Front-Rear Torque Distribution Using Yaw Moment Feedback
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Solution Overview
Problem
Existing vehicle torque distribution systems do not fully consider vehicle stability during steering, leading to potential loss of stability due to oversteer or understeer.
Innovation Solution
A method and apparatus for real-time torque distribution based on a correction yawing moment and a mapping relationship between the yawing moment and torque distribution coefficient, dynamically adjusting front and rear axle torques to improve stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the driver requests a sport mode, then the vehicle control unit distributes more drive torque to the front wheels, but the rear wheels may lose traction and cause oversteer
Solution Approach 1:
The vehicle control unit continuously monitors rear wheel speed and compares it with front wheel speed to detect speed differentials. When a differential exceeds a threshold, the system automatically adjusts torque distribution by reducing front wheel torque and/or increasing rear wheel torque, creating a feedback loop that maintains vehicle stability during sport mode operation.
Solution Approach 2:
The system dynamically adjusts torque distribution between front and rear wheels based on real-time driving conditions and detected speed differentials. The torque split is not fixed but adapts continuously through electronic control of the drive system, allowing the vehicle to transition between different torque distribution states to optimize both performance and stability.
2Power
If the driver requests a sport mode, then the vehicle control unit distributes more drive torque to the front wheels, but drive torque may be insufficient when the vehicle is accelerating on a low-friction surface
Solution Approach 1:
The vehicle control unit monitors wheel speed differentials and uses this feedback to detect loss of traction conditions. When rear wheel slip is detected on low-friction surfaces, the system responds by adjusting torque distribution to increase rear wheel torque, ensuring reliable acceleration performance adapts to surface conditions.
Solution Approach 2:
The system changes the torque distribution parameter dynamically based on detected driving conditions. By adjusting the torque split ratio between front and rear wheels according to real-time sensor data, the system optimizes traction and acceleration performance across varying surface friction conditions.
3Ease of operation
If a traditional open differential is used, then the drive shaft can accommodate differences in wheel speed, but drive torque is directed to the wheel with less traction
Solution Approach 1:
The patent replaces the mechanical limited-slip differential mechanism with an electronic torque distribution system. The vehicle control unit uses electronic sensors and actuators to control torque split between wheels, substituting mechanical torque limiting components with electronic control that achieves similar or superior torque distribution without the physical constraints of traditional differential mechanisms.
Solution Approach 2:
The electronic torque distribution system performs multiple functions: it accommodates wheel speed differences like a traditional differential, prevents torque transfer to slipping wheels, maintains vehicle stability, and optimizes traction. This single electronic system replaces multiple mechanical functions, providing universal control over torque distribution under various driving conditions.
Data Source
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AI summary
This application provides a method and an apparatus for front and rear driving torque distribution of a vehicle, and a vehicle. The method includes: determining an expected status parameter existing during steering of a vehicle based on a wheel angle of the vehicle; determining a current correction yawing moment based on an actual status parameter existing during the steering of the vehicle and the expected status parameter, where the expected status parameter is determined based on the wheel angle of the vehicle; determining a mapping relationship between a correction yawing moment and a torque distribution coefficient based on the wheel angle and acceleration information of the vehicle; determining a torque distribution coefficient of the vehicle based on the current correction yawing moment and the mapping relationship; and determining front and rear axle driving torques of the vehicle based on the torque distribution coefficient of the vehicle. This improves operation stability during steering of a vehicle and provides high applicability.