Analysis of structural dynamic response of multi-cylinder internal combustion engine block under the excitation of piston thrust forces

摘要

The structural dynamic response of a certain multi-cylinder internal combustion engine block is analyzed applying the finite element method, where the effects of piston secondary motion and the lubricant film are fully considered. Firstly, the three dimensional model of a 4-cylinder diesel engine block is established with the pro/Engineer software, and then the dynamic response analysis of the engine block is carried out using the ANSYS software. The influences of the piston secondary motion and the lubricant film have been taken into account while computing the piston thrust forces acting on the cylinder liners. Thus some more accurate and more creditable results are provided here. Through the analysis, the structural dynamic characteristics of the engine block, crankcase skirl and various positions on every cylinder liner are revealed. Besides, the impacts of the liner vibration on the lubricating behavior in cylinder liner-piston assembly pairs as well as the noise radiation caused by the pislon thrust forces are also discussed. Based on the results from the analysis, practical guidelines arc provided for engine design in order to reduce engine block vibration, suppress noise, improve lubrication condition and efficiency etc.