Wet clutch transmission fluid for AWD differentials: base fluid influence on friction characteristics

Tribotest ◽  
10.1002/tt.4 ◽  
2005 ◽  
Vol 12 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Rikard Mäki ◽  
Bager Ganemi ◽  
Richard Olsson
Keyword(s):  
Base Fluid ◽  
Friction Characteristics ◽  
Wet Clutch ◽  
Transmission Fluid

Wet clutch transmission fluid for AWD differentials: influence of lubricant additives on friction characteristics

10.1002/ls.33 ◽  
2007 ◽  
Vol 19 (2) ◽  
pp. 87-99 ◽  
Author(s):  
Rikard Mäki ◽  
Bager Ganemi ◽  
Erik Höglund ◽  
Richard Olsson
Keyword(s):  
Lubricant Additives ◽  
Friction Characteristics ◽  
Wet Clutch ◽  
Transmission Fluid

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

2020 ◽  
pp. 135065012098146
Author(s):  
Leonardo I Farfan-Cabrera ◽  
Ezequiel A Gallardo-Hernández ◽  
José Pérez-González ◽  
Benjamín M Marín-Santibáñez ◽  
Roger Lewis ◽  
...  
Keyword(s):  
Automatic Transmission ◽  
Viscosity Index ◽  
Jatropha Oil ◽  
Oxidative Aging ◽  
Lubrication Regime ◽  
Viscosity Increase ◽  
Bio Oil ◽  
Wet Clutch ◽  
Transmission Fluid ◽  
Pin On Disk

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.

Experimental study on the friction stability of paper-based clutches concerning groove patterns

2019 ◽  
Vol 72 (4) ◽  
pp. 541-548 ◽  
Author(s):  
Liang Yu ◽  
Biao Ma ◽  
Man Chen ◽  
He Yan Li ◽  
Jikai Liu
Keyword(s):  
Experimental Study ◽  
Surface Temperature ◽  
Design Methodology ◽  
Automatic Transmission ◽  
Applied Pressure ◽  
Friction Torque ◽  
Content Type ◽  
Rotating Speed ◽  
Wet Clutch ◽  
Transmission Fluid

Purpose This paper aims to study and compare the friction stability of wet paper-based clutches with regard to the radial grooves (RG) and waffle grooves (WG). Design/methodology/approach This paper presents an experimental study of a wet clutch concerning the effect of groove patterns on the friction torque and surface temperature. The friction stabilities of RG and WG are investigated with the applied pressure, rotating speed and automatic transmission fluid (ATF) temperature taken into consideration. Findings The friction torque and surface temperature of WG are larger than those of RG under the same operating condition. The friction torque difference between RG and WG grows with the increase of applied pressure and narrows with the increase of ATF temperature. Additionally, their temperature difference expands via increasing the rotating speed and ATF temperature or reducing the applied pressure; in this way, not only the variable coefficient difference between RG and WG can be narrowed, but also the friction stability of the clutch can be improved dramatically. Originality/value This paper explains the thermodynamic differences between RG and WG; moreover, it is verified experimentally that WG has a better friction stability than RG.

Optimizing the Smoothness and Temperatures of a Wet Clutch Engagement Through Control of the Normal Force and Drive Torque

1999 ◽  
Vol 122 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Mikael Holgerson
Keyword(s):  
Temperature Rise ◽  
Normal Force ◽  
Dynamic Performance ◽  
Automatic Transmission ◽  
Test Rig ◽  
Friction Characteristics ◽  
Drive Torque ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Transmission Gear

Automatic transmission gear shifts are handled by wet clutches, which determine the smoothness. The clutch face temperatures during the engagements are often an important parameter for the total clutch life. A wet clutch test rig has been used to evaluate how a wet clutch engagement can be improved in terms of smoothness and temperature. This was performed with control based upon knowledge about friction characteristics and dynamic performance. The parameters used for control were the drive torque and the normal force on the clutch. By drive torque shut-off and reduced normal force the torque variations were greatly reduced and the temperature rise was decreased by 37%. [S0742-4787(00)01601-5]

TRIBOLOGICAL ANALYSIS ON PALM FATTY ACID DISTILLATE (PFAD) AS ALTERNATIVE TRANSMISSION FLUID FOR CLUTCH APPLICATION

2017 ◽  
Vol 79 (7-4) ◽  
Author(s):  
M. A. A. Salleh ◽  
M. K. Abdul Hamid ◽  
Z. H. Che Daud ◽  
A. R. Abu Bakar ◽  
S. A. Abu Bakar
Keyword(s):  
Fatty Acid ◽  
Automatic Transmission ◽  
Viscosity Index ◽  
Tribological Behaviour ◽  
Low Viscosity ◽  
Palm Fatty Acid Distillate ◽  
Wet Clutch ◽  
Transmission Fluid ◽  
Tribological Analysis ◽  
Fatty Acid Distillate

Typically, a mineral based oil from petroleum refining has been widely used as automatic transmission fluid (ATF) in the wet clutch application. However, it has two major disadvantages: (1) It causes pollution to the environment and (2) It is a non-renewable source. Thus, Palm Fatty Acid Distillate (PFAD) is explored as an alternative lubricant for the wet clutch application. In present study, tribological behaviour of PFAD is first sought using a pin on disk tribo-tester and then its behavior will be compared with the behavior obtained in the commercial ATF. It is found in the friction analysis that PFAD has good anti friction ability at low speeds. In addition, PFAD generates almost identical dynamic friction coefficients obtained in the commercial ATF at velocity of 0.4m/s to 0.9 m/s. A slight positive slope in the friction coefficient–velocity graph indicates that PFAD has tendency to have anti-shudder properties, which can improve engaging quality of the wet clutch. However, PFAD has two weaknesses; low viscosity index and less anti wear ability. Some additives should be added into PFAD so that it can give better friction level and less wear rate. 

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