基于空运行辨识柴油机模态参数的激励方法

Excitation Method for Identifying Modal Parameters of Diesel Engine Based on Dry Running

提出一种基于空运行辨识柴油机模态参数的新方法。针对其激励规律进行分析,通过提高柴油机的转速,一定空间的燃烧室产生的气体冲击序列密度越大、气体敲击的时间越短,获得的激励源越大、频带越宽。进行空运行自激励试验,并与传统的敲击试验辨识结果进行对比。两种状态的辨识结果很相近,固有频率辨识结果最大的偏差为1.9 Hz,这种偏差可能是由于敲击试验在柴油机静止状态下进行,而空运行自激励试验在柴油机工作状态下进行。通过试验验证基于空运行自激励辨识柴油机模态参数的准确性。

A new method identifying the modal parameters of diesel engine based on the dry running is proposed.According to the analysis of its excitation law,by increasing the rotating speed of diesel engine,the larger the gas impact sequence density and the shorter the gas percussion time generated by the combustion chamber with a certain space,the larger the obtained excitation source and the wider the frequency band.The dry running self-excitation test is conducted,and its results are compared with the identification results of traditional percussion test.The identification results of two states are very similar,and the maximum deviation in natural frequency identification results is 1.9 Hz.The deviation may be due to the fact that the percussion test is conducted in the static state of diesel engine,while the dry running self-excitation test is conducted in the operational state of diesel engine.The accuracy identifying the modal parameters of diesel engine based on the dry running self-excitation is verified by the test.