Electric Vehicle Powertrain Fluid Conductivity Reduction
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Solution Overview
Problem
Electric and hybrid vehicle powertrain fluids face challenges in maintaining low electrical conductivity to prevent short circuits while ensuring adequate oxidation control and antiwear performance, as metal-containing detergents contribute to increased conductivity and are required for oxidation control.
Innovation Solution
A functional fluid composition comprising greater than 50 wt% base oil, a hydrocarbyl acid phosphate, calcium-containing detergents, and nitrogen-containing dispersants, which reduces electrical conductivity to a range of 80,000 pS/m to 180,000 pS/m while providing antiwear and oxidation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal-containing detergents are increased to provide oxidation control, then oxidation control performance is improved, but electrical conductivity increases
Solution Approach 1:
The patent changes the chemical composition parameters by using overbased calcium detergents with specific total base number ranges (200-400 mg KOH/g) and controlling calcium content (50-800 ppmw), while combining with phosphorus compounds and nitrogen-containing dispersants to achieve the desired balance between oxidation control and electrical conductivity
Solution Approach 2:
The patent creates a composite additive system combining overbased calcium detergents, phosphorus compounds (50-500 ppmw), and nitrogen-containing dispersants (20-1200 ppmw) that work synergistically to provide both oxidation control and reduced electrical conductivity compared to using metal-containing detergents alone
2Object-affected harmful factors
If metal-containing detergents are reduced to decrease electrical conductivity, then electrical conductivity is improved, but oxidation control performance deteriorates
Solution Approach 1:
The patent changes the detergent type from traditional metal-containing detergents to overbased calcium detergents with controlled base numbers and calcium content, combined with phosphorus and nitrogen additives, to achieve low electrical conductivity while maintaining oxidation protection
Solution Approach 2:
The patent employs a composite additive package where overbased calcium detergents, phosphorus compounds, and nitrogen-containing dispersants work together to provide sufficient oxidation control at reduced electrical conductivity levels
3Adaptability or versatility
If a multipurpose functional fluid is designed to provide multiple functions (lubrication, electrical insulation, antiwear, oxidation control), then versatility is improved, but formulation complexity increases
Solution Approach 1:
The patent designs a functional fluid that simultaneously provides lubrication, electrical insulation (80,000-180,000 pS/m conductivity), antiwear protection, and oxidation control through a coordinated additive system, allowing single-fluid application in electric vehicle powertrains
Solution Approach 2:
The patent optimizes specific parameter ranges including phosphorus (50-500 ppmw), calcium (50-800 ppmw), and nitrogen (20-1200 ppmw) content along with detergent base numbers to achieve multiple performance targets simultaneously
Data Source
AI summary
A method of lubricating at least a portion of a powertrain in a vehicle with an electric motor with a functional fluid composition containing greater than 50 wt% of a base oil; and an additive composition prepared by mixing: a) a hydrocarbyl acid phosphate of the formula (I) to provide at least 50 ppmw phosphorus to the functional fluid composition; wherein R is a C1-C6 hydrocarbyl group and R1 is selected from hydrogen and a C1-C6 hydrocarbyl group; b) an amount of one or more calcium-containing detergent(s) sufficient to provide at least 25 ppmw calcium to the functional fluid composition; and c) one or more nitrogen containing dispersants in an amount sufficient to provide greater than 20 ppmw of nitrogen to the functional fluid composition, all based on the total weight of the functional fluid composition. Functional fluid compositions containing the above-mentioned components and lubricating methods are also disclosed herein.