Vehicular Brake System Regenerative Friction Control
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Solution Overview
Problem
The existing vehicular brake systems face instability during braking due to unbalanced regenerative and friction braking forces, leading to potential shortages in braking force when wheel slip occurs, which can result in inadequate braking performance.
Innovation Solution
A vehicular brake system that integrates an electrical braking unit for friction braking and a regenerative braking unit, with an antilock control unit that maintains regenerative braking force on driving wheels and adjusts friction and regenerative braking forces to prevent wheel slip and ensure adequate braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking force is applied only to driving wheels while friction braking force is applied to all wheels, then regenerative braking efficiency is improved, but vehicle stability during braking deteriorates due to unbalanced braking forces
Solution Approach 1:
The patent applies different braking strategies to different wheel types. Driving wheels receive both regenerative and friction braking forces, while non-driving wheels receive only friction braking forces. This localized differentiation optimizes energy recovery at driving wheels while maintaining overall vehicle stability through coordinated control of all wheels.
2Reliability
If ABS control decreases friction braking force to stop wheel slip, then wheel slip is prevented, but braking force shortage occurs because regenerative braking force is decreased or stopped
Solution Approach 1:
The patent maintains continuous regenerative braking force application at driving wheels even during ABS control activation. While ABS modulates friction braking force to prevent wheel slip, the regenerative braking system continues to provide braking force, ensuring that total braking force remains sufficient and continuous without interruption.
Solution Approach 2:
The patent recovers braking force that would otherwise be lost during ABS operation. By maintaining regenerative braking force while ABS controls friction braking, the system recovers the braking force contribution from the regenerative system, preventing the braking force shortage that would occur if regenerative braking were stopped during ABS activation.
3Device complexity
If regenerative braking force is stopped during ABS operation, then wheel slip control is simplified, but total braking force becomes insufficient to meet driver's braking request
Solution Approach 1:
The patent maintains continuous regenerative braking force application during ABS operation, ensuring that the regenerative braking system operates continuously without interruption. This continuous operation provides additional braking force that compensates for the friction braking force reductions made during ABS control, meeting the driver's braking requests effectively.
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 reduces braking force shortages during wheel slip by maintaining regenerative braking on driving wheels and dynamically adjusting friction and regenerative braking forces, enhancing braking stability and performance.
Implementation Method 1
a regenerative braking unit for applying regenerative braking force generated by an electrical motor to a driving wheel
Implementation Method 2
an electrical braking unit that supplies operational pressure generated in operational fluid by an electrical brake actuator to wheel cylinders
Data Source
AI summary
The present invention addresses the problem of providing a vehicular brake system that uses both friction braking force generated by an electrical braking unit and regenerative braking force generated by a regenerative braking unit, and can reduce a shortage in braking force when a slip has occurred on a wheel and antilock control is activated. The vehicular brake system includes: an electrical braking unit that supplies operational pressure generated in operational fluid by an electrical brake actuator to wheel cylinders and thereby applies friction braking force to wheels; a regenerative braking unit for applying regenerative braking force generated by an electrical motor to a driving wheel; and an antilock control unit for activating antilock control that increases and decreases the friction braking force to stop slip of a wheel.