Traction Fluid Composition Using Composite Viscosity Modifiers
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Solution Overview
Problem
Traction fluids face a challenge in balancing high shear strength for torque transmission with good low temperature viscosity properties, as cycloaliphatic hydrocarbons offer superior shear strength but poor low temperature viscosity, while fluids like silicone and PAO provide good low temperature viscosity but compromise shear strength.
Innovation Solution
A traction fluid composition incorporating a base oil, a polyisobutene viscosity modifier, a polymethacrylate viscosity modifier, and anti-foaming agents, along with a performance additive package, to maintain high shear strength while minimizing low temperature viscosity and foaming issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cycloaliphatic hydrocarbons are used as base oil, then shear strength (traction coefficient) is improved, but low temperature viscosity properties deteriorate
Solution Approach 1:
The patent uses a composite base oil system combining cycloaliphatic hydrocarbon (providing shear strength) with PAO and ester (providing low temperature fluidity). This composite approach allows the traction fluid to simultaneously achieve high traction coefficient and good low temperature viscosity properties that neither component could provide alone.
2Temperature
If silicone or PAO is incorporated to improve low temperature viscosity, then low temperature viscosity properties are improved, but shear strength deteriorates
Solution Approach 1:
The patent creates a balanced composite formulation where silicone/PAO (improving low temperature viscosity) is combined with cycloaliphatic hydrocarbon (maintaining shear strength). The synergistic effect of this composite system resolves the trade-off, achieving both good low temperature fluidity and high traction coefficient.
Solution Approach 2:
The patent optimizes the concentration ratios of different base oil components to achieve the desired balance. By carefully controlling the proportions of cycloaliphatic hydrocarbon, PAO, and ester, the formulation achieves optimal low temperature viscosity while preserving sufficient shear strength for torque transmission.
3Temperature
If viscosity modifiers are added to improve low temperature viscosity, then low temperature viscosity properties are improved, but traction coefficient deteriorates
Solution Approach 1:
The patent carefully controls the concentration of viscosity modifiers (polyisobutene and polymethacrylate) to optimize low temperature viscosity while minimizing negative impact on traction coefficient. The low concentration range (0.01-20 wt%) is specifically selected to balance these competing requirements.
Solution Approach 2:
The patent uses a composite viscosity modification system combining polyisobutene and polymethacrylate with different viscosity modification mechanisms. This composite approach provides effective low temperature viscosity reduction while maintaining traction properties better than single viscosity modifiers.
4Object-generated harmful factors
If anti-foaming agents are added to reduce foaming, then foaming is reduced, but fluid composition complexity increases
Solution Approach 1:
The patent optimizes the concentration of anti-foaming agents (0.01-1 wt%) to achieve effective foam control while minimizing the impact on overall fluid composition. This controlled addition level provides sufficient anti-foaming performance without significantly complicating the base fluid formulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a traction fluid with improved low temperature viscosity without degrading shear strength, as evidenced by Brookfield viscosity below 32,000 cP at -30°C and reduced foaming, enhancing overall performance in CVT and IVT systems.
Implementation Method 1
a first viscosity additive, the first viscosity additive minimizes degrading the traction coefficient of the traction fluid
Implementation Method 2
a second viscosity additive, the second viscosity additive minimizes the increase of low temperature viscosity
Implementation Method 3
The traction fluid may also comprise anti-foaming agents in an amount greater than about 0.01 (w/w) % and less than about 1 (w/w) %
Data Source
AI summary
Traction fluid additive combination that is usable with any traction fluids base stock is provided. To optimize the traction, low temperature viscosity and shear stability performance, a combination of a polyisobutene and a polymethacrylate may be added to a base oil to obtain a traction fluid with good low temperature viscosity without degrading the shear strength properties of the fluid. To minimize foaming of the traction fluid, a combination of one, two, or more anti-foaming agents may be added to the fluid in addition to a standard additive package.