Efficient Machining of Microdimples for Friction Reduction

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
B. Denkena ◽  
J. Köhler ◽  
J. Kästner ◽  
T. Göttsching ◽  
F. Dinkelacker ◽  
...  
Keyword(s):  
Sliding Friction ◽  
Hydrodynamic Pressure ◽  
Cylinder Liner ◽  
Tribological Performance ◽  
Pattern Generation ◽  
Friction Reduction ◽  
Functional Surface ◽  
Cutting Kinematics ◽  
Machining Strategies ◽  
Cylinder Liners

In order to improve the tribological properties of thermomechanically highly stressed surfaces such as cylinder liners, microdimples are produced by fly-cutting kinematics along the functional surface. The structures are used to hold back lubricant but also to increase the hydrodynamic pressure, which is built up between the sliding friction partners. For that, machining strategies for the pattern generation in cylindrical components are developed as well as a mathematical model of the microdimple arrangement and distribution. The tribological performance of the machined microdimples is analyzed by means of ring-on-disk experiments. At low sliding speeds the friction coefficient can be decreased clearly by microdimples. This indicates the potential for low-speed or reciprocating tribosystems like cylinder liners. This potential is quantified by motor driven experiments and the comparison between structured and nonstructured cylinder liners. A honed (fine) liner with additional microdimples along the interstice area shows friction losses up to 19% compared to standard honed nonstructured cylinder liner.

Influence of positive texturing on friction and wear properties of piston ring-cylinder liner tribo pair under lubricated conditions

2019 ◽  
Vol 71 (4) ◽  
pp. 515-524 ◽  
Author(s):  
Venkateswara Babu P. ◽  
Ismail Syed ◽  
Satish Ben Beera
Keyword(s):  
Wear Resistance ◽  
Internal Combustion Engine ◽  
Friction And Wear ◽  
Piston Ring ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Tribological Performance ◽  
Friction Reduction ◽  
Content Type

Purpose In an internal combustion engine, piston ring-cylinder liner tribo pair is one among the most critical rubbing pairs. Most of the energy produced by an internal combustion engine is dissipated as frictional losses of which major portion is contributed by the piston ring-cylinder liner tribo pair. Hence, proper design of tribological parameters of piston ring-cylinder liner pair is essential and can effectively reduce the friction and wear, thereby improving the tribological performance of the engine. This paper aims to use surface texturing, an effective and feasible method, to improve the tribological performance of piston ring-cylinder liner tribo pair. Design/methodology/approach In this paper, influence of positive texturing (protruding) on friction reduction and wear resistance of piston ring surfaces was studied. The square-shaped positive textures were fabricated on piston ring surface by chemical etching method, and the experiments were conducted with textured piston ring surfaces against un-textured cylinder liner surface on pin-on-disc apparatus by continuous supply of lubricant at the inlet of contact zone. The parameters varied in this study are area density and normal load at a constant sliding speed. A comparison was made between the tribological properties of textured and un-textured piston ring surfaces. Findings From the experimental results, the tribological performance of the textured piston ring-cylinder liner tribo pair was significantly improved over a un-textured tribo pair. A maximum friction reduction of 67.6 per cent and wear resistance of 81.6 per cent were observed with textured ring surfaces as compared to un-textured ring surfaces. Originality/value This experimental study is helpful for better understanding of the potency of positive texturing on friction reduction and wear resistance of piston ring-cylinder liner tribo pair under lubricated sliding conditions.

scholarly journals The Rotating Liner Engine (RLE) Diesel Prototype: Reducing Internal Engine Friction by about 40% under Idle Conditions

2021 ◽  
Vol 11 (2) ◽  
pp. 779
Author(s):  
Dimitrios Dardalis ◽  
Amiyo Basu ◽  
Matt J. Hall ◽  
Ronald D. Mattthews
Keyword(s):  
Internal Combustion Engines ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Friction Reduction ◽  
Contact Boundary ◽  
Metal Contact ◽  
Load Testing ◽  
Gas Leakage ◽  
Brake Mean Effective Pressure ◽  
Economy Benefit

