3d-Elastohydrodynamic Simulation Model for Structure-Borne Noise Analyses of a DI Diesel Engine 2016-01-1854
The present article is concerned with the investigation of the engine noise induced by the piston slap of an actual passenger car Diesel engine. The focus is put on the coherence of piston secondary movement, impact of the piston on the cylinder liner, generated structure-borne noise excitation of the engine structure and the occurring acceleration on the engine surface. Additionally, the influence of a varying piston-pin offset and piston clearance is evaluated.
The analyses are conducted using an elastohydrodynamic multi-body simulation model, taking into account geometry, stiffness and mass information of the single components as well as considering elastic and hydrodynamic behavior of the piston-liner contact. A detailed description of the simulation model will be introduced in the article.
The obtained results illustrate the piston secondary motion and the related structure-borne noise on the engine surface for several piston-pin offsets and piston clearances. Detailed analyses of force and displacement in the transversal engine axis as well as the angular displacement of the piston and its derivatives are shown. Further on, the correlation between piston secondary movement and the occurring acceleration on the outer crankcase surface is investigated. Finally, several combinations of piston-pin offset and piston clearance are compared with respect to their NVH and friction behavior.