Vehicle Braking Control Device Regenerative Force Adjustment
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Solution Overview
Problem
The existing vehicle braking control systems face challenges in maintaining drivability during switching control, where regenerative braking force decreases and hydraulic braking force increases, leading to a decrease in operational reaction force on the brake pedal, causing unintended displacement and reduced drivability.
Innovation Solution
A vehicle braking control device that adjusts the differential pressure between the master cylinder and wheel cylinder by controlling the regenerative braking device and hydraulic braking device, using a correlation value output unit to predict and manage the operational reaction force decrease, thereby reducing the hydraulic braking force increase and minimizing brake pedal displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the supply pump pumps up brake fluid from the master chamber to increase hydraulic braking force during switching control, then the hydraulic braking force increases, but the operational reaction force on the brake pedal decreases causing brake pedal displacement and reduced drivability
Solution Approach 1:
The control device predicts the operational reaction force decrease before switching control starts, and preemptively adjusts the regenerative braking force to compensate for the expected decrease. This preliminary anti-action prevents the brake pedal displacement issue before it occurs by balancing the operational reaction force changes.
Solution Approach 2:
The system performs preliminary prediction of the operational reaction force decrease using correlation values before actual switching control begins. Based on this prediction, the regenerative braking force is adjusted in advance to offset the expected impact on brake pedal stability, ensuring smooth transition during switching control.
2Force
If the regenerative braking force is decreased during switching control to allow hydraulic braking force to increase, then the hydraulic braking force can compensate for regenerative braking loss, but the operational reaction force decrease causes unintended brake pedal displacement
Solution Approach 1:
The control device uses correlation values to predict the operational reaction force decrease and implements feedback control by adjusting the regenerative braking force accordingly. This closed-loop approach ensures that the brake pedal position remains stable during switching control by continuously monitoring and compensating for reaction force changes.
Solution Approach 2:
The system changes the regenerative braking force parameter dynamically based on the predicted operational reaction force decrease. By adjusting this parameter in response to predicted changes, the system maintains brake pedal position stability while enabling the necessary hydraulic braking force increase during switching control.
3Stress or pressure
If the differential pressure between master cylinder and wheel cylinder is increased by pumping brake fluid, then the hydraulic braking force increases, but the master piston displacement reduces operational reaction force acting on the brake pedal
Solution Approach 1:
The control device applies a counterbalancing approach by adjusting the regenerative braking force to offset the operational reaction force decrease caused by master piston displacement. This counterweight effect compensates for the loss in operational reaction force, maintaining brake pedal stability while achieving the required differential pressure increase.
Solution Approach 2:
The system dynamically changes the regenerative braking force parameter in response to the differential pressure increase and resulting master piston displacement. By coordinating parameter changes in both regenerative and hydraulic braking systems, the device maintains operational reaction force balance while achieving necessary pressure differential for increased hydraulic braking force.
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 suppresses the decrease in drivability by predicting and managing the operational reaction force decrease, ensuring stable brake pedal operation during switching control, reducing uncomfortable feelings and maintaining vehicle control.
Implementation Method 1
a supply pump configured to pump up the brake fluid from the interior of the master chamber and discharge the brake fluid to the pathway of the wheel cylinder side
Implementation Method 2
by adjusting the differential pressure between the master cylinder and the wheel cylinder
Implementation Method 3
a regenerative braking device that gives a regenerative braking force to the vehicle
Data Source
AI summary
A vehicle braking control device of the invention includes, when a direction in which a brake operating member is displaced to increase the hydraulic pressure in a master chamber is assumed to be an operating direction, a correlation value output unit that outputs a correlation value that correlates to an amount of decrease in operational reaction force acting on the brake operating member in a direction opposite to the operating direction during a braking operation, prior to start of the switching control; and a control unit that controls the regenerative braking device so that, as the amount of decrease in operational reaction force indicated by the correlation value being output from the correlation value output unit is large, the regenerative braking force at the start of the switching control decreases.