SAE International A Dual Grid Curved Beam Finite Element Model of Piston Rings for Improved Contact Capabilities 2014-01-1085

Piston rings are large contributors to friction losses in internal combustion engines. To achieve higher engine efficiency, low friction ring packs that can maintain good sealing performance must be designed. To support this effort, simulation tools have been developed to model the performance of piston rings during engine operation. However, the challenge of predicting oil consumption, blow by, and ring pack friction with sufficient accuracy remains. This is mostly due to the complexity of this system. Ring dynamics, deformation, interaction with liner and piston, gas and lubricant flow must all be studied together to make relevant predictions. In this paper, a new curved beam finite element model of piston rings is proposed. Ring structural deformation and contact with the liner are treated on two separate grids. A comparison with ring models in the literature and analytical solutions shows that it can provide accurate results efficiently. The proposed model can serve as a numerical framework to couple ring structural deformation, interaction with liner and piston, and predict oil transport. The new model is used to study conformability of piston rings to distorted bore. Results show that the differences between existing conformability criteria can be explained by the singular behavior of the ring gap region.