基于瞬时转速信号的柴油机角域转换方法

An angle-domain conversion method based on the instantaneous rotational speed signal of a diesel engine

针对往复机械故障分析诊断中通过平均转速等间隔划分角度的方法诊断效果不精确的问题,提出了一种利用瞬时转速对柴油机时域信号进行角域转换的方法。分析了转速波动较大工况下平均转速等角度划分方法中影响相位偏差产生的主要因素,根据转速波动量的大小以及预期的角域精度范围设定阈值参数,再通过该阈值实现角域转换方法的自动选择。研究结果表明,在转速波动工况下采用瞬时转速对时域信号进行角域转换能够有效避免相位偏差,为基于角域的柴油机故障诊断奠定基础。

In the fault diagnosis of reciprocating machinery,the traditional fault diagnosis method involving dividing the angle into equal intervals using the average rotational speed is inaccurate. A method of using the instantaneous rotational speed to transform the time-domain signal of a diesel engine into the angle-domain has been developed in this work. The main factors influencing the phase deviation in the method of the angular division of the average rotational speed under the condition of large rotational speed fluctuation are discussed,and the threshold parameter set according to the magnitude of the speed fluctuation rate and the expected angle-domain accuracy range. It is possible to automatically determine which method should be selected to perform the angle-domain conversion based on the threshold parameter. The results showed that phase deviation can be avoided by using the instantaneous rotation speed to transform the time-domain signal into the angle-domain under the conditions of speed fluctuation,which provides a basis for the fault diagnosis of diesel engines based on the angle-domain.