Investigation on Piston Secondary Dynamics: A Model That Considers Translation Along the Wrist-Pin and Second Land Interactions With the Cylinder Bore

In recent years several efforts have been made to model piston secondary dynamics in an attempt to assess piston performance accurately. In all these efforts, piston translation along the wrist-pin was ignored, and the piston land interactions with the cylinder bore were not considered. In this paper the authors present a model for piston secondary dynamics that considers piston translation along the wrist-pin and piston land interactions with the cylinder bore. A previously developed piston finite element program has been refined further to incorporate piston secondary dynamics. As its predecessor this model uses a full piston model to perform the analysis over a four-stroke cycle. The model is capable of considering an elastic skirt with deformations induced by thermal, inertial, combustive, hydrodynamic and contact effects. In the current model only the interactions of the second land with the cylinder bore are considered. Unlike the skirt, the land is assumed to be rigid. A brief discussion on the model development is presented. Piston secondary dynamics, hydrodynamic and contact forces, and piston wear results are shown. A comparison is made between the results obtained via three different piston secondary dynamics modeling approaches; no translation along the wrist-pin, translation along the writ-pin, and translation along the wrist-pin as well as second land-cylinder bore interactions.Copyright © 2007 by ASME