The influence of roughness distribution characteristic on the lubrication performance of textured cylinder liners

2019 ◽  
Vol 71 (3) ◽  
pp. 486-493
Author(s):  
Bifeng Yin ◽  
Huiqin Zhou ◽  
Bo Xu ◽  
Hekun Jia

Purpose The purpose of this paper is to investigate the coupling mechanism of the roughness distribution characteristic and surface textures on the cylinder liner. Design/methodology/approach The cylinder liner-piston ring lubrication model with non-Gaussian roughness distribution surface was proposed in this paper to find the optimum cylinder liner surface. The motored engine tests were carried out to verify the simulation results. Findings The calculation and experiment results show that the large negative skewness surface has the optimal lubrication performance in the un-textured liner, while in the textured liner, the small negative skewness surface is more appropriate, which means surface textures couple with small negative skewness surface can improve the lubrication performance. Originality/value Although there are some works related to liner surface roughness and textures, the combine of roughness distribution and surface textures is not usually taken into account. Therefore, this research is different from others, as the present model considers with real non-Gaussian roughness distribution liners.

Lubricants ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 89
Author(s):  
Chongjie Gu ◽  
Renze Wang ◽  
Tian Tian

In internal combustion engines, a significant portion of the total fuel energy is consumed to overcome the mechanical friction between the cylinder liner and the piston rings. The engine work loss through friction gradually reduces during the engine break-in period, as the result of liner surface topography changes caused by wear. This work is the first step toward the development of a physics-based liner wear model to predict the evolution of liner roughness and ring pack lubrication during the break-in period. Two major mechanisms are involved in the wear model: plastic deformation and asperity fatigue. The two mechanisms are simulated through a set of submodels, including elastoplastic asperity contact, crack initiation, and crack propagation within the contact stress field. Compared to experimental measurements, the calculated friction evolution of different liner surface finishes during break-in exhibits the same trend and a comparable magnitude. Moreover, the simulation results indicate that the liner wear rate or duration of break-in depends greatly on the roughness, which may provide guidance for surface roughness design and manufacturing processes.


Author(s):  
Jeffrey Jocsak ◽  
Yong Li ◽  
Tian Tian ◽  
Victor W. Wong

Frictional losses in the piston ring-pack of an engine account for approximately 20% of the total frictional losses within an engine. Although many non-conventional cylinder liner finishes are now being developed to reduce friction and oil consumption, the effects of the surface finish on ring-pack performance is not well understood. The current study focuses on modeling the effects of three-dimensional cylinder liner surface anisotropy on piston ring-pack performance. A rough surface flow simulation program was developed to generate flow factors and shear stress factors for three-dimensional cylinder liner surface textures. Rough surface contact between the ring and liner was modeled using a previously published methodology for asperity contact pressure estimation between actual rough surfaces. The surface specific flow factors, shear stress factors, and asperity contact model were used in conjunction with MIT’s previously developed ring-pack simulation program to predict the effects of different surface textures on ring-pack behavior. Specific attention was given to the effect of honing groove cross-hatch angle on piston ring-pack friction in a stationary natural gas engine application, and adverse effects on engine oil consumption and durability were also briefly considered. The modeling results suggest that ring-pack friction reduction is possible if the liner honing cross hatch angle is decreased by reducing the feed-to-speed ratio of the honing tool. Reducing the cross-hatch angle increased oil flow blockage and increased the lubricant’s effective viscosity during mixed lubrication. This allowed more load to be supported by hydrodynamic pressure, reducing ring-pack friction. However, there appeared to be a potential for increased oil consumption and scuffing tendency corresponding to a decrease in honing cross-hatch angle.


2019 ◽  
Vol 72 (3) ◽  
pp. 465-471
Author(s):  
Chao Zhen Yang ◽  
Zhiwei Guo ◽  
Changkun Xu

Purpose Frictions in cylinder liner-piston ring often cause an inevitable loss of energy loss in the diesel engine. This study aims at evaluating the effect of depths in the cylinder liner groove texture on friction, wear and sealing performances. Design/methodology/approach Five depths of groove texture cylinder liners (50, 100, 150, 200, 250 µm) were fabricated, and experiments were carried out using a special-purpose diesel engine tester. Comparative analyses of cylinder liner contact resistances, piston ring wear losses and surface appearances were conducted with respect to different surface textures and applied loads. Findings Under no-load conditions, the cylinder liner with a 100 deep thread groove can significantly improve sealing and optimize its lubrication performance. On the other hand, the sealing is highly correlated with the depth of groove and the load within the cylinder liner. Under loaded conditions, the thread groove has less effect on the sealing performance. Originality/value The findings can provide feasible basis for the tribological design and production of diesel engines.


2013 ◽  
Vol 51 (1) ◽  
pp. 9-23 ◽  
Author(s):  
Zhiwei Guo ◽  
Chengqing Yuan ◽  
Peng Liu ◽  
Zhongxiao Peng ◽  
Xinping Yan

2018 ◽  
Vol 70 (5) ◽  
pp. 829-837 ◽  
Author(s):  
Xia He ◽  
Wenling Liao ◽  
Guorong Wang ◽  
Lin Zhong ◽  
Mengyuan Li

Purpose The purpose of this study is to investigate the influence of texture on hydrodynamic lubrication performance of slide surface from the perspective of skewness and kurtosis. Design/methodology/approach Hydrodynamic lubrication theoretical model of textured surface was established based on two-dimensional Reynolds equation, and finite difference algorithm was used as the numerical approach in the paper. Skewness and kurtosis of surface were obtained by discrete calculation. Findings Numerical analysis results show that the influence law of texture types on skewness, kurtosis and hydrodynamic lubrication was the more negative skewness and higher kurtosis, the better hydrodynamic lubrication performance when texture cross section contour and geometric parameters were the same. Similarly, the same influence law of skewness, kurtosis and hydrodynamic lubrication performance by texture cross-section contour was observed. However, it was unable to evaluate the effect of texture angle on hydrodynamic lubrication performance of textured surface from the perspective of skewness and kurtosis. Originality/value This paper confirms the feasibility of evaluating influence of texture types and texture cross-section contour on hydrodynamic lubrication performance from the perspective of skewness and kurtosis and provides a way to optimize texture type and texture cross section.


