发动机壳体噪声辐射控制研究

为降低摩托车发动机辐射噪声,以某摩托发动机壳体为研究对象,采用有限元法/边界元法（FEM/BEM）,对发动机壳体的辐射噪声进行仿真计算,确定了辐射噪声的频带和辐射位置,结合声强实验测试,验证了数值计算的正确性。根据数值模拟的结果,对该发动机壳体结构进行优化,并对优化后的壳体进行了噪声辐射预测,将优化前后的声学量进行对比。结果表明：优化后的发动机壳体表面辐射噪声较优化前有所降低,其噪声值降低约4 dB。

Study on Controlling Noises Radiated from Engine Shell

With a motorcycle engine shell as the research object, analyzed the noise radiation of the engine shell by means of FEM / BEM, and determined the frequency range of the noise radiation and the critical region. Combining with sound intensity test, verified the correctness of the calculation result. The engine shell structure was optimized according to the numerical simulation results, and the noise radiation of the optimized model was predicted. Comparing the noise test results before and after the optimization, it is obtained that the surface radiated noise of the optimized engine shell is reduced about 4dB.