The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Eduardo Tomanik - One of the best experts on this subject based on the ideXlab platform.
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Combined lubricant-surface system approach for potential passenger car CO2 reduction on piston-ring-Cylinder Bore assembly
Tribology International, 2020Co-Authors: Eduardo Tomanik, Francisco J. Profito, Brett Sheets, Roberto A. SouzaAbstract:Abstract The impact of reducing friction losses on the fuel consumption and CO2 emissions was investigated through computational simulation of piston ring dynamics. Experimentally determined Cylinder Bore surface finishes, low viscosity oil and ring coatings response to oil additives were used as simulation inputs. Oil viscosity grades from SAE10W-40 to SAE0W-4 were considered. 3D roughness measurements of regular and “mirror-like” Cylinder Bores were used to estimate the flow factors coefficients for the average Reynolds equation and asperity contact stiffness. The combination of smooth Cylinder Bores, low viscosity oils with appropriate additives promoted ring pack FMEP reductions of up to 66% at part load and WOT with consequent CO2 reductions of up to 10% at part load and 1.5% at WOT.
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modelling the hydrodynamic support of Cylinder Bore and piston rings with laser textured surfaces
Tribology International, 2013Co-Authors: Eduardo TomanikAbstract:An one-dimensional computer model was used to simulated surface texture effects on engine Cylinder Bore, top and oil control rings. Steady state, reciprocating tests and engine conditions were considered. For the engine simulation, conditions close to the top reversal and at mid-stroke were simulated. Different micro-dimple geometries were considered, as well as full and partial texturing. As main conclusion, micro-dimples on the Bore and rings were able to generate significant hydrodynamic support with potential to reduce both friction and wear. A special benefit was predicted when the micro-dimples were on the flat surface of the oil control rings.
Homer Rahnejat - One of the best experts on this subject based on the ideXlab platform.
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Asperity level frictional interactions of Cylinder Bore materials and lubricant composition
2020Co-Authors: Michael Forder, Sebastian Howell-smith, Jamal Umer, Nick Morris, Ramin Rahmani, Homer RahnejatAbstract:Parasitic frictional losses in internal combustion engines of race vehicles adversely affect their performance. A significant proportion of these losses occur within the piston-Cylinder system. This paper presents a study of the compatibility of Cylinder Bore surface materials with typical lubricant base constituent stock (Poly Alpha Olefin (PAO) and Polyolester (POE)) as well as a fully formulated lubricant. Nanoscale boundary friction is measured using lateral force microscopy. The effect of material properties, nanoscale roughness and lubricant species upon underlying mechanisms of generated friction is presented. Advanced Cylinder materials and coatings and lubricant molecular species used for high performance engines are investigated, an integrated approach not hitherto reported in literature.
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Asperity level tribological investigation of automotive Bore material and coatings
Tribology International, 2018Co-Authors: J. Umer, N. Morris, Sebastian Howell-smith, Michael Leighton, R. Wild, Rahim Rahmani, Homer RahnejatAbstract:Choosing in-Cylinder surfaces is complex. A well-chosen surface has low friction and wear. Conversely, poor oversight often leads to premature failure through wear and scuffing. Typically Cylinder Bore surfaces are selected experientially. This paper demonstrates the use of Atomic Force Microscopy in LFM mode, characterising typical Cylinder Bore materials and coatings. The approach uses integrated LFM with continuum contact mechanics. It evaluates the real contact area and effective elastic modulus of the surface, including the effect of any reactive surface film. Surface energy and shear strength, as well as the coefficient of friction in nanoscale interactions are also determined. These properties are measured for 6 Cylinder Bore materials, including for composite Nickel-Silicon Carbide and DLC, used for high performance engines.
Larry Brombolich - One of the best experts on this subject based on the ideXlab platform.
