The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Roland Larsson - One of the best experts on this subject based on the ideXlab platform.
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Wet Clutch Friction Interfaces under Water-Contaminated Lubricant Conditions
Tribology Transactions, 2016Co-Authors: Nowshir Fatima, A P Mathew, Pär Marklund, Roland LarssonAbstract:ABSTRACTThe performance of wet clutches used for Automatic Transmissions or other applications usually includes the desired positive friction characteristics and a shudder-free torque generation. Changes in the operating variables such as the lubricant conditions influence the formation of a tribofilm, and friction characteristics and can alter the degradation of the friction interfaces. In this work, the friction characteristics and degradation of the paper–steel friction interfaces were monitored when a commercial fully formulated Automatic Transmission Fluid (ATF) was contaminated with water. It was found that water in ATF influenced the clutch stability by increasing the mean coefficient of friction (µ) and the negative friction–velocity slope. Surface studies of the posttest friction interfaces clearly indicated reduced surface porosity and permeability, increased wettability, and changed elemental composition on the contacting surfaces after tested with water-contaminated ATF. Moreover, water-contam...
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Surface chemistry of wet clutch influenced by water contamination in Automatic Transmission Fluids
Tribology International, 2016Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Roland LarssonAbstract:Lubricated friction interfaces used for wet clutches produce different friction behaviours depending on the lubricant conditions. Usually the lubricant conditions vary for water contamination in Automatic Transmission Fluid (ATF). The presence of water retards the ATF performance by increasing the friction and can influence the deterioration of the clutch plates. Water as a polar contaminant can change the absorbability of the surface active additives, which might cause the characteristic friction behaviour. The aim of this paper is to verify the surface chemistry of tribotested standard friction interfaces lubricated with water contaminated commercial ATF (DEXRON® VI). The evidences of the influence of water on ATF performances were shown by surface analyses.
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Influence of water on the tribological properties of zinc dialkyl-dithiophosphate and over-based calcium sulphonate additives in wet clutch contacts
Tribology International, 2015Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Kim Berglund, Roland LarssonAbstract:Abstract Usually the wet clutch lubricant properties vary with different formulations of base oil types and additives. The aim of this paper was to evaluate the effect of water on the performance of additives in ATF. Simplified lubricants, ZDDP and over-based Ca-sulfonates detergent additives in an API Group I mineral base oil, were employed to compare with the commercial fully-formulated Automatic Transmission Fluid (DEXRON ® VI) during water-contamination. A full-scale wet clutch test rig was used to evaluate the frictional response due to water contamination of the lubricants. Fourier Transform Infrared Spectroscopy was utilized to evaluate the variation in the solubility of these polar organic additives in the water phase and Karl-Fischer titration was utilized to evaluate the post-test water content for different formulations.
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Degradation mechanism of Automatic Transmission Fluid by water as a contaminant
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2014Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Roland LarssonAbstract:The degradation mechanism of water-contaminated Automatic Transmission Fluids (ATF) was experimentally investigated. Water-contaminated ATF was tribotested in a full-scale wet clutch test rig to mo...
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Degradation Mechanism of Water Contaminated Automatic Transmission Fluid (ATF) in Wet Clutch System
2013Co-Authors: Nowshir Fatima, A P Mathew, Pär Marklund, Allan Holmgren, Roland LarssonAbstract:Degradation mechanism of water contaminated Automatic Transmission Fluid (ATF) in wet clutch system
Nowshir Fatima - One of the best experts on this subject based on the ideXlab platform.
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Original Article Degradation mechanism of
2016Co-Authors: Nowshir Fatima, Allan Holmgren, Ichiro MinamiAbstract:Automatic Transmission Fluid by water as a contaminan
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Wet Clutch Friction Interfaces under Water-Contaminated Lubricant Conditions
Tribology Transactions, 2016Co-Authors: Nowshir Fatima, A P Mathew, Pär Marklund, Roland LarssonAbstract:ABSTRACTThe performance of wet clutches used for Automatic Transmissions or other applications usually includes the desired positive friction characteristics and a shudder-free torque generation. Changes in the operating variables such as the lubricant conditions influence the formation of a tribofilm, and friction characteristics and can alter the degradation of the friction interfaces. In this work, the friction characteristics and degradation of the paper–steel friction interfaces were monitored when a commercial fully formulated Automatic Transmission Fluid (ATF) was contaminated with water. It was found that water in ATF influenced the clutch stability by increasing the mean coefficient of friction (µ) and the negative friction–velocity slope. Surface studies of the posttest friction interfaces clearly indicated reduced surface porosity and permeability, increased wettability, and changed elemental composition on the contacting surfaces after tested with water-contaminated ATF. Moreover, water-contam...
