Gas Engine Lubricating Composition for Low-Ash Oxidation Control
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Solution Overview
Problem
Existing gas engine oils suffer from severe oxidation and nitration processes due to high temperature and pressure conditions, leading to alkaline reserve depletion, increased viscosity, reduced cleanliness, and engine reliability issues.
Innovation Solution
A lubricating composition comprising a blend of API Group I and Group II base oils with a sulphated ash content of 0.4-1.0 wt%, TBN of 6.0-12 mg KOH/g, and aromatics content of 1-20 wt%, along with an aminic antioxidant, enhances oxidation stability and cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If low ash gas engine oil products with sulphated ash content of 0.5 wt% and below are used, then ash-related deposits are reduced, but oxidation stability deteriorates leading to severe lubricant oxidation and nitration processes
Solution Approach 1:
The invention changes the chemical composition parameters of the base oil by using a specific blend of Group I, Group II, and Group III base oils with controlled proportions. This blend achieves optimal balance between oxidation stability and low ash content by leveraging the complementary properties of each base oil group, where Group I provides natural antioxidants, Group II offers low sulphated ash, and Group III contributes high oxidation stability.
Solution Approach 2:
The invention creates a composite base oil system by combining multiple base oil groups (Group I, II, and III) in specific ratios. This composite approach allows the lubricant to exhibit synergistic properties that overcome the limitations of individual base oil groups, achieving both low ash content and high oxidation stability simultaneously.
2Reliability
If high TBN values are used to counteract alkaline reserve depletion, then neutralization capacity is improved, but viscosity increases and cleanliness performance deteriorates
Solution Approach 1:
The invention optimizes the TBN parameter within a specific range (6.0-12 mg KOH/g) rather than using excessively high values. This controlled parameter adjustment, combined with the multi-group base oil blend, provides sufficient alkaline reserve to counteract oxidation and nitration products while maintaining appropriate viscosity and cleanliness characteristics.
3Productivity
If extended oil drain intervals are implemented to reduce maintenance costs, then operational efficiency is improved, but oxidation and nitration processes intensify leading to reduced engine reliability
Solution Approach 1:
The invention incorporates a pre-formulated base oil blend with optimized oxidation and nitration resistance properties before the lubricant is put into service. This preliminary configuration of the base oil composition enables the lubricant to withstand extended operational periods without significant degradation, thereby supporting extended drain intervals while maintaining engine reliability.
4Object-generated harmful factors
If Group II and Group III base oils are used to reduce sulphated ash content, then ash-related deposits are minimized, but oxidation stability deteriorates under high temperature and pressure conditions
Solution Approach 1:
The invention creates a composite base oil system by combining multiple base oil groups (Group I, II, and III) in specific ratios. This composite approach allows the lubricant to exhibit synergistic properties that overcome the limitations of individual base oil groups, achieving both low ash content and high oxidation stability simultaneously.
Solution Approach 2:
The invention changes the chemical composition parameters of the base oil by using a specific blend of Group I, Group II, and Group III base oils with controlled proportions. This blend achieves optimal balance between oxidation stability and low ash content by leveraging the complementary properties of each base oil group, where Group I provides natural antioxidants, Group II offers low sulphated ash, and Group III contributes high oxidation stability.
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 provides improved oxidation stability, deposit control, and engine cleanliness, resulting in longer oil drain intervals and reduced maintenance costs.
Implementation Method 1
the lubricant in use is exposed to a sustained high temperature and high pressure environment. These operating conditions may cause relatively severe lubricant oxidation and nitration processes
Data Source
AI summary
A lubricating composition comprising a base oil and one or more additives, wherein the composition has: a sulphated ash content (according to ASTM D 874) of at least 0.4 wt% and at most 1.0 wt.%, by weight of the lubricating composition; a total base number (TBN) value (according to ASTM D 2896) of at least 4.0 mg KOH/g and at most 12 mg KOH/g; a total aromatics content contributed by the base oil in the range from 1 wt% to 30 wt%, by weight of the lubricating composition; and a sulphur content contributed by the base oil of 0.4 wt% or less, by weight of the lubricating composition; and wherein the base oil comprises a blend of (i) a first base oil which is a mineral base oil selected from an API Group I mineral base oil and an API Group II mineral base oil, and mixtures thereof, and (ii) a second base oil selected from an API Group II base oil and an API Group III base oil, preferably wherein the first base oil belongs to a different API group to that of the second base oil.