Lubricant Additive Package for Timing Chain Stretch Reduction
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Solution Overview
Problem
Current lubricants fail to adequately address timing chain stretch in internal combustion engines, with conventional anti-wear agents and dispersants providing inadequate protection, and existing solutions do not effectively reduce roller pin wear caused by rolling and sliding friction.
Innovation Solution
A lubricating oil composition comprising a major amount of base oil and a minor amount of an additive package including overbased calcium detergent, borated ashless dispersant, metal dialkyl dithiophosphate, and oil-soluble molybdenum compound, with specific ratios of calcium, molybdenum, and boron to enhance wear resistance and friction reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anti-wear agents are used to reduce timing chain wear, then wear protection is improved, but timing chain stretch increases
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricant by specifying precise ratios of calcium (0.01-0.1%), molybdenum (0.001-0.01%), and boron (0.001-0.005%) in the additive package. This parameter optimization allows the lubricant to achieve both wear protection and timing chain stretch reduction simultaneously, resolving the contradiction between these two performance requirements.
Solution Approach 2:
The patent employs a composite additive package combining multiple functional components: calcium-based detergents for wear protection, molybdenum compounds for friction reduction, and boron-containing dispersants for soot management. This composite formulation synergistically addresses both wear protection and timing chain stretch issues that cannot be solved by single additives.
2Reliability
If dispersants and viscosity index improvers are used to address wear problems, then wear resistance is improved, but timing chain stretch reduction is inadequate
Solution Approach 1:
The patent optimizes the concentration parameters of specific additives: calcium content at 0.01-0.1%, molybdenum at 0.001-0.01%, and boron at 0.001-0.005%. This precise parameter control ensures that the lubricant achieves superior timing chain stretch reduction (0.1% or less over 216 hours) while maintaining effective wear resistance, overcoming the limitations of conventional dispersant formulations.
Solution Approach 2:
The patent introduces molybdenum compounds as intermediary friction modifiers that mediate between the calcium detergent's wear protection function and the dispersant's soot management function. This intermediary component specifically targets timing chain stretch reduction while allowing the other additives to maintain their primary functions.
3Force
If anti-wear agents are used to reduce roller pin wear, then friction reduction is improved, but timing chain stretch increases
Solution Approach 1:
The patent specifies precise parameter ranges for molybdenum (0.001-0.01%) and calcium (0.01-0.1%) content to optimize the balance between friction reduction and timing chain stretch control. This parameter optimization enables the lubricant to reduce roller pin wear friction while preventing the timing chain from stretching, resolving the contradiction between these opposing effects.
Solution Approach 2:
The patent employs a composite additive system where molybdenum compounds provide friction reduction, calcium detergents provide wear protection, and boron-containing dispersants control soot. This composite formulation synergistically achieves both friction reduction and timing chain stretch reduction, overcoming the limitation of single-function anti-wear agents.
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 lubricating oil composition significantly reduces timing chain stretch to 0.1% or less over 216 hours, as measured by the Ford Chain Wear Test, while maintaining effective friction reduction and wear protection.
Implementation Method 1
lubricants are used to reduce wear between moving parts where there is metal to metal contact
Implementation Method 2
a solution for reducing the rolling and sliding friction forces that cause roller pin wear is sought
Implementation Method 3
soot caused abrasive wear on liners, crossheads and top ring faces
Data Source
AI summary
A method for reducing timing chain stretch in an engine comprising a step of lubricating said timing chain with a lubricating oil composition that includes a major amount of a base oil; and a minor amount of an additive package including (a) at least one overbased calcium detergent, (b) at least one borated dispersant, (c) a metal dialkyl dithiophosphate, and (d) at least one molybdenum compound. The lubricating oil composition has a TBN value of at least 7.5 mg KOH/g of the lubricating oil composition, at least 80 ppm of molybdenum, based on the total weight of the lubricating oil composition, a weight ratio of total calcium in the lubricating oil composition to total molybdenum in the lubricating oil composition of less than 8.4; and a weight ratio of nitrogen from the dispersant in the lubricating composition to total boron in the lubricating oil composition of from 2.6 to 3.0.