A GENERIC SIMULATION MODEL FOR CYLINDER KIT VIBRO-ACOUSTICS PART Ⅱ: PISTON SLAP AND ENGINE STRUCTURE INTERACTION

摘要

In specific speed and load ranges mechanical noise excitation contributes significantly to the overall noise of an internal combustion (IC) engine. Piston slap induced noise is a very important mechanical noise source. As the second part of two sequential papers, this contribution describes the numerical simulation of the structure noise of an entire IC engine. The findings for the cylinder kit models in part I are considered specifically. The mathematical model for an elasto-hydrodynamic contact of piston skirt and liner wall in a mixed lubrication regime is applied to a fully coupled simulation of the entire engine block vibration. The contribution of piston slap excitation is evaluated against other sources of excitation, like crankshaft dynamics and combustion gas pressure. Measurements of the engine block surface accelerations are performed in fired conditions and are compared to the results obtained by the simulation. It is shown how noise sources in the piston cylinder kit are transferred to the engine block surface structure. The paper demonstrates the reliability of a comprehensive model for engine noise simulation in the development process for future engine designs.