Transmission Shift Torque Compensation During Regenerative Braking
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Solution Overview
Problem
The Lift Foot Up (LFU) shift control in automatic transmissions experiences a sense of double deceleration and degraded driving performance when regenerative brake control is activated, as the shift and regenerative braking occur simultaneously, leading to a less noticeable gear shift and reduced fuel efficiency.
Innovation Solution
A transmission control apparatus and method that adjusts the release clutch torque based on RPM variations during regenerative brake control, using a determination device to identify conditions for regenerative braking and a torque compensation device to modify clutch torques, thereby eliminating the sense of double deceleration and improving driving performance and fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative brake control is activated during LFU shift, then fuel efficiency is improved, but a sense of double deceleration occurs and driving performance degrades
Solution Approach 1:
The determination device identifies the regenerative brake mode entrance condition before the LFU shift is completed, and the controller pre-adjusts the release clutch torque accordingly. This preliminary detection and adjustment prevents the double deceleration sensation before it occurs, allowing both fuel efficiency and driving performance to be maintained
Solution Approach 2:
The controller dynamically adjusts the release clutch torque parameter based on the identified regenerative brake condition. By changing the torque parameter from the standard LFU shift torque to a compensated torque that accounts for regenerative braking forces, the system eliminates the double deceleration sensation while maintaining the fuel efficiency benefits of regenerative braking
2Ease of operation
If release clutch torque is adjusted according to RPM variation, then the sense of double deceleration is eliminated, but control complexity increases
Solution Approach 1:
The torque compensation device uses RPM variation as feedback to dynamically adjust the release clutch torque. By monitoring the RPM change during the shift process and comparing it with expected values, the system automatically compensates for the regenerative brake effect, maintaining smooth shifting without requiring complex manual intervention or additional hardware
3Productivity
If regenerative brake control is performed during LFU shift, then braking efficiency is improved, but shift performance degrades
Solution Approach 1:
The determination device detects the regenerative brake mode entrance condition before the shift is completed, allowing the controller to prepare the appropriate torque compensation in advance. This preliminary detection ensures that the shift performance is maintained while still utilizing regenerative braking for improved braking efficiency
Solution Approach 2:
The controller adjusts the release clutch torque parameter based on the identified regenerative brake condition and RPM variation. By dynamically changing the torque parameter, the system maintains reliable shift performance while preserving the braking efficiency benefits of regenerative brake control
Data Source
AI summary
An apparatus for controlling a transmission of a vehicle includes a determination device that determines whether a condition for a regenerative braking based lift foot up shift is satisfied, a controller that performs regenerative brake control and performs a shift by controlling release clutch torque and lock-up clutch torque, when the condition for the regenerative braking based lift foot up shift is satisfied, and a torque compensation device that compensates for the release clutch torque according to an RPM variation during the shift.