Lubricating Composition for EGR Engine Viscosity Control
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Solution Overview
Problem
Heavy duty diesel engines with exhaust gas recirculation (EGR) systems face challenges with soot-mediated oil thickening due to different soot structures and increased viscosity, which existing viscosity improvers and dispersant viscosity modifiers struggle to effectively manage across a wide temperature range.
Innovation Solution
A lubricating composition comprising a copolymer derived from α-olefin and ethylenically unsaturated carboxylic acid or derivatives, esterified and amidated with an alcohol and an aromatic amine, which is used in combination with an oil of lubricating viscosity to maintain stable viscosity and control soot accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas recirculation (EGR) is used to reduce emissions, then environmental emissions are reduced, but soot-mediated oil thickening increases and viscosity control becomes difficult
Solution Approach 1:
The invention changes the chemical structure parameters of the viscosity improver by using a copolymer with specific monomer ratios (ethylene:alpha-olefin = 1:4 to 1:16) and specific functional group compositions (carboxylic acid derivatives: 5-20 mol%). This optimized parameter combination allows the viscosity improver to effectively manage soot-mediated thickening while maintaining viscosity stability across a wide temperature range, resolving the contradiction between emission reduction and viscosity control.
Solution Approach 2:
The invention creates a composite functional material by combining multiple components in a specific copolymer structure: ethylene backbone, alpha-olefin grafts, carboxylic acid derivatives, and aromatic amine reactants. This composite structure provides both viscosity improvement and soot dispersancy functions in a single additive package, effectively addressing the dual challenge of emission reduction and viscosity stabilization in EGR engines.
2Stability of the object's composition
If viscosity improvers are used to maintain viscosity stability, then viscosity change with temperature is reduced, but soot accumulation control is insufficient
Solution Approach 1:
The copolymer viscosity improver is designed to perform multiple functions simultaneously: it provides viscosity improvement through its molecular structure while also controlling soot accumulation through its aromatic amine-functionalized carboxylic acid groups that interact with soot particles. This multi-functionality eliminates the need for separate soot dispersants and achieves both viscosity stability and soot control in a single additive.
Solution Approach 2:
The invention merges the viscosity improvement function and soot dispersancy function into a single copolymer additive package. The copolymer structure integrates hydrocarbon chains for viscosity modification with polar aromatic amine groups for soot interaction, combining what were traditionally separate additive functions into one unified material that addresses both challenges.
3Object-generated harmful factors
If dispersant viscosity modifiers are used to control soot, then soot dispersancy is improved, but viscosity stability across wide temperature range is compromised
Solution Approach 1:
The invention optimizes the molecular weight and structural parameters of the copolymer to achieve both soot dispersancy and viscosity stability. By controlling the ethylene:alpha-olefin ratio and carboxylic acid derivative content, the copolymer maintains appropriate molecular size and polarity to interact with soot while preserving sufficient hydrocarbon character to provide viscosity improvement across wide temperature ranges.
Data Source
AI summary
The invention provides a lubricating composition containing a copolymer comprising units derived from monomers (i) a-olefin and (ii) an ethylenically unsaturated carboxylic acid or derivatives thereof esterified and amidated with an alcohol and an aromatic amine respectively, and an oil of lubricating viscosity. The invention further relates to the use of the lubricating composition in an internal combustion engine.