e-4WD Regenerative Braking Torque Split for Slip-Stable Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current regenerative braking control technologies for electronic four-wheel drive vehicles are not optimized, leading to decreased fuel efficiency due to the same braking methods being used as in two-wheel drive vehicles, which results in suboptimal energy recovery and potential wheel slip issues.
Innovation Solution
A regenerative braking control device that distributes regenerative braking amounts between the front and rear wheel motors based on speed differences, prioritizing rear wheel braking for efficiency and stability, and utilizing a Hybrid Starter Generator for additional braking when necessary to maximize fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same regenerative braking control method as two-wheel drive vehicles is used, then the control system is simple, but fuel efficiency is degraded
Solution Approach 1:
The regenerative braking control is segmented into wheel-specific control strategies. The rear wheel receives priority regenerative braking torque, and when slip is detected, the front wheel is engaged to provide additional regenerative braking. This segmentation allows optimized energy recovery for four-wheel drive vehicles while maintaining manageable control complexity through modular decision logic.
2Use of energy by moving object
If rear wheel regenerative braking is prioritized, then fuel efficiency is improved, but wheel slip may occur
Solution Approach 1:
The control system continuously monitors wheel speed to detect slip conditions. When the rear wheel speed exceeds the front wheel speed by a predetermined threshold, slip is detected and the control strategy automatically adjusts by engaging the front wheel for regenerative braking. This feedback mechanism maintains braking stability while preserving fuel efficiency benefits.
Solution Approach 2:
The regenerative braking control strategy is dynamic rather than static. The system adapts its torque distribution in real-time based on detected wheel slip conditions, transitioning from rear-wheel-priority braking to combined front-rear wheel braking when necessary. This dynamic adjustment resolves the contradiction between fuel efficiency and braking stability.
3Loss of energy
If regenerative braking amount is increased, then energy recovery is maximized, but wheel slip is induced
Solution Approach 1:
The regenerative braking torque is selectively applied to specific wheels based on local conditions. The rear wheel receives priority torque allocation for maximum energy recovery, but when slip is detected at the rear wheel, the control system transitions to applying regenerative braking torque at the front wheel instead. This localized, condition-based torque application maximizes energy recovery while preventing wheel slip.
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
The solution improves fuel efficiency by optimizing regenerative braking distribution, preventing wheel slip, and ensuring braking stability while maximizing energy recovery through coordinated control of front and rear wheel motors and the Hybrid Starter Generator.
Implementation Method 1
a hybrid starter generator (HSG) connected to the engine to start the engine
Implementation Method 2
a front wheel motor, and a rear wheel motor with a smaller size than that of the front wheel motor
Data Source
AI summary
A regenerative braking control device for an electronic four-wheel drive vehicle, may improve fuel efficiency through a regenerative braking control optimized for the electronic four-wheel drive vehicle.