共查询到19条相似文献,搜索用时 171 毫秒
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柴油机缸套磨损故障的机体振动监测研究 总被引:3,自引:0,他引:3
研究了柴油机缸套磨损故障的机体振动监测,包括缸套破坏性磨损故障时的机体振动。首先分析了活塞对气缸套的冲击,建立了活塞撞击气缸套侧推力的数学模型,探讨侧推力的大小及作用时间。分析表明,柴油机活塞撞击是机体表面振动的主要激励源。通过模拟试验得知,缸套磨损状态有4种,当缸套间隙正常或中等磨损时,机体振动的增长速度较慢;严重磨损时,振动特征参数值明显增大;如果缸套处于破坏性磨损程度时还继续工作,机体振动则呈指数式增长。这说明机体表面振动特征值的改变可以反映缸套间隙的变化,因此,基于柴油机机体振动对缸套的磨损进行监测是可行的、有效的。 相似文献
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通过对不同磨损程度的柴油机缸套进行实验 ,采集柴油机机身的振动信号。计算柴油机机身振动信号的小波包能量、最大幅值、奇异性指标 ,并建立了振动信号的 AR和 ARMA模型 ,最后利用遗传算法进行自动再生最佳特征参数 ,得到了优化的缸套磨损故障判别函数 ,结果表明利用该判别函数可以简洁有效地计算出缸套磨损等级 ,从而对缸套进行故障诊断。 相似文献
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本文介绍利用柴油机表面振动信号不解体诊断活塞-气缸套磨损、气阀漏气和主轴承磨损状态的研究,通过实测柴油机的表面振动信号和分析与计算,提取了振动信号的特征参数。研究表明:可以用表面振动信号诊断活塞-气缸套磨损、气阀漏气及主轴承磨损等主要运动部件的机械状态。 相似文献
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王义亮 《机械工程与自动化》2009,(4):1-4
应用有限元方法对某四缸内燃机机体在缸内气体压力、活塞侧推力、活塞摩擦力以及主轴承力作用下的结构动力响应进行了分析,在此基础上,重点对各缸套结构振动的位移响应做了深入研究,并就缸套结构振动对各缸套-活塞系统摩擦学行为的影响做了探讨.研究结果表明:各缸套除了低频整体振动以外,还都包含有比较明显的高频局部振动;缸套结构振动的高频成分将对缸套与活塞之间的摩擦学行为产生影响,使得各缸缸套-活塞系统的摩擦学行为具有时变性,且不同缸缸套-活塞系统的摩擦学行为表现出差异. 相似文献
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分析了柴油发动机活塞销振动信号的高阶循环平稳性,提出了一种基于高阶循环平稳理论提取柴油发动机活塞销磨损故障特征的新方法。利用循环双谱分析活塞销振动信号,考察了振动信号循环双谱图中频率成分的分布情况。定义循环双谱图中幅值的平均累加值与发动机活塞销磨损间隙变化相对应的区域为特征频率平面,提出一种全局搜索策略以搜索特征频率平面。仿真结果及试验结果表明了循环双谱的有效性。利用所述方法在实际活塞销振动信号的循环双谱图中提取的5个特征频率平面内幅值的平均累加值可以作为活塞销磨损故障诊断的特征值。 相似文献
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为研究多缸柴油机实车使用中各缸磨损分布状况,建立某12150型多缸柴油机缸套-活塞环磨损仿真计算模型,并进行验证。通过联合仿真计算得出:多缸柴油机各缸的缸套-活塞环磨损热力学参数(燃烧温度、燃烧压力、缸套壁温和冷却水温)和动力学参数(油膜厚度、微凸体载荷)差异显著,造成各缸套表面磨损不均匀,其中1缸磨损最为剧烈,最大磨损深度位于曲轴转角9°所对应位置,额定工况点工作400 h后磨损深度为51.22μm,其次为第5、4、3、2缸,6缸磨损最轻,其轴向最大磨损深度为39.37μm,相比1缸下降了23.14%。主要是由于1缸进气最晚且存在冷却死区,使得缸内燃烧状况最差,缸套壁面温度高、硬度低,润滑油膜薄,导致摩擦副微凸体载荷大,磨损深度最大;而6缸进气最早且冷却状况最好,综合作用使得该缸套磨损深度相对最小。因此,可确定1缸缸套上止点9°主、侧推力面磨损深度作为12150型柴油机缸内技术状况检测及磨损量计算的依据。 相似文献
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Jang Kyu Kim Min Cheol Lee 《International Journal of Precision Engineering and Manufacturing》2009,10(3):51-58
Damage that originates from abnormal wear in the cylinder liner of marine diesel engines causes a considerable loss of property
to manage shipping vessels. However, because multiple factors contribute to such damage, it is difficult to anticipate the
damage that is caused by abnormal wear, such as scuffing, by investigating the mechanism of abnormal wear. Therefore, several
methods have been explored for predicting the abnormal wear between the cylinder liner and the piston ring in marine diesel
engines. For example, methods that are based on an analysis of the temperature, vibration, or cylinder drain oil have been
researched. However, the response time of such methods is too slow for an operator to have enough time to promptly cope with
severe damage. The implementation of such methods also requires prior modifications to the engine, which cost time and money.
