Development of Automatic Transmission Fluid for Slip-Controlled Lock-Up Clutch Systems

Kugimiya, Takanori; Mitsui, Jun'ichi; Yoshimura, Narihiko; Kaneko, Hiroyuki; Akamatsu, Hideaki; Ueda, Fumio; Nakada, Takanori; Akiyama, S.

doi:10.4271/952348

Cited by 27 publications

(2 citation statements)

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“…A FM additive in automatic transmission fluid (ATF) plays an important role in controlling the wet clutch friction properties of automatic transmissions. It is used not only to reduce static and sliding friction but also to control the sliding friction so it increases with sliding velocity. , These properties provide smooth clutch operations, improve driveability, and enable advanced automatic transmission designs that require frequent and vigorous wet-clutch slipping to improve fuel economy.…”

Section: Introductionmentioning

confidence: 99%

Packing of Simulated Friction Modifier Additives under Confinement

Greenfield

Ohtani

2005

Langmuir

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Molecular dynamics simulations have been conducted to obtain detailed information regarding molecular structure and packing of surfactant-like "friction modifier" (FM) chains adsorbed to two confining surfaces under sliding conditions. The simulations are interpreted via the density profile, position-dependent fluctuations in the density profile, and parallel, interlayer position correlation functions. Heterogeneous FM structures were obtained. The adsorbed FM chains were found to form semi-ordered monolayers perpendicular to the atomically well-defined surface, with distinct segment positions in the density profile. More fluid layers with broader density profiles and larger fluctuations were formed by some unoriented FM chains oriented preferentially parallel to the surface, between the opposing monolayers. Segment position correlations parallel to the surface in the adsorbed layers were found at separations up to 30 A. These packings persisted for longer than 4 ns under sliding conditions that ranged from 0 to 7.5 m s(-1) (0 to 0.075 A ps(-1)). Monolayer structures were observed to remain unchanged under a wide range of normal pressures, with the corresponding changes in volume occurring in the gap between monolayers or between a monolayer and trapped fluid.

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Section: Introductionmentioning

confidence: 99%

Packing of Simulated Friction Modifier Additives under Confinement

Greenfield

Ohtani

2005

Langmuir

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“…Although several researchers have investigated shudder (1)- (7) , the underlying mechanism has not yet been fully clarified. In order to suppress shudder, an improved automatic transmission fluid (ATF) (8) (9) and frictional material (10) have been developed. However, no research has so far been reported into methods of eliminating shudder by the use of an optimized dynamic absorber, nor has such an dynamic absorber been evaluated under engine forced vibration conditions.…”

Section: Introductionmentioning

confidence: 99%

Occurrence Mechanism and Suppression Method for Shudder in Automatic Transmission Powertrain

Rosbi

Ryu

Matsuzaki

et al. 2014

IJAE

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Shudder occasionally occurs in the lock-up clutch of automatic transmissions when the frictional characteristics of the lock-up clutch have a negative slope with respect to the relative slip velocity. This study evaluates the effect of a dynamic absorber on reducing shudder in an automatic transmission powertrain. The automatic transmission is modeled as a linear multi-degree-of-freedom system using Lagrange's equation of motion. The optimal dynamic absorber characteristics for suppression of shudder are calculated. The experimental results reveal the optimized dynamic absorber can completely suppress shudder. Engine forced vibration analysis shows that the dynamic absorber can reduce vibration without any detrimental effects.

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