某新车型排气系统尾管声学性能优化

针对某新车型排气噪声怠速超标问题,采用GT-Power软件对排气消声器结构进行了消声性能优化,并使用计算流体动力学软件Fluent验证了优化方案的内部流场分布较为理想。建立了用于计算排气尾管噪声的发动机与排气系统耦合仿真模型,并用发动机台架实验数据修正了模型精度,计算对比了原消声器方案和优化方案的三挡全油门加速尾管噪声。整车实验测试了原方案和优化方案的怠速及三挡全油门加速尾管噪声,实验结果表明优化方案较原方案有较大程度改进,满足了工程实际要求。

Acoustics Performance Optimization of the Tail Pipe for a New Car Model

For exhaust noises exceeding the manufacture’s standard limits, the inner structure of the exhaust mufflers of a new car model is optimized using the GT-Power software. Then the inner stream fields of the optimized mufflers are verified reasonable based on the Fluent software analysis results. Based on the brake torque and the brake power datum of the engine bench experiments, the coupling simulation model of the engine and the exhaust system is calibrated. The calculated tail pipe noises of the original and the optimized schemes are compared under the case of third gear wide open throttle(3WOT) accelerating. To verify the optimized scheme, the tail pipe noises under cases of idle speed and 3WOT accelerating are tested. The experimental results show that both the total and the order sound pressure levels are improved significantly compared with the original ones, which meets the technical requirements.