The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Gunther Knoll - One of the best experts on this subject based on the ideXlab platform.
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Numerical Analysis of Laser-Textured Piston-Rings in the Hydrodynamic Lubrication Regime
Journal of Tribology, 2012Co-Authors: Gonzalo Brito Gadeschi, Katja Backhaus, Gunther KnollAbstract:In this work, the performance of barrel-shaped laser-textured Piston Rings is numerically investigated. The surface texture, parameterized by the dimple density, dimple depth, and dimple distribution pattern, is optimized to minimize the friction coefficient for Piston Rings of variable curvature. We consider fully textured as well as partially textured Piston Rings with two different dimple distributions patterns: a central dimple distribution, and a distribution along the Piston ring edges. Finally, the sensitivity of the optimal surface parameters to the Piston ring curvature is assessed.
Eran Sher - One of the best experts on this subject based on the ideXlab platform.
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improving fuel efficiency with laser surface textured Piston Rings
Tribology International, 2009Co-Authors: Izhak Etsion, Eran SherAbstract:Abstract An experimental study is presented to evaluate the effect of partially laser surface textured Piston Rings on the fuel consumption and exhaust gas composition of a compression–ignition IC engine. Dynamometer tests were performed with a Ford Transit naturally aspirated 2500 cm 3 engine at a wide range of engine speeds under near-half-load conditions. A comparison was made between the performance of reference non-textured conventional barrel-shaped Rings and optimum partial laser surface texturing (LST) cylindrical-shape Rings. It was found that the partial LST Piston Rings exhibited up to 4% lower fuel consumption, while no traceable change in the exhaust gas composition or smoke level was observed.
Izhak Etsion - One of the best experts on this subject based on the ideXlab platform.
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improving fuel efficiency with laser surface textured Piston Rings
Tribology International, 2009Co-Authors: Izhak Etsion, Eran SherAbstract:Abstract An experimental study is presented to evaluate the effect of partially laser surface textured Piston Rings on the fuel consumption and exhaust gas composition of a compression–ignition IC engine. Dynamometer tests were performed with a Ford Transit naturally aspirated 2500 cm 3 engine at a wide range of engine speeds under near-half-load conditions. A comparison was made between the performance of reference non-textured conventional barrel-shaped Rings and optimum partial laser surface texturing (LST) cylindrical-shape Rings. It was found that the partial LST Piston Rings exhibited up to 4% lower fuel consumption, while no traceable change in the exhaust gas composition or smoke level was observed.
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Testing Piston Rings with partial laser surface texturing for friction reduction
Wear, 2006Co-Authors: Grigory Ryk, Izhak EtsionAbstract:An experimental study is presented to evaluate the effect of partial laser surface texturing (LST) on friction reduction in Piston Rings. Tests were performed on a reciprocating test rig with actual Piston Rings and cylinder liner segments. A comparison was made between the performance of a reference non-textured conventional barrel shape Rings and optimum partial LST cylindrical shape Rings. It was found that the partial LST Piston Rings exhibited about 25% lower friction.
Ulf Sjödin - One of the best experts on this subject based on the ideXlab platform.
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Initial sliding wear on Piston Rings in a radial Piston hydraulic motor
Wear, 2003Co-Authors: Ulf Sjödin, Ulf OlofssonAbstract:The initial sliding wear of boundary lubricated Piston Rings used in a hydraulic motor is studied in terms of the changes in mass, form and surface roughness. The Piston ring in a hydraulic motor makes an important contribution to high volumetric efficiency by properly sealing the cylinder bore and Piston. The results show that the wear on the Piston ring in this particular test rig takes place at the top of the asymmetric crowning at the outer surface contacting the cylinder bore. Initially, the roughness amplitude decreased rapidly, and had decreased by one-third after sliding 10 m. The dominant wear mechanism was mild wear. Abrasive wear also clearly influences the amount of wear.
