Linkage Between Auxiliary Motion Source and Main Load Path
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Solution Overview
Problem
Existing systems for compression release braking in internal combustion engines require robust and costly components to open exhaust valves during high-pressure compression strokes, leading to potential valve misseating and poor performance due to lash adjuster overextension.
Innovation Solution
A linkage system is introduced between the auxiliary motion source and the main motion load path, allowing force sharing between the auxiliary and main motion sources, which reduces the need for robust components and controls lash adjustment to prevent overextension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robust components are used to open exhaust valves during high-pressure compression strokes, then the valve opening reliability is improved, but the manufacturing cost and component weight increase
Solution Approach 1:
The patent combines the auxiliary motion source with the main motion load path through a linkage mechanism. The auxiliary motion source (such as a spring or elastic element) works together with the main motion source (cam or crankshaft) to open the exhaust valve. This merging allows the system to utilize existing robust components for both functions, avoiding the need for separate robust auxiliary components and reducing manufacturing costs while maintaining reliability.
Solution Approach 2:
The linkage mechanism enables the main motion load path components to serve dual purposes: their primary function during power generation and an auxiliary function during compression release braking. The same rocker arm, valve bridge, and exhaust valve that handle main valve actuation also participate in the compression release braking function, eliminating the need for dedicated robust components solely for auxiliary operations.
2Reliability
If robust components are used to open exhaust valves during high-pressure compression strokes, then the valve opening reliability is improved, but the component weight increases
Solution Approach 1:
The patent merges the auxiliary motion function with the main motion load path, allowing the same components (rocker arm, valve bridge, exhaust valve) to serve both purposes. This eliminates the need for separate robust auxiliary components, thereby reducing overall component weight while maintaining valve opening reliability through the combined action of auxiliary and main motion sources.
3Productivity
If the exhaust valve is opened during compression stroke, then compression release braking is achieved, but the lash adjuster may overextend causing valve misseating
Solution Approach 1:
The linkage mechanism acts as an intermediary between the auxiliary motion source and the main motion load path. It mediates the force transmission, ensuring that the auxiliary motion from the compression release braking operation is properly integrated with the main valve actuation system. This intermediary linkage controls the lash adjuster extension by distributing forces appropriately, preventing overextension and valve misseating while maintaining braking function.
Solution Approach 2:
The linkage system provides feedback control for the lash adjuster during auxiliary operations. As the auxiliary motion source acts on the linkage, the system automatically adjusts the force distribution to prevent excessive lash adjuster extension. This feedback mechanism ensures that the valve remains properly seated during compression release braking by continuously monitoring and adjusting the mechanical forces in the valve train.
4Weight of moving object
If a linkage is introduced to share forces between auxiliary and main motion sources, then component weight and cost are reduced, but the device complexity increases
Solution Approach 1:
The patent merges the auxiliary motion source with the main motion load path using a relatively simple linkage mechanism. By combining these functions, the system reduces the need for separate robust components, thereby reducing overall weight. The linkage itself is designed to be straightforward, utilizing existing structural elements and connection points within the valve train, which minimizes the added complexity while achieving the weight reduction goal.
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
This solution enables the design of lighter, cheaper components for auxiliary motion systems and prevents valve misseating by sharing forces between the auxiliary and main motion sources, improving engine performance and reducing manufacturing costs.
Implementation Method 1
the automatic lash adjuster may include a hollow, sliding plunger operated by a hydraulic fluid, such as engine oil. When the engine valve is closed, the automatic lash adjuster may be free to fill with the hydraulic fluid, expanding the automatic lash adjuster and thereby taking up lash space as it expands.
Implementation Method 2
A linkage system is introduced between the auxiliary motion source and the main motion load path, allowing force sharing between the auxiliary and main motion sources
Data Source
AI summary
In an internal combustion engine, a linkage is provided between an auxiliary motion source and a main motion load path, such that motions received by the linkage from the auxiliary motion source result in provision of a first force to at least one engine valve and a second force to the main motion load path in a direction toward a main motion source. Where an automatic lash adjuster is associated with the main motion load path, the second force may be selected to aid in the control of lash adjustments made by the automatic lash adjuster. In various embodiments, the linkage may be embodied in an mechanical linkage, whereas in other embodiments, an hydraulic linkage may be employed. The linkage may be incorporated into, or otherwise cooperate, a valve bridge or a rocker arm.