End-Pivot Finger Follower Valve Train Lash Adjuster Lubrication
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Solution Overview
Problem
There is a lack of effective lubricant solutions for passenger car diesel engines with end-pivot finger follower valve trains, which experience high wear rates, particularly in designs like the Peugeot DW10 Lash Adjuster Test, where current lubricants often fail to achieve the required wear rating of 7 or higher.
Innovation Solution
A lubricating composition comprising an oil of lubricating viscosity, 0.01 wt % to 3 wt % of a dispersant viscosity modifier, and 0.01 wt % to 3 wt % of a zinc-free sulphur-containing antiwear agent, with sulphur content less than 5000 ppm, phosphorus content of 1000 ppm or less, and sulphated ash content of 3000 to 12,000 ppm, is supplied to the engine to reduce wear in the valve train components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lubricants are used in passenger car diesel engines with end-pivot finger follower valve trains, then the engine can operate, but high wear rates occur in the valve train components
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the lubricant, specifically incorporating zinc-free sulphur-containing antiwear agents at controlled concentrations (0.01-3 wt%) and limiting sulphur content to less than 5000 ppm, phosphorus to 1000 ppm or less, and sulphated ash to 12000 ppm or less. This resolves the contradiction by changing the lubricant's chemical parameters to achieve superior wear protection without compromising engine operation.
Solution Approach 2:
The patent employs composite materials by creating a multi-component lubricating composition that combines base oil with specific dispersant viscosity modifiers (0.01-3 wt%) and zinc-free sulphur-containing antiwear agents. This composite formulation achieves synergistic effects where the combination of components provides enhanced wear resistance that individual components cannot achieve alone, directly addressing the high wear rate problem in end-pivot finger follower valve trains.
2Object-generated harmful factors
If the sulphur content is reduced to protect emission control systems, then emission compliance is achieved, but antiwear performance may be compromised
Solution Approach 1:
The patent converts the potential harm of sulphur limitation into a benefit by introducing zinc-free sulphur-containing antiwear agents that provide superior antiwear performance while maintaining low overall sulphur content (less than 5000 ppm). This approach transforms the emission compliance constraint into an opportunity to use more efficient, zinc-free antiwear chemistry that protects both emission control systems and engine components.
Solution Approach 2:
The patent changes the chemical parameters by specifying precise limits: sulphur content less than 5000 ppm, phosphorus 1000 ppm or less, and sulphated ash 12000 ppm or less. These parameter changes ensure emission compliance while the specific formulation with zinc-free sulphur-containing antiwear agents maintains adequate antiwear performance for the valve train components.
3Reliability
If zinc-containing antiwear agents are used to improve wear protection, then antiwear performance increases, but compatibility with emission control systems deteriorates
Solution Approach 1:
The patent extracts zinc from the antiwear agent formulation, specifically using zinc-free sulphur-containing antiwear agents. This extraction of the harmful zinc element maintains effective antiwear performance through alternative chemistry while ensuring compatibility with emission control systems such as diesel particulate filters and selective catalytic reduction systems that are sensitive to zinc and other metal contaminants.
Solution Approach 2:
The patent converts the limitation of being zinc-free into a benefit by developing specialised sulphur-containing antiwear agents that provide effective wear protection without zinc. This approach benefits both emission control system compatibility and antiwear performance, as the zinc-free formulation avoids contaminating emission controls while the sulphur-containing chemistry delivers the necessary protective film formation on valve train components.
Data Source
AI summary
The invention provides a method of lubricating an end-pivot finger follower valve train lash adjuster of a passenger car compression ignition internal combustion engine having a reference mass not exceeding 2610 kg comprising supplying to the internal combustion engine a lubricating composition comprising an oil of lubricating viscosity 0.01 wt % to 3 wt % of a dispersant viscosity modifier, and 0.01 wt % to 3 wt % of a zinc free sulphur-containing antiwear agent, wherein the lubricating composition has a sulphur-content of less than 5000 ppm, a phosphorus content of 1000 ppm or less, and a sulphated ash content of (typically 3000 to 12,000 ppm).