An improved contact model considered the effect of boundary lubrication regime on piston ring-liner contact for the two-stroke marine engines from the perspective of the Stribeck curve

Abstract

The prediction of lubrication performance is required to be the basement of friction optimization for marine engines. This paper simulates the lubrication performance of marine engines based on statistical models which have the advantages of fast, efficient, and macroscopic fault location. Boundary lubrication exists in the piston ring-cylinder liner (PRCL) of two-stroke marine engines because of the harsher load, lower speed, and larger structure. It has been proposed that there would be tribofilm under boundary lubrication which has a significant influence on the contact. To understand the boundary lubrication, it is necessary to study the lubrication regime transition. In this paper, firstly, the coefficient of friction curve combined with the thickness ratio embodies the lubrication regime transition process of two-stroke engines under work conditions. However, the phenomenon that the coefficients under boundary lubrication are smaller than that of other regimes shows the non-objectivity of this curve. Therefore, the Stribeck curve is introduced for objectively evaluating the transition. Then, the calculation of asperities contact pressure under boundary lubrication, which Wen proposed, is introduced into the classic Greenwood-Williamson model, the problem that the original model cannot reflect the boundary lubrication regime in the form of the Stribeck curve is improved. Finally, the results are compared before and after modifying the model to verify this study’s practicability. It provides more precise asperities contact pressure for the tribofilm growth calculation from the perspective of the Stribeck curve under the PRCL statistical model in future work.

Study on the influence of non-Gaussian honing surface on contact and flow characteristics

“…To investigate the effect of roughness on lubrication, the average Reynolds equation was developed (Patir and Cheng, 1978). This approach has been widely used in the investigation of ring-liner lubrication (Khan et al , 2021; Li et al , 2021; Lyu et al , 2022). Homogenization technology was used to investigate the effects a of honing texture (Spencer et al , 2011).…”

Research on tribological performance of piston ring/liner conjunction considering non-Gaussian roughness and cavitation

“…Garcia et al 23 showed and experimentally verified that by surface texturing 25% and 5% reduction in asperity contact force and total friction force can be achieved. Xiuyi et al 24 proposed an improved contact model for analysis of tribological performance of PRCLC from the perspective of Stribeck curve. They concluded that there is a tribofilm growth in boundary lubrication regime and that directly relates with asperity contact pressure.…”

Friction Response of Piston Rings for Application-like Starvation and Benefit of Amorphous Carbon Coatings

“…Concludingly, an X-ray photoelectron spectroscopy (XPS) or electron energy loss spectroscopy (EELS)-analysis with the worn specimen surfaces coupled with molecular dynamic simulations could be carried out. Furthermore, advanced friction models could be used, e.g., as proposed by Xiuyi et al [59], to improve the predictability of friction in the case of occurring tribofilm formation and removal.…”