诊断内燃机各缸作功均匀性的曲轴简谐扭振反算法

A new method to calculate inversely the power evenness of each cylinder using multi-order components of torsional vibration of crankshaft

简要介绍了各种诊断内燃机各缸作功均匀性的方法及其局限性;依据内燃机动力学的基本理论,提出了一种利用轴系一个惯量的扭振信号多谐次分量反算内燃机各缸作功均匀性的新方法;详细推导和说明了该方法的基本原理;以某6L 240柴油机为对象,进行了选用3个谐次的扭振简谐分量准确反算出各缸作功均匀性的仿真研究。理论分析和仿真研究表明,新方法只需以各缸停缸实验得到的扭振幅频特性参数为基础,利用一个惯量的扭振信号多谐次分量就可反算出内燃机各缸平均有效压力。方法简便准确,既不依靠轴系结构参数等较难获得的先验知识,又适用于内燃机轴系存在扭振的情况。

The present paper introduced briefly different kinds of methods for diagnosing the power evenness of each cylinder of ICE and their limitations. On the basis of basic theory of ICE dynamics, to calculate inversely the power evenness of each cylinder a new approach that uses the multi-order components of torsional vibration signal of one inertia on crankshaft system is presented. The basic principle the new approach is deducedon and explained. A^For a 6L240 diesel engine, a simulation investigation is presented, within which the simple harmonic components of three order torsinal vibrations are selected and the exact results of the inverse computations of the power evenness of each cylinder are given. B：The theoretical analysis and the simulation result showed that for the new approach, only the amplitude-frequency characteristic parameters of the torsional vlbratlon,that were obtained by misfiring each cylinder, were needed as a premise of the computation, and further wre more by using only the multi-order components of the torsional vibration signal of one inertia, the average effective pressure of each cylinder can be figured out inversely. It is an accurate and simple approach, which is not only independent of the structural parameters of crankshaft system and other prior knowledges obtained difficultly, but also a method which can be used under the conditions such that the torsional vibration of the crankshaft of ICE exists.