Ashless Thiocarbamate Additive for Engine Corrosion Control
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Solution Overview
Problem
Existing lubricating oils face challenges in reducing corrosion of copper and lead in internal combustion engines while meeting emission regulations, as traditional antiwear additives like ZDDP are corrosive and need to be minimized, and ashless additives can increase metal corrosion.
Innovation Solution
A lubricating composition containing an ashless thiocarbamate compound with optionally-substituted hydrocarbyl groups on S and N atoms, which provides antiwear, friction modification, antioxidant, and corrosion inhibition performance, reducing lead or copper corrosion without increasing metal corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional antiwear additives like ZDDP are used to protect engines from wear, then antiwear performance is improved, but lead and copper corrosion increases
Solution Approach 1:
The patent changes the chemical composition parameters by using ashless thiocarbamate compounds with specific molecular structures (containing sulfur and nitrogen atoms in the molecule) instead of traditional ZDDP additives. This chemical parameter change allows achieving antiwear performance while reducing metal corrosion, as the ashless nature and specific molecular structure reduce corrosiveness to lead and copper components.
Solution Approach 2:
The patent employs ashless additives that do not leave harmful residues after consumption. These ashless thiocarbamate compounds are designed to be consumed without forming corrosive ash deposits, effectively replacing traditional additives that leave harmful residues and cause long-term corrosion issues in engine components.
2Object-generated harmful factors
If ashless additives are used to reduce phosphorus and sulfur content, then emission standards are met, but metal corrosion increases
Solution Approach 1:
The patent modifies the chemical parameters by introducing ashless thiocarbamate compounds containing sulfur and nitrogen atoms within their molecular structure. This allows the additive to be classified as ashless (meeting emission standards) while the specific molecular structure provides corrosion protection, resolving the contradiction between being ashless and causing corrosion.
Solution Approach 2:
The patent uses composite molecular structures in the thiocarbamate compounds that combine multiple functional elements (sulfur, nitrogen, and hydrocarbyl groups) within a single molecule. This composite structure enables the additive to simultaneously achieve ashless properties and corrosion inhibition, addressing both requirements.
3Reliability
If dispersants are used to protect from soot deposits, then dispersancy is improved, but friction performance deteriorates
Solution Approach 1:
The ashless thiocarbamate compounds disclosed in the patent are designed to perform multiple functions simultaneously: they provide dispersancy to protect against soot deposits, maintain friction performance, and inhibit metal corrosion. This multi-functionality resolves the contradiction by enabling a single additive class to address multiple performance requirements that were previously traded off against each other.
Data Source
AI summary
The invention provides a lubricating composition containing an oil of lubricating viscosity and an ashless thiocarbamate compound having an optionally-substituted hydrocarbyl group on an S-atom and an optionally-substituted hydrocarbyl group on an N-atom. The invention further relates to a method of the lubricating an internal combustion engine with the lubricating composition.