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Three-Dimensional Piston Ring–Cylinder Bore Contact Modeling
Journal of Engineering for Gas Turbines and Power, 2015Co-Authors: Chao Cheng, Ali Kharazmi, Harold Schock, Richard Wineland, Larry BrombolichAbstract:Increasing durability, preventing knocking combustion, improving fuel efficiency and reducing pollutant emission characterize the needs for modern internal combustion engine design. These factors are highly influenced by the power Cylinder system design. In particular, the piston ring to Cylinder Bore contact force distribution around the circumference of the piston rings must be optimized under all running conditions. To accomplish this, the ring manufacturers make the ring curvature non-constant along the circumference. Most existing analytical tools are not able to simulate the variation along the ring circumference. In order to improve the understanding of this contact distribution and provide a high-fidelity ring design tool, a three-dimensional finite element piston ring model was developed to accomplish this variation.The modeling procedure and results are presented in this work. Experiments using a commercially available ring with negative ovality were conducted to validate the model. The ring free shape profile and the ring cross-section geometries were used as inputs to the model. Typical piston ring groove and Cylinder wall temperatures were also model inputs to characterize thermal influences on the ring/Bore interface forces. The ring/Bore conformability was analyzed as a function of the ring radial displacements, Cylinder Bore constraint forces and thermal load changes to the ring. The model output showed radially separation gaps between the ring front face and the Bore. This analysis provides an insight to evaluate the piston ring design. Together with an optimizer, the model can be used as a ring design tool to predict the ring free shape with a specified constraint force distribution pattern. Examples are given to demonstrate the capabilities of this numerical analytical tool. In addition, the 3D ring model can be used to improve the accuracy of existing lubrication, friction and wear analysis tools and therefore improve the entire internal combustion engine power Cylinder system design.Copyright © 2014 by ASME
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Three Dimensional Piston Ring-Cylinder Bore Contact Modeling
Volume 2: Instrumentation Controls and Hybrids; Numerical Simulation; Engine Design and Mechanical Development; Keynote Papers, 2014Co-Authors: Chao Cheng, Ali Kharazmi, Harold Schock, Richard Wineland, Larry BrombolichAbstract:Increasing durability, preventing knocking combustion, improving fuel efficiency and reducing pollutant emission characterize the needs for modern internal combustion engine design. These factors are highly influenced by the power Cylinder system design. In particular, the piston ring to Cylinder Bore contact force distribution around the circumference of the piston rings must be optimized under all running conditions. To accomplish this, the ring manufacturers make the ring curvature non-constant along the circumference. Most existing analytical tools are not able to simulate the variation along the ring circumference. In order to improve the understanding of this contact distribution and provide a high-fidelity ring design tool, a three-dimensional finite element piston ring model was developed to accomplish this variation. The modeling procedure and results are presented in this work. Experiments using a commercially available ring with negative ovality were conducted to validate the model. The ring free shape profile and the ring cross-section geometries were used as inputs to the model. Typical piston ring groove and Cylinder wall temperatures were also model inputs to characterize thermal influences on the ring/Bore interface forces. The ring/Bore conformability was analyzed as a function of the ring radial displacements, Cylinder Bore constraint forces and thermal load changes to the ring. The model output showed radially separation gaps between the ring front face and the Bore. This analysis provides an insight to evaluate the piston ring design. Together with an optimizer, the model can be used as a ring design tool to predict the ring free shape with a specified constraint force distribution pattern. Examples are given to demonstrate the capabilities of this numerical analytical tool. In addition, the 3D ring model can be used to improve the accuracy of existing lubrication, friction and wear analysis tools and therefore improve the entire internal combustion engine power Cylinder system design.
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three dimensional piston ring Cylinder Bore contact modeling
Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2014Co-Authors: Chao Cheng, Ali Kharazmi, Harold Schock, Richard Wineland, Larry BrombolichAbstract:Increasing durability, preventing knocking combustion, improving fuel efficiency and reducing pollutant emission characterize the needs for modern internal combustion engine design. These factors are highly influenced by the power Cylinder system design. In particular, the piston ring to Cylinder Bore contact force distribution around the circumference of the piston rings must be optimized under all running conditions. To accomplish this, the ring manufacturers make the ring curvature non-constant along the circumference. Most existing analytical tools are not able to simulate the variation along the ring circumference. In order to improve the understanding of this contact distribution and provide a high-fidelity ring design tool, a three-dimensional finite element piston ring model was developed to accomplish this variation.The modeling procedure and results are presented in this work. Experiments using a commercially available ring with negative ovality were conducted to validate the model. The ring free shape profile and the ring cross-section geometries were used as inputs to the model. Typical piston ring groove and Cylinder wall temperatures were also model inputs to characterize thermal influences on the ring/Bore interface forces. The ring/Bore conformability was analyzed as a function of the ring radial displacements, Cylinder Bore constraint forces and thermal load changes to the ring. The model output showed radially separation gaps between the ring front face and the Bore. This analysis provides an insight to evaluate the piston ring design. Together with an optimizer, the model can be used as a ring design tool to predict the ring free shape with a specified constraint force distribution pattern. Examples are given to demonstrate the capabilities of this numerical analytical tool. In addition, the 3D ring model can be used to improve the accuracy of existing lubrication, friction and wear analysis tools and therefore improve the entire internal combustion engine power Cylinder system design.Copyright © 2014 by ASME
