国五标准柴油机排气系统声学性能研究与设计  

Acoustic Research and Muffler Design of Diesel Engine Exhaust Systems according to CN V Standard

作　　者：郑子健 翁建生[1] 袁磊 孙鹏飞 ZHENG Zijian;WENG Jiansheng;YUAN Lei;SUN Pengfei(College of Power and Energy Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学能源与动力学院,南京210016

出　　处：《噪声与振动控制》2018年第4期91-95,共5页Noise and Vibration Control

摘　　要：针对满足国家第五阶段排放标准的排气系统,设计具有良好消声性能的消声结构。首先通过实验分析的方法研究发动机排气声源特性,发现与发动机点火频率相关的低频阶次噪声在排气噪声中占主导地位。然后基于平面波理论计算催化转化器传递损失,通过GT-Power声学仿真与阻抗管传递损失测试进行验证,分析出载体在中高频具有良好的消声性能,这种性能可以使其代替吸声棉对排气中的高频气流噪声产生很好抑制效果。基于发动机声源特性以及催化器的声学性能,设计出针对低频噪声的消声器方案,并针对长尾管的声模态共振问题,在尾管中添加穿孔管消声器,降低特定转速下的模态噪声。实验表明设计方案达到预期的消声效果,且与相同型号发动机的国四标准排气系统对比具有更低的排气背压,可提升发动机效率与燃油经济性。To design a muffler for the exhaust system which can meet CN V standard,the characteristics of exhaust sound source are tested.The results show that the low frequency order noise plays an important role in the exhaust noise.Then,the transmission loss of the catalytic converter is calculated according to the planar wave theory and verified by GTPower acoustic simulation and transmission loss test with impedance tubes.It is found that the catalytic converter has a good sound elimination performance at mid and high frequencies.It can replace the sound absorbing cotton in exhaust systems to effectively suppress the high-frequency exhaust noise.Based on the sound source characteristics of the engine and the acoustic performance of the catalyst,a new muffler scheme aiming at low frequency noise elimination is designed.The experimental test shows that this scheme can meet the sound elimination requirements and the back-pressure generated by the system is lower than that of CN IV typical exhaust systems.

关 键 词：声学 排气系统 国五标准 催化器 声源特性 GT-POWER 

分 类 号：P733.22[天文地球—物理海洋学] U27[天文地球—海洋科学]