瞬态工况壁面温度对燃烧噪声的影响

研究了直喷式柴油机瞬态工况壁面温度对燃烧噪声的影响机理。开展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壁面温度差异的研究分析,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。瞬态工况壁面温度高于同负荷同转速的稳态工况。壁面温度的差异导致两种工况下滞燃期的改变,影响燃烧压力和缸内压力升高率以及压力高频振荡的频率和幅值。结果表明,瞬态与稳态工况壁面温度的差异影响到动力载荷与压力高频振荡,是两种工况下燃烧噪声产生差异的主要二级影响因素之一。

EFFECT OF COMBUSTION CHAMBER'S WALL TEMPERATURE IN TRANSIENT CONDITIONS ON COMBUSTION NOISE OF INTERNAL COMBUSTION ENGINE

Study the effect of combustion chamber's temperature in transient conditions on combustion noise mechanism of DI-Diesel engines. By developing testing technique and method of transient conditions and studying the difference of combustion chamber's wall temperature between transient conditions and steady conditions, the different combustion noise mechanism between transient conditions and steady conditions is analyzed from the point of aerodynamic load and high-frequency oscillation of combustion pressure. The combustion chamber's wall temperature in transient conditions is higher than steady conditions in the same load and at the same rotation speed. It results in the changing of ignition delay in two conditions and affects the combustion pressure, rate of pressure rise, frequency and amplitude of the high-frequency oscillation of combustion pressure. The result shows that the difference of combustion chamber's wall temperature between transient and steady conditions in the same load and at the same rotation speed affects the dynamic load and high-frequency oscillation of combustion noise. It is one of the important second level factors resulting in the difference of combustion noise in two conditions.