Comb-Polymer Lubricating Oil for Fuel Economy and Shear Stability
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Solution Overview
Problem
Existing lubricating oil compositions struggle to simultaneously achieve excellent fuel consumption saving performance and high shear stability, particularly when used in internal combustion engines under high temperatures and shear conditions.
Innovation Solution
A lubricating oil composition comprising comb polymers with different weight-average molecular weights, specifically a comb polymer with a weight-average molecular weight of less than 300,000 and another with 400,000 or more, blended in a specific mass ratio, to enhance both fuel consumption saving performance and shear stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a viscosity index improver such as PMA is used to improve fuel consumption saving performance, then fuel efficiency improves, but cleanliness decreases under high temperature and high shear conditions
Solution Approach 1:
The patent changes the molecular weight parameter of the viscosity index improver from conventional high molecular weight (e.g., PMA) to a specific range of 40,000 to 200,000. This parameter change allows the lubricating oil to maintain fuel consumption saving performance while improving resistance to shear degradation, thereby preserving cleanliness under high temperature and high shear conditions.
Solution Approach 2:
The patent uses a composite approach by combining the viscosity index improver with specific additives including ashless dispersants and metal salts. This composite formulation enhances the overall stability and cleanliness of the lubricating oil while maintaining fuel efficiency, resolving the contradiction between fuel consumption saving and cleanliness.
2Stability of the object's composition
If high molecular weight viscosity index improvers are used to maintain viscosity at high temperatures, then viscosity stability improves, but shear stability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the viscosity index improver to a specific range (40,000 to 200,000) that balances viscosity stability and shear stability. This intermediate molecular weight range provides sufficient viscosity at high temperatures while being resistant to shear breakdown, unlike conventional high molecular weight additives.
Solution Approach 2:
The patent introduces ashless dispersants and metal salt additives that locally enhance the oil film properties and protective characteristics in high-stress zones. These additives provide localized reinforcement that improves shear stability without compromising the overall viscosity stability of the lubricating oil.
Data Source
AI summary
A lubricating oil composition may have excellent fuel economy and high shear stability. Such a lubricating oil composition may include: a comb-like polymer (A1) having a weight average molecular weight (Mw) of less than 300,000; and a comb-like polymer (A2) having a Mw of at least 400,000. The (A1)/(A2) mass content ratio of the comb-like polymer (A1) to the comb-like polymer (A2) in terms of resin content may be at least 0.25.