Hybrid Power Path Switching Torque Control for Drive Shaft Vibration
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Solution Overview
Problem
In vehicles with series hybrid and engine traveling configurations, switching between power transmission paths leads to delayed torque adjustments, causing vibration in the drive shaft due to differential rotation, resulting in prolonged switching times.
Innovation Solution
A power transmission method and device that utilize a controller to perform synchronized rotation and torque control between the traveling motor and internal combustion engine, employing feedforward control to adjust torque slopes and timing to minimize vibration, allowing for prompt switching between power transmission paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the torque of the power source is adjusted to suppress drive shaft vibration during clutch engagement, then vibration is reduced, but the torque shifting time is prolonged
Solution Approach 1:
The controller performs preliminary torque adjustment on the power source in the power transmission path after switching before clutch engagement. By pre-adjusting the torque to match the target torque, the system eliminates the need for post-engagement torque correction, thereby suppressing drive shaft vibration without prolonging the overall switching time.
Solution Approach 2:
The controller continuously monitors the actual torque of the power source and compares it with the target torque, dynamically adjusting the torque output. This feedback mechanism ensures precise torque control during the switching process, suppressing vibrations while maintaining efficient timing by making real-time corrections rather than using conservative pre-adjustments.
2Device complexity
If a meshing clutch mechanism is used for cost advantage, then device complexity is reduced, but differential rotation causes vibration during engagement
Solution Approach 1:
The controller acts as an intermediary between the power source and the meshing clutch mechanism. By precisely controlling the torque of the power source during engagement, the controller mediates the interaction between the clutch components, ensuring smooth meshing while suppressing vibrations caused by differential rotation, thus maintaining the simplicity of the mechanical clutch design.
Solution Approach 2:
The system dynamically changes the torque parameter of the power source during clutch engagement. By adjusting the torque magnitude and rate of change, the system optimizes the engagement process to minimize differential rotation effects and suppress vibrations, allowing the use of simple meshing clutch mechanisms without suffering from their inherent vibration problems.
Data Source
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AI summary
The method includes, based on a torque variation of a drive shaft after an engagement timing of an engine clutch 21 and before a release timing of a motor clutch 19 when switching a power transmission path from a first power transmission path 24 to a second power transmission path 25, increasing a slope of a torque increase of a power generation motor 4 in an absolute value with respect to a slope of a torque decrease of a traveling motor 2 in at least a part of a period from a timing T12 to a timing T14, and increasing a slope of a torque decrease of the power generation motor 4 in the absolute value with respect to a slope of a torque increase of the traveling motor 2 in at least a part of a period from the timing T14 to a timing T16.