Main aims in the development process for the cylinder assembly of internal combustion engines are the reduction of friction and wear due to the contact between piston and liner as well as the minimization of piston slap induced noise.
In this paper, the authors extend their methodology for the simulation of structural dynamics in the area of piston and liner with the aim of predicting structure borne noise excited by the piston slap phenomenon. The simulation model uses linear, flexible bodies subjected to highly non-linear joint forces, as occurring in the piston-to-liner contact. Both, the theoretical background and the advantages of the coupled simulation procedure for such complex systems are discussed. The models are validated by comparison of measured and computed values of piston movements and modal structure behavior.
The result examples focus on the effects of piston secondary movement, the resulting impact on the lubricated liner and the analysis of vibration transfer behavior in the block structure. It is shown how noise excitation and structure borne vibration transfer paths can be analyzed in order to assess engine design. Result plots show typical results on the surface of a 4 Cylinder Diesel engine and the contribution of piston slap induced noise.