Selectable One-Way Clutch Torque Direction Control
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Solution Overview
Problem
Hybrid powertrains face inefficiencies due to the need for complex clutch management to selectively ground or freewheel gears in planetary gear sets, leading to energy loss and reduced efficiency, particularly when transitioning between torque directions.
Innovation Solution
Incorporating a selectable one-way clutch (SOWC) to automatically freewheel in one direction and ground in another, reducing the need for hydraulic clutch activation and minimizing drag, thereby optimizing torque transmission and reducing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic clutches are used to selectively ground or freewheel gears in planetary gear sets, then torque direction control is achieved, but energy loss increases and efficiency decreases
Solution Approach 1:
The one-way clutch automatically selects between locked and freewheeling states based on the direction of torque applied to the planetary gear set, eliminating the need for external hydraulic actuation. The device serves itself by using the torque direction itself as the control signal, thereby eliminating energy loss associated with hydraulic system operation while maintaining full adaptability for torque direction control
2Reliability
If hydraulic clutches are continuously activated to manage gear transitions, then torque transmission control is maintained, but operational complexity increases
Solution Approach 1:
The one-way clutch automatically transitions between locked and freewheeling states in response to torque direction changes without requiring external hydraulic control systems. This self-actuating mechanism maintains reliable torque transmission control while dramatically reducing operational complexity by eliminating continuous hydraulic activation and associated control infrastructure
3Adaptability or versatility
If traditional clutches are used to ground planetary gear set components, then torque path selection is achieved, but drag increases and efficiency reduces
Solution Approach 1:
The one-way clutch converts the potentially harmful drag of continuously engaged hydraulic clutches into a beneficial feature by designing the clutch to freewheel in one direction. This allows torque to pass through with minimal resistance when freewheeling is desired, while still providing firm grounding when needed, thereby reducing overall drag while maintaining torque path selection capability
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
The SOWC enhances powertrain efficiency by automatically adjusting to freewheel or ground settings based on torque balance, reducing drag and operational complexity, and enabling seamless transitions between torque directions without the need for continuous hydraulic clutch activation.
Implementation Method 1
Incorporating a selectable one-way clutch (SOWC) to automatically freewheel in one direction and ground in another
Data Source
AI summary
A hybrid powertrain includes a plurality of torque generative devices, a transmission input shaft, and a planetary gear set connecting the torque generative devices to the transmission input shaft. A method to control the powertrain includes monitoring a desired configuration of the powertrain and selectively grounding a gear of the planetary gear set with a selectable one way clutch based upon the desired configuration of the powertrain.