developed in this study generates the desired front wheel hydraulic pressure specified by the regenerative braking control algorithm.     

基于前向建模的ISG型CVT混合动力系统再生制动仿真研究

基于对CVT混合动力汽车制动力分配的分析,综合考虑发动机反拖制动、CVT速比及夹紧力控制、电池快速充电特性与电机高效发电特性对再生制动性能的影响,制订了相应的再生制动控制策略。根据前向建模思想,利用数值建模与理论建模的方法,建立了CVT混合动力汽车再生制动系统综合模型,进行了EUDC等四种典型循环工况下的再生制动性能仿真,在保证安全制动的条件下,实现了较高比率的制动能量回收,仿真结果证明了所提出的再生制动控制策略和系统模型的正确性与适用性。     

基于转矩的低附路面机械式自动变速器控制策略

从机械式自动变速器控制系统所能获取的有限数据,判断行驶路面的附着系数以及车辆轮胎打滑情况,并进行驱动防滑控制;通过发动机转矩、变速器数据、整车状态等对车辆正常的加速度范围进行计算,并和轮速加速度进行比较,以确定车轮打滑情况。根据轮加速度的大小进一步判断路面附着系数。轮胎打滑时,通过对发动机的降扭和离合器的控制,实现驱动防滑的控制;在试验车辆上进行低附路面识别和控制的试验,能够正确识别出路面附着系数。在低附路面起步时,通过打滑时发动机转矩和离合器的控制,避免了车轮连续的滑转,大大提高了车辆的稳定性。这说明该低附路面识别和控制方法是可行的,能够在车上使用。     

基于参数统计特征的无级变速车辆智能控制策略

装备无级变速器(Continuously variable transmission,CVT)的车辆采用经济性控制时,发动机后备功率小,急加速工况下只能通过提高转速来增加功率输出,而发动机转速提高要消耗相应功率,导致车辆动力不足。基于实时参数的控制策略只能在加速过程开始后再控制发动机工作点向动力性线偏移,这一过程仍需要通过提高发动机转速来实现,对提高CVT车辆的动力性作用有限。车辆行驶参数的统计值包含车辆行驶的历史信息,且能随行驶工况的变化而变化,这是制定控制策略的重要依据。针对已有控制策略的不足,在对各参数统计特征进行分析的基础上,提出根据行驶参数的统计值来调整发动机稳态工作线的控制策略。仿真及试验表明,新的控制策略能根据统计参数的变化合理调整发动机稳态工作点,对车辆工况变化具有自适应能力;同时,该控制策略避免了对实时参数的依赖,可以在某一动态过程开始前就使发动机工作在后备功率较大的稳态工作线上,有利于提高动态过程的动力性。     

基于液力变矩器性能及NIC功能的无级变速器经济性分析

液力变矩器液力性能的选型和控制策略是CVT开发工作中一项关键内容。通过对液力变矩器性能的分析和对比,分析液力变矩器泵轮扭矩的规律,通过整车模型和控制模型的搭建,对比分析3种液力性能和NIC功能的开关对燃油经济性的影响。分析得到:有效降低行车过程中发动机怠速扭矩,有利于提升车辆的燃油经济性;燃油经济性提升幅度的大小与液力变矩器性能和发动机怠速燃油消耗量有关。     

考虑操纵稳定性的适时四驱扭矩分配策略

以某款全新开发的电控适时四驱SUV为研究对象,为同时发挥四轮驱动(4WD)与直接横摆力矩控制(DYC)的优势,建立适应于动力性及操纵稳定性的汽车动力学系统模型,提出基于轮胎最小滑移率同时保持横摆角速度跟随的适时四驱智能扭矩分配策略,采用PID算法计算出保持车辆最小滑移率及横摆角速度跟随所需的四驱控制器控制电流并加以控制。然后将该算法移植到单片机中进行低附试验,全油门加速工况、蛇形工况及定圆加速工况试验结果表明:制定的智能扭矩分配策略在迅速抑制车轮打滑的同时能有效提升车辆在低附路面的操纵稳定性,进一步提高了车辆的主动安全性,具有较强的工程实用性。     

无人驾驶越野车辆纵向速度跟踪控制试验

以无人驾驶轻型战术轮式越野车辆为平台,开展模型预测纵向速度跟踪控制实车试验研究。针对平台控制特性设计合适的下位控制器,使用Matlab/Simulink与包含气压制动系统的TruckSim车辆联合仿真初步测试系统可行性,并在沥青路和土路分别进行实车试验。试验结果表明：模型预测速度跟踪控制系统能够克服气压制动延时长、整车质量重、越野路况行驶阻力波动大等模型误差和不确定干扰,自适应调节期望加速度大小,实现不同行驶工况高精度速度跟踪。试验过程驱动/制动切换平稳、无振荡,且能够像熟练驾驶员一样充分利用发动机辅助制动,必要时既不施加电控制动,也不请求发动机输出转矩。系统使用现代车辆易于获得的车辆状态参数,便于向其他车辆移植,可作为无人车辆车体控制得力技术加以推广。     

Control Algorithm of Electric Vehicle in Coasting Mode Based on Driving Feeling

Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine (ICE), and the assistant braking function of ICE is utilized to decelerate the vehicl...     

ENERGY MANAGEMENT STRATEGY FOR PARALLEL HYBRID ELECTRIC VEHICLES

Energy management strategy (EMS) is the core of the real-time control algorithm of the hybrid electric vehicle (HEV). A novel EMS using the logic threshold approach with incorporation of a stand-by optimization algorithm is proposed. The aim of it is to minimize the engine fuel consumption and maintain the battery state of charge (SOC) in its operation range, while satisfying the vehicle performance and drivability requirements. The hybrid powertrain bench test is carried out to collect data of the engine, motor and battery pack, which are used in the EMS to control the powertrain. Computer simulation model of the HEV is established in the MATLAB/Simulink environment according to the bench test results. Simulation results are presented for behaviors of the engine, motor and battery. The proposed EMS is implemented for a real parallel hybrid car control system and validated by vehicle field tests.     

新型并联式混合动力汽车模式切换协调控制

针对一种基于行星齿轮机构的新型并联式混合动力汽车,以实现整车系统效率最优为目标,对混合动力系统工作模式区域进行划分,制定出整车能量分配策略。研究了各工作模式切换之间的扭矩协调控制算法,并进行了驱动工况仿真分析。结果表明,综合了系统效率最优的能量分配策略与协调控制算法既能优化动力系统效率,又能够有效提高混合动力汽车模式切换过程中动力传递的平稳性。