Limited Slip Wet Clutch Transmission Fluid for AWD Differentials; Part 1: System Requirements and Evaluation Methods

Mäki, Rikard; Ganemi, Bager; Olsson, Richard T.; Lundström, Bo

doi:10.4271/2003-01-1980

Cited by 17 publications

(23 citation statements)

References 12 publications

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“…More detailed descriptions of the AWD system can be found in the literature. 5,6 The friction material used in the Haldex LSC is sintered brass, which, in combination with the fillfor-life demands of the product, necessitates the use of transmission fluids designed specifically for the application on hand. Fluid development has been conducted for a number of years by Statoil.…”

Section: Introductionmentioning

confidence: 99%

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

Mäki

Ganemi

Höglund

et al. 2006

Lubrication Science

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In recent years, several electronically controllable automotive transmission systems using wet clutches as intelligent differentials have emerged on the market. These applications place great demands on the anti-shudder properties of the transmission fluids used.The aims of this study were (i) to investigate the influence of different additives on the friction characteristics of a transmission fluid for all-wheel drive systems featuring wet multi-plate clutch with a sintered brass-based friction material and, based on this knowledge, (ii) to formulate a new transmission fluid with the desired frictional properties. In addition to excellent anti-shudder properties, the new fluid was required to lubricate hypoid gears under high load. To meet this requirement, it is necessary to add significant amounts of extreme pressure additives to the base oil, which are known to have an unfavourable influence on anti-shudder properties, necessitating the adoption of novel additive technologies.The additives studied include anti-wear additives, friction modifiers, corrosion inhibitors, detergents, antioxidants and extreme pressure additives. This paper shows how different additives affect friction in different ways, and that the interactions between the different additives are important to consider. It was concluded that it is feasible to combine good anti-shudder properties for wet clutches with good lubrication of hypoid gears. Copyright

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Section: Introductionmentioning

confidence: 99%

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

Mäki

Ganemi

Höglund

et al. 2006

Lubrication Science

Self Cite

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“…The normal force on the test clutch is applied by a double-acting hollow piston cylinder (4). In this case the normal force was limited to 30,000 N by a pressure-limiting valve.…”

Section: Test Equipmentmentioning

confidence: 99%

“…More detailed descriptions of the AWD system can be found in the literature. 4,5 Common challenges in this type of application, which arise from low continuous sliding velocities during engagement, are the demands on the anti-shudder properties and durability of the transmission fluid/friction material combination. 3,6 The friction material in the Haldex LSC is sintered bronze which, in combination with the fill-for-life demand on the product, necessitates the use of transmission fluids specially designed for the application at hand.…”

Section: Haldex Limited-slip Couplingmentioning

confidence: 99%

“…The accuracy of the measurements from this rig is well within ± 1%. 4 Thermocouples were installed in the oil sump to measure the oil bulk temperature, and in the separator disc to measure friction surface temperature. More detailed descriptions of this equipment can be found in the literature.…”

Section: Test Equipmentmentioning

confidence: 99%

“…The dynamic friction should also increase with increasing velocity. [4][5][6] Commonly used base fluids for transmission fluids are mineral oils and synthetic fluids. [9][10][11] According to Haviland et al the base oil viscosity is of less importance, and generally it does not affect the additive-dependent friction characteristics.…”

Section: Haldex Limited-slip Couplingmentioning

confidence: 99%

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

Mäki

Ganemi²,

Olsson³

2005

Tribotest

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During the past few years several electronically controllable automotive transmission systems, where wet clutches are used as intelligent differentials, have emerged in the market. In this type of application the anti-shudder properties of the lubricants are of vital importance. This paper investigates the influence of base fluids on the anti-shudder properties of transmission fluids for wet clutches in all-wheel-drive systems. The investigated all-wheel-drive system featuring a wet multi-plate clutch with a sintered brass-based friction material is described. The test equipment used to determine the frictional characteristics of the transmission fluid is described. The parameters studied include base fluid type and base fluid viscosity. It is shown that the choice of base fluid has no impact on torque capacity, but that the base fluid influences the temperature dependence of the dynamic friction and the anti-shudder properties. It is also shown that the major effect on the friction characteristics is caused by additive effects rather than base fluid effects.

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Friction and Contact of Solid Interfaces

2018

Dynamics and Control of Robotic Manipulators With Contact and Friction

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Limited Slip Wet Clutch Transmission Fluid for AWD Differentials; Part 1: System Requirements and Evaluation Methods

Cited by 17 publications

References 12 publications

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

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

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

Friction and Contact of Solid Interfaces

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