柴油机缸内燃烧激励的振动响应机理研究

摘要

For the cylinder head of 12150 diesel engine ,the transient dynamic calculation of in-cylinder combustion excitation was carried out with the direct integral method .By comparing theory analysis with test data ,the correlations of vibration dis-placement ,vibration velocity and vibration acceleration with combustion parameters were disclosed and the influence of speed variation on vibration response of in-cylinder combustion excitation was researched .The results show that the vibration dis-placement of cylinder head ,the vibration velocity and the vibration acceleration signal can reflect the trend of cylinder pressure , the pressure rise rate and the pressure rise acceleration respectively .When speed changes ,the corresponding correlations of the three parameters can still keep good stability .The cylinder pressure recognition model established based on AdaBoost_BP inte-grated neural networks with vibration displacement signal can identify the combustion faults of diesel engine accurately and has good generalization and accuracy .%以某12150柴油机缸盖为研究对象，采用直接积分法进行了缸内燃烧激励的瞬态动力学计算；通过理论分析和试验数据对比，揭示了振动位移、振动速度、振动加速度与缸内燃烧特征参数的对应关系，并研究了转速变化对缸内燃烧激励振动响应的影响。结果表明：缸盖表面振动位移能够反映缸内压力的变化趋势；振动速度能够反映缸内压力升高率的变化趋势；振动加速度信号能够反映缸内压力升高加速度的变化趋势；并且当转速发生变化时，三者对应关系表现出了良好的稳定性。利用振动位移信号建立了基于AdaBoost_BP集成神经网络的缸内压力识别模型，经验证，模型能够准确识别柴油机缸内燃烧故障，具有良好泛化性和精确度。