Brake Control System Regenerative Friction Mode Switching
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Solution Overview
Problem
Existing brake control systems face challenges in achieving both excellent fuel consumption performance and good brake feeling, particularly when regenerative braking is used, as they often impose limits on regenerative braking torque to compensate for the late response of fluid pressure braking systems.
Innovation Solution
A brake control system that includes a friction brake unit, a regenerative brake unit, and a control unit capable of selecting between a regeneration permission mode and a regeneration prohibition mode, where the control unit adjusts delays and filtering processes to optimize the distribution of braking forces and match the response properties of both systems, ensuring maximum utilization of regenerative braking while minimizing variations in brake feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative braking torque command value is limited to allow margin for correction, then reliability of braking force control is improved, but fuel consumption performance deteriorates
Solution Approach 1:
The control system performs preliminary actions by anticipating the late response of the fluid pressure brake system and proactively adjusting the regenerative braking torque command value before the fluid pressure brake responds. This allows the regenerative brake to compensate for the expected delay, ensuring accurate total braking torque without needing to impose conservative limits that would reduce fuel efficiency.
2Use of energy by moving object
If regenerative braking is maximally utilized, then fuel consumption performance is improved, but brake feeling uniformity deteriorates
Solution Approach 1:
The control system dynamically adjusts the regenerative braking torque command value based on real-time feedback from the fluid pressure brake's actual response. By continuously monitoring the difference between commanded and actual braking forces, the system optimizes regenerative brake utilization while maintaining uniform brake feeling across different braking scenarios.
3Loss of energy
If regenerative braking torque is increased to improve fuel consumption, then energy recovery is improved, but response timing uniformity deteriorates
Solution Approach 1:
The control system employs feedback mechanisms to monitor the actual braking force from the fluid pressure brake and adjusts the regenerative braking torque command value accordingly. This feedback loop ensures that energy recovery is maximized while maintaining uniform response timing by compensating for the fluid pressure brake's late response characteristics.
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 system effectively improves fuel consumption by maximizing regenerative braking while reducing differences in brake feeling between modes, ensuring a comfortable and efficient braking experience.
Implementation Method 1
a regenerative brake unit configured to generate a regenerative braking force
Implementation Method 2
a friction brake unit configured to generate a friction braking force
Data Source
AI summary
A brake control system includes: a friction brake unit for generating a friction braking force; a regenerative brake unit for generating a regenerative braking force; and a control unit for controlling the regenerative and friction brake units based on a regenerative target value and a friction target value defined based on a target deceleration, and for controlling a braking force by selecting one of a plurality of control modes including both a regeneration permission mode in which a total braking force is generated by the regenerative and friction braking forces, and a regeneration prohibition mode in which the target deceleration is generated by the friction braking force. In the permission mode, the control unit generates the total force by providing a delay, while in the prohibition mode, the control unit provides a delay smaller than the above delay to the friction braking force or does not provide a delay.