大缸径柴油机增压器BPF噪声控制研究

Study on BPF Noise Control of Diesel Engine Turbochargers with Large-diameter Cylinders

为降低大缸径柴油机增压器BPF噪声,通过试验验证增压器增加消声环、进气空滤包裹吸声棉对BPF噪声的控制效果,结果表明:增压器增加消声环可以有效降低中高负荷工况下的BPF噪声,消声环轴向安装间隙对降噪效果有一定影响,当安装间隙小于流量拓宽槽间隙时,尽管降噪效果最好,但会对降低柴油机进气流量,增加喘振风险,当安装间隙大于流量拓宽槽间隙时,降噪效果并不理想,当两者间隙一致时,既能保证柴油机进气正常,也能有较好的降噪效果;在不影响柴油机进气的前提下,进气空滤包裹吸声棉后,所有工况下的柴油机噪声均有不同程度的降低,主要降低增压器BPF及倍频噪声,对中低频的进气噪声和结构辐射噪声也有一定的衰减作用。研究结果可为大缸径柴油机降噪设计提供参考。

Reduction of the BPF noise produced by diesel turbochargers with large-diameter cylinders is studied.The effect of adding muffler rings and wrapping the intake air filter with sound-absorbing cotton on BPF noise control is verified by experiments.The results show that,adding muffler ring to the supercharger can effectively reduce BPF noise under medium and high load conditions.In addition,different axial installation clearance of muffler ring results in different noise reduction effects:when the installation clearance is smaller than the flow widening slot clearance,the air intake of diesel engine will be reduced and the risk of surge will be increased although the noise reduction effect is the best;when the clearance is larger than the flow widening slot clearance,the noise reduction effect is not ideal;when both clearances are equal,the muffler ring can not only ensure the normal air intake,but also have a good noise reduction effect.Besides,on the premise of not affecting the air intake of diesel engine,the noise under all working conditions can be reduced by wrapping the intake air filter with sound-absorbing cotton,which mainly reduces the BPF noise,and has a certain attenuation effect on the intake noise and structural radiation noise of middle and low frequency.The results of this paper provide a reference for noise reduction design of diesel engines with large-diameter cylinders.