Braking Force Distribution Control for Hybrid Vehicle Collision Safety
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Solution Overview
Problem
Existing vehicle collision systems face issues with increased braking distance and sudden torque changes when high-voltage circuits are shut off, leading to potential relay seizing and instability in braking force control.
Innovation Solution
A braking-force distribution control apparatus and method that reduces the regenerative braking force and increases the frictional braking force when a collision is detected, allowing for controlled shutdown of the high-voltage circuit without relay seizing, thereby maintaining stable braking and preventing increased braking distance and torque changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high-voltage circuit is shut off when a collision is detected, then the reliability of preventing short circuits is improved, but the braking distance increases and the braking force becomes unstable
Solution Approach 1:
The controller reduces the regenerative braking force and increases the frictional braking force in advance before shutting off the high-voltage circuit. This preliminary adjustment of braking force distribution ensures that the frictional brake is already engaged at an appropriate level, preventing sudden braking force changes and excessive braking distance when the circuit shutdown occurs
Solution Approach 2:
The system cushions the potential harmful effect of circuit shutdown by pre-adjusting the braking force distribution. By increasing the frictional braking force before shutdown, the system creates a buffer that compensates for the loss of regenerative braking, ensuring stable and reliable braking performance throughout the collision event
2Use of energy by moving object
If the regenerative braking force is maintained at high level during collision, then energy recovery is improved, but the braking force distribution becomes unstable and relay seizing occurs
Solution Approach 1:
The controller performs preliminary action by reducing the regenerative braking force and increasing the frictional braking force before the high-voltage circuit shutdown. This ensures that the frictional brake is already providing sufficient braking force, preventing sudden instability and relay seizing when the circuit is shut off, while still allowing some energy recovery before the critical shutdown moment
3Speed
If the frictional braking force is increased before collision, then the braking distance is reduced, but the energy recovery efficiency decreases
Solution Approach 1:
The system dynamically adjusts the braking force distribution based on the collision detection state. During normal braking, regenerative braking is prioritized for energy recovery. Upon collision detection, the controller dynamically shifts the braking force distribution toward frictional braking in preparation for circuit shutdown, optimizing both braking distance and energy recovery at different stages of the braking-collision 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
The solution effectively prevents increased braking distance and sudden torque changes, ensuring stable vehicle motion and reliable high-voltage circuit shutdown, even during collisions, by adjusting the braking force distribution between regenerative and frictional brakes.
Implementation Method 1
the motor-generator generates electric power to regenerate kinetic energy when the vehicle is decelerating
Implementation Method 2
a frictional brake device that performs frictional braking with a frictional braking force
Data Source
AI summary
An apparatus and method for controlling a braking-force distribution in a vehicle collision is used in a vehicle including at least one electric storage device and at least one motor-generator for driving and braking. When the vehicle decelerates or stops in response to a brake operation, regenerative cooperative brake control is performed in which a braking force of a frictional brake is reduced or eliminated while a braking force of a regenerative brake applied by the motor-generator is increased by an amount corresponding to the reduction in the braking force of the friction brake. When the vehicle collides, the apparatus reduces the braking force of the regenerative brake applied by the motor-generator and increases the braking force of the friction brake.