The effect of piston skirt tooling marks on hydrodynamic lubrication at small clearances in internal combustion engines

2008 ◽  
Vol 6 (1) ◽  
pp. 1-8
Author(s):  
F McClure ◽  
Y Li ◽  
T Tian
Keyword(s):  
Internal Combustion Engines ◽  
Hydrodynamic Lubrication ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Piston Skirt

scholarly journals Study of Break-In Process and its Effects on Piston Skirt Lubrication in Internal Combustion Engines

Lubricants ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 98 ◽  
Author(s):  
Zhen Meng ◽  
Linfeng Zhang ◽  
Tian Tian
Keyword(s):  
Internal Combustion Engines ◽  
Rapid Change ◽  
System Optimization ◽  
Internal Combustion ◽  
Quantitative Agreement ◽  
Asperity Contact ◽  
Combustion Engines ◽  
Piston Skirt ◽  
Calculation Results ◽  
Realistic Prediction

The piston skirt is one of the main contributors to the total mechanical loss in internal combustion engines. Usually, the skirt friction experiences a rapid change during the break-in period largely due to the wear of the machine marks or roughness against soft coatings. It is thus important to consider the effect of the change of the roughness for a realistic prediction of the piston skirt friction and system optimization. In this work, an existing model of piston skirt lubrication was improved with the consideration of a breaking in process for the most commonly used triangle machine marks. A new set of flow factors in the averaged Reynolds equation were analytically derived for the trapezoid shape formed after wear of the original triangle shape. A new asperity contact model was developed for the trapezoid shape. The calculation results reflect the trend of friction mean effective pressure (FMEP) during break-in in an engine test and showed quantitative agreement under the same amount of wear.

scholarly journals Advanced Tribological Characterization of DLC Coatings Produced by Ne-HiPIMS for the Application on the Piston Rings of Internal Combustion Engines

2021 ◽  
Vol 11 (21) ◽  
pp. 10498
Author(s):  
Alireza Vahidi ◽  
Diogo Fonseca ◽  
João Oliveira ◽  
Albano Cavaleiro ◽  
Amílcar Ramalho ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Hydrodynamic Lubrication ◽  
Research Work ◽  
Internal Combustion ◽  
Tribological Performance ◽  
Combustion Engines ◽  
Piston Rings ◽  
Dlc Coatings ◽  
Lubrication Regimes ◽  
Lubrication Regime

Piston rings (PR) are known for almost a quarter of the friction losses in internal combustion engines. This research work aims to improve the tribological performance of PR by a recently developed variant of Diamond-like Carbon (DLC) coatings deposited in a mixture of Ar and Ne plasma atmosphere (Ne-DLC) by high-power impulse magnetron sputtering (HiPIMS). For the benchmark, the widely used Chromium Nitride (CrN) and DLCs deposited in pure Ar plasma atmosphere (Ar-DLC) were used. The tribological tests were performed on a block-on-ring configuration under different lubrication regimes by varying temperatures and sliding speeds. The analysis of the results was performed by Stribeck curves corresponding to each sample. An improvement of the tribological performance was observed for Ne-DLC films by up to 22.8% reduction in COF compared to CrN in the boundary lubrication regime, whereas, for the Ar-DLC film, this reduction was only 9.5%. Moreover, the Ne-DLC films achieved ultralow friction of less than 0.001 during the transition to a hydrodynamic lubrication regime due to better wettability (lower contact angle) and higher surface free energy. Increasing the Ne up to 50% in the discharge gas also leads to an increase of hardness of DLC films from 19 to 24 GPa.

Numerical Study of Piston Skirt-Liner Lubrication Considering the Effects of Deformation in Internal Combustion Engines

2012 ◽  
Author(s):  
Lipu Ning ◽  
Xianghui Meng ◽  
Youbai Xie
Keyword(s):  
Elastic Deformation ◽  
Internal Combustion Engines ◽  
Numerical Study ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Surface Geometry ◽  
Piston Skirt ◽  
Lubrication Performance ◽  
Liner System

This paper presents a comprehensive lubrication model for piston skirt-liner system of internal combustion engines. In the model it is included that the effects of the surface roughness, the piston skirt surface geometry, the piston pin offset, the crankshaft offset, and the lubricant viscosity on the piston secondary motion and lubrication performance. Especially, the effects of the thermal and the elastic deformation of the piston skirt and the cylinder liner, and the piston skirt deformations due to the combustion pressure and the piston axial inertia, are considered as the key task in this study. The results show that the combustion force, the working temperature and the piston axial inertia all play important roles in the piston-skirt lubrication. Also, considering the elastic deformation of the piston skirt and the cylinder liner is beneficial to the prediction of piston-skirt lubrication more accurately. The developed program in this study can provide a useful tool for the analysis of the piston-liner system lubrication problem.

Piston dynamics, lubrication and tribological performance evaluation: A review

2018 ◽  
Vol 21 (5) ◽  
pp. 725-741 ◽  
Author(s):  
Cristiana Delprete ◽  
Abbas Razavykia
Keyword(s):  
Power Loss ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Tribological Performance ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Design Parameters ◽  
Combustion Engines ◽  
Piston Skirt ◽  
Secondary Motion

Mechanical power loss of lubricated and bearing surfaces serves as an attractive domain for study and research in the field of internal combustion engines. Friction reduction at lubricated and bearing surface is one of the most cost-effective ways to reduce gas emission and improve internal combustion engines’ efficiency. This thus motivates automotive industries and researchers to investigate tribological performance of internal combustion engines. Piston secondary motion has prime importance in internal combustion engines and occurs due to unbalanced forces and moments in a plane normal to the wrist pin axis. Consequently, piston executes small translations and rotations within the defined clearance during the piston reciprocating motion. Mechanical friction power loss and lubrication at piston skirt/liner and radiated engine noise are dramatically affected by piston secondary dynamics. The lubrication mechanism, piston secondary motion and tribological performance are affected by piston design parameters (piston/liner clearance, wrist pin offset, skirt profile, etc.), lubricant rheology, oil transport mechanism and operating conditions. Therefore, this review is devoted to summarize the synthesis of main technical aspects, research efforts, conclusions and challenges that must be highlighted regarding piston skirt/liner lubrication and piston dynamics and slap.

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