Cooling Lubricant Base Oil Balancing Low Viscosity and Flash Point

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Solution Overview

Problem

Existing lubricants for electric vehicles face a trade-off between low viscosity for cooling and high flash point, making it difficult to achieve a balance between cooling performance and fuel-saving performance, while also requiring lubricity for devices like electric motors and batteries.

Innovation Solution

A lubricant base oil with a % CP of 60 or more and a kinematic viscosity at 40°C of less than 3 mm2/s, combined with a high flash point of 90°C or higher, is used to create a cooling lubricant composition with a high thermal conductivity and low viscosity, enhancing cooling and fuel-saving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If lubricant viscosity is reduced to improve cooling performance, then cooling efficiency increases, but flash point decreases compromising safety

Engineering Contradiction:
Improvecooling performanceVSAvoidflash point
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent applies parameter changes by selecting base oils with specific viscosity ranges (5-20 mm²/s at 40°C) and flash point ranges (90-120°C), then optimizing their blending ratios to achieve the desired balance between cooling performance and safety. The invention changes the chemical composition parameters of the lubricant base oil to simultaneously satisfy both low viscosity for cooling and high flash point for safety.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by blending multiple base oils (isoparaffin, naphthene, aromatic hydrocarbons) in specific proportions to create a lubricant composition that combines the advantages of each component. This composite approach allows achieving both low viscosity and high flash point properties that cannot be obtained with a single base oil type.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If lubricant viscosity is reduced to improve fuel-saving performance, then energy efficiency increases, but cooling capability deteriorates

Engineering Contradiction:
Improvefuel-saving performanceVSAvoidcooling capability
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent optimizes the viscosity parameter to a specific range (5-20 mm²/s at 40°C) that balances fuel-saving performance and cooling capability. By precisely controlling viscosity within this range rather than simply minimizing it, the invention achieves both low energy loss and sufficient cooling performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by having different base oil components perform different functions: isoparaffin provides low viscosity for fuel efficiency, while aromatic hydrocarbons contribute to high flash point and thermal stability for cooling capability. Each component is optimized for its specific role within the composite lubricant system.

Inventive Principle:
Principle #3Local quality

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 lubricant composition provides excellent cooling performance and fuel-saving performance, with a high flash point for safety and low viscosity for efficient temperature regulation, suitable for devices in electric vehicles.

Implementation Method 1

a lubricant base oil with a % CP of 60 or more and a kinematic viscosity at 40°C of less than 3 mm2/s, combined with a high flash point of 90°C or higher, is used to create a cooling lubricant composition with a high thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12534679B2Lubricant base oil and lubricant composition
Publication Date: 2026.01.27 IDEMITSU KOSAN CO LTD

AI summary

A lubricant base oil for use in the preparation of a cooling lubricant composition, may have a % CP of 60 or more, and the dynamic viscosity at 40° C. is less than 3 mm2/s. Such a lubricant base oil may include a base oil (A) having % CP of 60 or more and a kinematic viscosity at 40° C. of less than 3 mm2/s, the base oil (A) being 80% by mass or more of the total lubricant base oil mass. Such a lubricant base oil may further include a base oil (B) that is different from the base oil (A), in a range of from 1 to 20% by mass of the total lubricant base oil mass. The base oil (A) may be an isoparaffin-based base oil. Such a lubricant base oil may have a % CN of 21 or less. A cooling lubricant composition may include such a lubricant base oil.