Cylinder Lubricating Oil Composition for Crosshead Diesel Engines
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Solution Overview
Problem
Crosshead-type diesel engines face challenges with corrosion from acidic components like sulfuric acid due to high combustion pressures and temperatures, leading to severe lubrication conditions that require improved oxidation stability and anti-scuffing properties in cylinder lubricating oils, which existing compositions fail to adequately address.
Innovation Solution
A cylinder lubricating oil composition with a base oil having an aromatic content of 8.5% or more, combined with an alkaline earth metal phenate, an aminic antioxidant, and an oil-soluble molybdenum compound at specific ratios, providing enhanced oxidation stability and anti-scuffing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cylinder wall temperature is increased to inhibit corrosion by sulfuric acid, then the anti-corrosion property is improved, but the oxidation stability and anti-scuffing properties of the lubricating oil deteriorate due to severe thermal conditions
Solution Approach 1:
The patent applies preliminary action by incorporating specific antioxidants (diphenylamine and N-phenyl-α-naphthylamine) and corrosion inhibitors into the lubricating oil composition before the engine operates. These additives pre-establish protective mechanisms that will activate under high-temperature conditions, preventing both oxidation and corrosion simultaneously. The base oil is specifically selected with aromatic content of 8.5% or more to provide inherent thermal stability before exposure to operating conditions.
Solution Approach 2:
The patent employs composite materials by creating a multi-component lubricating oil formulation that combines a base oil with specific aromatic content, multiple additives including antioxidants, corrosion inhibitors, and viscosity modifiers. This composite composition synergistically addresses multiple contradictory requirements: the base oil provides thermal stability, antioxidants prevent oxidation, and corrosion inhibitors protect against sulfuric acid, allowing the oil to maintain performance under severe high-temperature conditions.
2Productivity
If the amount of lubricating oil is decreased to reduce fuel consumption, then the productivity is improved, but the anti-scuffing properties deteriorate due to insufficient lubrication film formation
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the lubricating oil, specifically setting the base oil aromatic content at 8.5% or more and incorporating specific concentrations of additives. These parameter adjustments enhance the oil's film-forming capability and extreme pressure properties, allowing adequate lubrication protection even when the quantity of oil is reduced. The optimized composition ensures sufficient anti-scuffing performance while maintaining fuel efficiency.
3Stability of the object's composition
If a base oil with less aromatic component is used to improve oxidation stability, then the oxidation stability is improved, but the anti-scuffing properties and heat resistance deteriorate under high combustion pressure conditions
Solution Approach 1:
The patent applies parameter changes by optimizing the aromatic content parameter of the base oil to be 8.5% or more, rather than using conventional low-aromatic bases. This parameter adjustment, combined with specific additive packaging, achieves a balance where sufficient oxidation stability is maintained while anti-scuffing and heat resistance properties are enhanced for high-combustion-pressure applications.
Solution Approach 2:
The patent uses composite materials by formulating a lubricating oil that combines a base oil with specific aromatic content with a synergistic package of additives including antioxidants, corrosion inhibitors, and extreme pressure agents. This composite approach allows the base oil to provide thermal and oxidation stability while the additives contribute anti-scuffing and heat resistance properties, resolving the contradiction between oxidation stability and anti-scuffing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition exhibits excellent heat resistance and anti-scuffing properties, suitable for high-stress conditions such as ultra-long stroke and high combustion pressures, maintaining effective lubrication and preventing corrosion in crosshead-type diesel engines.
Implementation Method 1
the cylinder oil is required to have a function to neutralize the acidic components such as sulfuric acid so as to prevent corrosion
Implementation Method 2
addition of a specific antioxidant can improve significantly not only the antioxidation properties but also the anti-scuffing properties of a cylinder oil
Implementation Method 3
a cylinder lubricating oil composition having improved heat resistance and cleaning capability at high temperature, the composition comprising a lubricant base oil, a metal detergent and at least one kind of a metal dithiocarbamate selected from a molybdenum dialkyldithiocarbamate and a zinc dialkyldithiocarbamate
Data Source
AI summary
The present invention provides a cylinder lubricating oil composition for a crosshead-type diesel engine, which is improved in oxidation stability and anti-scuffing properties besides the properties of the conventional cylinder lubricating oil composition and comprises a base oil having an aromatic content of 8.5 percent by mass or more and on the basis of the total mass of the composition (A) an alkaline earth metal phenate in an amount of 0.005 mole/kg or more on the basis of phenate soap content, (B) an aminic antioxidant in an amount of 0.1 to 5 percent by mass and (C) an oil-soluble molybdenum compound in an amount of 30 to 500 ppm by mass on the basis of molybdenum and having a base number of 20 to 100 mgKOH/g and a 100°C kinematic viscosity of 12.6 mm2/s or higher.