Hybrid Drive Clutch Slip Control During Transmission Shifts
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Solution Overview
Problem
Existing vehicle drive devices face challenges in appropriately limiting torque transferred to the automatic transmission when the engagement device is in a slip engaged state, especially during shift speed changes, as conventional torque down control methods are ineffective in such scenarios.
Innovation Solution
A vehicle drive device with a control system that performs torque response slip control and transfer torque limit control to manage the engagement device's torque transfer, ensuring it remains below a predefined limit, even when the engagement device is in a slip engaged state, thereby stabilizing the torque transferred to the automatic transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque down control is performed by limiting output torques of the internal combustion engine and rotating electrical machine, then torque transferred to the automatic transmission can be reduced when the engagement device is directly engaged, but torque transfer cannot be appropriately limited when the engagement device is slip engaged
Solution Approach 1:
The control method dynamically adapts based on the engagement state of the engagement device. When slip engagement is detected, the system switches from torque limitation control to slip ratio control, adjusting the control strategy according to the actual operational state to ensure effective torque transfer control in all conditions
Solution Approach 2:
The control system changes the controlled parameter from output torque limitation to slip ratio control when transitioning from direct engagement to slip engagement state. This parameter adaptation allows the system to effectively manage torque transfer characteristics specific to each engagement state, resolving the limitation of conventional torque down control
2Reliability
If the engagement device is in slip engaged state during shift operation, then torque transfer is determined by transfer torque of engagement device rather than output torques of power sources, but conventional torque down control becomes ineffective
Solution Approach 1:
The control system continuously monitors the engagement state and slip ratio, using feedback from these parameters to determine the appropriate control strategy. When slip engagement is detected during shift operations, the system activates slip ratio control with a predetermined threshold, ensuring stable input rotational speed control while maintaining manageable system operation through clear conditional logic
Data Source
AI summary
A control device is configured to perform torque response slip control for bringing an engagement device into a slip engaged state so that transfer torque of the engagement device has a magnitude corresponding to required torque, shift control for shifting the shift speed of an automatic transmission, and transfer torque limit control for limiting the transfer torque of the engagement device to a value equal to or less than a limit value smaller than the required torque, the required torque being torque that is required to be transferred from the rotating electrical machine side to the automatic transmission via the engagement device that connects and disconnects power transmission between the rotating electrical machine and the automatic transmission. The control device performs the transfer torque limit control instead of the torque response slip control in a case where the torque response slip control is being performed when performing the shift control.