Life-cycle wear evolution model for engine Cu-based bushings

Abstract

Monitoring wear particle concentrations in lubricating oil during durability testing is essential for identifying failure mechanisms in internal combustion engines. Traditional durability bench tests lasting hundreds or thousands of hours are costly, inefficient, and lack adaptability to diverse operating conditions. Simulation models offer a viable alternative but struggle to accurately model complex interactions among wear evolution, lubrication, dynamics, structural deformation, and frictional contact, especially the life-cycle assessment. This study introduces a novel multi-physics model that integrates equations governing wear particle generation and concentration, fluid lubrication, dynamics, contact, elastic deformation, and wear evolution. The model employs a coupled iterative solving process and an extrapolation strategy, ensuring stability, efficiency, and accuracy during long-term simulations implemented in FORTRAN. The model is applied to the piston pin–Cu-based bearing bushing tribo-system under the 400-h durability conditions. The model is rigorously validated through a 400-h durability test on a full-size internal combustion engine. Comparative analysis of tribo-dynamics from single-cycle, 1-h, and 400-h intervals demonstrates strong agreement with lubrication theory and condition changes. Furthermore, the wear distribution of the Cu-based bearing bushings closely matches the model's predictions after the durability test. The evolution of copper particle content of each 100 h is accurately predicted, with a prediction error of 6.85 % after the 400-h test. The cost-effectiveness is assessed by comparing the high fuel costs of this test with the low costs of model simulation. Compared to conventional testing methods, this model reduces the evaluation cycle by 52 % and decreases costs by up to two orders of magnitude. This efficient and cost-effective approach provides a valuable alternative to traditional engine reliability tests and offers substantial technological and economic benefits for the engine industry.