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Characterisation of wear on Piston Rings in a radial Piston hydraulic motor
2002Co-Authors: Ulf SjödinAbstract:This study focuses on the wear of Piston Rings in a hydraulic radial Piston motor. The Piston ring has to satisfy increasing demands for reliability and longer service life. It has two contacting surfaces, the face and the flank, and operates under a boundary lubrication state. This first part of the project aimed to detect and characterise Piston ring wear. Measurement by weighing gives an overall value for wear defined as loss of mass. Two-dimensional form and surface roughness measurements show the distribution of wear on the Piston ring face in contact with the cylinder bore and the Piston ring flank in contact with the Piston groove. Three-dimensional analyses, both quantitative and qualitative, allow the wear mechanisms to be identified. The wear of Piston Rings from an actual hydraulic motor was characterised. As well, rig testing was performed in two different test rig set-ups, one simulating the sliding movement of the Piston ring and the other the tilting movement at the end of the strokes. Wear during the running-in period was investigated, and the findings indicate that the period when this takes place is of short duration. In the long term, mild wear makes the surfaces smoother than they were when new, resulting in a very low wear coefficient. Significant levels of wear were measured on both contacting surfaces of the Piston ring. In cases in which the flank exhibits more wear than the face, the wear on the flank can be reduced by proper design of the Piston groove. The second part of the project aimed to evaluate use of a textured surface for the cylinder bore counter surface and a coated surface for the Piston ring. Three modelling experiments were performed to characterise the friction and wear properties under lean boundary lubrication conditions. Under such conditions, textured surfaces have the advantage of retaining more lubricant and supplying it over a longer time. Stable friction was also a distinctive feature of the textured surface. Use of a coating could also possibly reduce the amount of wear. Though a smooth surface, like a polished one, is hard to beat for a working texture, a coated surface is far ahead of a smooth uncoated one. Different manufactured and commonly used cylinder bore surfaces, including textured ones, were evaluated in the sliding movement test rig. That allowed favourable wear properties, such as lowest wear coefficient, to be determined with the use of a roller burnished surface. A final part of the research involved simulating wear on the Piston ring face throughout the entire service life of a hydraulic motor. This allowed us to determine the roles of surface roughness and coating in prolonging service life and achieving acceptable and secure Piston ring operation. The model is simple and realistic, but still needs to be refined so as to correspond even better to reality.
Shanhong Wan - One of the best experts on this subject based on the ideXlab platform.
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investigating the corrosion fatigue wear on crn coated Piston Rings from laboratory wear tests and field trial studies
Wear, 2019Co-Authors: Shanhong Wan, Guang An Zhang, A K Tieu, Hui Wang, Yana Xia, Bach H Tran, Hongtao Zhu, Qiang ZhuAbstract:Abstract The interacting mechanisms of corrosion and fatigue wear of the CrN coated Piston Rings were investigated in two ways: (1) by comparing the laboratory test data to field results, and (2) by simulating the stress distribution and crack origins in the CrN coating using a Finite Element Method (FEM). The surface and interface characterizations confirmed that fatigue wear resulted in cracking and spalling of the CrN coating. At the same time, corrosive wear was promoted by sulfur incursion along boundary defects in the CrN coating. FEM simulations showed that the magnitude of stresses at the interface of Cr particle/CrN matrix was a function of Cr particulate sizes, and they also identified crack initiation sites at rubbing contacts. The dominant factors contributing to the propagation of the surface/subsurface cracking were elucidated. Inherent defects initiated cracks, and the repetitive shear stress coupled with the effects of corrosive species gave rise to an acceleration of crack enlargement and subsequent severe spalling of the CrN coating.
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comparison of the scuffing behaviour and wear resistance of candidate engineered coatings for automotive Piston Rings
Tribology International, 2017Co-Authors: Shanhong Wan, Guang An Zhang, A K Tieu, Bo ZhangAbstract:Abstract Continuous optimization of advanced coatings is required to achieve technology advances and strict emission standards in automotive systems. Integration of conventional ceramic coatings and hard amorphous graphite-like carbon (GLC) with low friction is an economically feasible way of achieving superior efficiency of oil and durability as well as scuffing resistance. This work evaluates the scuffing resistant capacity and durability of engineered coating materials. The presence of GLC not only combats the scuffing damage and running instability effectively for conventional chromium-based coatings, and also improves the reliability and robustness of the Piston Rings. The scuffing mechanism of the engineered Rings with and without GLC surface will be discussed by the observation of the damaged characteristics and the chemistry of the rubbing parts. This will potentially benefit to optimize the coating material in the Piston assembly of engine.
