Views:5 Author:Site Editor Publish Time: 2020-03-26 Origin:Site
In 2012, the production capacity of the mainstream enterprises in the domestic exhaust silencing system industry was further improved, and the scale of the enterprises was gradually expanded. The product structure began to enter the adjustment, the product level increased, the output obtained the steady growth, the production and marketing rate, the capital turnover rate obviously increased. Enterprises to achieve profits and tax increases faster. Compared with 2011, the whole industry has a new development, especially in the automotive exhaust muffler aspect.
Development of automobile exhaust muffler at home and abroad
Research method and design method of exhaust muffler
There are two main types of exhaust mufflers used in automobiles: passive muffler and active muffler. Among passive mufflers, the most commonly used one is resistant muffler, which mainly reduces the noise by using the repeated attenuation of sound in the resonance chamber and the extended chamber. In addition, exhaust muffler and impedance compound muffler are often used in automobiles. The noise reduction principle of exhaust muffler is different from that of exhaust muffler. The impedance compound muffler combines the exhaust muffler and the exhaust muffler reasonably to achieve the silencing.
The active exhaust muffler uses the principle of acoustic interference to reduce the noise, it needs to introduce the secondary sound source in the original sound field to interact with the original sound source, and reduce the noise, it is a form of active control of the noise.
The progress of science and technology has led to the rapid development of various industries, muffler research and design methods are the same, from the original manual analysis, constantly developed for the current computer-aided design. Initially in the early 1920s, Stewart of the United States first proposed the theory of exhaust muffler research design, which is known as the resistance sound filter theory. In the middle of the 1940s, the design of the exhaust muffler introduced mathematical methods, and Cai Chao calculated the acoustic transfer matrix of the muffler through the mathematical matrix. in the mid-fifties, davis analyzed the characteristics of the expansion cavity and the lateral branch resonance based on the continuity of the sound pressure and volume vibration velocity at the section mutation and the one-dimensional wave equation. By the late 1950s, Igarashi introduced the four-terminal network principle in the research design. He used the equivalent circuit method to study the transmission characteristics of the exhaust muffler and use the form of the four-level parameter matrix to express it. After more than ten years of continuous research, summary and innovation, the design of muffler has introduced linear sound wave method, which considers the influence of airflow in the calculation and analysis, and once again improves the theoretical research level of muffler, and also forces the change of test method, which makes the accuracy of experimental data become higher and more consistent with the actual situation.