某汽油发动机排气系统的分析与设计

Analysis and design of exhaust system of one gasoline engine

为有效控制发动机尾气所排放的污染物和排气噪声,针对某型号轿车汽油发动机排气系统进行设计,对排气系统的声学特性进行分析与数值计算,阐述了噪声的产生机理和降低噪声的方法,并对阻性消声器和阻抗复合型消声器的结构和主要尺寸参数进行了设计.分析了尾气污染物的主要成分及其净化方法,参考北京绿创的轿车整体型三元催化器的结构尺寸,设计了基于低温等离子体(NTP,Non-Thermal Plasma)的汽车尾气四效净化器,根据汽车设计的相关要求,对排气系统的各零部件进行合理布置,确定了悬挂方式;该汽车排气系统可同时净化发动机尾气中其中一氧化碳(CO)、碳氢化合物(HC)、氮氧化合物(NO x)和可吸入碳烟颗粒物(PM,particulate materia),同时具有净化效率高,排气背压低、降噪效果好等优势.

In order to control pollutants and exhaust noise emitted by engine exhausteffectively.In this paper,the exhaust system of one certain type of vehicle gasoline engine was designed.The acoustic characteristics of exhaust system were analyzed and calculated,and the mechanism of noise generation and the method of noise reduction were described.On this basis,the structure and main size parameters of resistance muffler and impedance compound mufflerwere designed.The main components and purification methods of exhaust pollution were analyzed,and the four-way purifier of automobile exhaust was designed based on Non-Thermal Plasma.According to the relevant requirements of automobile design,the components of the exhaust system were arranged reasonably to determine the suspension mode.This automobile exhaust system can simultaneously purify carbon monoxide,hydrocarbons,nitrogen oxides and inhalable particulate matter emitted by engine exhaust,and has the advantages of high purification efficiency,low exhaust back pressure and good noise reduction effect.