Lubricant Oil Composition for Engine Fuel Efficiency
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Solution Overview
Problem
Conventional lubricating oils fail to adequately balance fuel savings and low temperature viscosity characteristics, leading to issues such as wear, seizure, and fatigue under severe lubrication conditions.
Innovation Solution
A lubricating oil composition comprising a mineral oil base with a saturated component content of 95% or greater, a viscosity index of 120 or more, and a viscosity index improver with a weight average molecular weight of 50,000 or more, along with a friction modifier, to maintain high-temperature high-shear viscosity while reducing kinematic viscosity and improving low temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the kinematic viscosity of the lubricating oil is lowered to improve fuel savings, then fuel efficiency is improved, but lubrication performance under severe conditions deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the viscosity index (120 or greater) and saturated component content (95% or greater) of the base oil, along with optimizing the molecular weight and PSSI ratio of the viscosity index improver. This allows the oil to achieve low kinematic viscosity for fuel savings while maintaining high-temperature high-shear viscosity for lubrication performance through specific compositional parameters.
Solution Approach 2:
The patent uses composite materials by combining a specifically formulated base oil (with controlled saturated and cyclic saturated components) with a viscosity index improver having specific molecular weight and PSSI characteristics. This composite approach enables simultaneous achievement of low kinematic viscosity and maintained HTHS viscosity, resolving the contradiction between fuel savings and lubrication performance.
2Stability of the object's composition
If the viscosity index is improved by adding viscosity index improvers, then multi-grading is improved, but HTHS viscosity may increase under severe lubrication conditions
Solution Approach 1:
The patent applies parameter changes by specifying precise constraints on the viscosity index improver: weight average molecular weight of 50,000 or more and PSSI (persistence of shear stress) of 1 × 10^4 or less. These parameter controls ensure that the viscosity index improvement is achieved without excessive increase in HTHS viscosity, allowing the oil to maintain proper lubrication characteristics under severe conditions.
Solution Approach 2:
The patent applies local quality by differentiating the behavior of the base oil and viscosity index improver at different temperature conditions. The base oil provides low-temperature fluidity while the controlled viscosity index improver provides high-temperature viscosity maintenance. This local functional differentiation allows the oil to have optimal properties at both extremes of the temperature range without compromise.
3Reliability
If high viscosity index base oil is used to maintain lubrication performance, then lubricity is improved, but fuel savings are reduced
Solution Approach 1:
The patent applies parameter changes by selecting a base oil with viscosity index of 120 or greater and saturated component content of 95% or greater, combined with specific viscosity index improver parameters. This allows the oil to maintain adequate lubricity through proper high-temperature viscosity while achieving low kinematic viscosity at operating temperatures for fuel savings, rather than using inherently high-viscosity synthetic base oils.
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 lubricating oil composition achieves both excellent fuel savings and lubricity, maintaining high-temperature high-shear viscosity while enhancing low temperature viscosity characteristics and fuel efficiency, particularly effective for engines with roller tappet type valve train systems.
Implementation Method 1
a viscosity index improver having a weight average molecular weight of 50,000 or more and a ratio of the weight average molecular weight and PSSI at 1 × 10 4
Implementation Method 2
a lubricating base oil component being a mineral oil obtained by hydrocracking/hydroisomerisation of raw oil containing normal paraffin
Data Source
AI summary
The present invention provides a lubricating oil composition comprising: a lubricating base oil including as a main component, a lubricating base oil component having a saturated component content of 95% by mass or greater, a proportion of cyclic saturated component of 60% by mass or less in the saturated component, a viscosity index of 120 or greater, and ε-methylene content in total constituent carbons at a proportion of 15 to 20%; and a viscosity index improver having a weight average molecular weight of 50,000 or greater and a ratio of the weight average molecular weight to PSSI of 1 × 104 or greater, in an amount of 0.1 to 50% by mass based on a total mass of the lubricating oil composition, the lubricating oil composition having a kinematic viscosity of 3.0 to 12.0 mm2/s at 100 °C and a ratio of HTHS viscosity at 150 °C to HTHS viscosity at 100 °C of 0.50 or greater.