The influence laws of block vibration signal based on wavelet packet decomposition
DONG Yiming
HU Yuping
TIAN Xiaoqing
LI Meng
JI Shaobo
Abstract：To investigate the spectral characteristics of the vibration signals of a diesel engine block,the experimental method and signal analysis technology are used.By changing the operating state parameters such as diesel engine speed,torque and oil temperature and the cylinder clearance,the combustion pressure in the cylinder and the vibration acceleration signal of the body are measured.The vibration acceleration signals are decomposed into 16 frequency bands using wavelet packet decomposition(WPD),and the energy distribution of each band is compared with the cylinder pressure signals.The study identifies the variation patterns of wavelet packet energy distribution under different influencing factors and determines the frequency bands sensitive to combustion state and piston slap.The results indicate that:As engine speed increases,the reciprocating inertia force of the piston rises.When the speed increases from 1 000 r/min to 1 600 r/min,the energy of frequency band 16 increases by 3.55 times.With increasing torque,the energy of all frequency bands shows an upward trend.As oil temperature rises,most frequency bands exhibit no significant energy variation,but bands 15 and 16 still demonstrate an increasing trend.With larger piston-to-cylinder clearance,the energy of bands 6,7,8,10,15,and 16 increases significantly.
Keywords：engine block vibration signalwavelet packet decompositionoperating conditionpiston-liner clearance
Publication Date：2025-09-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：7( 32-37,45 )