The Rotating Liner Engine (RLE) concept is a design concept for internal combustion engines, where the cylinder liner rotates at a surface speed of 2–4 m/s in order to assist piston ring lubrication. Specifically, we have evidence from prior art and from our own research that the above rotation has the potential to eliminate the metal-to-metal contact/boundary friction that exists close to the piston reversal areas. This frictional source becomes a significant energy loss, especially in the compression/expansion part of the cycle, when the gas pressure that loads the piston rings and skirts is high. This paper describes the Diesel RLE prototype constructed from a Cummins 4BT and the preliminary observations from initial low load testing. The critical technical challenge, namely the rotating liner face seal, appears to be operating with negligible gas leakage and within the hydrodynamic lubrication regime for the loads tested (peak cylinder pressures of the order of 100 bar) and up to about 10 bar BMEP (brake mean effective pressure). Preliminary testing has proven that the metal-to-metal contact in the piston assembly mostly vanished, and a friction reduction at idle conditions of about 40% as extrapolated to a complete engine has taken place. It is expected that as the speed increases, the friction reduction percentage will diminish, but as the load increases, the friction reduction will increase. The fuel economy benefit over the US Heavy-Duty driving cycle will likely be of the order of 10% compared to a standard engine.

scholarly journals Fast laser surface texturing of spherical samples to improve the frictional performance of elasto-hydrodynamic lubricated contacts

Friction ◽  
2021 ◽  
Author(s):  
G. Boidi ◽  
P. G. Grützmacher ◽  
A. Kadiric ◽  
F. J. Profito ◽  
I. F. Machado ◽  
...  
Keyword(s):  
Surface Texturing ◽  
Hydrodynamic Pressure ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Textured Surfaces ◽  
Engineering Applications ◽  
Lubricated Contacts ◽  
Fluid Uptake ◽  
Direct Laser ◽  
Frictional Performance

AbstractTextured surfaces offer the potential to promote friction and wear reduction by increasing the hydrodynamic pressure, fluid uptake, or acting as oil or debris reservoirs. However, texturing techniques often require additional manufacturing steps and costs, thus frequently being not economically feasible for real engineering applications. This experimental study aims at applying a fast laser texturing technique on curved surfaces for obtaining superior tribological performances. A femtosecond pulsed laser (Ti:Sapphire) and direct laser interference patterning (with a solid-state Nd:YAG laser) were used for manufacturing dimple and groove patterns on curved steel surfaces (ball samples). Tribological tests were carried out under elasto-hydrodynamic lubricated contact conditions varying slide-roll ratio using a ball-on-disk configuration. Furthermore, a specific interferometry technique for rough surfaces was used to measure the film thickness of smooth and textured surfaces. Smooth steel samples were used to obtain data for the reference surface. The results showed that dimples promoted friction reduction (up to 20%) compared to the reference smooth specimens, whereas grooves generally caused less beneficial or detrimental effects. In addition, dimples promoted the formation of full film lubrication conditions at lower speeds. This study demonstrates how fast texturing techniques could potentially be used for improving the tribological performance of bearings as well as other mechanical components utilised in several engineering applications.

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.

scholarly journals Wear of different material pairings for the cylinder liner – piston ring contact

2018 ◽  
Vol 70 (4) ◽  
pp. 687-699 ◽  
Author(s):  
Thomas Wopelka ◽  
Ulrike Cihak-Bayr ◽  
Claudia Lenauer ◽  
Ferenc Ditrói ◽  
Sándor Takács ◽  
...  
Keyword(s):  
Steady State ◽  
Wear Mechanisms ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Wear Behaviour ◽  
Special Focus ◽  
Intermediate Step ◽  
Piston Rings ◽  
Content Type ◽  
Cylinder Liners

Purpose This paper aims to investigate the wear behaviour of different materials for cylinder liners and piston rings in a linear reciprocating tribometer with special focus on the wear of the cylinder liner in the boundary lubrication regime. Design/methodology/approach Conventional nitrided steel, as well as diamond-like carbon and chromium nitride-coated piston rings, were tested against cast iron, AlSi and Fe-coated AlSi cylinder liners. The experiments were carried out with samples produced from original engine parts to have the original surface topography available. Radioactive tracer isotopes were used to measure cylinder liner wear continuously, enabling separation of running-in and steady-state wear. Findings A ranking of the material pairings with respect to wear behaviour of the cylinder liner was found. Post-test inspection of the cylinder samples by scanning electron microscopy (SEM) revealed differences in the wear mechanisms for the different material combinations. The results show that the running-in and steady-state wear of the liners can be reduced by choosing the appropriate material for the piston ring. Originality/value The use of original engine parts in a closely controlled tribometer environment under realistic loading conditions, in conjunction with continuous and highly sensitive wear measurement methods and a detailed SEM analysis of the wear mechanisms, forms an intermediate step between engine testing and laboratory environment testing.

