Brake Fluid Composition Balancing Boiling Point and Low Viscosity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brake fluids struggle to meet the high dry and wet boiling point requirements of DOT 5.1 while maintaining a low viscosity, particularly at -40 °C, as exemplified by silicone ester-based fluids that exceed the viscosity limit of 900 mm²/s.
Innovation Solution
A balanced composition of alkoxyglycols and organic silicon compounds, including specific ratios of alkoxyglycols with varying degrees of alkoxylation, along with additives like corrosion inhibitors and lubricants, to achieve high boiling points and low viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silicone ester-based compounds are used to achieve high dry and wet boiling points, then the boiling point increases, but the viscosity becomes excessively high
Solution Approach 1:
The patent creates a composite brake fluid system combining silicone esters (for high boiling point) with alkoxy glycols and boric acid esters (for viscosity control). This multi-component composite approach allows the fluid to simultaneously achieve high thermal stability (dry boiling point ≥260°C, wet boiling point ≥180°C) and acceptable low-temperature viscosity (≤900 mm²/s at -40°C), resolving the contradiction between these two opposing properties.
Solution Approach 2:
The patent systematically adjusts the compositional parameters of the brake fluid, specifically controlling the silicon content (4-12 wt%), alkoxy glycol content (30-70 wt%), and boric acid ester content (5-30 wt%). By optimizing these parameters, the formulation achieves the desired balance between high boiling point and low viscosity, transforming the property parameters to satisfy both requirements simultaneously.
2Force
If low-molecular-weight glycols or alkoxyglycols are used to reduce viscosity, then the viscosity decreases, but the boiling point becomes too low
Solution Approach 1:
The patent combines low-molecular-weight alkoxy glycols (which provide low viscosity) with silicone esters and boric acid esters (which provide high boiling point). This composite formulation ensures that the viscosity contribution from alkoxy glycols keeps the fluid flowing properly at low temperatures, while the silicone ester component maintains the high thermal stability required for brake fluid operation.
Solution Approach 2:
The patent optimizes the molecular weight and alkoxylation degree parameters of the glycol components. By selecting specific alkoxy glycols with controlled chain lengths and ether group numbers, the formulation achieves low enough viscosity for proper brake system operation while the combined effect with high-boiling silicone esters maintains the required boiling point threshold.
3Temperature
If the degree of alkoxylation of alkoxyglycols is increased to raise boiling point, then the boiling point increases, but the viscosity increases and loses the advantage of low viscosity
Solution Approach 1:
The patent precisely controls the alkoxylation degree parameter of the glycol components, using alkoxy glycols with specific n values (where n ranges from 2-10 in the general formula). By selecting moderate alkoxylation degrees rather than maximum values, the formulation achieves sufficient boiling point elevation while preventing excessive viscosity increase, maintaining the balance between these two properties.
Solution Approach 2:
The patent applies different alkoxylation degrees to different glycol components in the mixture. Rather than using a single uniform alkoxy glycol, the formulation employs a blend of alkoxy glycols with varying chain lengths and ether group numbers, allowing each component to contribute optimally to either boiling point or viscosity characteristics depending on its specific molecular structure.
Data Source
AI summary
The present invention relates to low-viscosity functional liquids, in particular brake fluids on the basis of organic silicon compounds and alkoxy glycols.