Lubricating Oil Composition for Electric Vehicle Gearboxes
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Solution Overview
Problem
Existing lubricating oil compositions for electric vehicles and hybrid vehicles do not adequately address copper corrosion, flash point, and low temperature fluidity requirements for reduction gearboxes and transmissions.
Innovation Solution
A lubricating oil composition with a base oil having an aromatic ring content of 3,500 to 15,000 ppm, comprising a combination of Group 1 and GTL/PAO base oils, which reduces copper corrosion, improves flash point, and enhances low temperature fluidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfur-based compounds are added to lubricating oil to reduce copper corrosiveness, then copper corrosion resistance improves, but flash point decreases and low temperature fluidity worsens
Solution Approach 1:
The patent extracts and removes sulfur-based compounds from the lubricating oil composition entirely. By eliminating these harmful additives, the oil achieves high flash point and excellent low-temperature fluidity while maintaining copper corrosion resistance through the base oil selection and copper-containing anti-wear additives, without relying on sulfur compounds that would degrade thermal and cold-flow properties
Solution Approach 2:
The patent introduces copper-containing anti-wear additives as an intermediary substance to protect copper components. These additives form protective films on copper surfaces through controlled chemical reactions, providing corrosion protection without the harmful side effects of sulfur-based compounds. The intermediaries bridge the need for copper protection while maintaining compatibility with high flash point and low-temperature performance requirements
2Use of energy by moving object
If viscosity is reduced to improve low temperature fluidity and energy efficiency, then fuel economy improves, but copper corrosiveness increases
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricating oil by selecting specific base oils with appropriate viscosity grades (5W-30, 5W-40, 0W-30, 0W-40) and adjusting additive package composition. This enables the oil to achieve low viscosity for reduced stirring resistance and improved energy efficiency, while simultaneously maintaining copper corrosion resistance through controlled additive selection that does not rely on high-sulfur formulations
3Reliability
If sulfur-based compounds are used to protect copper components, then copper corrosion resistance improves, but flash point decreases
Solution Approach 1:
The patent extracts and eliminates sulfur-based compounds from the lubricating oil formulation. By removing these harmful substances entirely, the oil achieves high flash point (>208°C) while maintaining copper corrosion resistance through alternative mechanisms including copper-containing anti-wear additives and carefully selected base oil composition, avoiding the trade-off between corrosion protection and thermal stability
Solution Approach 2:
The patent employs copper-containing anti-wear additives that sacrificially protect copper components by forming protective films on metal surfaces. These additives are designed to be consumed gradually during operation, providing ongoing corrosion protection without requiring sulfur-based compounds that would compromise flash point. The protective function is achieved through controlled depletion of beneficial additives rather than reliance on harmful sulfur compounds
Data Source
AI summary
The present invention provides a lubricating oil composition used in the reduction gearbox or transmission of an electric vehicle or a hybrid vehicle, wherein the lubricating oil contains a base oil, and the aromatic ring content of the base oil is from 3,500 to 15,000 ppm in terms of the mass of the base oil.