汽车排气消声器传声损失分析及改进

为对某自主开发新车型的排气消声器进行正向开发,对其进行传声损失计算分析及改进。首先,建立初步设计消声器内部声场的三维有限元模型并模拟其内部声场分布,三点法计算的消声器整体及各腔室的传声损失曲线表明,2 000~2 800 Hz为该消声器的薄弱频段,其中,直通多孔共振腔消声性能最差;然后,在控制消声器整体外形尺寸不变的前提下提出三种不同的改进措施并分析对比其传声损失,结果表明,改进方案"直通多孔共振腔直径增大10 mm,其他结构不变"效果最佳。

Transmission Loss Analysis and Improvement of the Car Exhaust Muffler

In order to develop the exhaust muffler of a new independently developed car forwardly, its transmission loss was analyzed and improved. Firstly, the 3D finite element model of the preliminarily designed exhaust muffler was built to simulate its interior sound field distribution and the transmission loss curves of the entire exhaust muffler and each cavity were calculated. It is shown that the acoustic performance is poor in 2 000-2 800 Hz, particularly, for the straight through porous resonant cavity. Then, under the premise that the overall dimensions of the muffler are not changed, three improvement schemes are designed and their effects are simulated and compared. Resuhs show that the scheme that the diameter of the straight through porous resonant cavity is increased by 10 mm and the other parameters remain unchanged has the best effect.