Brake Control Device Differential Pressure Correction
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Solution Overview
Problem
Existing brake control systems face challenges in accurately reflecting brake operations when pump pressurization and driver brake operations overlap, leading to delays and inconsistencies in braking force due to feedback mechanisms based on pedal suction and deceleration.
Innovation Solution
A brake control device with a differential pressure control unit that calculates and corrects the differential pressure instructing output to account for the decrease in master cylinder pressure during pump suction, ensuring the differential pressure reflects the intended brake operation, even during overlapping pump pressurization and driver brake operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pump pressurization is performed during brake operation, then wheel cylinder pressure increases, but master cylinder pressure decreases causing brake operation to be inaccurately reflected
Solution Approach 1:
The system uses feedback from the differential pressure sensor to continuously monitor the pressure difference between master and wheel cylinders. This feedback enables the control unit to detect when pump pressurization is occurring and adjust the differential pressure instructing value accordingly, ensuring accurate reflection of brake operation despite pump intervention
Solution Approach 2:
A differential pressure sensor is introduced as an intermediary element to measure the pressure difference between master and wheel cylinders. This intermediary provides indirect information about pump pressurization and brake operation, enabling the control unit to make accurate adjustments without directly measuring master cylinder pressure changes
2Ease of operation
If feedback is performed based on deceleration, then braking force control is achieved, but delay occurs until deceleration reflects W/C pressure change
Solution Approach 1:
The system performs preliminary action by using differential pressure as an early indicator of brake operation and pump pressurization status. This preliminary information is available before deceleration changes occur, allowing the control unit to proactively adjust the differential pressure instructing value and maintain accurate brake operation reflection without waiting for deceleration feedback
Solution Approach 2:
The system replaces the mechanical deceleration-based feedback mechanism with a pressure-based sensing system. The differential pressure sensor provides direct pressure information that correlates immediately with brake operation, substituting the delayed mechanical response (deceleration) with an immediate pressure measurement that enables real-time control adjustments
3Power
If brake fluid is sucked from M/C by pressure pump, then W/C pressure increases, but brake pedal returns causing driver operation to become inconsistent
Solution Approach 1:
The differential pressure feedback mechanism continuously monitors the pressure difference between master and wheel cylinders. When pump pressurization occurs and causes master cylinder pressure to drop, the feedback signal enables the control unit to adjust the differential pressure instructing value to compensate for the pressure change, maintaining consistent brake operation reflection despite the pedal return effect
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 enables precise reflection of brake operations, reducing delays and inconsistencies in braking force, allowing for accurate control of wheel cylinder pressure and improved braking performance.
Implementation Method 1
a pump which sucks the brake fluid from a portion of the main pipe line between the differential pressure control valve and the master cylinder
Implementation Method 2
a differential pressure control valve which is disposed in the main pipe line and which generates a differential pressure corresponding to a fluid pressure difference between the master cylinder and the wheel cylinders
Data Source
AI summary
A brake control device for a vehicle includes: a hydraulic brake device including a master cylinder, a wheel cylinder, a differential pressure control valve, and a pump; and a differential pressure control unit that operates the pump and transmits a differential pressure instructing output to the differential pressure control valve to perform a differential pressure control such that a differential pressure is generated; wherein the differential pressure control unit includes a correcting unit, wherein the correcting unit calculates a differential pressure instructing correction amount, based on an increased amount of the differential pressure which is generated by the differential pressure control valve when the increased amount of the differential pressure during the differential pressure control and then corrects the differential pressure instructing output based on the differential pressure instructing correction amount such that the differential pressure instructing output becomes larger than the increased amount of the differential pressure.