基于瞬时转速的船用多缸柴油机故障诊断技术研究

发布时间：2018-10-17 08:50

【摘要】：瞬时转速信号中包含着丰富的能够反映柴油机气缸做功能力的信息。所以基于瞬时转速的柴油机故障诊断技术在国内外都进行了大量的研究，而其测量方便且简单实用的优点使得该技术在诊断柴油机气缸运行状态的应用上得到了极高的重视。但是目前对于瞬时转速的应用多集中在点火间隔角较大的直列柴油机，对于点火间隔角较小的16缸V型柴油机应用效果较差。这是因为反映在瞬时转速信号上的每个特征都可能是多个气缸耦合的作用，这就为故障的定位和识别增加了难度。而本文以此为出发点，对瞬时转速在16缸V型柴油机上的应用就行探索性研究。首先，本文研究了瞬时转速的测量方法，，构建了瞬时转速测量系统。通过分析实测飞轮端原始信号的特点，采用数字滤波的方法对信号进行预处理。并应用零点法和解调法两种计算原理完全不同的方法来相互辅证瞬时转速波形计算的准确性。其次，利用上文求得的瞬时转速波形，提取几种目前常用的特征参数，对柴油机气缸运行状态进行评价，对比分析评价结果简述其在16缸V型柴油机上应用效果不好的原因，并基于以上分析提出能够更好地反映气缸运行状态的特征参数：瞬时转速峰值、谷值的趋势变化以及经去均值处理的瞬时角速度与瞬时角加速度，同时指出这些特征参数的应用条件。最后，在能够准确定位故障缸的前提下应用统计分析的方法确定能够更为精确表征故障严重程度的特征参数，并结合以上分析建立诊断模型，通过实测数据验证模型的准确性
[Abstract]:The instantaneous speed signal contains abundant information which can reflect the work ability of diesel engine cylinder. Therefore, diesel engine fault diagnosis technology based on instantaneous speed has been studied extensively at home and abroad, and its advantages of convenient and practical measurement make the application of this technology in the diagnosis of diesel engine cylinder running state to be highly valued. But at present, most of the applications of instantaneous speed are focused on the in-line diesel engine with larger ignition interval angle, but the application effect is poor for 16-cylinder V-type diesel engine with small ignition interval angle. This is because each feature reflected in the instantaneous speed signal may be coupled with multiple cylinders, which makes it more difficult to locate and identify faults. In this paper, the application of instantaneous speed in 16 cylinder V diesel engine is studied. Firstly, the measurement method of instantaneous speed is studied, and the system of measuring instantaneous speed is constructed. By analyzing the characteristics of the original signal at the end of the flywheel, the digital filter is used to preprocess the signal. The zero point method and demodulation method are used to verify the accuracy of instantaneous speed waveform calculation. Secondly, by using the instantaneous speed waveform obtained above, several commonly used characteristic parameters are extracted to evaluate the operating state of diesel engine cylinder. The results of comparative analysis and evaluation describe the reasons for its poor application in 16-cylinder V-type diesel engine. Based on the above analysis, the characteristic parameters which can better reflect the running state of the cylinder are proposed, such as the peak speed of instantaneous speed, the trend change of valley value, and the instantaneous angular velocity and angular acceleration treated by de-mean value. At the same time, the application conditions of these characteristic parameters are pointed out. Finally, under the premise of locating the fault cylinder accurately, the statistical analysis method is applied to determine the characteristic parameters which can more accurately characterize the severity of the fault. Combined with the above analysis, the diagnostic model is established, and the accuracy of the model is verified by the measured data.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U664.121;U672.74

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