Optimization Of Vibration Of Oil Sump Of Non-road Diesel Engine

The non-road diesel engine has a severe challenge to its reliability,durability and comfort,because of its changing working conditions,heavy workload and long running time.In the third stage of the non-road diesel engine emission,the power strengthen increases the structural vibration and noise radiation.The main component of the general diesel engine is the shell part with the largest proportion of noise radiation,and the oil pan is about 25%.The research on the vibration and noise reduction technology of the valve chamber cover is very important to reduce the vibration and noise pollution and improve the reliability of the whole machine.The oil pan was used as the research object,the finite element method and multi-body dynamics based on structural shape optimization using Optistruct software,studied several effect of stiffeners structure layout scheme of the vibration and noise of the key point,through frequency analysis,fulid-solid coupling modal analysis and multi-body dynamics.Put forward the technical measures of reducing noise and vibration,noise and vibration has guiding significance for non road diesel engine.(1)Modal analysis and testing of the main components of the engineThe structural modal is the key basis for the analysis of the oil pan,the key basis for the calculation of the results of the multi-body dynamics,research the modal regular pattern of the main components of the engine by using the finite element analysis and the test method.The results show that the relative error of the test and calculation modes of the two parts of the body and the crankshaft is within 5%,the first-order deviation of the cylinder head cover is 6.11%,and the other steps modal are within 5%.The oil pan are typical of thin-walled welds.In the first six modes,the maximum deviation of the first and fourth order modes and the finite element analysis is less than 10%,modal shape have a good consistency.(2)Optimization of oil pan and analysis the modal influence factorsThe relationship between the stiffeners and the stiffness of the oil pan was studied by the method of topography optimization.Under the same number of stiffeners,the height of the ribs increased by 1mm and the first order modal of the structure increased by 35.4HZ.At the same stiffness requirements and under the height of the ribs,the groove is 50%less than the arc-shaped stiffeners,and the processing technology is better.The structual mode is analyzed by fluid-solid coupling method.The results show that the first-order mode of the bottom structure of the oil pan is reduced by at least 32.77HZ under the coupling of the oil,and the effect on the high-order mode is small,and the first-order mode frequency decreases with the increase of the oil volume.(3)Analysis of vibration noise and dynamic stress of oil pan under the coupling of whole machineFirstly,the distribution law of the engine air distribution mechanism,the piston side impact force and the main bearing are analyzed,and then the vibration noise and the dynamic stress analysis under the whole machine coupling excitation are carried out.The results show that the maximum speed of the key nodes on the surface of the oil sands is reduced by 6.9dB.After optimization,the structural modal increases,the dynamic stress increases at the critical point,the maximum stress decreases and the average stress decreases.After the maximum torque working condition 500HZ center frequency,the engine side pressure side of the sound pressure level of the largest reduction of 6.14dB.