Low Viscosity Engine Oil with High Abrasion Resistance
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Solution Overview
Problem
Current engine oils with low viscosity struggle to maintain abrasion resistance under high temperature and high shear rate conditions, leading to increased friction and potential seizure, while increasing the amount of anti-abrasion agents like ZnDTP can poison catalysts used in exhaust gas cleaning.
Innovation Solution
An engine oil composition with a HTHS 150° C. viscosity below 2.6 mPa·s is achieved by controlling the ratio of 100° C. kinematic viscosity to HTHS 100° C. viscosity (KV100/HTHS100) to 1.3 or lower, without increasing the amount of ZnDTP, using a base oil and additives that stabilize the viscosity and prevent film breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the viscosity of engine oil is reduced to improve fuel savings, then fuel efficiency is improved, but the lubricating oil film is destroyed under high shear conditions, leading to increased friction and abrasion
Solution Approach 1:
The patent applies parameter changes by carefully controlling the HTHS viscosity to be less than 2.6 mPa·s (improving fuel efficiency) while simultaneously controlling the KV100/HTHS100 ratio to be 1.3 or lower (maintaining film stability). This dual parameter control resolves the contradiction between reducing viscosity for fuel savings and maintaining sufficient viscosity for lubrication under high shear conditions.
2Reliability
If the amount of ZnDTP is increased to improve abrasion resistance, then abrasion resistance is improved, but the catalyst used to clean exhaust gas is poisoned
Solution Approach 1:
The patent changes the approach from increasing ZnDTP quantity to optimizing viscosity parameters. By controlling HTHS viscosity and KV100/HTHS100 ratio, the patent achieves excellent abrasion resistance without increasing ZnDTP content, thereby avoiding catalyst poisoning while maintaining protective lubrication films under high shear conditions.
3Reliability
If high polymers are added as viscosity index improvers to guarantee high abrasion resistance, then abrasion resistance is improved, but temporary viscosity decrease occurs during high speed/high load operation
Solution Approach 1:
The patent extracts or removes the high polymer viscosity index improvers from the formulation. By eliminating these polymers, the patent avoids the temporary viscosity decrease that occurs during high shear operation, while achieving the desired viscosity characteristics through controlled base oil selection and additive package optimization.
Solution Approach 2:
The patent changes the viscosity control strategy from using polymer additives to controlling physical parameters of the base oil and additives. By selecting base oils and additives with appropriate viscosity characteristics and controlling the KV100/HTHS100 ratio, the patent achieves stable viscosity without the shear-thinning effects of high polymers.
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 engine oil composition maintains excellent abrasion resistance and fuel savings effects, even at high shear rates, without degrading the lubricating film, and is suitable for both standard and high-output engine conditions.
Implementation Method 1
the high-temperature high-shear viscosity at 150° C. and at a shear rate of 1×106 s−1 is less than 2.6 mPa·s
Implementation Method 2
the shear rate in a dynamic valve system is also as high as 107-108 s−1
Implementation Method 3
lubrication of the piston ring/cylinder liner and crankshaft bearing mainly belongs to the area of fluid lubrication, while lubrication of the dynamic valve mechanism, that is, the cam/tappet, mainly belongs to the area of elastic fluid lubrication—the area of mixed/boundary lubrication
Implementation Method 4
lowering the viscosity of engine oil is effective in reducing friction in the fluid lubricating area
Data Source
AI summary
An engine oil composition that has lower viscosity then the lowest viscosity grade specified by the current standard (SAE (Society of Automotive Engineers) viscosity classification) and achieves excellent abrasion resistance under conditions of high temperature and high shear rate without an increase in the amount of anti-abrasion agent, said engine oil composition characterized by the following facts: the engine oil composition contains 0.02-0.12 mass % of zinc dithiophosphate, measured in the phosphorous amount based on the total weight of the composition, in a base oil compromised of a mineral oil and/or a synthetic oil;(1) the high-temperature high-shear viscosity at 150° C. and at a shear rate of 1×106 s−1 is less than 2.6 mPa·s;(2) the engine oil composition satisfies the following equation:kinematicviscosityat100∘C.(mm2/s)high-temperaturehigh-shearviscosityat100∘C.andatashearrateof1×106s-1(mPa·s)≤1.3.