Vehicle Drive System Mode Switching Stability
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Solution Overview
Problem
The existing vehicle drive systems experience an influence on vehicle behavior when switching between four-wheel drive and two-wheel drive modes, especially during turns, due to changes in driving force distribution between the front and rear wheels.
Innovation Solution
A vehicle drive system with an electronic control unit that manages a differential mechanism, preventing drive mode switching when the vehicle is turning and allowing quick return to the original mode if switching is incomplete, thereby minimizing behavioral impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If drive mode switching is allowed during vehicle operation, then the vehicle can adapt to different driving conditions and improve fuel efficiency, but the vehicle behavior becomes unstable when switching occurs during turns
Solution Approach 1:
The control unit detects turning operations through steering angle sensors and proactively prevents drive mode switching during turns by prohibiting engagement/disengagement of the differential mechanism. This preliminary anti-action eliminates the instability issue before it can occur, maintaining vehicle behavior stability while preserving drive mode adaptability during normal conditions
2Productivity
If the connect-disconnect mechanism is used to switch between four-wheel drive and two-wheel drive, then the vehicle can efficiently switch drive modes, but the engagement element may fail to completely disengage causing incomplete switching
Solution Approach 1:
The control unit continuously monitors the engagement state of the engagement element through sensors and provides feedback control. When incomplete disengagement is detected during a switching operation, the system sends corrective control signals to ensure complete disengagement, thereby guaranteeing switching completeness while maintaining fast switching performance
Solution Approach 2:
Before executing drive mode switching, the control unit performs preliminary detection of vehicle state (whether the vehicle is turning) and prepares the differential mechanism accordingly. This preliminary action prevents switching operations that would result in incomplete engagement/disengagement, ensuring reliable switching completion
Data Source
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AI summary
A drive system including first and second power sources, first and second output shafts, a differential mechanism, and an electronic control unit, and a control method therefor are provided. The differential mechanism is configured such that the second power source is connected to a first rotating element, one output shaft of a vehicle is connected to a second rotating element, and the other output shaft of the vehicle is connected to a third rotating element so as to be able to be connected to or disconnected from the third rotating element by a connect-disconnect mechanism, and includes at least one of an engagement element that selectively engages any two of the three rotating elements and an engagement element that selectively engages the third rotating element to a fixing member. The electronic control unit is configured to, during turning (ST3), prohibit switching between a first drive mode and a second drive mode (ST4).