Nested Dual Shaft Valve Train Actuation for Independent Rocker Control
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Solution Overview
Problem
Existing valve train assemblies for internal combustion engines lack efficient control mechanisms for dual body rocker arms, particularly in allowing independent control of rocker arms to switch between valve-lift modes, leading to complex actuation systems and reduced efficiency.
Innovation Solution
An actuation arrangement featuring two independent shafts with selector cams, where one shaft is received within the other, allowing each group of dual body rocker arms to be controlled separately through independent rotation, utilizing simple ON/OFF actuators or torque motors for multi-step actuation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single shaft with selector cams is used to control all rocker arms, then the actuation system is simpler, but independent control of different rocker arm groups is not achieved
Solution Approach 1:
The actuation system is segmented into two independent shafts (first shaft and second shaft), each capable of independently controlling different groups of rocker arms. This segmentation allows selective and independent control of rocker arm groups, enabling adaptability while maintaining manageable complexity through modular design
2Ease of operation
If multiple independent shafts are used to control different rocker arm groups, then per-group control is achieved, but the actuation system becomes more complex
Solution Approach 1:
The first shaft is received within the second shaft, creating a nested configuration where one shaft is positioned inside the other. This nesting arrangement allows both shafts to coexist in a compact space, enabling independent control of different rocker arm groups while minimizing the overall spatial footprint and reducing structural complexity
3Measurement precision
If rocker arms are controlled in groups rather than individually, then the actuation system is simpler, but control precision for specific groups is reduced
Solution Approach 1:
Each shaft is equipped with selector cams that have specific cam profiles tailored for controlling particular groups of rocker arms. This local customization of cam profiles ensures precise control for each group's specific requirements while maintaining overall system simplicity through the grouped control approach
Data Source
AI summary
An actuation arrangement for actuating a plurality of latching arrangements of a respective plurality of dual body rocker arms of a valve train assembly of an internal combustion engine includes: a first shaft comprising one or more first selector cam for controlling the latching arrangements of a first group of one or more of the dual body rocker arms; and a second shaft comprising one or more second selector cams for controlling the latching arrangements of a second group of one or more of the dual body rocker arms. At least a portion of the first shaft is received in the second shaft, and the first shaft and the second shaft are controllable to rotate independently of one another, thereby to allow control of the latching arrangements of the dual body rocker arms on a per group basis.