Rocker Arm Latching Actuator with Self-Returning Shaft
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Solution Overview
Problem
Existing valve train assemblies in internal combustion engines face challenges in efficiently switching between different valve-lift modes due to complex synchronization requirements and inefficiencies in actuating rocker arm latching arrangements, which can lead to costly and unreliable operation.
Innovation Solution
An apparatus comprising a rotatable shaft with selector cams and a return apparatus featuring radial protrusions and biasing means, allowing for precise control of rocker arm latching and unlatching, enabling efficient switching between valve-lift modes by rotating the shaft in specific directions to align selector cams with rocker arms, and ensuring the shaft returns to a rest orientation automatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a moveable latch pin is used to switch between valve-lift modes, then the rocker arm can be latched and unlatched to provide different modes of operation, but the synchronization requirements become complex and the operation becomes less reliable
Solution Approach 1:
The return apparatus automatically returns the shaft to the rest orientation without requiring external control or synchronization signals. The biasing means (spring) provides self-service by automatically biasing the shaft toward the rest orientation, eliminating the need for complex synchronization control systems while maintaining reliable mode switching capability
2Measurement precision
If the shaft is rotated to align selector cams with rocker arms for precise control, then accurate latching and unlatching is achieved, but the system requires precise synchronization with engine conditions which reduces reliability when synchronization is lost
Solution Approach 1:
The biasing means is pre-configured to automatically return the shaft to the rest orientation whenever it deviates, providing preliminary corrective action before desynchronization issues can cause problems. This preliminary self-correcting mechanism ensures the system maintains reliable operation even when external synchronization signals are lost or inaccurate
3Ease of operation
If an actuation source is used to rotate the shaft for controlling latching arrangements, then precise mode switching is enabled, but the system becomes more complex and costly
Solution Approach 1:
The invention extracts and isolates the complex actuation and return functions into separate, independent components. The return apparatus with biasing means is extracted as an independent self-contained mechanism that automatically manages shaft positioning, separating this function from the main actuation source and reducing overall system complexity and cost
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 reliable and efficient control of rocker arm modes, improving the engine's operational efficiency and reducing complexity, allowing for features like cylinder deactivation and early exhaust valve opening, while ensuring consistent performance even when the actuation source is not synchronized with engine conditions.
Implementation Method 1
a biasing means arranged for contacting the reaction body and for contacting the one or more radial protrusions; wherein the return apparatus is arranged such that, in use, when the shaft is in the rest orientation the biasing means applies substantially no rotational force to the shaft, when the shaft is rotated from the rest orientation in the first direction the biasing means contacts the reaction body and one or more of the radial protrusions so as to bias the shaft rotationally in the second direction
Data Source
Figure 1
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Figure 3a~3b
AI summary
Disclosed is apparatus for actuating one or more latching arrangements of one or more respective rocker arms of a valve train assembly of an internal combustion engine. The apparatus comprises a shaft rotatable by an actuation source, one or more selector cams rotatable by the shaft, and a return apparatus. When the shaft is rotated from a rest orientation in a first direction or a second opposite direction, a biasing means contacts one or more radial protrusions of the shaft so as to bias the shaft rotationally in the second direction or the first direction, respectively, to towards a rest orientation.