中文摘要：

为了综合研究曲轴扭振与发动机前端附件驱动的系统（FEAD）的旋转振动，建立了发动机FEAD一曲轴扭振系统的耦合模型。两系统之间的连接是通过曲轴前端的扭转减振器。扭转减振器的惯量环可为驱动FEAD的皮带轮，或独立。利用建立的模型，计算系统的固有特性，研究曲轴前端安装不同形式的扭转减振器时，FEAD对曲轴扭振的影响和FEAD的动态负载波动对曲轴扭振的影响。研究结果表明：FEAD与曲轴扭振系统之间存在振动耦合；发动机的低频激励不会激起曲轴扭振，但易激起FEAD的旋转振动；高频激励易同时激起FEAD和曲轴系统的共振；FEAD对曲轴扭振有一定的衰减作用；考虑FEAD、扭转减振器具有独立的惯量环时，曲轴系统的扭振较皮带轮兼做惯量环时曲轴的扭振要小。只有当FEAD的动态负载波动等于或大于发动机单缸激振力矩的最大值时，FEAD动态负载波动的增大将增大曲轴的扭振。

英文摘要：

Usually performances of an engine crankshaft system （CS） and an engine front end accessory drives （FEAD） are analyzed in-dependently based on the assumption that their motions are decoupled. Few investigations about the relation of FEAD and CS are published. For a more accurate model, the effect of FEAD should be considered when calculating torsional vibration of a CS. A coupled model of an engine CS and an FEAD for analyzing torsional vibrations is presented. The natural frequencies and mode shapes and torsional vibration under different connections with or without single-torsional vibration damper （STVD） or FEAD are calculated. Also torsional vibrations of a coupled model consisting of a CS, an FEAD and a STVD of different types are included. One type of STVD （External inertia ring） is that the inertia ring is also a pulley that drives the FEAD~ the other STVD （Internal inertia ring） is that the inertia ring is used for absorbing the energy of crankshaft and is not used to drive the FEAD. The results show that the vibrations of a CS and an FEAD are coupled. The FEAD would resonate under a low frequency excitation, which would amplify the torsional vibration of the CS, while the FEAD and the CS would resonate simultaneously under a high frequency excitation. The crankshaft vibration of the coupled model using a STV＇D with internal inertia ring is smaller than using a STVD with external inertia ring. The torsional vibration of a CS with an FEAD and without a STVD （System 1） is larger than that with a STVD and without an FEAD （System II）, while the vi- bration of the system I is smaller than that of a CS without a STVD and without an FEAD （system III）. Therefore, FEAD reduces the torsional vibration of the crankshaft, but it is not obvious compared with that using STVD. In addition, the load fluctuations of the components in FEAD have some effects on the crankshaft torsional vibration if the load fluctuations are e- qual or greater than the maximum excitation torque from firing in