Vehicle Brake Pressure Control for Smooth Direction Changes
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Solution Overview
Problem
Existing vehicle control systems using braking force differences between wheels to prevent lane departure can cause driver discomfort due to sudden changes in deceleration and noise from pressure reducing solenoid valves.
Innovation Solution
A vehicle control apparatus that adjusts brake fluid pressure between wheels to minimize deceleration changes and reduce noise by using a fluid pressure difference to increase pressure on one side while decreasing it on the other, without operating the pressure reducing solenoid valve, thereby maintaining a consistent deceleration and reducing discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If braking force difference between left and right wheels is applied to turn the vehicle in one direction and then temporarily stopped before turning in another direction, then the vehicle can change direction, but the driver feels momentary brake loss and discomfort due to sudden deceleration changes
Solution Approach 1:
The system performs preliminary action by increasing the brake fluid pressure on the second side before reducing pressure on the first side. This ensures that braking force is already present on the second side when the first side's braking is reduced, preventing momentary brake loss and maintaining driver comfort during direction changes.
Solution Approach 2:
The system maintains continuity of useful action by ensuring that braking force remains applied to at least one side throughout the direction change process. By overlapping the increase of braking force on the second side with the reduction on the first side, the system avoids complete cessation of braking force, eliminating the momentary brake loss sensation.
2Speed
If pressure reducing solenoid valve is operated to reduce brake fluid pressure quickly, then the vehicle can respond faster to direction changes, but noise is generated causing driver discomfort
Solution Approach 1:
The system extracts the pressure reducing function from the solenoid valve by using a communication passage that directly connects the first and second sides. This eliminates the need for the solenoid valve to reduce pressure, thereby removing the noise source while maintaining fast pressure response capability through direct fluid communication.
Solution Approach 2:
The communication passage acts as an intermediary mechanism between the first and second sides for pressure equalization. Instead of using the solenoid valve as the mediator for pressure reduction, the direct fluid passage provides a noiseless intermediary path that achieves the same pressure balancing function without generating harmful noise.
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 driver discomfort by maintaining consistent deceleration and reducing noise from solenoid valve operation, allowing for smooth vehicle direction changes without sudden braking force shifts.
Implementation Method 1
increase the second brake fluid pressure by using a fluid pressure difference between the first brake fluid pressure and the second brake fluid pressure
Data Source
AI summary
A vehicle control apparatus is provided with: a controller (i) configured to set first brake fluid pressure associated with wheels on one of left and right sides out of a plurality of wheels to be higher than second brake fluid pressure associated with wheels on the other side in order to turn a vehicle in one direction, and configured (ii) to then increase the second brake fluid pressure by using a fluid pressure difference between the first brake fluid pressure and the second brake fluid pressure, and (iii) to set the first brake fluid pressure to be lower than the second brake fluid pressure while holding the second brake fluid pressure in order to turn the vehicle in another direction, which is different from the one direction.