In order to solve the problem that the background noise of diesel engine vibration signals interferes with operating condition monitoring and fault diagnosis

a vibration signal denoising method based on variational mode decomposition(VMD) and detrended fluctuation analysis(DFA) was proposed. The variational mode decomposition was used to decompose the vibration signal into several components

and then the detrended fluctuation analysis was used to calculate the scale index of each component to select the components with a long-range correlation for signal reconstruction

thus eliminating the noise in the vibration signals. The proposed method was applied to the simulation signals and diesel engine fault vibration signals

and a good denosing effect was obtained.