柴油机怠速声音品质试验研究

主要对一台配有博世高压共轨系统的柴油机进行怠速声音品质试验研究。建立主观噪声评价指标后，对比该柴油机开启预喷后，发动机怠速声音品质的变化。通过调整不同主预喷间隔角和预喷油量，分析怠速声音品质的变化，找出最优的预喷射参数。并讨论相同预喷射参数下，整机噪声和声音品质的对应关系。结果表明：加预喷射后，柴油机的声音品质明显改善；预喷射参数的变化对声音品质影响不大；并不是噪声值越小，声音品质就越好。

Experimental Study on Idle Speed Sound Quality of Diesel Engine

This paper focuses on a six-cylinder diesel engine’s sound quality test with a high-pressure common rail system.After establishing the evaluation index of subjective noise,it is the contrast of the changes of the idle speed sound quality before and after pilot injection.By changing the pilot injection timing and fuel injection quantity,analysis the changes of idle speed sound quality,and find the optimal parameters of the pilot injection.And in the same parameters discuss the relation between the engine noise and sound quality.The results show that: adding pilot injection,engine sound quality improved obviously;The changes of the pilot injection parameters is not obviously impact to the sound quality;Not the smaller noise value,the sound quality is better.