Effects of Cast-Iron Surface Texturing on the Anti-Scuffing Performance under Starved Lubrication.

Wenhua Li,Bin Ye,Fengming Du,Ruoxuan Huang,Yan Shen,Baihong Yu

doi:10.3390/ma12101586

Abstract

Advances in heavy-duty diesel engine designs place higher demands on the friction and wear performance of the piston ring and cylinder liner (PRCL) interface. The potential of using micro-textures machined on the whole stroke of a cast-iron cylinder liner was investigated in this work. A set of running-in and starved lubrication experiments was performed using a custom reciprocating test rig that imparts a combination of combustion-level pressures and the resulting impacts. Based on a comparison of micro-dimple parameters, the friction coefficient for the running-in period at the shocking dead center was the smallest at a designed combination of 1000-μm diameter, 22% area fraction, and arrangement with half-radius intersecting distance of two adjacent micro-dimple columns. The non-scuffing time under starvation was the longest at a designed combination of the following parameters: 800 μm diameter, 22% area fraction, and quarter-radius intersecting distance arrangement. From finite element analysis, it was found that stress concentrates at the micro-dimple periphery and at the connections between adjacent micro-dimples. However, surface topography examination showed that scuffing initiates in the non-dimpled regions between the micro-dimpled columns rather than at their edges. Finally, under reciprocating motion, micro-dimples can collect wear debris to inhibit further propagation of scuffing in the micro-dimpled region.

Highlights

As the explosive pressure in heavy-duty diesel engines increased to more than 20 MPa, the lubrication state existing in the interface of the piston ring and cylinder liner (PRCL) became even worse than ever before
The running-in and starved lubrication experiment was divided into four stages: the running-in stage with the light load (RLL), the running-in stage with the heavy load (RHL), the heating stage (HS), and the oil starvation stage (OS)
The running-in starved lubrication experiment was divided into four stages: the running-in stage with the light load (RLL), the running-in stage with the heavy load (RHL), Maximum

Summary

Introduction

As the explosive pressure in heavy-duty diesel engines increased to more than 20 MPa, the lubrication state existing in the interface of the piston ring and cylinder liner (PRCL) became even worse than ever before. Many efforts were made to investigate the scuffing phenomenon to prevent such failure [7,8,9,10,11,12]. Coating on the piston ring proved to be an effective method, which may provide advantages such as friction reduction and improved wear and scuffing resistance. Shen et al compared heavy-duty scuffing behavior between chromium-based ceramic composite and nickel–chromium–molybdenum-coated ring sliding against a cast-iron liner [13]

Methods

Results

Conclusion