CAJ | 학술논문

运用噪声分离、频谱分析等技术手段，找出了GZ6921型后置柴油机大客车噪声超过国家标准的原因，并对主要噪声源及其频谱分布进行了分析.对各主要噪声源--排气系统、冷却系统和发动机舱采取相应的降噪措施，如降低风扇转速，改善抗性消声器的降噪能力，修改冷却风进风道，平衡车两侧的噪声源，在发动机舱中粘贴吸音材料等.改进后GZ6921型大客车最大加速度时的车外噪声由91.5dB(A)降到86dB(A)以下，达到国标GB1495-75"机动车允许噪声"的规定.
운용조성분리、빈보분석등기술수단，조출료GZ6921형후치시유궤대객차조성초과국가표준적원인，병대주요조성원급기빈보분포진행료분석.대각주요조성원--배기계통、냉각계통화발동궤창채취상응적강조조시，여강저풍선전속，개선항성소성기적강조능력，수개냉각풍진풍도，평형차량측적조성원，재발동궤창중점첩흡음재료등.개진후GZ6921형대객차최대가속도시적차외조성유91.5dB(A)강도86dB(A)이하，체도국표GB1495-75"궤동차윤허조성"적규정.
In this Paper,noise separation and frequency spectrum analyzingtechniques are used to find out why the noise level of the bus of GZ6921 model with rear-placed diesel engine layout exceeds the limit set by the national standard,the nain noise sources and their frequency spectrum distribution are thus identified.Noise reduction measures which are aimed at the main noise sources such as the exhaust system,the cooling air-intake system and the engine cabin are applied,including slowing down the fan's rotation speed,enhancing noise reduction ability of the acoustic-reactive type muffler,modifying the shape of cooling air-intake path,balancing noise in both sides of the bus and adopting sound-absorber in the engine cabin.After these treatments,outside noise level of the bus with maximum acceleration declines from 91.5 dB(A) to lower than 86 dB(A),which meets the "permitted Noise Level of Motor Vehicle"defined by the “GB 1495-79”national standard.