M. Priest - One of the best experts on this subject based on the ideXlab platform.
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lubrication of an electroplated nickel matrix silicon carbide coated eutectic aluminium silicon alloy automotive Cylinder Bore with an ionic liquid as a lubricant additive
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2009Co-Authors: K Mistry, M. PriestAbstract:AbstractFor a chromium-nitrided steel piston ring section sliding against an electroplated nickel matrix silicon carbide coated eutectic aluminium—silicon alloy automotive Cylinder Bore in a reciprocating tribometer, the ionic liquid (IL) imidazolium tetrafluoroborate has an excellent tribological performance as a lubricant additive in the presence of tritolyl phosphate (TTP). A low friction coefficient of 0.015 and a substantial tribofilm was generated. The performance of this base oil/additive combination was superior to the base oil alone or the separate additives in the base oil. The substantial improvement in tribological performance given by addition of an IL and TTP, 1 per cent by volume of each, to a group III base oil indicates a synergistic interaction between the IL and TTP. The need to understand the chemical and physical nature of the tribofilm is emphasized.
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lubrication of an electroplated nickel matrix silicon carbide coated eutectic aluminium silicon alloy automotive Cylinder Bore with an ionic liquid as a lubricant additive
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2009Co-Authors: K Mistry, Malcolm F Fox, M. PriestAbstract:AbstractFor a chromium-nitrided steel piston ring section sliding against an electroplated nickel matrix silicon carbide coated eutectic aluminium—silicon alloy automotive Cylinder Bore in a recipr...
Lisa M Wiese - One of the best experts on this subject based on the ideXlab platform.
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spatially resolved nanoscale chemical and mechanical characterization of zddp antiwear films on aluminum silicon alloys under Cylinder Bore wear conditions
Tribology Letters, 2005Co-Authors: Mark A Nicholls, P R Norton, G M Bancroft, M Kasrai, G De Stasio, Lisa M WieseAbstract:Understanding the lubrication of aluminum–silicon (Al–Si) alloys (>18 Si) under conditions similar to those in the Cylinder/Bore system is vital to determining their applicability to current engine designs. A novel investigation of the location of zinc-dialkyl-dithiophosphate (ZDDPs) antiwear (AW) film formation on an Al–Si alloy has been performed using X-ray absorption near edge structure (XANES) analysis, X-ray photoelectron emission spectroscopy (X-PEEM), and imaging nanoindentation techniques. A study of the initial stages of wear (10 min) to prolonged rubbing (60 min) was performed. The findings show that the film forms primarily on the raised silicon grains and is consistent with a zinc polyphosphate glass. The film has an elastic modulus of ~70 GPa and a similar elastic response to a ZDDP AW film formed on steel under the same conditions. This provides the first direct observation and characterization of a ZDDP antiwear film on Al–Si alloys using spatially resolved chemical and mechanical techniques at the nanoscale.
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Spatially resolved nanoscale chemical and mechanical characterization of ZDDP antiwear films on aluminum–silicon alloys under Cylinder/Bore wear conditions
Tribology Letters, 2005Co-Authors: Mark A Nicholls, P R Norton, G M Bancroft, M Kasrai, G. De. Stasio, Lisa M WieseAbstract:Understanding the lubrication of aluminum–silicon (Al–Si) alloys (>18 Si) under conditions similar to those in the Cylinder/Bore system is vital to determining their applicability to current engine designs. A novel investigation of the location of zinc-dialkyl-dithiophosphate (ZDDPs) antiwear (AW) film formation on an Al–Si alloy has been performed using X-ray absorption near edge structure (XANES) analysis, X-ray photoelectron emission spectroscopy (X-PEEM), and imaging nanoindentation techniques. A study of the initial stages of wear (10 min) to prolonged rubbing (60 min) was performed. The findings show that the film forms primarily on the raised silicon grains and is consistent with a zinc polyphosphate glass. The film has an elastic modulus of ~70 GPa and a similar elastic response to a ZDDP AW film formed on steel under the same conditions. This provides the first direct observation and characterization of a ZDDP antiwear film on Al–Si alloys using spatially resolved chemical and mechanical techniques at the nanoscale.
