Adaptive Regenerative Braking Control for Rear-Wheel Drive Vehicles
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Solution Overview
Problem
In rear-wheel-drive environmentally-friendly vehicles, existing regenerative braking systems face challenges in distributing braking force effectively between the front and rear wheels, leading to increased likelihood of rear wheel locking and reduced fuel economy, as they fail to consider the traveling situation before initiating braking and do not adapt braking modes during braking operations.
Innovation Solution
A method of cooperatively controlling regenerative braking that determines the traveling risk degree before and during braking, selectively applying different braking modes to distribute braking force between the front and rear wheels, and re-evaluating and adjusting these modes in real-time to optimize braking stability and fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking force is increased on the rear wheel to improve fuel economy, then energy recovery is maximized, but the rear wheel locks first causing vehicle spin
Solution Approach 1:
The braking control system dynamically adjusts the braking force distribution between front and rear wheels based on real-time vehicle state (speed, acceleration, steering angle). The rear wheel regenerative braking force is adjusted according to vehicle speed and deceleration rate, allowing maximum energy recovery while preventing rear wheel lockup across different driving conditions
Solution Approach 2:
The system changes the regenerative braking force parameters based on vehicle operating conditions. At high speeds, higher regenerative braking force is applied to maximize energy recovery. At low speeds or during deceleration, the regenerative braking force is reduced to prevent rear wheel lockup, while friction braking supplements the braking force as needed
2Reliability
If regenerative braking force is reduced on the rear wheel to prevent locking, then vehicle stability is maintained, but fuel economy improvement is decreased
Solution Approach 1:
The system dynamically optimizes the balance between stability and energy recovery by continuously monitoring vehicle state. During steady-state cruising, maximum regenerative braking is applied to improve fuel economy. During deceleration or turning, the system adjusts the regenerative braking force to maintain stability while still recovering energy
Solution Approach 2:
The braking control operates in periodic cycles, alternating between maximizing regenerative braking for energy recovery and adjusting for stability maintenance. The control system periodically evaluates vehicle state and adjusts the braking force distribution accordingly
3Device complexity
If braking force is distributed without considering traveling situation, then control simplicity is maintained, but braking performance and stability are reduced
Solution Approach 1:
The control system performs preliminary assessment of the traveling situation before initiating braking by monitoring vehicle speed, acceleration, and steering angle. This preliminary information is used to pre-determine the appropriate braking force distribution ratio, ensuring optimal braking performance from the start of braking action
Solution Approach 2:
The system continuously monitors vehicle state during braking and provides feedback to the control unit. Based on this feedback, the braking force distribution is adjusted in real-time to maintain optimal braking performance and vehicle stability throughout the braking process
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 enables active and adaptive distribution of braking force, improving braking stability and fuel economy by maximizing energy recovery through regenerative braking, while preventing rear wheel locking and maintaining vehicle stability.
Implementation Method 1
a drive motor disposed on the rear wheel of the vehicle... Regenerative braking force is generated when the drive motor recovers energy by charging a battery
Implementation Method 2
frictional braking force generated by hydraulic pressure
Data Source
AI summary
A method of cooperatively controlling regenerative braking step by step for a vehicle, such as a rear-wheel-drive environmentally-friendly vehicle, performs a braking mode in accordance with a traveling risk degree determined in advance before initiating braking and changes the selectively performed braking mode by re-determining the traveling risk degree during a braking operation. The method includes: a first step of determining in advance the traveling risk degree before initiating braking; a second step of selectively performing any one of braking modes defined based on the traveling risk degree during braking; a third step of re-determining the traveling risk degree after the second step; and a fourth step of changing the selectively performed braking mode based on the traveling risk degree determined in the third step.