车用多模式无级变速器的性能研究

A Research on the Performance of a Vehicular CVT

提出一种调速范围为0.7~1.5的车用多模式无级变速器,通过模式切换和功率分流,能保证无级变速支路功率分流比小于65%,而无级变速器传动比在0.5~1.0范围内。建立装备多模式无级变速器的整车键合图模型,并推导出该系统的状态方程。以MATLAB/Simulink为平台建立整车仿真模型,选取UDDS循环工况,采用最佳燃油经济性控制策略,对多模式无级变速器进行仿真。结果表明:在UDDS循环工况下,多模式无级变速器,在低速大转矩时,工作于PX型模式,高速时,工作于XP型模式,能有效减少流过金属带无级变速器支路的功率流,提高车辆传动系统效率和承载能力;且通过过渡模式,有效避免XP模式与PX模式切换引起的系统振动。

A vehicular multi-mode continuously variable transmission （CVT） with a speed ratio range of0. 7-1. 5 is presented,which can ensure by mode switch and power split that its branch power split ratio is less than65%,with a transmission ratio range of 0. 5-1. 0. The bond graph model for vehicle equipped with multi-mode CVTis established and the state equation of the system is derived. Then vehicle model is created with MATLAB/Simulinkand a simulation on multi-mode CVT is conducted with UDDS driving cycle and optimal fuel economy control strate-gy adopted. The results show that throughout the UDDS driving cycle, multi-mode CVT works in PX mode at lowspeed with high torque,and works in XP mode at high speed,effectively reducing the power flowing through metalbelt CVT,enhancing the efficiency and load-bearing capacity of powertrain,and effectively avoiding the system vi-bration ,caused by the mode switch between XP mode and PX mode through transition mode.