直列4缸发动机曲轴平衡重优化

Optimization of Counterweight for a Four-Cylinder In-Line Diesel Engine

曲轴平衡性对轴承载荷、振动与噪声具有较大影响。基于轴承润滑理论,针对某直列4缸发动机曲轴不同平衡重配置方案,运用AVL EXCITE Designer建立不同曲轴模型,研究了不同平衡率对曲轴的载荷、润滑、扭振、强度等性能的影响。研究表明:在曲轴上设置平衡重可以有效地平衡发动机不平衡的离心力和离心力矩,改善轴承载荷;随着平衡率的增加,主轴承的最大载荷相应增大,但平均载荷相对减小;随着平衡率的增加,主轴承最大油膜压力呈现不规律的变化,但在平衡率最大时,最大油膜压力最小,曲轴润滑性能最好;曲轴加上平衡重后,固有频率减小;曲轴最小圆角应力安全系数随着平衡率的增加而减小。

The crankshaft balance has a great influence on the bearing load, vibration and noise. The different counterweight configuration crankshaft models of inline 4-cylinder engine were built with AVL EXCITE Designer software based on the bearing lubrication theory. The influence of different equilibrium rates on the crankshaft properties, such as load, lubrication, torsional vibration, strength, etc. was studied. The results show that the balance weight can effectively balance the centrifugal force and the centrifugal force of the engine, and reduce the bearing load. With increasing balancing rate, the maximum load of main bearing is increased, but the average load is reduced; With the increase of the balance rate, the maximum oil film pressure of the main bearing is irregular, but when the equilibrium rate is maximum, the maximum oil film pressure is the smallest and the crankshaft lubrication performance is the best; The natural frequency decreases after the crankshaft with the balance weight; The minimum fillet stress safety factor decreases with balancing rate increasing.