基于摩擦动力学的柴油机拉缸仿真研究

摘要

柴油发动机活塞、活塞环与缸套润滑油膜破坏会发生剧烈的干摩擦而使柴油机发生拉缸故障,进而引起严重后果.为此,研究了干摩擦状态下柴油机活塞轴向加速度信号的振荡特性,建立了柴油机拉缸故障下活塞与缸套间的摩擦力模型,根据摩擦力的动态特性验证了该模型的可靠性.研究结果表明:活塞经过上、下止点时其加速度振动信号会发生剧烈波动,产生冲击信号;导致故障产生的原因为自激振动和摩擦力换向.研究结果为利用振动信号诊断拉缸故障提供了依据.%The severe dry friction caused by the damage of the diesel engine piston, piston ring and cylinder liner lubricating oil film could result in diesel scuffing fault, leading to serious consequences.To address the issue, the oscillating characteristics of the axial acceleration signal of diesel engine piston under dry friction state have been studied.The friction model between the piston and the cylinder under diesel scuffing fault has been established, and the reliability of the model has been verified according to the dynamic characteristics of the friction.The results show that the acceleration vibration signal will fluctuate violently and the shock signal is generated when the piston passes through the upper and lower dead ends.The cause of the fault is the self-excited vibration and the friction direction change.The study results provide a basis for diagnosing the diesel scuffing fault by means of vibration signals.