Actuation Lever Biasing for Switchable Valve Train
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Solution Overview
Problem
The implementation of actuation for switchable rocker arms in internal combustion engines is challenging due to tight packaging constraints, and existing solutions require precise timing synchronization with the engine cycle.
Innovation Solution
An actuation apparatus featuring a shaft, an actuation lever, and a biasing means, such as a compliance spring, that automatically switches the rocker arm between modes of operation by pivoting from a de-actuation to an actuation position when the latching arrangement becomes actuatable, ensuring immediate mode switching without requiring synchronized control with the engine cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a leaf spring actuation mechanism is used to switch the rocker arm between modes, then the rocker arm can be actuated between latched and unlatched positions, but the system requires precise timing synchronization with the engine cycle and has complex control requirements
Solution Approach 1:
The biasing means automatically urges the actuation lever toward the actuation position, enabling the system to self-regulate and switch modes based on mechanical conditions rather than requiring external timed control signals. The actuation occurs automatically when the component becomes actuatable, eliminating the need for complex synchronization control.
Solution Approach 2:
The biasing means pre-positions the actuation lever toward the actuation position, so that when the latching arrangement becomes actuatable, the actuation can occur immediately without waiting for a control signal. This preliminary positioning enables faster response and eliminates timing synchronization requirements.
2Volume of moving object
If tight packaging constraints are imposed in the engine, then the engine size is reduced, but the implementation of actuation mechanisms becomes more difficult
Solution Approach 1:
The actuation lever is integrated with the existing rocker arm structure, with the lever pivoting on the shaft that is already part of the rocker arm assembly. The biasing means is incorporated within the same space, nesting multiple functions into a compact configuration that fits tight packaging constraints.
Solution Approach 2:
The shaft serves multiple functions: it supports the rocker arm bodies, provides the pivot point for the actuation lever, and works with the biasing means to enable automatic actuation. This multi-functionality reduces the number of separate components needed, simplifying implementation in constrained spaces.
3Speed
If the actuation lever is held in the de-actuation position by the biasing means, then the system is ready for immediate actuation, but the biasing means must be strong enough to overcome resistance when actuation is required
Solution Approach 1:
The biasing means applies a continuous partial force to urge the actuation lever toward the actuation position, keeping the system in a state of readiness without requiring full actuation force. When actuation is needed, the lever is already positioned to move quickly, achieving fast response with moderate continuous force rather than requiring large intermittent forces.
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 simplifies control and improves packaging efficiency by allowing actuation to occur as soon as the rocker arm is physically possible, reducing the need for precise timing and enabling more flexible and cost-effective design.
Implementation Method 1
a biasing means configured to urge the actuation lever from the second position towards the first position, wherein the apparatus is configured such that, in use, the biasing means is biased when an actuation source attempts to cause the actuation lever to be in the first position when the component is non-actuatable
Data Source
AI summary
An actuation apparatus for actuating a component of a switchable valve train device of an internal combustion engine including: a shaft; an actuation lever mounted on the shaft for pivotal motion of the actuation lever between a first position for actuation of the component and a second position for de-actuation of the component; and a biasing means for urging the actuation lever from the second position towards the first position. In use, the biasing means is biased when an actuation source attempts to cause the actuation lever to be in the first position when the component is non-actuatable, such that the biasing means causes the actuation lever to pivot from the second position to the first position, thereby to actuate the component when the component becomes actuatable again.