Shock Absorber Fluid Low-Temperature Viscosity
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Solution Overview
Problem
Conventional shock absorber fluids face challenges in maintaining satisfactory damping force and lubricity at low temperatures, particularly at -40°C, due to high Brookfield viscosity and impaired antifoaming properties, which leads to reduced viscosity and increased foam generation.
Innovation Solution
A shock absorber fluid with a lubricating base oil having a urea adduct value not greater than 4% and a viscosity index of 100 or higher, combined with a reduced viscosity index improver content, which enhances low-temperature viscosity characteristics and antifoaming performance, while maintaining shear stability and lubricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low viscosity solvent components are added to lower base oil viscosity, then low-temperature flow property is improved, but lubricity is impaired
Solution Approach 1:
The invention changes the chemical composition parameters of the base oil by specifying a urea adduct value of not greater than 4% and viscosity index of 100 or higher. This parameter control allows achieving low-temperature flow properties without needing to add large amounts of low viscosity solvents that would harm lubricity.
Solution Approach 2:
The invention uses a composite approach by combining specific base oil components with controlled viscosity index improver additives. The base oil itself is formulated with specific molecular structure characteristics (low urea adduct value) that provide inherent low-temperature performance while maintaining lubricity, supplemented by minimal viscosity index improver content.
2Temperature
If viscosity index improver is added in large amount, then viscosity-temperature characteristic is improved, but shear stability is reduced
Solution Approach 1:
The invention applies partial action by adding viscosity index improver in controlled, limited amounts rather than large quantities. The base oil's inherent properties (low urea adduct value ≤4%, high viscosity index ≥100) provide the primary viscosity-temperature performance, requiring only supplemental viscosity index improver to achieve the desired Brookfield viscosity at -40°C, thereby minimizing shear degradation.
Solution Approach 2:
The invention changes the formulation parameters by specifying the base oil's urea adduct value and viscosity index, which fundamentally alters how much viscosity index improver is needed. This parameter optimization allows achieving target viscosity characteristics with minimal additive content, preserving shear stability.
3Object-generated harmful factors
If defoaming agents and viscosity index improvers are added, then antifoaming property is improved, but long-term stability is reduced
Solution Approach 1:
The invention changes the base oil's molecular structure parameters (urea adduct value ≤4%, viscosity index ≥100) to inherently reduce foam generation tendencies. This structural optimization reduces reliance on defoaming agents, allowing the use of smaller amounts of additives that maintain both antifoaming properties and long-term stability.
Data Source
AI summary
The shock absorber fluid according to the invention is characterized by comprising a lubricating base oil that has a urea adduct value of not greater than 4 % by mass and a viscosity index of 100 or greater. The shock absorber fluid according to the invention can exhibit a high level of all properties including viscosity-temperature characteristic, shear stability and antifoaming property.