Glycol Magnetorheological Fluid Anti-Settling Additives
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Solution Overview
Problem
Glycol-based magnetorheological fluids used in engine mounts face issues with settling and foaming, which are problematic for vacuum-filling operations and compatibility with natural rubber, limiting their application.
Innovation Solution
A magnetorheological fluid comprising a glycol-water mixture with fumed silica and an ionic thixotropic additive, which provides improved anti-settling and non-foaming properties, allowing for easier use in engine mounts and similar devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If organoclay is used as a thickening agent in glycol-based magnetorheological fluid, then the fluid viscosity is increased, but the fluid forms persistent foam when exposed to vacuum
Solution Approach 1:
The patent changes the chemical composition parameters by replacing organoclay with a specific combination of fumed silica and ionic thixotropic additives in glycol-water mixtures. This parameter change achieves the desired viscosity increase while eliminating the foaming problem that occurred with organoclay thickening agents.
Solution Approach 2:
The patent uses a composite thickening system combining fumed silica particles with ionic thixotropic additives. This composite approach provides effective viscosity enhancement and anti-settling properties without the harmful foaming effect, resolving the contradiction between achieving high viscosity and avoiding foam formation.
2Ease of operation
If hydrocarbon-based carrier fluid is used in magnetorheological fluid, then the fluid provides good lubricity, but it is incompatible with natural rubber in engine mounts
Solution Approach 1:
The patent changes the chemical composition parameter by substituting hydrocarbon-based carrier fluid with glycol-water mixture. This parameter change eliminates the incompatibility issue with natural rubber while maintaining acceptable lubricity properties through the glycol base and additive system.
3Reliability
If silicone-based carrier fluid is used in magnetorheological fluid, then the fluid is compatible with natural rubber, but it causes silicone cross-contamination and has higher cost
Solution Approach 1:
The patent changes the carrier fluid composition parameter by using glycol-water mixture instead of silicone-based fluid. This substitution maintains compatibility with natural rubber (resolving the reliability issue) while eliminating silicone cross-contamination problems and reducing cost.
Solution Approach 2:
The glycol-water mixture acts as an intermediary carrier fluid that provides the desired compatibility with natural rubber without introducing the harmful silicone cross-contamination. It serves as a middle ground that achieves the benefits of silicone compatibility while avoiding its drawbacks.
4Reliability
If magnetic-responsive particles are added to carrier fluid, then the fluid exhibits magnetorheological properties, but the particles settle over time
Solution Approach 1:
The patent employs a composite system combining fumed silica particles with ionic thixotropic additives to create a stabilized suspension matrix. This composite structure prevents magnetic-responsive particle settling while preserving magnetorheological functionality, resolving the contradiction between functionality and stability.
Solution Approach 2:
The fumed silica and ionic thixotropic additives serve as intermediary substances that create a stable suspension environment. These intermediaries prevent direct particle settling by providing a structured carrier matrix, allowing magnetic-responsive particles to remain suspended while maintaining MR fluid functionality.
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 fluid exhibits a unique rheology with a gel-like structure at rest and reduced yield stress upon shearing, simplifying degassing and filling procedures, while maintaining high temperature stability and compatibility with natural rubber.
Implementation Method 1
an ionic thixotropic additive, which provides improved anti-settling properties
Implementation Method 2
In the presence of a magnetic field, the magnetic-responsive particles become polarized and are thereby organized into chains of particles or particle fibrils. The particle chains increase the apparent viscosity (flow resistance) of the fluid
Implementation Method 3
The fluids are low foaming and thus an improvement over fluids made with organoclay thickeners. The addition of small quantities of water to the glycol fluids is expected to decrease their low-temperature viscosity.
Data Source
AI summary
A magnetorheological fluid comprising magnetic-responsive particles, a thickener, an ionic thixotropic additive, and a carrier fluid wherein the carrier fluid comprises a glycol- water mixture comprising at least 50 percent by weight of a glycol compound. The thickener is preferably fumed silica and the ionic thixotropic additive is preferably one of sodium nitrite, sodium chloride, sodium acetate, and sodium benzoate.