内燃机轴系扭振阻尼系数的识别

Identification of Torsional Damping Coefficients for Internal Combustion Engine Crankshafts

为了解决内燃机轴系扭振理论分析中阻尼系数难以选取的问题,提出了一种利用轴系角振动模态阻尼比识别轴系各主要部件扭振阻尼系数的方法.该方法将轴系多质量系统简化成当量扭摆系统,利用扭振能量理论推导了轴系角振动模态阻尼比与轴系各部件扭振阻尼系数的关系式.如果已知轴系角振动模态阻尼比,通过分析轴系扭振阻尼特性,并选择合适的轴系角振动模态,即可识别出对轴系扭振起主要作用的阻尼系数.对某6缸和4缸柴油机的仿真和试验研究表明,所识别的轴系部件扭振阻尼系数的最大误差为4.89%,也证明了本文方法的正确性.

In order to solve the difficulty of selecting the damping coefficients in torsional vibration theoretical analysis of internal combustion engine （ICE） crankshafts, an identification method of torsional damping coefficients of main crankshafts components was proposed based on the modal damping ratio of crankshafts angular vibration. In this method, the multi-mass system of crankshafts was simplified to an equivalent torsion pendulum system, and the relationship between the modal damping ratio of crankshafts angular vibration and the torsional damping coefficient of each crankshaft component was derived by vibratory energy theory. Thus, if the damping ratio of crankshafts angular vibration is given, the main torsional damping coefficients of crankshafts could be identified by analyzing the damping property of crankshafts torsional vibration and selecting a proper mode of angular vibration. As a case study, the damping coefficients of a 4-and a 6-cylinder diesel engine were identified by simulation and experiment. The results show that the identified torsional damping coefficients of the main crankshafts components obtained by simulation have a maximum error of 4.89% compared to the experimental one. This demonstrates the validity of the proposed identification method.