Lubricating Composition for Lead Copper Corrosion Inhibition
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Solution Overview
Problem
Existing lubricating oils face challenges in providing antiwear performance, friction modification, and corrosion inhibition while meeting stringent industry specifications that limit the use of phosphorus and sulfur-containing additives, which can be corrosive to metal components like lead and copper.
Innovation Solution
A lubricating composition comprising an oil of lubricating viscosity, an ashless thiocarbamate compound with optionally-substituted hydrocarbyl groups on sulfur and nitrogen atoms, and a boron-containing compound, which provides antiwear performance, friction modification, and corrosion inhibition without deleteriously affecting copper or lead corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If phosphorus-containing antiwear agents such as ZDDP are used, then antiwear performance is improved, but lead and copper corrosion increases
Solution Approach 1:
The patent extracts and removes phosphorus-containing additives (ZDDP) from the lubricating composition to eliminate their corrosive effects on lead and copper components, while seeking alternative antiwear mechanisms that do not rely on phosphorus chemistry
Solution Approach 2:
The patent changes the chemical composition parameters by introducing ashless additives (thiocarbamates and boron-containing compounds) with different chemical properties than traditional ZDDP, maintaining antiwear functionality while altering the chemical interaction profile with metal surfaces to reduce corrosion
2Force
If sulfur-containing additives are used, then friction modification is improved, but corrosive effects on metal components increase
Solution Approach 1:
The patent removes sulfur-containing additives from the composition to eliminate their corrosive effects on copper and lead, while maintaining friction modification capabilities through alternative chemical mechanisms using ashless compounds
Solution Approach 2:
The patent employs ashless additives that do not leave harmful residues or deposits on metal surfaces, effectively replacing sulfur-containing additives that create long-term corrosive problems, even if the alternative requires more frequent monitoring or replacement
3Object-generated harmful factors
If ashless additives are used to reduce emissions, then ash content is reduced, but corrosion of copper and lead increases
Solution Approach 1:
The patent modifies the chemical structure and composition of ashless additives by selecting specific thiocarbamate and boron-containing compounds with tailored molecular characteristics that provide corrosion protection without generating ash, demonstrating that not all ashless additives have the same effect on metal corrosion
Solution Approach 2:
The patent creates a composite additive system combining ashless thiocarbamates with boron-containing compounds, where the synergistic interaction between these components provides both corrosion inhibition and emission reduction benefits that neither additive could achieve alone
Data Source
AI summary
The invention provides a lubricating composition containing an oil of lubricating viscosity, an ashless thiocarbamate compound having an optionally-substituted hydrocarbyl group on an S-atom and an optionally-substituted hydrocarbyl group on an N-atom, and a boron-containing compound. The invention further relates to a method of lubricating an internal combustion engine with the lubricating composition.