Cylinder Liner Deformation: An Investigation of its Decomposition Orders under Varied Operational Load

Enhancing the efficiency of the internal combustion engine is of most interest to achieve sustainability, for instance in connection with sustainable fuels, like hydrogen or biofuels. Regardless of the type of fuel, great development possibilities are seen in reducing the friction of the piston group. Analyzing the cylinder liner deformation is essential to understanding the behavior of the piston rings-cylinder liner (PRCL) coupling in the hot operation state. This paper describes the liner deformation at the hot operation state over the liner depth for different operational points. To do so, a validated mathematical model based on a physical model of a terminal cylinder in an internal combustion engine has been introduced. The validated mathematical model is then simulated using FEM software to numerically calculate liner deformations at different operational conditions. Subsequently, the deformations are analyzed using Fourier decomposition to find the variation trends for each order of deformation over the liner's depth and engine operational points. It is found that the second-order deformation is dominant over the liner depth. This deformation order is highly dependent on the operational load. The fourth-order deformation is highly dependent on the liner depth with low dependency on the operational load. The trends for first and third orders are also discussed. The simulation was repeated for aluminum alloy as a different engine material to investigate the material effects. The results show that although the deformation values differ significantly with different materials, the trends for the deformation's order remain almost the same. In an outlook, the possible application to real engines is discussed.