The Study About Optimizing Ofnoise And Sound Quality Of YC489 Diesel Engine

According to market feedback,the noise of YC489 diesel engine is big,which makes both driver and passengers annoyed.In order to improve the noise radiation and sound quality of the engine,this paper explores noise radiation and sound quality of YC489 diesel engine from the perspective of noise source.On the mechanical noise of the engine radiation,this paper studies the effect of the grinded gear with displacement and piston pin of eccentricity on the engine.As to the combustion noise,this paper studies the influence of different injection proposals on the engine.Carried out in test bench of a semi-anechoic chamber,this research tests the noise of YC489 diesel engine by adapting noise test equipment,Bosch electronically controlled high pressure common rail system and the corresponding test equipment.Then the sound pressure level and sound quality of the engine are analyzed and evaluated through engineering 9 point method.Study shows that using either modified gear or grinded gear can reduce the noise radiation;both grinded gear and modified gear can reduce the noise to 2.8 dB(A)in the idle speed condition;furthermore,the noise has been improved within different loads of full speed conditions.Meanwhile,the sound quality of both grinded gear and modified gear has been improved.After comparing the testing results of the piston of eccentricity,it is concluded that noise radiation of 0.3 mm piston pin of eccentricity is minimum under idle conditions and the full load of whole speed range.Besides,tests on different pre-spray parameters show that different pre-spray angles and fuel injection quantities,and twice pre-sprayes hold relatively small effect on the engine noise.Therefore,under the satisfied condition of engine emission,either pre-spray parameter could be chosen.