Low-Ash Lubricating Oil Composition for Deposit Control
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Solution Overview
Problem
Exhaust after-treatment devices in internal combustion engines are sensitive to sulfated ash from fuel and lubricant combustion byproducts, leading to durability issues, and reducing detergent levels can cause deposit formation.
Innovation Solution
A lubricating oil composition with controlled sulfated ash and sulfur content, comprising a major amount of oil of lubricating viscosity, 0.00010 to 0.025 wt% alkaline earth metal detergent, nitrogen-containing dispersant, and up to 0.10 wt% zinc dithiophosphate, maintaining a nitrogen-to-alkaline earth metal ratio of 20 or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the amount of detergent is reduced to limit sulfated ash, then sulfated ash content decreases, but deposit formation increases
Solution Approach 1:
The patent changes the chemical composition parameters by using ashless dispersants instead of traditional metal-based detergents, and by carefully controlling the sulfur content of the base oil. This substitution fundamentally alters how deposits are managed - from chemical neutralization to physical dispersion - thereby reducing sulfated ash while preventing deposit formation
Solution Approach 2:
The patent introduces ashless dispersants as intermediary substances that perform the deposit control function traditionally handled by metal detergents. These dispersants capture and hold deposit precursors in suspension without forming sulfated ash, acting as a mediator between the need for deposit protection and the requirement for low ash content
2Object-generated harmful factors
If detergent level is reduced to improve lubricity, then sulfated ash production decreases, but deposit control capability deteriorates
Solution Approach 1:
The patent changes the functional parameters of the lubricant by replacing metal-based detergents with ashless dispersants and controlling base oil sulfur content. This parameter change allows the system to maintain deposit control capability through different mechanisms - physical dispersion and adsorption rather than chemical neutralization - thereby decoupling deposit control from sulfated ash production
Solution Approach 2:
The patent applies local quality by using very low concentrations of sulfur (0.003-0.10 wt%) in the base oil, just enough to provide necessary lubricity and film formation, while the bulk of the lubricant remains low-ash. This localized optimization allows maintaining essential protective functions without excessive ash generation
Data Source
AI summary
A lubricating oil composition is provided. The composition includes major amount of an oil of lubricating viscosity, or more alkaline earth metal detergent, one or more nitrogen-containing dispersant, and up to about 0.10 wt % of zinc from zinc dithiophosphate. The lubricating oil composition has sulfur content of up to 0.10 wt %, sulfated ash content of up to 0.30 wt %, and the ratio of total nitrogen concentration to total alkaline earth metal concentration from the one or more alkaline earth metal detergent is about 20 or greater.