Effect of laser textured dimples on the lubrication performance of cylinder liner in diesel engine

Abstract

Laser surface texturing (LST) technique was utilised on a cylinder liner in a diesel engine. In order to analyse the effect of LST micro‐dimples on the lubrication and friction properties of cylinder liner–piston ring (CL–PR), we developed a new mixed lubrication model on the basis of the average Reynolds equation and asperity contacts equation. The model can consider the coupling effects between the surface roughness of non‐texturing regions and micro‐dimples and the synergistic effects of multi‐micro‐dimples. The results show that cylinder liner surface by LST can form effective hydrodynamic lubrication effect in most regions of the strokes, only near the dead points, the friction pair is in mixed lubrication state, asperity contact plays a major role in balancing the external load and the asperity friction force is obvious. The micro‐dimple parameters were optimised to obtain a better lubrication effect with the following optimised results: rp = 30–60 µm, Sp = 0.2–0.4 and e = 0.03–0.1. Copyright © 2012 John Wiley & Sons, Ltd.

The Analysis of Secondary Motion and Lubrication Performance of Piston considering the Piston Skirt Profile

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Modelação matemática de contatos lubrificados micro-texturizados

“…Making use of Reynolds model, Gadeschi et al [44], and later Checo et al [21] employing Elrod-Adams model, showed that for a fixed load it is possible to obtain a configuration that minimizes the friction only for moderate R/L (≈ 10) or higher. These results are in agreement with pioneering experiments made by Costa & Hutchins [31], and with latter studies by Tomanik [85,86], Kovalchenko et al [60], Yin et al [90], Scaraggi et al [81], among others [33,2,50].…”

“…For instance, there are several works (both numerical and experimental) where textured surfaces are described by h being discontinuous [91,90,82,21]. For handling this, we need to look beyond the classical definition of derivative: here is where the tools of Functional Analysis appear.…”

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