Actuator Arrangement for Dual Body Rocker Arm Latching
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Solution Overview
Problem
Internal combustion engine valve train assemblies face challenges in efficiently controlling switchable rocker arms for valve operation modes, particularly in cylinder deactivation scenarios, where existing systems rely on complex latch mechanisms and timing requirements.
Innovation Solution
An actuator arrangement featuring a cam-controlled shaft and gear mechanism translates continuous rotation into intermittent rotation, allowing precise control of the latching arrangement in dual body rocker arms to switch between valve-lift modes, enabling flexible cylinder operation from 0 to 4 cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a moveable latch pin is used to switch between valve-lift modes, then the rocker arm can be controlled to latch and unlatch the first body and second body, but the control mechanism becomes complex with multiple components and timing requirements
Solution Approach 1:
The patent extracts the complex latch mechanism and replaces it with a simplified cam-based system. The cam profile directly controls the latch pin movement through its geometric shape, eliminating the need for complex actuating mechanisms while maintaining the latching functionality. The cam's rotation automatically sequences the latching operations for multiple rocker arms.
Solution Approach 2:
The cam acts as an intermediary element between the rotating actuator and the latch pins. Instead of directly actuating each latch pin with complex mechanisms, the cam translates rotational motion into the precise linear and angular movements required for latching, simplifying the overall control system.
2Adaptability or versatility
If multiple rocker arms are controlled simultaneously, then cylinder deactivation can be achieved, but the timing and coordination of latching operations becomes difficult
Solution Approach 1:
The cam rotates periodically to sequentially actuate different latch pins at predetermined intervals. Each cam lobe is positioned to engage a specific latch pin at the appropriate time in the engine cycle, enabling automatic timing coordination for cylinder deactivation without complex control systems. The periodic rotation of the cam ensures synchronized operation across multiple rocker arms.
3Manufacturing precision
If a complex latch mechanism is used for precise control, then valve-lift mode switching is accurate, but the number of moving parts increases
Solution Approach 1:
The cam mechanism is self-regulating through its geometric profile. The cam's shape automatically ensures that latch pins are actuated with the correct timing and force, eliminating the need for additional sensors, actuators, or control electronics. The mechanical design inherently provides the precision needed for accurate latch positioning and timing.
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 the control of rocker arms, allowing seamless switching between engine operation modes by changing the orientation of the cam relative to the latching arrangement, thereby enhancing flexibility and efficiency in cylinder activation and deactivation.
Implementation Method 1
a gear mechanism configured to translate a continuous rotation of the actuation source into an intermittent rotation of the shaft in steps of a predefined degree
Implementation Method 2
a shaft comprising a cam configured to control the latching arrangement
Data Source
AI summary
An actuator arrangement for controlling a latching arrangement of a dual body rocker arm of an internal combustion engine, the dual body rocker arm comprising a first body, a second body, and the latching arrangement, the latching arrangement being controllable to latch and unlatch the first body and the second body. The actuator arrangement includes: an actuation source; a shaft including a cam for controlling the latching arrangement; and a gear mechanism for translating a continuous rotation of the actuation source into an intermittent rotation of the shaft in steps of a predefined degree. In use, a continuous rotation of the actuation source causes, via the gear mechanism, the shaft to rotate in steps of a predefined degree, thereby to change an orientation of the cam relative to the latching arrangement by a predefined amount, so as to control the latching arrangement.