共查询到19条相似文献,搜索用时 125 毫秒
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以168 F小型汽油机为例,用试验和模拟计算的方法研究了无平衡轴、用曲轴平衡块平衡往复惯性力的通用小型汽油机的振动特性。结果表明:低怠速时汽油机的振动主要受缸内燃烧循环波动的影响;高速时与整机平衡性和气缸布置等结构设计有关,转速愈高,整机当量振动烈度愈大。用 Adams软件模拟计算气缸斜置角不同时小型汽油机的振动特性,结果表明:气缸斜置45°时高速工况振动最小;卧式或立式气缸布置时高速工况振动都较大;气缸45°斜置结构较气缸卧式布置,整机当量振动烈度低41.9%,气缸斜置45°较原机25°斜置结构的整机当量振动烈度也可减少29.5%。气缸斜置角度不同,汽油机激振力在各个方向分力也不同,气缸斜置45°时激振力分布最合理,汽油机振动最小。 相似文献
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排气系统悬挂引发汽车NVH问题研究 总被引:1,自引:1,他引:0
排气系统的振动主要是通过排气系统的悬挂传递到车身,悬挂点的合理布置可以有效降低由排气系统引起的整车振动和噪声,提高整车舒适性.本文主要论述了排气系统悬挂影响整车NVH的原因,通过论证分析、试验验证,提供解决方法. 相似文献
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文章采用ABAQUS和HyperMesh软件,对某商用车皮卡排气系统进行了CAE自由模态、约束模态和强度分析,多方面校核了排气系统力学性能,结果显示排气系统避开了发动机怠速共振频率,排气系统支架最大应力小于材料屈服强度,满足设计目标。 相似文献
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为改进某乘用车排气系统的振动性能,建立了其有限元模型,用Nastran软件进行静力学和动力学计算、吊耳位置评估和排气系统的运动包络面计算。以最小化挂钩垂向动态载荷最大值与标准差和吊耳的静变形量与预载力标准差为目标,以吊耳隔振量不小于20dB为约束条件,以吊耳和波纹管动刚度为优化变量,建立了排气系统振动性能的多目标优化模型。优化结果表明,挂钩垂向动态载荷最大值与标准差和吊耳的静态变形量与预载力标准差都有明显降低,文中提出的优化方法对控制排气系统振动和提升结构疲劳耐久性有重要的参考价值。 相似文献
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J. -G. Ih C. -Y. Choi T. -K. Kim S. -H. Jang H. -J. Kim 《International Journal of Automotive Technology》2011,12(4):617-630
At the idle engine speed, the exhaust discharge noise is influenced by resonances in the whole system, which is composed of
connecting pipes and silencers. This pipe resonance radiates a high level of low frequency discharge noise, which is dominated
by the low order harmonics of the engine firing frequency. This low frequency noise deteriorates the vehicle’s interior noise
level and quality. The following study attempted to optimize the layout of an exhaust system to minimize low frequency noise
by changing the position of silencers and the lengths of inlet and outlet pipes in each silencer. After modeling the exhaust
system using four-pole parameters, the acoustical performance of the system was evaluated using the system insertion loss.
In the optimization, the virtual attenuation coefficient, which corresponds to the amount of attenuation coefficient required
for the silencers, was calculated to find a minimum value for the layout. The simulated annealing method, which is also known
as finding an optimal, was employed in searching for the optimized exhaust layout. Test examples of two cases, for two and
six design variables, were used. When the number of design variables was two, the positions of the center and rear silencers
were considered. When the number of design variables was six, the positions of the two silencers and the lengths of the inlet
and outlet pipes were considered. Three typical layouts for the exhaust system of each case were designed, including the given
system and an optimal system. By comparing the predicted and measured discharge noise level, it was confirmed that the optimized
exhaust layout has a higher noise reduction than the other layout designs. 相似文献
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车用柴油机排气微粒分流式稀释取样测量系统的研制 总被引:10,自引:1,他引:10
本文设计了一种测量车用柴油机排气微粒的分流式稀释取样系统并制出了实验样品。文中说明了系统的布置和主要参数。重点是用CO2示踪法标定了不同发动机工部下的稀释比。用该系统测量一台车用柴油机的排气微粒结果表明该系统效果好,很实用。 相似文献
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强噪声背景下的柴油机失火故障诊断 总被引:1,自引:0,他引:1
柴油机失火是常见的故障模式,传统的诊断方法不仅参数获取困难且准确性差。针对此问题,以3缸四冲程柴油机为研究对象,设计了柴油机失火故障的预置试验,采集排气噪声和缸盖振动信号进行故障诊断研究。为提取强噪声背景下的微弱信号,采用二次采样随机共振系统提取柴油机故障特征频率完成柴油机的失火故障诊断。研究结果表明,通过二次采样处理,随机共振系统可以将噪声能量转移到柴油机微弱特征信号上,达到大参数条件下微弱信号特征提取的目的,能有效识别柴油机的早期故障,对其他复杂机械的振动诊断同样具有参考价值。 相似文献
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