Hybrid Torque Reduction Control via Engine-Motor Split
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Solution Overview
Problem
Conventional methods for torque reduction in hybrid electric vehicles are inadequate when the demand torque is low or the battery state of charge is high, as they rely solely on motor torque or engine torque, leading to incomplete torque reduction.
Innovation Solution
The method involves calculating and dividing the total torque reduction request into engine and motor torque reduction based on their respective contributions, with adjustments for battery state of charge to ensure efficient torque management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If torque reduction is performed using motor torque only for rapid control, then torque responsiveness is improved, but torque reduction cannot be performed completely when demand torque is too low or battery SOC is too high
Solution Approach 1:
The patent segments the torque reduction function into two parts: motor torque reduction for rapid response and engine torque reduction for complete torque control. The controller divides the total torque reduction request into motor torque reduction amount and engine torque reduction amount, allowing each power source to contribute according to its capabilities and the current operating conditions.
Solution Approach 2:
The patent dynamically adjusts the torque reduction strategy based on real-time conditions including demand torque level and battery state of charge. When demand torque is high, motor torque reduction is prioritized for rapid response. When demand torque is low or battery SOC is high, engine torque reduction is engaged to ensure complete torque control. This dynamic switching resolves the contradiction between speed and reliability.
2Reliability
If engine torque is used for torque reduction, then complete torque reduction can be achieved, but torque responsiveness is reduced compared to motor-only control
Solution Approach 1:
The patent merges the torque reduction capabilities of both the motor and engine into a unified control system. The controller coordinates both power sources to work together for torque reduction, combining the rapid response advantage of motor control with the complete control capability of engine control. This merging allows the system to achieve both responsiveness and completeness simultaneously.
3Adaptability or versatility
If motor outputs sufficient negative torque for torque reduction, then torque control flexibility is improved, but battery SOC management becomes more complex
Solution Approach 1:
The patent implements feedback control by continuously monitoring battery state of charge and adjusting the torque reduction strategy accordingly. When battery SOC is high, the system prioritizes motor torque reduction to capture regenerative energy. When battery SOC is low, the system reduces motor torque reduction demand to protect the battery. This feedback mechanism manages battery complexity while maintaining torque control flexibility.
Data Source
AI summary
A method for controlling torque reduction of a hybrid electric vehicle including a motor and an engine as a power source includes: calculating a total request amount of torque reduction when a torque reduction is requested; calculating a driving torque contribution of the engine and a driving torque contribution of the motor when the engine is turned on; dividing the total request amount of torque reduction into an amount of engine torque reduction and an amount of motor torque reduction based on the driving torque contribution of the engine and the driving torque contribution of the motor; determining an engine torque command and a motor torque command according to the amount of engine torque reduction and the amount of motor torque reduction; and performing torque reduction according to the engine torque command and the motor torque command.