中文摘要：

给出了单环路系统实现功率分流的结构方案，建立了装备XP型和PX型功率分流式无级变速系统的整车键合图模型，并推导出该系统的状态方程。以MATLAB／Simulink为平台建立了整车仿真模型，选取UDDS循环工况，采用最佳燃油经济性控制策略，对XP型和PX型功率分流式单环路系统进行经济性选型，发现XP型单环路系统经济性更好。当循环工况的加速度突变时，发动机转矩和单环路系统传动比突变，导致差动轮系的基本构件振动。

英文摘要：

Power split structure scheme of the single loop system was given, bond graph model oI the vehicle which equipped with XP and PX type power split continuously variable transmission was established, and the state equation of the system was deduced. Taking MATLAB/Simulink as a plat- form, the simulation model of the vehicle was established. Given UDDS driving cycles, using the best fuel economy control strategy for the economics selection of the XP type and PX type power split sin- gle loop system, the XP type single loop system has better economy. When the driving cycle accelera- tion rapidly changing, the engine torque and the single loop system transmission ratio has abrupt varia- tion, which leads to the vibration of the basic component of the differential gear train.