Multi beam microprocessing for printing and embossing applications with high power ultrashort pulsed lasers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Stephan Bruening ◽  
Arnold Gillner ◽  
Keming Du
Keyword(s):  
High Power ◽  
Average Power ◽  
Ablation Rate ◽  
Friction Reduction ◽  
Laser Source ◽  
Limiting Factor ◽  
Functional Surface ◽  
Roll To Roll ◽  
Micro Patterning ◽  
Tool Diameter

Abstract Micro structuring of surfaces is of great interest for various applications, e.g. for the tooling industry, the printing industry and for consumer goods. In suitable mass production applications, such as injection molding or roll-to-roll processing for various markets, the final product could be equipped with new properties, such as hydrophilic behavior, adjustable gloss level, soft-touch behavior, light management properties etc. To generate functionalities at reasonable cost, embossing dies can be augmented with additional micro/nano-scale structure using laser ablation technologies. Despite the availability of ultrashort pulsed (USP) high power lasers (up to several hundred watts), it is still a challenge to structure large areas, as required on embossing rolls, in an acceptable processing time for industrial production. In terms of industrial implementation, direct digital transfer is a limiting factor for ultrahigh resolution. Shorter machining times by further increasing spot or workpiece motion are limited. Enlarging the ablation diameter, and thus the tool diameter, delivers a higher ablation rate with the comparable ablation quality, but entails a reduction in resolution. While maintaining the achieved state-of-the-art performance, upscaling of single modulated lasers provides a less demanding way to increase productivity. In the processing of steel surfaces, an increase in material removal can also be achieved by using pulse burst. In this work, the parallel process of single modulated multi laser sources is compared with a laser source split by diffractive optical elements (DOE) for applications in a cylinder micro patterning system. A newly developed highly compact ps laser with repetition rates up to 8 MHz and an average power of 300 or 500 W was divided into 8 or 16 parallel beamlets by a DOE. The ablation rate of each approach was investigated by typical microstructures on copper surfaces. At surface speeds of 10 m/s and a resolution of 5080 dpi, an ablation rate of up to 27 mm³/min was achieved. Different functional surface geometries were realized on an embossing roll as master, which is used for replication of the structures in roll-to-roll processes. Functional structures, such as friction reduction, improved soft touch or light guiding elements on large surfaces are demonstrated.

Detailed analysis of piston secondary motion and tribological performance

2019 ◽  
Vol 21 (9) ◽  
pp. 1647-1661 ◽  
Author(s):  
Cristiana Delprete ◽  
Abbas Razavykia ◽  
Paolo Baldissera
Keyword(s):  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Tribological Performance ◽  
System Of Nonlinear Equations ◽  
Piston Skirt ◽  
Wide Range ◽  
Secondary Motion ◽  
Piston Ring Pack ◽  
Ring Pack

This article presents a detailed analytical model to evaluate piston skirt tribology under hydrodynamic lubrication. The contribution of the piston ring pack lubrication has been taken into account to study piston secondary motion and tribological performance. A system of nonlinear equations comprising Reynolds equation and force equilibrium is solved to calculate piston ring pack friction force and its moment about wrist pin axis. Instantaneous minimum oil film thickness at piston ring/liner interface has been estimated considering different boundary conditions: full Sommerfeld, oil separation, and Reynolds cavitation and reformation. The ring pack model has capability to be used for a wide range of ring face profiles under boundary and hydrodynamic lubrication. Piston secondary motion is evaluated using lubrication theory and equilibrium of forces and moments, to examine the effect of wrist pin location, piston skirt/liner clearance, and oil rheology. Numerical method and finite difference scheme have been used to define piston eccentricity and hydrodynamic pressure acting over the skirt.

