Brake Control Device Valve Differential Pressure Management
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Solution Overview
Problem
Existing brake control systems face challenges in preventing hydraulic pressure confinement in wheel cylinders during mode switching, leading to potential wheel drag and deceleration declination phenomena.
Innovation Solution
A brake control device with a wheel cylinder pressure control system, a manual hydraulic pressure source, a separation valve, and open-close valves that manage differential pressure to ensure smooth mode switching and maintain braking force, avoiding pressure confinement and deceleration declination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the open-close valve is kept closed due to differential pressure effect during mode switching, then the valve remains in closed state despite valve-opening command, but hydraulic pressure becomes confined in wheel cylinders causing wheel drag
Solution Approach 1:
The control portion closes the separation valve after issuing the valve-opening command to the open-close valve. This preliminary action creates a pressure release path that reduces the differential pressure across the open-close valve, enabling it to open properly during mode switching and preventing hydraulic pressure confinement in the wheel cylinders
Solution Approach 2:
The separation valve acts as an intermediary component that provides a temporary pressure release path. By closing the separation valve after the valve-opening command, the system creates an intermediate state where pressure can be equalized, allowing the open-close valve to transition smoothly from closed to open state without causing harmful pressure confinement
2Speed
If mode switching is performed promptly by altering control valves simultaneously, then switching speed is improved, but hydraulic pressure may be confined in wheel cylinders due to switching operation
Solution Approach 1:
The control portion issues the valve-opening command to the open-close valve before closing the separation valve. This preliminary action sequence ensures that the pressure release path is established in advance, allowing simultaneous valve alteration while preventing pressure confinement through the pre-established release path
Solution Approach 2:
The system dynamically adjusts the timing of valve operations during mode switching. By making the separation valve closure occur after the open-close valve opening command, the system creates a dynamic pressure management strategy that maintains fast switching speed while preventing harmful pressure buildup through controlled pressure release
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 enables seamless mode switching while preventing hydraulic pressure confinement and maintaining braking force, thus ensuring smooth operation and minimizing deceleration declination.
Implementation Method 1
an open-close valve that is provided between the manual hydraulic pressure source and the wheel cylinders, and that is kept in a closed state despite a valve-opening command, due to an effect of a differential pressure between an outlet opening and an inlet opening of the open-close valve, if the differential pressure is greater than a predetermined pressure
Implementation Method 2
a manual hydraulic pressure source that pressurizes the working fluid contained in the manual hydraulic pressure source in accordance with amount of operation of a brake operating member performed by the driver
Data Source
AI summary
In a brake control device and a brake control method, when a shift to a brake mode for backup involving separation of a supply path of working fluid is performed at the time of detection of an abnormality during braking, a differential pressure acting between an outlet opening and an inlet opening of an open-close valve which is provided between a hydraulic pressure source that is used during the backup brake mode and wheel cylinders and which needs to be opened during the backup brake mode is lessened prior to the separation of the supply path of working fluid so that the open-close valve is opened in accordance with a valve-opening command. Therefore, at the time of switch of the control mode, the confinement of wheel cylinder pressure is avoided.