Brake Apparatus Regenerative Cooperative Control
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Solution Overview
Problem
The existing brake control apparatus for vehicles experiences degradation in brake pedal operation feeling during regenerative cooperative control due to the weakening of regenerative braking force as vehicle speed reduces, causing changes in hydraulic pressure that affect the brake pedal operation.
Innovation Solution
A brake apparatus with a regenerative brake device, a hydraulic pressure generating device, and a pump mechanism that supplies hydraulic fluid to the wheel cylinder based on the brake pedal position and operation quantity, with a control unit managing the fluid supply to maintain optimal braking force distribution between regenerative and hydraulic braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic control device adjusts the hydraulic pressure to be supplied to the hydraulic brake during regenerative braking, then the regenerative cooperative control is performed to obtain desired braking force, but the change in hydraulic pressure in the master cylinder is transmitted to the brake pedal, degrading the brake pedal operation feeling
Solution Approach 1:
The pump mechanism is activated in advance to supply hydraulic fluid to the wheel cylinder before the master cylinder starts generating brake hydraulic pressure. This preliminary action ensures that the hydraulic pressure adjustment occurs independently of the master cylinder, preventing pressure changes from being transmitted to the brake pedal while still achieving the desired braking force through regenerative cooperative control
2Use of energy by moving object
If the regenerative brake device generates maximum regenerative braking force at a certain brake pedal position, then the regenerative braking efficiency is maximized, but the brake hydraulic pressure must be generated by the master cylinder at the same position, causing hydraulic pressure changes that affect pedal feeling
Solution Approach 1:
The pump mechanism supplies hydraulic fluid to the wheel cylinder before the master cylinder generates brake hydraulic pressure at the maximum regenerative braking pedal position. This timing arrangement allows the regenerative brake to operate at maximum efficiency while the hydraulic pressure adjustment is performed by the pump mechanism independently, preventing any hydraulic pressure changes from affecting the brake pedal operation feeling
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 solution effectively suppresses the degradation of brake pedal operation feeling by ensuring consistent hydraulic pressure and braking force distribution, enhancing the overall braking performance and pedal feedback.
Implementation Method 1
a regenerative brake device applying a regenerative braking force to a wheel of a vehicle by generating electric power from rotation of the wheel
Implementation Method 2
a pump mechanism delivering the hydraulic fluid from the hydraulic pressure generating device to the wheel cylinder by a pump
Data Source
AI summary
A controller controls a hydraulic control device to generate a target braking force corresponding to the stroke of a brake pedal by adjusting a controlled hydraulic braking force portion generated by the hydraulic control device on the basis of the relationship with a master hydraulic braking force portion generated from the brake hydraulic pressure in a master cylinder and a regenerative braking force portion generated by a regenerative brake device. The regenerative brake device maximizes the regenerative braking force portion before the stroke of the brake pedal reaches an idle stroke, and thereafter, the hydraulic control device 5 starts braking by the controlled hydraulic braking force portion. When the stroke of the brake pedal reaches the idle stroke, the master cylinder starts braking by the master hydraulic braking force portion.