内燃机机体噪声特性的数值仿真分析

Study on noise emission of engine block based on numerical simulation

结合多体动力学仿真技术与有限元法(FEM)和边界元法(BEM)对一台4缸发动机的机体噪声辐射进行了预测.建立了一台4缸4冲程柴油机曲柄连杆系统的多体动力学模型,通过多体动力学仿真的方法,求解出活塞、连杆、曲轴系统在工作过程中对机体的激励.利用有限元法求解出主轴承作用力、活塞侧向力和在燃烧激励作用下的机体振动特性.建立了机体噪声辐射的边界元模型,利用边界元技术对机体的辐射噪声进行了求解.并根据仿真分析的结果对机体的外声场的噪声特性进行了研究.研究表明,机体裙部的刚度是影响内燃机噪声辐射的重要原因.

The noise radiation of internal combustion engine block was calculated by multi-body system simulation （MSS）, finite element method （FEM） and boundary element method （BEM）. The four-cyllndered diesel engine＇s piston side force and main bearing force were achieved through simulation of dynamic mechanism system which consisted of crankshaft and connecting rods. FEM/BEM was used to predict the noise radiation of engine block induced by the combustion excitation, main bearing force and piston slap. The analysis indicated that the stiffness of engine block skirt was closely related to the block radiating noise.