Impact of Boundary Lubrication Performance of Engine Oils on Friction at Piston Ring-Cylinder Liner Interface

2014 ◽  
Vol 7 (3) ◽  
pp. 875-881 ◽  
Author(s):  
Kazushi Tamura ◽  
Moritsugu Kasai ◽  
Yukinobu Nakamura ◽  
Tomoyuki Enomoto
Keyword(s):  
Boundary Lubrication ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Engine Oils ◽  
Lubrication Performance

scholarly journals 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

2021 ◽  
pp. 095440622110272
Author(s):  
Lyu Xiuyi ◽  
Bowen Jiao ◽  
Yuechang Wang ◽  
Abdullah Azam ◽  
Xiqun Lu ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Boundary Lubrication ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Work Conditions ◽  
Stribeck Curve ◽  
Regime Transition ◽  
Lubrication Regime ◽  
Lubrication Performance ◽  
Marine Engines

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.

Mutual influence of plateau roughness and groove texture of honed surface on frictional performance of piston ring–liner system

2016 ◽  
Vol 231 (7) ◽  
pp. 838-859 ◽  
Author(s):  
Yang Hu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Jiazheng Fan
Keyword(s):  
Piston Ring ◽  
Cylinder Liner ◽  
Texture Features ◽  
Groove Depth ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Lubrication Performance ◽  
Liner System ◽  
Frictional Performance

The cylinder liner surface finish, which is commonly produced using the honing technique, is an essential factor of engine performance. The characteristics of the texture features, including the cross-hatch angle, the plateau roughness and the groove depth, significantly affect the performance of the ring pack–cylinder liner system. However, due to the influence of the honed texture features, the surface roughness of the liner is not subject to Gaussian distribution. To simulate the mixed lubrication performance of the ring–liner system with non-Gaussian roughness, the combination of a two-scale homogenization technique and a deterministic asperities contact method is adopted. In this study, a one-dimensional homogenized mixed lubrication model is established to study the influence of groove parameters on the load-carrying capacity and the frictional performance of the piston ring–liner system. The ring profile, plateau roughness, and operating conditions are taken into consideration. The main findings are that for nonflat ring, shallow and wide groove textures are beneficial for friction reduction, and there exists an optimum groove density that makes the friction minimum; for flat ring, wide and sparse grooves help improving the tribological performance, and there exists an optimum groove depth that makes the friction minimum.

Numerical and Experimental Analysis of the Honing Texture on the Lubrication Performance of Piston Ring–Cylinder Liner Tribosystem

2019 ◽  
Vol 62 (6) ◽  
pp. 991-1006 ◽  
Author(s):  
Tongyang Li ◽  
Xiqun Lu ◽  
Xuan Ma ◽  
Hanzhang Xu ◽  
Bowen Jiao ◽  
...  
Keyword(s):  
Experimental Analysis ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Lubrication Performance

Numerical Simulation on the Lubrication Performance of Surface Textured Piston Rings

2011 ◽  
Vol 199-200 ◽  
pp. 734-738 ◽  
Author(s):  
Qiu Ying Chang ◽  
Xian Liang Zheng ◽  
Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Friction Force ◽  
Friction And Wear ◽  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Area Density ◽  
Oil Film ◽  
Lubrication Performance

Surface texturing has been successfully employed in some tribological applications in order to diminish friction and wear. This technology may be used in a piston ring to decrease the friction and wear of the contact between a piston ring and cylinder liner. A numerical simulation of lubrication between a surface textured piston ring and cylinder liner based on the hydrodynamic lubrication theory was conducted. The influence of surface texture parameters on piston ring lubrication performance was obtained by solving the mathematical equations with a multi-grid method. The results show that under the micro-dimple area density of 5%-40% the minimum oil film thickness increases and the dimensionless friction force decreases with the increasing of it. Under the dimple area density of 40%-60%, the minimum oil film thickness and the dimensionless friction force change slightly. Under various dimple area densities the optimum dimple depth at the given working condition in this paper is about 5µm.

scholarly journals Lubrication Performance of Engine Commercial Oils with Different Performance Levels: The Effect of Engine Synthetic Oil Aging on Piston Ring Tribology under Real Engine Conditions

