Low-Viscosity Engine Oil Composition for Journal Bearing Wear
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Solution Overview
Problem
Low viscosity lubricating oils used in internal combustion engines, particularly with start/stop technology, lead to increased wear in journal bearings due to boundary lubrication, which is not effectively addressed by traditional lubricant additives.
Innovation Solution
A lubricating oil composition comprising a Group I, II, III, or IV base oil, overbased or neutral metal detergents, and a friction modifier such as glycerol monooleate, dioleate, or trioleate, which provides improved wear protection and durability for journal bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low viscosity lubricating oils are used to improve fuel economy, then fuel economy is improved, but journal bearing wear increases due to boundary lubrication
Solution Approach 1:
The patent introduces a friction modifier additive that changes the tribological parameters of the lubricating oil, specifically reducing the coefficient of friction in boundary lubrication conditions. This allows the use of low viscosity base oils (improving fuel economy) while the additive package maintains adequate wear protection by modifying the friction characteristics at the bearing surface
Solution Approach 2:
The patent creates a composite lubricating oil system combining low viscosity base oil with specific friction modifier additives (such as organic friction modifiers). This composite formulation achieves the dual benefit of low viscosity for fuel economy and enhanced boundary lubrication properties for wear protection, effectively merging the advantages of both low viscosity oils and traditional protective additives
2Object-generated harmful factors
If low viscosity lubricating oils are used to reduce engine emissions, then engine emissions are reduced, but journal bearing durability deteriorates
Solution Approach 1:
The friction modifier additive changes the friction and wear parameters of the lubricating film, enabling low viscosity oils (which reduce emissions) to provide adequate boundary lubrication protection. The additive modifies the surface interaction characteristics to reduce wear scar volume and improve bearing durability despite the lower viscosity
Solution Approach 2:
The friction modifier acts as an intermediary substance between the low viscosity lubricating oil and the journal bearing surface. It mediates the interaction by forming a protective film or modifying surface properties, thereby protecting the bearing from wear that would otherwise occur with low viscosity oils
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 lubricating oil composition achieves a 10% to 80% decrease in journal bearing wear as measured by wear scar volume using the MTM-R test method, compared to oils of comparable viscosity without the friction modifier.
Implementation Method 1
Low viscosity lubricating oils used in internal combustion engines, particularly with start/stop technology, lead to increased wear in journal bearings due to boundary lubrication
Implementation Method 2
a friction modifier comprising glycerol monooleate, glycerol dioleate, glycerol trioleate or combinations thereof
Data Source
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AI summary
This invention relates to a lubricating oil composition comprising or resulting from the admixing of: (i) a base oil; (ii) one or more overbased or neutral metal based detergents; and (3) a friction modifier comprising glycerol monooleate, glycerol dioleate, glycerol trioleate or combinations thereof at from 0.2 to 1.0 wt.% of the composition. The composition has a total sulfated ash of less than or equal to 1.0 wt.%, a high temperature high shear viscosity at 150°C (HTHS) as determined according to ASTM D4683-20 of greater than or equal to 1.8 mPa.s and less than or equal to 2.9 mPa.s, and a total phosphorous level of less than or equal to 0.080 wt.%. The inventive composition provides a 10% to 80% decrease in journal bearing wear as measured by wear scar volume in µm3 using the MTM-R test method compared to a lubricating oil composition of comparable HTHS, but not including a friction modifier comprising glycerol monooleate, glycerol dioleate, glycerol trioleate or combinations thereof. Also provided are a method of decreasing journal bearing wear in an internal combustion engine and a method of making the lubricating oil composition.