考虑内燃机系统耦合振动的活塞拍击研究

Piston slap reduction considering coupled vibration of an internal combustion engine

为研究内燃机中主要机械噪声源—活塞拍击,考虑活塞、连杆、曲轴及缸体的耦合振动对活塞拍击影响,建立活塞拍击动力学分析模型,研究某型柴油机活塞拍击及缸体振动响应。探讨活塞裙部轮廓形状、偏置活塞销对活塞拍击及缸体辐射噪声影响,计算结果及实验数据表明,活塞轮廓形状对活塞拍击频率成分分布及噪声品质有重要影响,活塞销向主推力面适当偏置有助于降低活塞拍击及辐射噪声水平。

Piston slap is a major noise source of an internal combustion engine. Reducing piston slap is one of the most important measures to improve noise and vibration of an internal combustion engine. The influence of the coupled vibration of piston, connecting rod, crankshaft and engine block on piston slap was taken into consideration, and a dynamic analytsis model of piston slap was developed here. The piston slap and the vibration response of the engine block of a certain type of Diesel engine were investigated based on the proposed model. The effect of piston skirt profile and piston pin offset on piston slap and radiated noise of engine block was discussed. The calculation results and test data showed that the profile of piston skirt has a significant influence on higher frequency components of piston slap and engine noise quality, the piston pin offset toward major thrust side can decrease the maximum value of piston slap and sound pressure level of radiated noise.