Untitled

Kugimiya, Takanori; Yoshimura, Narihiko; Mitsui, Jun'ichi

doi:10.1023/a:1019156716891

Cited by 39 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This involves anti-wear properties, foam performance, efficiency requirements, and durability demands. Furthermore, the performance criteria must be met, including, for instance, the friction behavior of wet clutches, which is shaped by the use of friction modifiers [7]. Previous studies have shown that adding detergent and dispersants, which are also used for oxidation stability, significantly increases the CoF for organic friction lining [8][9][10].…”

Section: Motivation and State Of The Artmentioning

confidence: 99%

Influence of Water Contamination, Iron Particles, and Energy Input on the NVH Behavior of Wet Clutches

Wirkner,

Baese,

Lebel

et al. 2023

Lubricants

View full text Add to dashboard Cite

The driving comfort and safety of the automotive powertrain are significantly related to the performance, lifetime, and functionality of the lubricant. The presented study focuses on investigating the performance loss of the lubricant due to water contamination resulting from environmental influences and iron particles originating from the wear of different machine elements. The main purpose is to determine critical factors that contribute to the degradation of the lubricant, and increase the tendency to NVH behavior, leading to adverse comfort losses to the respective user. Therefore, this performance loss is evaluated by test rig-based analysis of the friction behavior of wet clutches. Due to physical adsorption, a significant impact of water and iron contamination on the degradation of the lubricant is found, while the influence of the energy input is secondary.

show abstract

Section: Motivation and State Of The Artmentioning

confidence: 99%

Influence of Water Contamination, Iron Particles, and Energy Input on the NVH Behavior of Wet Clutches

Wirkner,

Baese,

Lebel

et al. 2023

Lubricants

View full text Add to dashboard Cite

show abstract

“…However, the dμ/dv measurements in the pin-on-disk tester help to discard all those other factors by focusing only in the local friction produced in the wet clutch plates interface [31]. A good anti-shudder property is expected for positive dμ/dv values, while poor property is expected for negative dμ/dv values [8]. According to the present results, anti-shudder property of Jatropha oil and ATF could be improved by thermo-oxidation at 26°C, but worsened at 100°C.…”

Section: Wet Clutch Frictionmentioning

confidence: 99%

“…Wet clutch shudder is produced by undesirable self-excited vibrations caused by stick-slip effects at the plates´ interface [7]. According to the model proposed by Kugimiya et al [8], shudder occurs when wet clutch friction increases as the sliding speed decreases, so low dynamic friction coefficients at low sliding speeds are suitable to prevent shudder within the ATF service life [8,9]. The potential and reliable use of neat vegetable oils as ATFs, as well as in other applications, is limited by their significantly poor oxidation stability resulting from their chemical composition based on fatty acids [10].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of thermo-oxidized Jatropha bio-oil in lubrication of actual wet clutch materials

Farfán-Cabrera

Gallardo-Hernández

Perez‐González

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

View full text Add to dashboard Cite

In this work, an assessment of the performance of thermo-oxidated Jatropha oil as a lubricant for actual wet clutch materials was performed and compared with a commercial automatic transmission fluid. For this, Jatropha oil, a commercial automatic transmission fluid and a blend of 20 vol% Jatropha oil–80 vol% automatic transmission fluid were subjected to thermo-oxidative aging at 26 °C and 100 °C, followed by a pin-on-disk testing with disk samples from an actual wet clutch. Evaluation of the film thickness at the sliding interface resulted in a boundary lubrication regime for all the tests. The changes in oxidation, viscosity, and a viscosity index of the samples were evaluated along with friction coefficients at various sliding speeds. Jatropha oil was the most sensitive to thermo-oxidation. Jatropha oil and the blend showed a higher viscosity increase than automatic transmission fluid with thermo-oxidation, while the viscosity index of all oils was decreased considerably, Jatropha oil and the blend being the most reduced. Finally, the anti-shudder property, as measured by the change in the friction coefficient with a sliding speed, of Jatropha oil and automatic transmission fluid was improved by thermo-oxidation at 26 °C but worsened at 100 °C, meanwhile it was barely affected in the blend. Therefore, these results indicate that using pure Jatropha oil as automatic transmission fluid would be unsuitable, but blending it with automatic transmission fluids in specific proportions may be apposite for improving the friction properties of wet clutches even under thermo-oxidative conditions.

show abstract

“…To the best of the authors' knowledge, the current scientific literature on the subject identifies three main factors responsible for clutch judder. In several cases, it is attributed to a negative gradient of the coefficient of friction between the clutch plates (in this case referred to as cold judder) [1][2][3][4][5][6][7]. In fact, if the friction coefficient decreases with increasing slip speed, the system becomes unstable in most operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Friction-induced parametric oscillations in automotive drivelines: experimental analysis and modelling

Tentarelli

2023

Theoretical and Applied Mechanics - AIMETA 2022

View full text Add to dashboard Cite

Abstract. Clutch judder is a friction-induced self-excited vibration occurring in automotive drivelines, an NVH issue studied for more than forty years and attributed by the scientific community to three possible causes: stick-slip, negative gradient of the coefficient of friction and geometric disturbances. However, these explanations fail to describe the kind of judder studied in this contribution, arising in presence of an oscillating component (dither) in the clutch actuation pressure. The analysis of experimental data collected on a dual-clutch transmission mounted on a specific test bench suggested the presence of a parametric resonance, generated by the dither. A specific 4 degrees of freedom model was then developed, able to predict with good accuracy the unstable parametric region in which judder occurs and useful in the design stage.

show abstract

Untitled

Cited by 39 publications

References 0 publications

Influence of Water Contamination, Iron Particles, and Energy Input on the NVH Behavior of Wet Clutches

Influence of Water Contamination, Iron Particles, and Energy Input on the NVH Behavior of Wet Clutches

Evaluation of thermo-oxidized Jatropha bio-oil in lubrication of actual wet clutch materials

Friction-induced parametric oscillations in automotive drivelines: experimental analysis and modelling

Contact Info

Product

Resources

About