摘要
表面辐射噪声是除空气动力性噪声外柴油机的主要噪声源.采用近场声压法和表面振速法进行试验,以识别柴油机的主要辐射噪声源,探讨了不同工况下,各辐射噪声源对总噪声的贡献率.研究了两种不同组合吸声材料对柴油机辐射噪声的影响规律,探讨了正时齿形带罩盖和机体的结构改进的降噪效果.结果表明,喷油栗、油底壳和正时齿形带罩盖为柴油机的主要辐射噪声源,对整机噪声的贡献率达70%左右;随着柴油机转速的降低,材料的吸声性能下降,海绵在里层时对辐射噪声的控制效果较好,吸声材料主要吸收31.5-100Hz的低频段噪声的声能量;正时齿形带罩盖和机体结构改进,降低了中、高频率段的噪声声压级和近场噪声;综合运用降噪措施,可使柴油机整机辐射噪声,在标定工况、最大转矩工况和怠速工况下分别降低1.2,1.4和1.3dB（A）.
Surface radiation noise is the main noise source of diesel engine,besides aerodynamic noise. In this paper,tests are conducted with near-field sound pressure method and surface vibration velocity method,to identify the main radiation noise sources of diesel engine. Th e contribution rates of each noise source to overall noise in the different conditions are investigated. T he influences of two different combinations of sound-absorbing materials on the radiation noise of diesel engine are studied and the noise reduction effects of the structural modification of toothed timing belt cover and cylinder block are explored. The results show that the fuel injection pump,oil pan and toothed timing belt cover are the main radiation noise sources of diesel engine,with the sum of contribution rates of their noises to the overall noise of engine reaching about 70%. With the lowering of engine speed,the sound absorbing performance of materials declines,the material with sponge in its inner layer has better control effects of radiation noise,and the sound absorbing material mainly absorbs the sound energy of noises at a low-frequency band of 31.5 ？100Hz . The structural modification of toothed timing belt cover and cylinder block lower the sound pressure level of noises at medium and high frequency bands and near-field noises. Concurrently adopting various noise reduction measures can lower the total radiation noise of diesel engine by 1.2, 1.4 and 1.3d B （ A ） in rated condi-tion, maximum torque condition and idling condition respectively.
出处
《汽车工程》
EI
CSCD
北大核心
2016年第9期1114-1119,共6页
Automotive Engineering
基金
国家自然科学基金(51376083)
江苏省高校自然科学基金(10KJA470009和13KJA470001)
江苏省2013年度普通高校研究生科研创新计划项目(CXZZ13-0672)
江苏省2014年度普通高校研究生科研创新计划项目(KYLX-10635)
2011年江苏高校优势学科建设工程项目(PAPD)资助
关键词
柴油机
辐射噪声
噪声源识别
降噪效果
diesel engine
radiation noise
noise source identification
noise reduction effects
