Diurea Grease Density Matching for Flywheel Oil Bleeding
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Solution Overview
Problem
Current lubricating greases for dual mass flywheel applications face challenges in achieving improved oil bleeding and shear stability, which are crucial for maintaining performance and longevity in high-demand vehicles.
Innovation Solution
A lubricating grease composition comprising at least 30 wt.% of a base oil with a density between 800 to 1000 Kg/m³ and 2 to 20% of a diurea compound, where the diurea is obtained by reacting a diisocyanate with a mixture of C6-C10 and C14-C20 aliphatic amines, ensuring a density difference of less than 50 Kg/m³ between the base oil and diurea, enhancing shear stability and reducing oil bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lubricating greases are used in dual mass flywheel applications, then basic lubrication is provided, but oil bleeding and poor shear stability occur
Solution Approach 1:
The patent changes the chemical composition parameters of the grease by using specific base oils with controlled density (800-1000 kg/m³) and incorporating diurea compounds (2-20 wt%) with carefully matched density (within 50 kg/m³ of base oil). This parameter optimization resolves the contradiction by preventing oil separation while maintaining lubrication effectiveness.
Solution Approach 2:
The invention creates a composite grease system combining base oil with diurea thickener and additional additives (calcium salts, organic molybdenum compounds, fatty acid metal salts) in specific proportions. This composite formulation achieves both reduced oil bleeding and improved shear stability that cannot be obtained with conventional single-component greases.
2Reliability
If grease formulations are optimized for reduced oil bleeding, then shear stability improves, but formulation complexity increases
Solution Approach 1:
Rather than adding numerous components, the patent achieves reduced oil bleeding by optimizing the density parameter match between base oil (800-1000 kg/m³) and diurea compound (within 50 kg/m³ difference). This single parameter optimization approach reduces formulation complexity while maintaining effectiveness.
3Ease of operation
If lithium soap complex greases are used, then satisfactory lubrication is achieved, but oil separation and poor shear stability persist
Solution Approach 1:
The patent replaces lithium soap complex thickeners with diurea compounds and optimizes the density parameter of the base oil (800-1000 kg/m³) to match the diurea density within 50 kg/m³. This parameter change eliminates oil separation while preserving lubrication performance.
Solution Approach 2:
The invention transitions from conventional lithium-based composite grease to a diurea-based composite system with specifically selected base oils and additive packages. This composite material substitution resolves the oil separation issue while maintaining ease of operation.
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 grease composition demonstrates significantly reduced oil separation and improved shear stability, with diurea greases prepared using a C8-C18 monoamine mixture showing excellent performance, achieving acceptable oil separation values and high shear stability values, outperforming comparative examples.
Implementation Method 1
having a density value close to that of the base oil, such that a difference in density values of less than 50 Kg/m³ is achieved between the base oil and the diurea
Implementation Method 2
The primary purpose of lubrication is separation of solid surfaces moving relative to one another, to minimise friction and wear
Data Source
AI summary
Use of a lubricating grease composition in a mass flywheel application wherein the lubricating grease composition comprises: (i) a base oil having a density in the range of from 800 to 1000 Kg/m3;and (ii) a urea compound having a density in the range of from 850 to 1050 Kg/m3; wherein the difference in the densities of the base oil (i) and the urea compound (ii) is less than 50 Kg/m3. The lubricating grease compositions according to the present invention are particularly useful for reducing oil bleeding and for improving shear stability properties in a dual mass flywheel application.