Overbased Friction Modifiers for Transmission Shudder
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Solution Overview
Problem
Traditional friction modifiers for automatic transmission fluids and manual transmission lubricants often result in low static coefficient of friction and lack durability, leading to issues like transmission shudder and inadequate wear protection, while also being environmentally unfriendly due to dependency on detergents that can decompose and cause long-term wear.
Innovation Solution
Development of overbased salts from the reaction product of hydrocarbyl-substituted amines with itaconate, which provide improved friction modifying performance, multi-functionality as detergents, anti-wear agents, and dispersants, and enhanced solubility, allowing for higher treat rates without precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional friction modifiers are used in ATF formulations, then the fluid can provide some friction modification, but the static coefficient of friction becomes too low and the positive slope durability is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of friction modifiers to create overbased compounds with specific properties. The overbased friction modifiers have a metal ratio (moles of metal base divided by moles of acidic organic compound) greater than 0.5, which fundamentally changes the friction characteristics compared to traditional modifiers. This structural parameter change enables simultaneously achieving high static coefficient of friction and durable positive slope performance.
Solution Approach 2:
The invention uses composite materials by combining overbased metal salts with specific organic acid structures. The overbased compounds represent a composite chemical structure where metal bases are combined with organic acid components in controlled ratios, creating a material that exhibits both high static friction and durable positive slope characteristics that neither component alone could achieve.
2Reliability
If conventional detergents and friction modifiers are used together, then wear protection is provided, but the formulation complexity and cost increase
Solution Approach 1:
The overbased friction modifiers exhibit multi-functionality by simultaneously providing friction modification, wear protection, and detergent functions. These compounds can replace multiple separate additives (traditional friction modifiers plus detergents) with a single additive that performs all three functions, thereby reducing formulation complexity while maintaining or improving performance.
3Reliability
If high amounts of friction modifiers are added to achieve desired friction characteristics, then friction performance improves, but solubility limitations cause precipitation
Solution Approach 1:
The patent applies parameter changes by modifying the solubility characteristics of friction modifiers through the overbasing process. The overbased compounds have improved solubility parameters that allow them to remain dissolved at higher concentrations in lubricating oils, enabling treatment rates sufficient to achieve desired friction characteristics without precipitation or separation.
Data Source
AI summary
The present invention provides a multipurpose overbased metal salt of the reaction product of a hydrocarbyl substituted amine with an itaconate, such as an N-substituted 4-carboxypyrrolidin-2-one, and methods of employing the same in lubricating compositions. Overbasing the N-substituted 4-carboxypyrrolidin-2-one can provide improved friction modifying performance to the compound as well as impart multi-functionality to the compound, i.e., the compound may function as a friction modifier as well as, for example, a detergent, anti-wear or extreme pressure agent and dispersant in lubricating compositions. The lubricating compositions containing the overbased N-substituted 4-carboxypyrrolidin-2-one are preferably intended to be employed in a method for lubricating a mechanical device, such as an automatic or manual transmission. However, it is envisioned that the compound can be employed in engine oil lubricants and any other type of functional fluid.