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 90 ◽  
Author(s):  
Pantelis Nikolakopoulos ◽  
Stamatis Mavroudis ◽  
Anastasios Zavos
Keyword(s):  
Piston Ring ◽  
Engine Oil ◽  
Performance Levels ◽  
Automotive Engine ◽  
Engine Oils ◽  
Shear Rates ◽  
Lubrication Performance ◽  
Computational Fluid Dynamics Cfd ◽  
Engine Systems

To further improve efficiency in automotive engine systems, it is important to understand the generation of friction in its components. Accurate simulation and modeling of friction in machine components is, amongst other things, dependent on realistic lubricant rheology and lubricant properties, where especially the latter may change as the machine ages. Some results of research under laboratory conditions on the aging of engine commercial oils with different performance levels (mineral SAE 30, synthetic SAE10W-40, and bio-based) are presented in this paper. The key role of the action of pressure and temperature in engine oils’ aging is described. The paper includes the results of experiments over time in laboratory testing of a single cylinder motorbike. The aging of engine oil causes changes to its dynamic viscosity value. The aim of this work is to evaluate changes due to temperature and pressure in viscosity of engine oil over its lifetime and to perform uncertainty analysis of the measured values. The results are presented as the characteristics of viscosity and time in various temperatures and the shear rates/pressures. This paper also includes a Computational Fluid Dynamics (CFD) model, applying the experimental results in the piston ring tribology problem.

Effect of grooved cylinder liner depths on the tribological performances of cylinder liner-piston ring

2019 ◽  
Vol 72 (3) ◽  
pp. 465-471
Author(s):  
Chao Zhen Yang ◽  
Zhiwei Guo ◽  
Changkun Xu
Keyword(s):  
Diesel Engine ◽  
Design Methodology ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Content Type ◽  
Sealing Performance ◽  
Lubrication Performance ◽  
Highly Correlated ◽  
Cylinder Liners ◽  
Groove Texture

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.

scholarly journals Experimental Study on the Effect of Marine Engine Lubricant Degradation on Tribological Performance of Cylinder Liner and Piston Rings Contact Using a Tuning Fork Technology Based Oil Sensor

2019 ◽  
Author(s):  
M Anand ◽  
M Hadfield ◽  
JL Viesca ◽  
B Thomas
Keyword(s):  
Boundary Lubrication ◽  
Piston Ring ◽  
Tuning Fork ◽  
Cylinder Liner ◽  
Tribological Performance ◽  
Gas Pressure ◽  
Piston Rings ◽  
Marine Engine ◽  
Marine Engines ◽  
Lubrication Conditions

An investigation was carried out to study the effect of changes in oil quality on its tribological performance using a tuning fork technology based oil sensor. In this research, a tribological testing system was commissioned, to simulate the piston ring-cylinder liner sliding contact, and to measure the lubricant condition in real-time using an oil sensor. Tribological contact between cylinder liners and piston rings in marine engines is the most affected region due to excessive thermo-mechanical stresses. At top dead centre, the effect of such stresses is at a maximum where piston-sliding speed is lowest, while the temperature is high due to fuel combustion, and radial load behind the piston rings compressing against the cylinder liner surface is at a maximum due to gas pressure and the compression fit of piston rings within the cylinder liner. At bottom dead centre, this effect is less severe due to a reduction in temperature and gas pressure on the piston rings, as the piston is positioned away from the combustion chamber. These two regions experience boundary lubrication conditions, where anti-wear and anti-friction additives are responsible for forming a protective lubricious film on sliding surfaces. At mid-stroke, piston-sliding speed is maximum, therefore, a full hydrodynamic film is formed in this region separating the piston rings and cylinder liner. The formation of oil film depends upon, the physical properties of oil (such as viscosity and density) under hydrodynamic lubrication conditions, and the oil chemistry (such as presence of additives in oil) under mixed or boundary lubrication conditions. Lubricants in marine engines undergo intense degradation in quality due to contamination with wear particles, water, soot, un-burnt fuel, coolant, and additives depletion. Such degradation of lubricants leads to a reduction in their capability to form a minimum thickness of oil film between two moving engine components to avoid direct metal-to-metal contact, which may cause wear. Therefore, monitoring the condition of marine engine lubricants is vital in order to predict any significant change in its quality. The results obtained from tribology testing and oil condition monitoring in the current research showed a good correlation and are useful to understand the performance of lubricants for piston ring-liner contacts.

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