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Surface chemistry of wet clutch influenced by water contamination in Automatic Transmission Fluids
Tribology International, 2016Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Roland LarssonAbstract:Lubricated friction interfaces used for wet clutches produce different friction behaviours depending on the lubricant conditions. Usually the lubricant conditions vary for water contamination in Automatic Transmission Fluid (ATF). The presence of water retards the ATF performance by increasing the friction and can influence the deterioration of the clutch plates. Water as a polar contaminant can change the absorbability of the surface active additives, which might cause the characteristic friction behaviour. The aim of this paper is to verify the surface chemistry of tribotested standard friction interfaces lubricated with water contaminated commercial ATF (DEXRON® VI). The evidences of the influence of water on ATF performances were shown by surface analyses.
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Influence of water on the tribological properties of zinc dialkyl-dithiophosphate and over-based calcium sulphonate additives in wet clutch contacts
Tribology International, 2015Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Kim Berglund, Roland LarssonAbstract:Abstract Usually the wet clutch lubricant properties vary with different formulations of base oil types and additives. The aim of this paper was to evaluate the effect of water on the performance of additives in ATF. Simplified lubricants, ZDDP and over-based Ca-sulfonates detergent additives in an API Group I mineral base oil, were employed to compare with the commercial fully-formulated Automatic Transmission Fluid (DEXRON ® VI) during water-contamination. A full-scale wet clutch test rig was used to evaluate the frictional response due to water contamination of the lubricants. Fourier Transform Infrared Spectroscopy was utilized to evaluate the variation in the solubility of these polar organic additives in the water phase and Karl-Fischer titration was utilized to evaluate the post-test water content for different formulations.
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Degradation mechanism of Automatic Transmission Fluid by water as a contaminant
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2014Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Roland LarssonAbstract:The degradation mechanism of water-contaminated Automatic Transmission Fluids (ATF) was experimentally investigated. Water-contaminated ATF was tribotested in a full-scale wet clutch test rig to mo...
Pär Marklund - One of the best experts on this subject based on the ideXlab platform.
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Wet Clutch Friction Interfaces under Water-Contaminated Lubricant Conditions
Tribology Transactions, 2016Co-Authors: Nowshir Fatima, A P Mathew, Pär Marklund, Roland LarssonAbstract:ABSTRACTThe performance of wet clutches used for Automatic Transmissions or other applications usually includes the desired positive friction characteristics and a shudder-free torque generation. Changes in the operating variables such as the lubricant conditions influence the formation of a tribofilm, and friction characteristics and can alter the degradation of the friction interfaces. In this work, the friction characteristics and degradation of the paper–steel friction interfaces were monitored when a commercial fully formulated Automatic Transmission Fluid (ATF) was contaminated with water. It was found that water in ATF influenced the clutch stability by increasing the mean coefficient of friction (µ) and the negative friction–velocity slope. Surface studies of the posttest friction interfaces clearly indicated reduced surface porosity and permeability, increased wettability, and changed elemental composition on the contacting surfaces after tested with water-contaminated ATF. Moreover, water-contam...
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Surface chemistry of wet clutch influenced by water contamination in Automatic Transmission Fluids
Tribology International, 2016Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Roland LarssonAbstract:Lubricated friction interfaces used for wet clutches produce different friction behaviours depending on the lubricant conditions. Usually the lubricant conditions vary for water contamination in Automatic Transmission Fluid (ATF). The presence of water retards the ATF performance by increasing the friction and can influence the deterioration of the clutch plates. Water as a polar contaminant can change the absorbability of the surface active additives, which might cause the characteristic friction behaviour. The aim of this paper is to verify the surface chemistry of tribotested standard friction interfaces lubricated with water contaminated commercial ATF (DEXRON® VI). The evidences of the influence of water on ATF performances were shown by surface analyses.
