【作者】 陈龙；

【导师】 袁晓红；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2016， 硕士

【摘要】 本文将提升CVT的燃油经济性作为目标,从发动机匹配以及控制优化等多方面入手,提出了优化策略,并利用计算机仿真和硬件在环仿真进行了双重验证。利用理论与试验相结合的研究方法进行数学建模,并确定优化目标以及优化算法。利用迭代算法对系统传动效率进行求解,将所得结果进行数据处理后得出新的目标速比模型和目标节气门开度模型。由此确定新的速比控制策略,并在MATLAB/Simulink中建立速比控制器模型。研究CVT的传动机理,并对其基本运动情况进行探讨。对CVT的关键部分进行静力学受力分析和理论计算。基于CVT的运动分析和受力分析,研究CVT的动态受力分布。研究CVT传递转矩时的功率损耗,分别对机械传动损耗和液压系统损耗进行探讨。根据功率损耗情况,提出相应措施以提升CVT传动效率。对传统的夹紧力控制方法及理论基础进行研究。对滑移率的定义以及其对CVT传动的影响进行分析,由此提出两种不同的滑移率控制策略。基于这两种滑移率控制策略在MATLAB/Simulink中设计夹紧力控制器,并在AMESim中建立整车及液压系统模型,由此完成联合仿真建模。仿真结果表明:匹配最佳摩擦系数的滑移率控制策略可以在提升传动效率的前提下,保证系统鲁棒性。确定整体优化方案,对比滑移控制和传统控制:滑移控制可以提升传动效率,且在低转矩和高速比的工况下效率提升更为显著。建立油耗模型对整体优化效果作出评价,由仿真结果可知:优化后的等速百公里油耗可在原有基础上减小5%~10%。搭建dSPACE硬件在环仿真平台,主要包括在MATLAB/Simulink环境中的建模、利用RTW Build进行C代码的编译下载、控制器的设计制作以及相关接线和参数设置。基于城市+城郊循环工况进行在环仿真试验,试验结果显示:经过夹紧力和速比优化后的控制器可以满足降低整车油耗的要求;真实控制器的控制效果和虚拟控制器相比有一定差距,需要进一步完善。更多还原

【Abstract】 This paper aims to improve the fuel economy of CVT.Starting from engine matching and control optimization,optimization strategies are put forward.Computer simulation and hardware in the loop simulation are carried out.The theoretical and experimental combined method is used to build mathematical modeling.Optimization objective and optimization algorithm are proposed.The iterative algorithm is used to solve the transmission efficiency of the system.New target ratio model and target throttle opening model are obtained after data processing of the results.The new speed ratio control strategy is determined.The speed ratio controller model is established in MATLAB/Simulink.CVT transmission mechanism is studied,and the basic movement of CVT is analyzed.The static force analysis and theoretical calculation of the key parts in CVT is conducted.The dynamic force distribution is researched based on CVT motion analysis and force analysis.The power loss from CVT transmitting torque is researched,including mechanical transmission and hydraulic system loss.Measures are put forward to optimize the efficiency of CVT.The traditional clamping force control theory is researched.Slip ratio is defined and its influence of CVT are analyzed,with the proposal of two different slip ratio control strategies.The clamping force controller is designed in MATLAB/Simulink based on the two strategies.Co-simulation model is established.The simulation results show that the slip ratio control strategy with the best matching coefficient of friction can ensure the robustness of the system under the premise of improving the transmission efficiency.Slip ratio control strategy and traditional control strategy are compared after the overall optimization scheme determined,which shows that the slip rate control strategy can improve the transmission efficiency;lower torque and higher speed ratio make the improvement of efficiency more significant.Fuel consumption model is established to evaluate the overall optimization effect.The simulation results show that the fuel consumption can be reduced by 5%~10% on the original basis.The dSPACE hardware in the loop simulation platform is established,including modeling in MATLAB/Simulink environment,compiling and downloading C code with RTW Build,controller designing,related wiring and parameter settings and so on.The loop simulation test is conducted based on ECE+EUDC.Test results show that the controller with the optimization of clamping force and ratio can meet the requirements to reduce vehicle fuel consumption;the control effect of the real controller has a certain gap compared to the virtual controller and needs further improvement.更多还原