scholarly journals Surface Characterization and Tribological Performance of Anodizing Micro-Textured Aluminum-Silicon Alloys

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1862 ◽  
Author(s):  
Luanxia Chen ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Qinghua Song ◽  
Yi Wan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Sliding Friction ◽  
Tribological Performance ◽  
Area Ratio ◽  
Micro Milling ◽  
Dry Sliding ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Aluminum Silicon

Eutectic aluminum-silicon alloys present high frictional coefficient and a high wear rate due to the low hardness under sliding friction conditions. In this paper, the eutectic aluminum-silicon alloy was textured firstly by micro-milling operations. Then, the micro-textured specimen was subjected to anodizing to fabricate alumina films. The surface topography, surface roughness, and bearing area ratio of micro-textured and anodizing micro-textured specimens were measured and characterized. For the anodizing micro-textured specimens, the surface roughness and superficial hardness increase compared with those for micro-textured ones. Tribological tests indicate that anodizing micro-textured samples present lower friction coefficient of 0.37 than that of flat samples of 0.43 under dry sliding conditions. However, they exhibit higher friction coefficient at 0.16 than that of flat samples of 0.13 under oil-lubricated conditions. The difference between the friction coefficient of anodizing micro-textured and flat samples under dry and oil-lubricated conditions is ascribed to the influence mechanism of surface roughness, bearing area ratio curves, and its relative parameters on the tribological performance of testing samples. The dry sliding friction coefficient has a positive correlation with bearing area ratio curves, while they present negative correlation with bearing area ratio curves under oil-lubricated conditions. The synergy method treated with micro-milling and anodizing provides an effective approach to enhance the dry sliding friction property of eutectic aluminum-silicon alloys.

Synergistic Effects of MoDTC and Overbased Calcium Sulfonate Additive

2013 ◽  
Vol 651 ◽  
pp. 73-76 ◽  
Author(s):  
Zhao Zhou ◽  
Yan Qiu Xia ◽  
Xiang Yu Ge
Keyword(s):  
Sliding Friction ◽  
Synergistic Effects ◽  
Tribological Performance ◽  
Wear Properties ◽  
Sulfonate Additive ◽  
Alkyl Benzene ◽  
Friction Tester ◽  
Calcium Sulfonate ◽  
Alpha Olefin ◽  
Pure Poly

The synergetic effects of molybdenum dialkyldithiocarbamate (MoDTC) and overbased liner alkyl benzene synthetic calcium sulfonate (OBCaS) on the tribological performance of lubricant were investigated using reciprocating ball-on-disk sliding friction tester. The results showed that the two kinds of additives with a certain range of concent ration could improve tribological properties of alone MoDTC. The mass percent of 0.5% MoDTC and 2% OBCaS in pure poly-alpha-olefin (PAO) has the best friction reducing and anti-wear properties.

Fabrication of Bionic Silicon Surfaces with Lotus Effect and their Micro Tribological Performance

2010 ◽  
Vol 97-101 ◽  
pp. 1393-1398 ◽  
Author(s):  
Xi Qiu Fan
Keyword(s):  
Surface Effect ◽  
Tribological Performance ◽  
Friction Reduction ◽  
Silicon Surfaces ◽  
Test Results ◽  
Feature Size ◽  
Lotus Effect ◽  
Lotus Leaf ◽  
Novel Approach ◽  
Leaf Surfaces

With the miniature of micro-electromechanical systems (MEMS), surface effect is substantially increased, and the resulting friction, abrasion and stiction are becoming bottlenecks of the development of MEMS industry. In this paper, firstly, the feature size and topography on lotus leaf surfaces is investigated, as well as the mechanism of lotus effect applied in MEMS to reduce friction and prevent stiction is analyzed; secondly, two approaches of fabricating bionic silicon surfaces with lotus effect are proposed; finally, test results on the micro tribological performance of the mimicked silicon surfaces are presented, which demonstrates that to mimic lotus effect on silicon surfaces is a novel approach to prevent stiction and reduce friction . However, the effectiveness of stiction prevention and friction reduction is related to the size and shape of the textured structures.

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