Low-Ash Lubricating Composition for Corrosion-Resistant Engine Oils
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Solution Overview
Problem
Automotive manufacturers face challenges in reducing the ash content of lubricating oils without compromising performance, as traditional metal-containing antiwear additives like ZDDP contribute to ash content and their removal affects corrosion resistance, stable emulsions, and corrosion resistance in engine oils.
Innovation Solution
Formulating passenger car lubricating compositions with low sulfated ash content using ashless phosphorus-containing antiwear compounds and optional metal-containing antiwear compounds, balanced phosphorus ratios, and specific TBN profiles, along with detergent systems, to maintain performance in engine oil tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal-containing antiwear additives like ZDDP are used to protect engine components, then corrosion resistance and antiwear performance are improved, but sulfated ash content increases
Solution Approach 1:
The patent changes the chemical composition parameters by using ashless phosphorus-containing antiwear compounds instead of traditional metal-containing additives like ZDDP. This substitution maintains the protective function while eliminating metal ash formation, directly resolving the contradiction between corrosion resistance and ash content
Solution Approach 2:
The patent employs a composite additive system combining ashless phosphorus-containing antiwear compounds with specific detergent systems (overbased calcium and magnesium sulfonates). This composite approach maintains overall protective performance while controlling ash content through the synergistic interaction of components
2Object-generated harmful factors
If metal-containing antiwear additives are removed to decrease ash content, then sulfated ash content is reduced, but corrosion resistance and emulsion stability deteriorate
Solution Approach 1:
The patent extracts the harmful metal component from the antiwear additive system while retaining the beneficial phosphorus-containing antiwear function through ashless compounds. This selective removal decreases ash content while preserving corrosion protection
Solution Approach 2:
The patent introduces overbased calcium and magnesium sulfonate detergents as intermediary compounds that provide corrosion protection and emulsion stability. These intermediaries compensate for the removal of metal-containing antiwear additives, maintaining reliability without ash content penalty
3Reliability
If traditional ZDDP is used as a multi-functional additive, then antiwear and oxidation protection are achieved, but ash content increases
Solution Approach 1:
The patent replaces durable metal-containing additives with ashless phosphorus-containing compounds that function as effective but ash-free protective agents. This substitution achieves the same protective function without the long-term ash accumulation problem of metal additives
Solution Approach 2:
The patent fundamentally changes the compositional parameters by eliminating metal content from the antiwear additive while maintaining phosphorus content at effective levels. This parameter change preserves antiwear protection while eliminating the source of sulfated ash
Data Source
AI summary
This disclosure describes low-ash lubricating composition achieving the same or better performance of higher ash compositions by including selected antiwear system with ashless phosphorus-containing antiwear compounds and select detergent systems matching TBN contributions to the antiwear systems.