瞬态工况对内燃机燃烧噪声的影响研究

研究了内燃机瞬态工况对燃烧噪声影响机理,开展了内燃机瞬态工况测试技术和测试方法研究,通过对瞬态与稳态过程的缸内压力、缸内压力最大值、压力升高率、压力升高率最大值、压力高频振荡以及气缸压力级等参数在不同频率范围的差异的研究分析,从气体动力载荷和高频压力振荡两方面分析研究瞬态噪声与稳态噪声产生差异的机理.瞬态与稳态工况压力升高率变化趋势与两种工况下燃烧噪声变化趋势基本相似,但在一些工况上存在差异,这是由于受到了缸内压力高频振荡对燃烧噪声影响的结果.结果表明：瞬态与稳态工况燃烧噪声的差异是由压力动力载荷与压力高频振荡共同影响的结果.

Effect of Transient Conditions on Combustion Noise of Internal Combustion Engines

This article studied the effect of transient conditions on combustion noise of DI-Diesel engines. By developing testing technique and method of transient conditions and studying the difference of cylinder pressure, maximal cylinder pressure, rate of pressure rise, maximal rate of pressure rise, high-frequency oscillation of combustion pressure and cylinder pressure level in different frequency between transient conditions and steady conditions, the mechanism of difference between transient conditions and steady conditions was analyzed from the point of aerodynamic load and high-frequency oscillation of combustion pressure. The changing trend of rate of pressure rise was similar to the combustion noise, but there were differences existing in some conditions. It was the result of effect of the high-frequency oscillation of combustion pressure on combustion noise. The result shows that the aerodynamic load and high-frequency oscillation of combustion pressure working together result in difference of combustion noise in transient conditions compared with steady conditions in the same load and at the same rotation speed.