Research on abnormal wear mechanism and optimization design of piston ring-ring groove system of high loaded diesel engine

The abnormal wear of the piston ring-ring groove system of high loaded diesel engine is a key bottleneck factor restricting its reliability and durability. In this study, the cross-scale research method combining thermal-mechanical coupling numerical simulation and bench test is used to systematically reveal the coupling mechanism of piston-piston ring structure parameter matching on ring groove wear behavior. Aiming at the abnormal wear of ring grooves in a type of high loaded diesel engine, the whole process system research from failure mechanism analysis, multi-physics coupling simulation to structural optimization design and test verification is carried out. The results show that: (1) the circumferential non-uniform deformation of the ring groove is one of the main cause of abnormal wear, and the maximum deformation of the ring groove can be reduced by 25%–30.7% by optimizing the piston structure to improve the piston stiffness. (2) Optimizing the piston ring gap transition geometry (arc transition ≥ 0.01/0.03 mm) could reduce groove fretting wear by 23.9%–46% during piston ring’s secondary motion. (3) A trapezoidal ring process platform wider than 0.3 mm causes concentrated contact stress on the outer ring groove, increasing the abnormal wear. The multi-parameter optimization scheme, validated by a 3000-h composite durability test, reduced ring groove wear from 0.067 to 0.017 mm, effectively resolving abnormal wear under 27 MPa design power cylinder pressure. This study provides critical theoretical and engineering guidance for enhancing the durability of high-power engine tribo-systems.