2017 ◽  
Vol 69 (2) ◽  
pp. 282-299 ◽  
Author(s):  
Yang Hu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Jiazheng Fan

Purpose During running-in, the change in the honed cylinder liner surface alters the performance and efficiency of the piston ring-pack system. The present paper, thus, aims to investigate the surface topography and wear and friction evolution of a cylinder liner surface during the running-in tests on a reciprocating ring–liner tribometer under a mixed lubrication regime. After an initial period of rapid wear termed “running-in wear”, a relatively long-term steady-state surface topography can emerge. A numerical model is developed to predict the frictional performance of a piston ring-pack system at the initial and steady-state stages. Design/methodology/approach The liner surfaces are produced by slide honing (SH) and plateau honing (PH). The bearing area parameter (Rk family), commonly used in the automotive industry, is used to quantitatively characterize the surface topography change during the running-in process. A wear volume-sensitive surface roughness parameter, Rktot, is used to show the wear evolution. Findings The experimental results show that a slide-honed surface leads to reduced wear, and it reduces the costly running-in period compared to the plateau-honed surface. The simulation results show that running-in is a beneficial wear process that leads to a reduced friction mean effective pressure at the steady-state. Originality/value To simulate the mixed lubrication performance of a ring–liner system with non-Gaussian roughness, a one-dimensional homogenized mixed lubrication model was established. The real surface topography instead of its statistical properties is taken into account.


2018 ◽  
Vol 70 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Shuwen Wang ◽  
Feiyan Yan ◽  
Ao Chen

Purpose The purpose of this paper is to investigate the tribological effects of laser surface texturing (LST) and residual stress on functional surfaces. Design/methodology/approach Three different surface textures (circular dimple, elliptical dimple and groove) with two different textured area ratios (10 and 20 per cent) are designed and fabricated by a Picosecond Nd YAG Laser machine. The friction and wear performance of textured specimens is tested using a UMT-2 friction and wear testing machine in mixed lubrication. Findings Test results show that elliptical dimples exhibit the best performance in wear resistance, circular dimples in friction reduction and grooves in stabilization of friction. The surfaces with larger textured area density exhibit better performance in both friction reduction and wear resistance. The improved performance of LST is the coupled effect of surface texture and residual stress. Originality/value The findings of this study may provide guidance for optimal design of functional surface textures in reciprocating sliding contacts under mixed or hydrodynamic lubrication, which can be used in automotive and other industrial applications.


2014 ◽  
Vol 966-967 ◽  
pp. 175-183 ◽  
Author(s):  
Mohammed Yousfi ◽  
Sabeur Mezghani ◽  
Ibrahim Demirci ◽  
Mohamed El Mansori

The cylinder liner surface texture, widely generated by the honing technique, contributes a lot on engine functional performances (friction, oil consumption, running-in, wear etc.). In order to improve these functional performances, different honing processes are being developed. These different honing processes generate surfaces with various texture features characteristics (roughness, valleys depth, valley width, cross hatch angle, etc.). This paper addresses a comparison of ring-pack friction for cylinder texture with different cross-hatch angles and valley sizes. It takes in consideration the mutual effect of valley depth and honing angle. A numerical model is developed to predict friction within the cylinder ring-pack system in mixed lubrication regime and a morphological method is used to characterize groove depth. The results show the effect of different honing variables (rotation speed, stroke speed and indentation pressure) on cylinder bore surface textures and hydrodynamic friction of the ring-pack system.


Author(s):  
Z Dimkovski ◽  
F Cabanettes ◽  
H Löfgren ◽  
C Anderberg ◽  
R Ohlsson ◽  
...  

2018 ◽  
Vol 70 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Jun-peng Shao ◽  
Guang-dong Liu ◽  
Xiao-dong Yu ◽  
Yan-qin Zhang ◽  
Xiu-li Meng ◽  
...  

Purpose The purpose of this paper is to describe a simulation and experimental research concerning the effect of recess depth on the lubrication performance of a hydrostatic thrust bearing by constant rate flow. Design/methodology/approach The computational fluid dynamics and finite volume method have been used to compute the lubrication characteristics of an annular recess hydrostatic thrust bearing with different recess depths. The performances are oil recess pressure, oil recess temperature and oil film velocity. The recess depth has been optimized. A test rig is established for testing the pressure field of the structure of hydrostatic thrust bearing after recess depth optimization, and experimental results show that experimental data are basically identical with the simulation results, which demonstrates the validity of the proposed numerical simulation method. Findings The results demonstrate that the oil film temperature decreases and the oil film pressure first increases and then decreases with an increase in the recess depth, but oil film velocity is constant. To sum up comprehensive lubrication performance, the recess depth of 3.5 mm is its optimal value for the annular recess hydrostatic thrust bearing. Originality/value The computed results indicate that to get an improved performance from a constant flow hydrostatic thrust bearing, a proper selection of the recess depth is essential.


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