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Influence of water on the tribological properties of zinc dialkyl-dithiophosphate and over-based calcium sulphonate additives in wet clutch contacts
Tribology International, 2015Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Kim Berglund, Roland LarssonAbstract:Abstract Usually the wet clutch lubricant properties vary with different formulations of base oil types and additives. The aim of this paper was to evaluate the effect of water on the performance of additives in ATF. Simplified lubricants, ZDDP and over-based Ca-sulfonates detergent additives in an API Group I mineral base oil, were employed to compare with the commercial fully-formulated Automatic Transmission Fluid (DEXRON ® VI) during water-contamination. A full-scale wet clutch test rig was used to evaluate the frictional response due to water contamination of the lubricants. Fourier Transform Infrared Spectroscopy was utilized to evaluate the variation in the solubility of these polar organic additives in the water phase and Karl-Fischer titration was utilized to evaluate the post-test water content for different formulations.
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Degradation mechanism of Automatic Transmission Fluid by water as a contaminant
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2014Co-Authors: Nowshir Fatima, Pär Marklund, Ichiro Minami, Allan Holmgren, Roland LarssonAbstract:The degradation mechanism of water-contaminated Automatic Transmission Fluids (ATF) was experimentally investigated. Water-contaminated ATF was tribotested in a full-scale wet clutch test rig to mo...
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Degradation Mechanism of Water Contaminated Automatic Transmission Fluid (ATF) in Wet Clutch System
2013Co-Authors: Nowshir Fatima, A P Mathew, Pär Marklund, Allan Holmgren, Roland LarssonAbstract:Degradation mechanism of water contaminated Automatic Transmission Fluid (ATF) in wet clutch system
Richard J Vickerman - One of the best experts on this subject based on the ideXlab platform.
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Tribochemistry on Clutch Friction Material Lubricated by Automatic Transmission Fluids and the Link to Frictional Performance
Journal of Tribology, 2013Co-Authors: Hongyuan Zhao, Ardian Morina, Anne Neville, Richard J VickermanAbstract:Automatic Transmissions (AT) for passenger cars are becoming more popular globally, including some countries that traditionally prefer manual Transmissions. Some new friction modifiers for Transmission Fluid technologies have also emerged due to the downsizing trend of Transmissions. In order to study the tribology and tribochemistry effects of some new Automatic Transmission Fluid (ATF) additive formulations, both steel and wet-clutch friction materials were assessed by using surface analysis techniques. A variable speed friction test (VSFT) rig was used to study the antishudder properties in lock-up clutch tests and friction modifying mechanisms of ATFs. A test oil matrix containing basic ATF components was tested. The friction results were analyzed using both the linear-defined multiple parameter spider chart ATF evaluation (LSAE) method (Zhao et al., 2008, “A New Method to Evaluate the Overall Anti-Shudder Property of Automatic Transmission Fluids—Multiple Parameters Spider Chart Evaluation,” Proc. Inst. Mech. Eng., Part J: J. Eng. Tribol., 222(J3), pp. 459–470) and the friction coefficient ratio index method (Zhao et al., 2011, “Understanding Friction Behavior in Automatic Transmission Fluid LVFA Test: A New Positive Curve Parameter to Friction Coefficient Ratio Index Evaluation,” ASME J. Tribol., 133(2), p. 021802) (e.g., μ1/μ50 on the low-velocity friction apparatus (LVFA) μ-v curve results to compare the overall tribosystem and the snapshot friction performance during the test). Surface analysis results were obtained by using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and attenuated total reflectance Fourier transformed infrared spectroscopy (ATR FT-IR), and they are presented in this study to investigate the tribofilm compositions formed by different additive formulations. Some organic functional groups were found at the sample surfaces, such as –OH and O–C–O, and their presence is proposed to have a beneficial influence on the ATF friction performance. This paper discusses the surface analysis results of the test sample pieces, the possible links between specific functional groups and friction performance, and the proposed pathways of additive decompositions by using chemical bond dissociation energy comparisons.
