Anti-Shudder Properties of ATFs—Investigation into Tribofilm Composition on Clutch Friction Material and Steel Surfaces and the Link to Frictional Performance

Zhao, Hongyuan; Morina, Ardian; Neville, Anne; Vickerman, Richard

doi:10.1080/10402004.2012.709921

Cited by 10 publications

(9 citation statements)

References 15 publications

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“…One is the dark area, which contains P, Ca and O, and the other is white area, which contains no P, Ca and O. These results were also reported by Zhao in 2012 [17,18]. From EDX results we found that the element ratio of Ca/P/O in the dark areas is almost constant, which has never been reported before in the tribological field of clutch discs.…”

Section: Introductionsupporting

confidence: 88%

Surface chemical characterization of steel clutch plate in ATF

Di²,

Cheng³

et al. 2016

Tribology International

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Section: Introductionsupporting

confidence: 88%

Surface chemical characterization of steel clutch plate in ATF

Di²,

Cheng³

et al. 2016

Tribology International

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“…7 and Table 3. The peak positions identified in this study presented a good agreement with the report by Zhao et al [22], which investigated the behavior of the OFMs with the nitrogen-containing polar group on the steel plate after the clutch performance test. The C 1s spectra of the post-test specimens after the 40°C test (Fig.…”

Section: Xps Analysissupporting

confidence: 81%

Advanced Control of Frictional Properties on Paper Clutch Materials by a Combination of Friction Modifiers

2017

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This study proposes a novel approach for controlling frictional performances at paper clutch systems by a combination of organic friction modifiers (OFMs). The OFMs are commonly used for modifying the frictional properties at the paper clutch. Although the effect of the OFMs tends to be dependent on temperature due to their working mechanism based on the surface adsorption, the frictional properties are preferable to be stable in all the operating temperature for the consistent and precise clutch control. Aiming to modify the temperature dependence of the OFM effect, an OFM with an Advanced Concept (FMAC) was newly developed, and the impact on the clutch frictional performance was investigated using Low Velocity Friction Apparatus (LVFA). Only with the conventional OFM, the friction values experienced excessive reduction at 80 or 120°C, while an optimal property was achieved at 40°C. In the presence of the FMAC, it was possible to inhibit the conventional OFM selectively at the high temperature conditions preventing the friction reduction, leading to the ideal frictional property in all the temperature conditions. The surface analysis revealed that the FMACs were capable of adsorbing on the substrate more intensively at high temperature, which should be the reason of the temperature dependent competitive effect of the FMACs.

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“…According to Figs. 7 and 8, aged 1ATF at both temperatures and 2ATF at 100 °C exhibited increase of friction coefficients mainly at low sliding speeds, which can be mainly attributed to additives depletion, such as ZDDPs and friction modifiers as that reported by Zhao et al [26]. They reported that friction modifiers have a considerable effect of reducing friction coefficient at low speed as well as detergents help to enhance the anti-shudder property of ATFs.…”

Section: Influence Of Atf Oxidation On Wet Clutch Frictionmentioning

confidence: 66%

Influence of oxidation of automatic transmission fluids (ATFs) and sliding distance on friction coefficients of a wet clutch in the running-in stage

et al. 2020

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In this paper, the influence of oxidation of automatic transmission fluids (ATFs) and sliding distance on the friction coefficients of a wet clutch in approached running-in conditions was investigated. The ATFs were oxidized by a laboratory process approaching oxidation occurred in actual ATFs. Oxidation was evaluated by means of increase in carbonyl compounds and depletion of zinc dialkyldithiophosphates (ZDDPs) additives. Also, the changes in kinematic viscosity and viscosity index were evaluated. Pin-on-disk tests were conducted to replicate the actual sliding contact in a wet clutch. The pin specimens were cut from friction material composite plates and the disks were actual steel separators both from an automotive wet clutch. Friction coefficient, μ, was measured at progressive sliding velocity, ν, to obtain μ-ν curves at 26 and 100 ΰC. Three μ-ν tests were consecutively run using the same pair of specimens and oil. The cumulative sliding distance for each μ-ν test generated surface flattening using the oils. The friction coefficients of the wet clutch increased due to the ATFs oxidation meanwhile the dμ/dυ values decreased in most cases. It suggests that ATF oxidation can enhance torque capacity of the wet clutch, but it could reduce anti-shudder property. Progressive sliding distance improved the slopes in the μ-ν results using fresh ATFs meanwhile it generated a slope decrease by using aged ATFs.

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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

Cited by 10 publications

References 15 publications

Surface chemical characterization of steel clutch plate in ATF

Surface chemical characterization of steel clutch plate in ATF

Advanced Control of Frictional Properties on Paper Clutch Materials by a Combination of Friction Modifiers

Influence of oxidation of automatic transmission fluids (ATFs) and sliding distance on friction coefficients of a wet clutch in the running-in stage

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