外文翻译----降低汽车噪声的方法-汽车设计(编辑修改稿)

外文翻译----降低汽车噪声的方法-汽车设计(编辑修改稿)内容摘要：

materials and ponents into its vibrational energy to consume. It has the following structure: Freedom damping layer structure, and spacing of freely damping layer structure, and constrained damping layer structure and spacing of constrained damping layer. It is clear that the adoption of a decrease of resonance amplitude and accelerated the decay of free vibration, reducing the various parts of the ChuanZhen capacity, an increase of parts at or above the critical frequency of vibration isolation capacity. At present, some countries have designed an engine experts active vibration isolation system to reduce engine vibration, in order to achieve the purpose of noise reduction. (2) intake noise Engine intake noise is one of the main noise source, the Department of the engine noise of air power, with the engine speed increases to strengthen. Nonsupercharged engine intake noise major ponents, including the cyclical pressure fluctuation noise, vortex noise, the cylinder of the Helmholtz resonance noise. Diesel engine supercharger intake noise mainly from the turbocharger pressor. Two stroke engine noise from the Roots pump. In this regard, the most effective method is the use of intake muffler. There is a resistive type muffler (absorption type), resistant muffler (expansion type, resonance type, interferencetype and porous decentralized) and the posite muffler. To bine with the air filter (that is in the air filter on an additional resonance chamber and soundabsorbing material, for example, type R3238) has bee the most effective intake muffler, muffler volume of more than 20dBA. Chassis Noise (1) Department of exhaust noise Department of the chassis exhaust noise is the main noise sources, mainly from the exhaust pressure pulsation noise, air flow through the valve seat when issued by eddy current noise, because of boundary layer airflow disturbance caused by noise and exhaust Office jet noise position. (2) power train noise Powertrain noise from the vibration caused by change gear meshing and rotating shaft vibration. General measures taken are: First, choose lownoise transmission, engine and gearbox are two and the main reducer, such as rear axle and chassis ponents for flexible rubber pad connections, so as to achieve the purpose of isolation。 are threeaxis rotational control balance degrees, to reduce torsional vibration.。