Dual-Motor Powertrain Shift Torque Split for Lower Battery Loss
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Solution Overview
Problem
Conventional electrified powertrain control techniques for vehicles with electric motors before and after a transmission fail to optimize torque splits during transmission shift events, leading to sub-optimal battery consumption and reduced vehicle range.
Innovation Solution
A control system that determines optimal torque splits for electric motors before and after a transmission shift event by solving an optimization problem based on operating parameters, implementing gradual transitions through multiple phases during the shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional direct transition from pre-shift to post-shift torque split is used, then control simplicity is maintained, but battery consumption is not fully minimized and vehicle range is reduced
Solution Approach 1:
The torque split transition is segmented into multiple phases (pre-shift, during-shift, post-shift) with distinct optimal torque splits for each phase. This segmentation allows the system to optimize battery consumption at each stage rather than using a single direct transition, thereby resolving the contradiction between energy efficiency and control complexity.
Solution Approach 2:
The system performs preliminary action by pre-calculating and storing optimal torque splits for different shift phases before actual shifting occurs. This preliminary preparation enables optimized torque distribution during shifting without requiring complex real-time calculations, thus minimizing battery consumption while maintaining manageable control complexity.
2Loss of energy
If optimal torque split is optimized for each shift phase, then vehicle range is maximized, but control system complexity increases
Solution Approach 1:
The control system performs preliminary action by pre-calculating optimal torque splits for different shift phases and storing them in lookup tables. This offline preparation reduces real-time computational requirements, enabling the system to maximize energy efficiency during shifting while keeping the control system complexity manageable through standardized pre-computed solutions.
Solution Approach 2:
The system applies parameter changes by adjusting torque split parameters according to different shift phases (pre-shift, during-shift, post-shift). Each phase has optimized torque split parameters that minimize energy loss. This parameter-based approach allows systematic optimization of energy efficiency while maintaining structured control logic.
3Use of energy by moving object
If torque split transitions during shift event, then battery consumption is reduced, but transmission shift smoothness may be affected
Solution Approach 1:
The shift process is segmented into distinct phases with optimized torque splits for each. By segmenting the transition and managing torque changes phase-by-phase, the system can reduce battery consumption while maintaining shift smoothness through controlled, staged adjustments rather than abrupt changes.
Solution Approach 2:
The system applies dynamics by continuously adjusting torque splits during the shift event based on the current phase. This dynamic adjustment allows the torque distribution to adapt smoothly throughout the shift process, minimizing energy consumption while maintaining transmission stability and shift smoothness through real-time optimization.
Data Source
AI summary
A control method for an electrified powertrain of an electrified vehicle having a first electric motor before a transmission and a second electric motor after the transmission includes receiving, by a control system and from a set of sensors, a set of operating parameters of the electrified powertrain, each operating parameter of the set of operating parameters relating to a torque split between the first and second electric motors, determining, by the control system, first and second optimal torque splits between the first and second electric motors for a transmission shift event by solving a torque split optimization problem based on the set of operating parameters, and controlling, by the control system, the first and second electric motors based on the first optimal torque split followed by the second optimal torque split relative to the transmission shift event.