Lubricating Oil Composition for Supercharged Engines
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Solution Overview
Problem
Lubricating oils for supercharged engines face challenges in achieving a balance between coking resistance, Low Speed Pre-Ignition (LSPI) suppression, and high-temperature cleaning properties, as existing compositions often compromise on one or more of these performance metrics due to the decomposition of additives at high temperatures.
Innovation Solution
A lubricating oil composition that combines a calcium-based cleaning agent, a magnesium-based cleaning agent, and a specific polymer viscosity index improver, with adjusted nitrogen content, along with optional ashless friction modifiers, molybdenum-containing compounds, and zinc alkylphosphate as an anti-wear agent, to enhance coking resistance and LSPI suppression while maintaining high-temperature cleaning properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of calcium-based cleaning agent is reduced to reduce LSPI occurrence frequency, then LSPI suppression improves, but cleaning dispersibility of the lubricating oil composition deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the calcium content within 1100-1900 mass ppm and nitrogen content at 1000 mass ppm or more. This quantitative parameter optimization resolves the contradiction by finding the optimal range where LSPI suppression is effective while cleaning dispersibility is maintained through the synergistic effect of calcium and nitrogen components.
Solution Approach 2:
The patent uses a composite additive package combining calcium-based cleaning agents, magnesium-based cleaning agents, ashless dispersing agents, and viscosity index improvers. This composite approach allows the lubricating oil to achieve both LSPI suppression and cleaning dispersibility through the synergistic interaction of multiple components rather than relying on a single additive.
2Reliability
If the amount of friction modifiers containing molybdenum or anti-wear agents containing phosphorus is increased to reduce LSPI occurrence frequency, then LSPI suppression improves, but cleaning properties at high temperature deteriorate due to decomposition and deposit formation
Solution Approach 1:
The patent controls phosphorus and molybdenum content within specific ranges rather than using excessive amounts. By optimizing the concentration parameters and combining multiple additive types, the patent achieves LSPI suppression while minimizing high-temperature decomposition and deposit formation.
Solution Approach 2:
The patent applies different additive components for different functions: calcium-based and magnesium-based cleaning agents for cleaning properties, ashless dispersing agents for dispersibility, and controlled amounts of friction modifiers for LSPI suppression. This functional differentiation allows each component to perform its specific role without interfering negatively with other properties.
3Productivity
If viscosity is reduced in lubricating oils to improve fuel efficiency, then fuel efficiency improves, but coking resistance in superchargers deteriorates
Solution Approach 1:
The patent optimizes the viscosity parameter by selecting appropriate base oils and adding viscosity index improvers to achieve the right balance. The controlled viscosity reduction improves fuel efficiency while the additive package (calcium, magnesium, nitrogen components) maintains coking resistance in the supercharger environment.
Solution Approach 2:
The additive package acts as an intermediary between the reduced-viscosity lubricating oil and the supercharger system. The calcium-based cleaning agents, magnesium-based cleaning agents, and ashless dispersing agents serve as protective intermediaries that prevent coking deposits despite the lower viscosity oil being used for fuel efficiency.
Data Source
AI summary
[Problem to be solved] To provide a lubricating oil composition for a supercharged engine, which is capable of having a good balance of caulking resistance, LSPI suppression performance, and high-temperature cleaning properties. [Means to solve the problem] The lubricating oil composition for a supercharged engine according to the present invention is characterized by comprising: (A) a lubricating oil base oil; (B) a calcium-based cleaning agent, wherein the calcium amount is 1100 mass ppm or more to 1900 mass ppm or less on a total amount basis of the lubricant composition; (C) a magnesium-based cleaning agent; and (D) at least one viscosity index improver selected from a styrene-diene copolymer and an ethylene-α-olefin copolymer; and (E) a nitrogen-containing dispersing agent; and containing 700 mass ppm or more of nitrogen component, on a total amount basis of the lubricating oil composition.