Evaluating Engine Design for Low Noise Using Dynamic Structural Modeling

A study has been carried out with the aim to develop a model for the prediction of the vibration transmission from the piston top to the block structure via the crank train and for the prediction of the block noise radiation.

This paper outlines the basic work, which was done in this study on a 4-cy-linder tractor diesel engine with 98 mm bore. During the investigation some remarkable results have been obtained, e.g. that the influence of oil film stiffness and damping values on the vibration transmission is of less importance during the combustion period. Finally the influence of design parameters on the vibration transmission is described in this paper. Some of these parameters are more or less flexible bearing caps, increased main bearing wall thickness, stiffening ribs on the block outer surface, cantilevered main bearing design and reduced weight of the crankshaft.