Brake Pressure Equalization for Smooth By-Wire Mode Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing braking control devices experience discomfort in brake feeling when switching to the by-wire mode due to pressure differences between the separation and reaction force chambers, leading to undesirable movement of the input piston and brake operation member.
Innovation Solution
A braking control device with a pressurization unit, a master cylinder unit, and a control device that executes activation-time control to equalize pressures before switching to the by-wire mode, ensuring the electromagnetic valve is opened only when the pressure difference is minimal, thereby stabilizing the brake operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electromagnetic valve is opened to switch to the by-wire mode, then the braking control system can function in by-wire mode, but the pressure difference between the separation chamber and the reaction force chamber causes the input piston and brake operation member to move forward, giving a discomfortable feeling to the driver
Solution Approach 1:
The control device performs preliminary equalization of pressure between the separation chamber and the reaction force chamber before opening the electromagnetic valve to switch to by-wire mode. This preliminary action prevents the sudden pressure difference that would otherwise cause the input piston and brake operation member to move forward, thereby eliminating the uncomfortable feeling while maintaining the by-wire mode switching capability
Solution Approach 2:
The control device applies preliminary counter-action by equalizing the pressure in the separation chamber and the reaction force chamber before the electromagnetic valve is opened. This counter-balances the pressure forces that would otherwise cause unwanted movement of the input piston and brake operation member, preventing the discomfortable brake feeling before it occurs
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 improves the brake feeling by preventing unwanted movement of the input piston and brake operation member when the electromagnetic valve is opened, enhancing the overall braking control experience.
Implementation Method 1
a servo chamber of which a volume increases in accordance with a supply of the fluid from the pressurization unit
Implementation Method 2
an electromagnetic valve provided at the connection path
Data Source
AI summary
A brake control device includes a brake operation member, a pressurization unit, a master cylinder unit, a connection path connecting a separation chamber and a reaction force chamber, an electromagnetic valve at the connection path, and a control device. The control device includes a specified control section configured to, when the brake operation member is operated in a closed state of the electromagnetic valve, execute activation-time control in which the pressurization unit supplies fluid to a servo chamber based on a predetermined pattern, a determination section configured to determine whether a pressure difference between pressure in the reaction force chamber and pressure in the separation chamber, is equal to or less than a threshold value, and a valve control section configured to open the electromagnetic valve when the determination section determines the pressure difference is equal to or less than the threshold value after start of the activation-time control.