Regenerative Braking Torque Splitting for Vehicle Stability
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Solution Overview
Problem
Conventional electrified vehicles lack an efficient method to split regenerative braking torque between primary and secondary electric machines based on vehicle stability and machine efficiency, which affects energy capture and stability during braking.
Innovation Solution
A vehicle controller is programmed to dynamically split regenerative braking torque between primary and secondary electric machines by adjusting the proportion based on lateral and longitudinal acceleration, efficiency modifiers, and stability conditions, using a combination of base-split, lateral acceleration, efficiency, yaw, and slip modifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking torque is applied to secondary electric machine during high lateral acceleration, then energy capture increases, but vehicle stability deteriorates
Solution Approach 1:
The control system dynamically adjusts the torque distribution between primary and secondary electric machines based on real-time vehicle operating conditions including lateral acceleration, longitudinal acceleration, and electric machine efficiency. The proportion of regenerative braking torque assigned to the secondary electric machine is not fixed but varies continuously to optimize both energy capture and vehicle stability under different driving scenarios.
Solution Approach 2:
The system changes the parameter of torque proportion distribution based on detected vehicle conditions. When lateral acceleration exceeds a threshold, the proportion of torque to the secondary electric machine is reduced or eliminated, preventing instability while maintaining optimal energy recovery during stable driving conditions.
2Loss of energy
If regenerative braking torque is applied to secondary electric machine during high longitudinal acceleration, then energy capture increases, but vehicle stability deteriorates
Solution Approach 1:
The control system dynamically adjusts the torque distribution between primary and secondary electric machines based on real-time vehicle operating conditions including lateral acceleration, longitudinal acceleration, and electric machine efficiency. The proportion of regenerative braking torque assigned to the secondary electric machine is not fixed but varies continuously to optimize both energy capture and vehicle stability under different driving scenarios.
Solution Approach 2:
The system changes the parameter of torque proportion distribution based on detected vehicle conditions. When longitudinal acceleration exceeds a threshold, the proportion of torque to the secondary electric machine is reduced or eliminated, preventing instability while maintaining optimal energy recovery during stable driving conditions.
3Device complexity
If regenerative braking torque is split without considering electric machine efficiency, then control simplicity is maintained, but energy recovery efficiency deteriorates
Solution Approach 1:
The control system continuously monitors the efficiency of both primary and secondary electric machines and uses this feedback to optimize torque distribution. The vehicle controller adjusts the proportion of regenerative braking torque assigned to each electric machine based on real-time efficiency data, ensuring that torque is directed to the more efficient machine under current operating conditions to maximize energy recovery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances energy capture during regenerative braking and improves vehicle stability by optimizing torque distribution between the primary and secondary axles, allowing for more efficient energy recovery and enhanced braking performance.
Implementation Method 1
regenerative braking to recharge the battery by converting mechanical power into electrical power
Data Source
AI summary
A vehicle includes primary and secondary axles including primary and secondary electric machines, respectively. A vehicle controller is programmed to, responsive to a braking torque request, command regenerative torques, that are a proportion of the braking torque request, to the electric machines such that the proportion commanded to the secondary electric machine decreases responsive to lateral acceleration of the vehicle increasing.