Marine Engine Lubrication Using Star Polymers
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Solution Overview
Problem
Lubricating oil consumption is high in marine diesel engines due to evaporation and degradation of polyisobutylene in brightstock-free formulations, leading to increased lubricant evaporation and consumption.
Innovation Solution
Incorporating star polymers or olefin copolymers as viscosity modifiers dispersed in heavy diluent oils within marine diesel cylinder lubricants (MDCLs) and trunk piston engine oils (TPEOs) to reduce lubricant evaporation and consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If polyisobutylene is used as viscosity modifier in brightstock-free MDCLs and TPEOs, then cost is reduced and availability is improved, but lubricating oil evaporation and consumption increase
Solution Approach 1:
The patent changes the chemical parameters of the viscosity modifier by selecting star polymers (such as amorphous styrene-diene copolymer) or olefin copolymers (such as ethylene-propylene copolymer) instead of polyisobutylene. These alternative polymers have different molecular structures and chemical properties that result in lower evaporation rates and reduced lubricating oil consumption while maintaining the required viscosity modification function.
2Stability of the object's composition
If brightstock is replaced with polyisobutylene, then manufacturing cost is reduced, but lubricant stability and evaporation resistance deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters by replacing polyisobutylene with star polymers or olefin copolymers. These alternative viscosity modifiers exhibit superior thermal stability and evaporation resistance, thereby improving lubricant stability and reducing evaporation losses while maintaining cost-effectiveness.
3Reliability
If polyisobutylene is used as viscosity modifier, then viscosity control is achieved, but degradation products formation increases leading to higher oil consumption
Solution Approach 1:
The patent changes the chemical structure parameters of the viscosity modifier to star polymers or olefin copolymers, which have higher thermal and oxidative stability. This reduces the formation of degradation products that would otherwise lead to increased oil consumption, while maintaining effective lubrication and viscosity control.
Data Source
AI summary
Marine engine (two-or four-stroke) lubrication is effected by a composition comprising a major amount of an oil of lubricating viscosity blended with minor amounts of one or more additives and a star polymer or olefin co-polymer viscosity modifier dispersed in a heavy basestock diluent oil.