论文部分内容阅读
一、前言发动机的噪声以顿率为0.5—2.5kHz的中、高频成分为主,它们主要是混合气在气缸内燃烧时产生的。尤其近来以改善燃料消耗率为目的,大量采用废气再循环,加快了燃烧速率,使燃烧噪声有明显提高。由燃烧室燃烧压力而引起的中、高频振动,由活塞、连杆经曲轴或者是经过缸盖传到发动机各部表面,使其发出噪声。此外,由于活塞敲击也直接在缸套
First, the foreword The noise of the engine is mainly in medium and high frequency components of 0.5-2.5kHz, they are mainly produced when the mixture gas burns in the cylinder. In recent years, in order to improve the fuel consumption rate, a large amount of exhaust gas recirculation has been used to speed up the combustion rate and significantly increase the combustion noise. By the combustion chamber pressure caused by medium and high-frequency vibration, by the piston, connecting rod through the crankshaft or through the cylinder head spread to the engine surface, making it noise. In addition, the piston stroke directly in the cylinder