Torque Distribution Control for Electric Vehicle Motor Thermal Management
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Solution Overview
Problem
Existing vehicle systems face inefficiencies and stability issues when one of the front-wheel or rear-wheel motors exceeds temperature thresholds, leading to restricted output and loss of all-wheel drive capability, which can decrease traveling efficiency and stability.
Innovation Solution
A vehicle system incorporating a temperature detector and distribution ratio controller that adjusts torque distribution between the front-wheel and rear-wheel motors by decreasing the torque of the hotter motor and increasing the torque of the cooler motor when temperatures exceed a second threshold, set lower than a first threshold for output restriction, to prevent overheating and maintain all-wheel drive functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If torque distribution is adjusted when temperature exceeds threshold, then temperature balance is improved, but response time is delayed due to gradual adjustment
Solution Approach 1:
The system performs preliminary temperature monitoring and gradual torque adjustment before the temperature reaches the critical threshold. By detecting temperature trends early and making progressive corrections to torque distribution, the system prevents extreme temperature imbalances without requiring abrupt, time-consuming responses at the threshold moment.
Solution Approach 2:
The torque distribution is dynamically adjusted based on real-time temperature differences between front and rear motors. The system continuously monitors temperature and modifies torque allocation proportionally to the temperature differential, enabling flexible, adaptive response that balances temperature equilibrium with timely correction.
2Reliability
If output restriction is applied when temperature exceeds threshold, then motor protection is improved, but all-wheel drive capability is lost
Solution Approach 1:
Instead of applying uniform output restriction to both motors when temperature threshold is exceeded, the system applies selective torque adjustment only to the motor with higher temperature. This localized correction protects the overheating motor while maintaining normal operation of the cooler motor, thereby preserving all-wheel drive functionality while still providing necessary protection.
Solution Approach 2:
The system changes the torque parameter dynamically based on temperature conditions. When temperature difference exceeds the threshold, the torque distribution ratio is adjusted rather than completely restricting output. This parameter modification allows the system to adapt to thermal conditions while maintaining drivetrain functionality.
Data Source
AI summary
A vehicle includes a front-wheel motor, a rear-wheel motor, a temperature detector, and a distribution ratio controller. The front-wheel motor drives a front wheel. The rear-wheel motor drives a rear wheel. The temperature detector detects a temperature of the front-wheel motor and a temperature of the rear-wheel motor. If one of the temperature of the front-wheel motor and the temperature of the rear-wheel motor exceeds a second temperature, the distribution ratio controller decreases a torque of one of the front-wheel motor and the rear-wheel motor the temperature of which is higher than the other and increase a torque of the other. The second temperature is a value set lower than a first temperature that is a threshold used for determination as to whether output of the front-wheel motor or output of the rear-wheel motor is to be restricted.