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Anti-Shudder Properties of ATFs—Investigation into Tribofilm Composition on Clutch Friction Material and Steel Surfaces and the Link to Frictional Performance
Tribology Transactions, 2012Co-Authors: Hongyuan Zhao, Ardian Morina, Anne Neville, Richard J VickermanAbstract:The friction response of an Automatic Transmission Fluid (ATF) should ensure a smooth engagement process with no shudder in the process of power Transmission. To study the effect of ATF chemistry on anti-shudder properties, the frictional characteristics of the baseline additive system used in ATFs with various friction modifiers and detergent combinations were assessed using a variable-speed friction test (VSFT) machine. Tests were performed on steel-versus-clutch friction material tribocouples, with the aim of studying the tribofilm formation on both friction couple (steel and friction material) surfaces and to establish the link between the lubricant-surface interactions and anti-shudder performance. An SAE No. 2 test machine was also used to investigate the friction performance of the same ATFs for comparison with the VSFT results. Similar performance rankings were obtained from those two tests. This article focuses on the posttest surface analysis and surface chemistry results of the test samples. En...
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understanding friction behavior in Automatic Transmission Fluid lvfa test a new positive curve parameter to friction coefficient ratio index evaluation
Journal of Tribology-transactions of The Asme, 2011Co-Authors: Hongyuan Zhao, John Durham, Ardian Morina, Anne Neville, Richard J VickermanAbstract:The frictional characteristics of some basic additive systems used in Automatic Transmission Fluids (ATFs) were assessed using a variable speed friction test machine. The test evaluates the coefficient of friction in unidirectional sliding contact over a range of speeds, loads, and temperatures. Tests were performed on a steel-versus-clutch friction material tribocouple, mainly to establish the link between the lubricant/surface interactions and additive system performance. A new parameter that measures the positive μ-v curve slope speed range was applied, together with friction coefficient ratio index, to show the antishudder property. It is suggested that this is a good complimentary method to the friction coefficient ratio index evaluation. Lubricant formulation is important to the overall friction performance. Both friction modifiers and detergents are shown to be important to the ATF antishudder performance. Oil absorption ability of the post-test friction material surface is proposed to be an important parameter to indicate the anti-shudder durability in the test. The detergent and antiwear agents are also suggested to be responsible for the decreased oil absorption and pore plugging of the friction material surface.
Christian Alteheld - One of the best experts on this subject based on the ideXlab platform.
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design and demonstration of a wound field synchronous machine for electric vehicle traction with brushless capacitive field excitation
IEEE Transactions on Industry Applications, 2018Co-Authors: Antonio Di Gioia, Ian P. Brown, Yue Nie, Ryan Knippel, Daniel C. Ludois, Jiejian Dai, Skyler Hagen, Christian AlteheldAbstract:This paper describes the modeling, optimization, mechanical design, and experimental characterization of a high power density wound field synchronous machine (WFSM) for electric vehicle traction applications. The WFSM is designed for brushless rotor field excitation using an axial flux hydrodynamic capacitive power coupler (CPC). The flexible design environment, which was used for large-scale multiobjective optimization of the WFSM, is described. A prototype WFSM, spray cooled with Automatic Transmission Fluid, with an 80-kW output at a base speed of 4000 r/min has been tested. The prototyped WFSM achieves volumetric torque and power densities of 17.22 N·m/L and 7.19 kW/L referred to the envelope cylindrical volume of the active materials plus spray cooling rings. The specific torque and power densities are 4.69 N·m/kg and 1.95 kW/kg referred to the mass of the active materials and the shaft. The prototyped CPC provided up to 1-kW excitation power with a mass 600 g and volume of 0.271 L.
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Design of a wound field synchronous machine for electric vehicle traction with brushless capacitive field excitation
2016 IEEE Energy Conversion Congress and Exposition (ECCE), 2016Co-Authors: Antonio Di Gioia, Ian P. Brown, Yue Nie, Ryan Knippel, Daniel C. Ludois, Jiejian Dai, Skyler Hagen, Christian AlteheldAbstract:This paper describes the modeling, optimization, mechanical design, and experimental characterization of a high power density wound field synchronous machine (WFSM) for electric vehicle traction applications. The WFSM is designed for brushless rotor field excitation using an axial flux hydrodynamic capacitive power coupler (CPC). A flexible design environment is described which was used for large scale multi-objective optimization. A prototype WFSM, spray cooled with Automatic Transmission Fluid (ATF), with an 80 kW (peak) output at a base speed of 4,000 RPM has been tested. The prototyped WFSM achieves peak volumetric and specific torque and power densities of 17.22 Nm/l, 4.69 Nm/kg, 7.19 kW/l, and 1.95 kW/kg.
