Engine Noise Prediction by Using Multi-body Simulation

This paper presents a coupled multi-body and FEM (finite element method)-BEM (boundary element method) methodology used to carry out a comprehensive NVH (noise, vibration and harshness) investigation of a four-cylinder internal combustion engine prototype. Firstly, a MBDS (multi-body dynamic simulation) of the internal combustion engine has been carried out, at a defined operating condition, in order to determine the excitation force of the powertrain exciting the cylinder block. In this way, the dynamics of the engine powertrain have been described taking into account both the effects of the gas forces of the combustion process and the inertia forces of the moving parts. Afterwards, the cylinder block excitation forces have been used to evaluate the engine block vibrations and to predict the external noise radiated with both the well-known ATV (acoustic transfer vectors) and MATV (modal acoustic transfer vectors) methodologies at a distance of 1 m from the engine, according to the standard ISO 3744. The dynamics of the engine powertrain and its vibro-acoustic behaviour have been described using LMS (learning management system) Engineering Innovation Virtual.Lab tools.