A holistic approach for the vibration and acoustic analysis of combustion engines including hydrodynamic interactions

In the paper at hand, a holistic virtual engineering approach for the acoustic analysis of combustion engines is presented, which uses an elastic multi-body simulation to calculate the excitation forces of the engine during the combustion process. These forces are caused by the piston motion and affect the main bearings and the cylinder walls. Due to the fact that both the crankshaft and the piston are supported against the housing by fluid films, it is important to consider the hydrodynamics in the simulation of the crank drive dynamics. Based on the excitation forces, the vibration analysis of the engine is carried out, which provides the input data for the acoustic simulations. The entire simulation workflow is demonstrated on a four-stroke combustion engine. Finally, the presented approach is validated by sound pressure measurements of a running engine in an anechoic room.