Vehicle Drive Torque Split Control During Power Source Switching
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Solution Overview
Problem
The change in torque distribution ratio between the front wheels and rear wheels during power source switching in existing drive apparatuses for vehicles leads to deterioration in running stability.
Innovation Solution
A drive apparatus with a control device that maintains a fixed torque distribution ratio by switching the second engagement device to a slip state while keeping the first engagement device engaged during power source switching, and adjusts the torque distribution ratio by controlling the second engagement device to a slip state in the second drive mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power source is switched between the first power source and the second power source when switching drive modes, then the drive mode can be changed, but the torque distribution ratio between the front wheels and the rear wheels may change, causing deterioration in running stability
Solution Approach 1:
The control device maintains the torque distribution ratio at a predetermined value during the power source switching process. By preparing and maintaining the torque distribution ratio in advance during the transition period, the system prevents abrupt changes that would affect running stability while still enabling drive mode switching.
Solution Approach 2:
The control device acts as an intermediary that mediates between the power source switching operation and the torque distribution ratio. It actively manages the torque distribution during the transition, ensuring that the ratio remains stable even as the power source changes, thus protecting running stability.
2Adaptability or versatility
If the second engagement device is controlled to slip state while the first engagement device remains engaged, then the torque distribution ratio can be adjusted in the second drive mode, but the system complexity increases
Solution Approach 1:
The second engagement device is designed to be dynamically controllable, capable of switching between engaged and slip states. This dynamic capability allows the system to adjust the torque distribution ratio flexibly in the second drive mode, enabling adaptive torque control while managing complexity through controlled variability.
Data Source
AI summary
A drive apparatus for vehicle including a first power source, a first output rotating member, a second output rotating member, a second power source, a differential device, a first engagement device, a second engagement device, and a control device. The control device establishing, as drive modes driving a vehicle, a first drive mode putting the vehicle in all-wheel drive state by power from the second power source while fixing a torque distribution ratio between front wheels and rear wheels with both the first engagement device and the second engagement device kept in engaged state, and a second drive mode controlling the torque distribution ratio by putting the vehicle in all-wheel drive state by power from the first power source while controlling the second engagement device to be in slip state with the first engagement device kept in engaged state.