To overcome such problems, methods of prediction that use AE (acoustic emission) have been widely investigated. Studies on
the relationship between abnormal wear and AE signals have demonstrated that severe damage is preceded by a change in the
RMS value of AE and the FFT amplitude of a specific frequency. However, previous studies on the AE technique were based on
the offline analysis of stored data due to their focus on the relationship between abnormal wear and AE signals. Thus, for
direct implementation of the AE technique in industry, a real-time diagnostic system is needed. This paper focuses on the
development of a real-time diagnostic system for analyzing high speed AE signals and examining the wear status of cylinder
liners in marine diesel engines. 相似文献
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Duan Li-xiang Zhang Lai-bin Wang Zhao-hui 《Frontiers of Mechanical Engineering in China》2006,1(4):443-447
The vibration signals of diesel include excess noise that must be eliminated before extraction of characteristic parameters.
Firstly, the effects of vibration-signal de-noising among Fourier transform, wavelet decomposition and wavelet packet decomposition
are compared. Secondly, singular value decomposition is applied to de-noising vibration signals. Finally, a new de-noise method
integrated with wavelet packet and singular value is presented. In this method, vibration signals are decomposed by wavelet
packet, and the wavelet packet coefficient is de-noised by singular value decomposition again. The results indicate that the
new de-noising method is the best. The SNR (signal-to-noise ratio) of the vibration signals of a diesel cylinder lid is the
highest. The diesel vibration waveforms of combustion and valve become clear and the extracted characteristic parameters become
more precise.
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Translated from Journal of China University of Petroleum (Natural Science Edition), 2006, 30(1) (in Chinese) 相似文献
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Friction and wear tests of a piston ring against the cylinder of a marine diesel engine were conducted on a pin-on-disc tester. The vibration signals under different wear conditions were studied utilizing the discrete harmonic wavelet packet transform (DHWPT). It was shown that the weak friction-induced vibration signals could be extracted using the DHWPT. When the wear behavior is mild, the friction-induced vibration is linear. When the wear behavior is relatively severe, the friction-induced vibration changes from linear to nonlinear. When the wear behavior is more severe, the friction-induced vibration is nonlinear. 相似文献
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为提取摩擦振动的特征和实现摩擦副摩擦状态的识别,在往复摩擦磨损试验机进行摩擦副混合摩擦和干摩擦状态的摩擦磨损试验。应用谱减法对试验采集的摩擦振动信号进行降噪,计算降噪后的摩擦振动15个特征参数。应用自组织映射(Self-organizing map, SOM)神经网络对摩擦副不同摩擦状态的摩擦振动特征参数进行分析,得到摩擦振动的SOM神经网络神经元分类。研究结果表明,谱减法能消除摩擦磨损试验机的背景噪声,SOM神经网络算法能够有效分析摩擦振动信号的特征,实现摩擦副摩擦状态的识别。 相似文献
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内燃机气阀漏气故障的高阶谱分析 总被引:2,自引:0,他引:2
将高阶谱理论引入内燃机的振动诊断中,分析了不同状态时缸盖表面振动信号的三阶谱特性,并计算出三阶谱的峰值,用于刻划各状态时缸盖系统的非线性行为。结果表明:正常状态时缸盖表面振动信号的三阶谱接近为零,可以认为缸盖系统是线性系统;当气阀发生漏气故障时,缸盖表面振动信号的三阶谱就会出现较大的峰值,而且不同状态时所对应的峰值也存在着较大差别,说明不同气阀漏气状态时缸盖系统表现出不同程度的非线性。可以将三阶谱的峰值作为判断气阀是否漏气的一个诊断特征量,同时也为诊断内燃机气阀的早期漏气故障提供了依据。 相似文献
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为分析碳纤维增强树脂基复合材料(CFRP)/钛合金(TC4)叠层材料低频振动制孔工艺下刀具磨损状态,开展基于切削力信号的制孔刀具磨损状态研究.通过采集CFRP/TC4叠层材料低频振动制孔过程中的切削力信号,进行时域和频域分析,探讨各信号特征量与刀具磨损状态之间的联系.研究结果表明:CFRP/TC4叠层材料低频振动制孔轴... 相似文献