Variable Geometry Rocker Arm for Lash Adjustment
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Solution Overview
Problem
Existing valvetrains face issues with lash adjusters causing undesired variances due to overextension or sponginess, which can affect engine performance and prevent smooth engine braking and cylinder deactivation.
Innovation Solution
A valvetrain assembly with a valve bridge, capsule, and rocker arms that include a central and offset pressure point configuration, allowing for lash adjustment and deactivation modes without internal hydraulic supplies, enabling engine braking and variable valve actuation techniques without adding variances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lash adjuster is used to provide variances in valve actuation, then valve opening and closing functions are improved, but the lash adjuster causes undesired variances due to overextension or sponginess
Solution Approach 1:
The patent removes the traditional lash adjuster component from the valvetrain system. Instead of using a separate lash adjuster mechanism that causes pumping and sponginess, the invention integrates variance provision directly into the rocker arm through a variable geometry mechanism with adjustable pivot points, thereby extracting the problematic component while retaining the desired functionality.
Solution Approach 2:
The patent replaces the mechanical lash adjuster system with a variable geometry rocker arm mechanism. The new system uses adjustable pivot points and linkage geometry to provide valve actuation variances, substituting the old mechanical adjustment method with a geometrically variable mechanism that eliminates pumping and sponginess issues.
2Ease of operation
If a traditional lash adjuster mechanism is used, then valve lash can be adjusted, but the mechanism adds complexity to the valvetrain system
Solution Approach 1:
The patent combines the lash adjustment function with the rocker arm itself by incorporating a variable geometry mechanism and adjustable pivot points directly into the rocker arm structure. This merging eliminates the need for separate lash adjuster components, thereby maintaining lash adjustment capability while reducing overall system complexity.
Solution Approach 2:
The variable geometry rocker arm serves multiple functions: it provides valve actuation, enables lash adjustment through adjustable pivot points, and allows for engine braking and cylinder deactivation modes. This multi-functionality consolidates what were previously separate functions into a single integrated component, reducing complexity.
3Productivity
If engine braking and cylinder deactivation are implemented, then engine performance is improved, but the lash adjuster adds undesired variances to the valvetrain
Solution Approach 1:
The patent removes the traditional lash adjuster that causes unwanted variances during engine braking and cylinder deactivation. By extracting this problematic component and replacing it with a variable geometry rocker arm system, the invention enables these performance-enhancing features while maintaining valvetrain consistency and eliminating undesired variances.
Data Source
AI summary
A valvetrain assembly comprises a valve bridge, a capsule, a first rocker arm, and a second rocker arm. The valve bridge comprises an upper surface comprising a central pressure point and an offset pressure point and a lower surface comprising a lower pivot point, a first valve interface, and a second valve interface. The capsule can be connected to the lower pivot point, the capsule configured to provide to the pair of engine valves one or both of a lash adjusting function and a deactivating mode. The first rocker arm is configured to actuate against the central pressure point to transfer a first valve lift mode to the valve bridge. The second rocker arm is configured to actuate against the offset pressure point to transfer a second valve lift mode to the valve bridge.