Mixed AMS Dimer Traction Fluids for Low-Temperature Shear Strength
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Solution Overview
Problem
Existing traction fluids face challenges in maintaining high elastohydrodynamic (EHD) shear strength and low temperature performance while minimizing foaming issues at high speeds, particularly in outdoor applications.
Innovation Solution
A blend of two isomers of hydrogenated linear alpha-methylstyrene (AMS) dimers, namely 2,4-dicyclohexyl-2-methylpentane (HLD) and 1,4-dicyclohexyl-4-methylpentane (IsoHLD), is used to create lubricating fluids that maintain high EHD shear strength and excellent low temperature performance with reduced foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cycloaliphatic hydrocarbons are used to improve shear strength, then high EHD shear strength is achieved, but low temperature properties deteriorate
Solution Approach 1:
The patent combines two previously incompatible base oil types - cycloaliphatic hydrocarbons (for high EHD shear strength) and conventional hydrocarbons (for good low temperature properties) - into a blended mixture that achieves both high shear strength and acceptable low temperature flow characteristics
Solution Approach 2:
The invention creates a composite lubricating fluid composition by blending multiple base oil components (cycloaliphatic hydrocarbons, conventional hydrocarbons, and viscosity modifiers) to achieve properties that neither component alone can provide, specifically high EHD shear strength combined with improved low temperature performance
2Temperature
If polydimethylsiloxane fluids are added to improve low temperature flow, then low temperature properties improve, but foaming issues occur at high speeds
Solution Approach 1:
The patent removes polydimethylsiloxane fluids from the formulation entirely, replacing them with alternative base oil blends that achieve low temperature flow improvement through different mechanisms (conventional hydrocarbon blends and viscosity modifiers) without introducing foaming problems
Solution Approach 2:
The invention uses conventional hydrocarbon base oils and viscosity modifiers as temporary or alternative solutions to achieve low temperature performance without the long-term foaming issues associated with polydimethylsiloxanes, particularly in high-speed applications
3Strength
If HLD base oil is used to achieve high EHD shear strength, then traction coefficients improve, but dynamic viscosity increases at sub-ambient temperatures
Solution Approach 1:
The patent modifies the physical parameters of the base oil system by blending cycloaliphatic hydrocarbons with conventional hydrocarbons in specific ratios, changing the overall viscosity-temperature characteristics to reduce dynamic viscosity at sub-ambient temperatures while preserving high EHD shear strength
Solution Approach 2:
The invention introduces viscosity modifiers that dynamically adjust the fluid's viscosity based on operating conditions, allowing the lubricant to maintain high viscosity and shear strength at operating temperatures while reducing viscosity at low temperatures for better flow properties
Data Source
AI summary
A lubricating fluid includes a blend of at least two isomers of hydrogenated linear AMS dimers, one of which is a hydrogenated linear AMS dimer having a formula of 2,4-dicyclohexyl-2-methylpentane and another of which is a hydrogenated linear AMS dimer (HLD) isomer having a formula of 1,4-dicyclohexyl-4-methylpentane. The blend reduces viscosities at low temperatures (0° C. and lower), without severely lowering high shear stress EHD shear strength (or traction coefficients), and further inhibits foaming issues which are typical in mixtures of very different fluids such as silicones and hydrocarbons combinations.