Measuring and Modeling Analysis of Dynamic Characteristic for Automatic Tensioner in Accessory Drive System
ZENG Xiang-kun1, WANG Hongyun1, LIU Jianrong2
1. College of Electromechanical Engineering, Guangdong Polytechnic Normal University, Guangzhou 510665;2. School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510641
摘要介绍了发动机前端附件驱动(Front End Accessory Drive, 简称FEAD)系统中自动张紧器动态特性的实验测试方法和评价参数。测试和分析了预载扭矩、激振频率和激振振幅对张紧器动刚度和滞后角的影响。基于张紧器的预载扭矩、弹簧刚度、阻尼系数和张紧臂转动惯量四个参数,建立了表征张紧器扭矩-角位移关系的迟滞回线模型;采用最小二乘方法识别出张紧器迟滞回线模型的模型参数。对比张紧器动态特性的实测值和计算值,结果表明张紧器迟滞回线模型的建模方法是正确性。由张紧器扭矩-角位移关系曲线换算出张紧器的动刚度和等效粘性阻尼,建立了FEAD系统中张紧臂的旋转振动方程。FEAD系统旋转振动响应幅值的计算值和实验值吻合较好,这说明表征张紧器扭矩-角位移关系的迟滞回线模型,能为FEAD系统旋转振动的计算提供模型参考。
Experimental methods and parameters to evaluate the dynamic performances of an automatic tensioner in engine Front End Accessory Drive (FEAD) system are discussed. The dynamic performances of a tensioner include dynamic stiffness and loss angle. The influences of the pre-torque, excitation amplitude and excitation frequency on the dynamic characteristics of tensioner are measured and investigated. Considering the pre-torque, spring stiffness and damping coefficient of tensioner, and the moment of inertia for the tensioner arm, a hysteresis model used for modeling the relations between the torque and angular displacement of a tensioner is proposed. Parameters of the model are identified by the optimization process in the least-squares sense. The dynamical properties of a tensioner are calculated and compared well with experimental data, which validate the presented hysteresis model. Moreover, the equation of rotational vibration for a tensioner arm in a FEAD system is established. In the equation, dynamic stiffness and equivalent damping of a tensioner is used and is calculated based on the hysteresis model of the tensioner. Then, the rotational vibration responses of the FEAD system are calculated and compared well with experimental data, which validate the modeling method of hysteresis model and the calculation method of dynamic performances for a tensioner described in this paper.