180 / 2021-03-31 19:02:58

Simulation on Relation between Excitations and Structure-borne Noise of a Diesel Engine

internal combustion engine,noise and vibration,transfer function,finite-element method,transfer path

In this study a numerical simulation method was used to investigate the mechanism of vibration through the structure and the characteristics of the structure-borne noise of a turbocharged diesel engine. A finite element model was built and frequency response was analyzed. The modal test was conducted to calibrate the FE model. The transmission path experiment was carried out on a non-running engine block assembly, where the transfer functions between velocities and exciting forces were measured and used to be compared with simulation results. Five transmission paths through which the piston slap and combustion excitations transfer were analyzed to investigate the vibration and structure borne noise of the engine. The results illustrate that the structure vibration response of the engine is considerably influenced by the structural modal characteristics. The vibration and structure borne noise response via the paths of piston at TS and ATS are similar with small difference at high frequency band. The transmission path from the piston and head transfer most of the combustion energy in the analyzed frequency range considered, with relatively little contribution via the path from the liner. The contribution factor on the total noise of each component show that the thin wall components, including oil pan, fuel pump cover, head cover, and belt cover, is the main sources of engine structure borne noise.