Switchable Valve Train Actuation Apparatus
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Solution Overview
Problem
The implementation of switchable rocker arms in internal combustion engines is challenging due to tight packaging constraints, making it difficult to efficiently control valve actuation modes, such as valve-lift and valve deactivation, within the engine's compact design.
Innovation Solution
An electro-mechanical actuation apparatus with a rotatable body and offset portions, utilizing a rotary actuation source to control the rotational orientation of levers that actuate latch pins of rocker arms, allowing independent control of two groups of rocker arms, thereby enabling flexible control of valve train operations without direct actuation on the latch pins.
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 switchable rocker arm can provide multiple modes of operation, but the tight packaging constraints make it difficult to efficiently control the actuation mechanism
Solution Approach 1:
The actuation apparatus divides the control of multiple rocker arms into separate shafts, where each shaft independently controls a specific group of rocker arms through dedicated levers. This segmentation allows complex multi-mode control to be broken down into simpler, independent control units that can be packaged efficiently.
Solution Approach 2:
The patent introduces intermediary levers between the rotary actuation source and the latch pins. These levers translate rotational motion into the appropriate actuating forces on the latch pins, serving as mediators that simplify the direct control relationship and enable more compact packaging.
2Measurement precision
If direct actuation on latch pins is used, then the valve actuation can be controlled precisely, but the packaging space required increases due to the actuation mechanism complexity
Solution Approach 1:
The patent transitions from direct linear actuation of latch pins to rotational actuation through shafts. By moving the control action to a rotational dimension, the mechanism can achieve precise control while occupying less packaging space, as rotational motion can be transmitted more compactly through the shaft and lever system.
Solution Approach 2:
The levers act as intermediary elements that transmit and transform the rotational motion from the shafts into the necessary actuating forces on the latch pins. This intermediary mechanism enables precise control while maintaining a compact overall footprint by efficiently transmitting force through mechanical advantage.
3Adaptability or versatility
If independent control of multiple rocker arm groups is implemented, then engine flexibility is improved, but the actuation mechanism becomes more complex
Solution Approach 1:
The actuation apparatus segments the control of different rocker arm groups into separate shafts, each with its own levers. This segmentation enables independent control of each group while maintaining a modular structure that reduces overall complexity compared to a single integrated control mechanism.
Solution Approach 2:
Each shaft and lever assembly is designed as a universal control unit that can independently actuate its associated rocker arm group. This multi-functional design allows the same basic mechanism to control multiple groups, reducing the need for entirely separate control systems and thereby reducing overall complexity while maintaining flexibility.
Data Source
AI summary
An actuation apparatus for actuating one or more components of a respective one or more switchable valve train devices of a first group of switchable valve train devices, and for actuating one or more components of a respective one or more switchable valve train devices of a second group of switchable valve train devices, the actuation apparatus including: a body rotatable by an actuation source about a rotation axis; a first shaft including a first set of one or more levers for actuating the one or more components of the first group of switchable valve train devices, the first shaft including a first element for contacting the body and moveable by the body in use to cause the first shaft to rotate; and a second shaft including a second set of one or more levers for actuating the one or more components of the second group.