Brake Hydraulic Pressure Control Device for Vehicle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brake hydraulic pressure control systems for vehicles struggle to independently manage brake hydraulic pressures for left and right wheel brakes based on varying road surface conditions, particularly when the coefficient of friction is low, which can affect vehicle stability and control efficiency.
Innovation Solution
A brake hydraulic pressure control device that includes a hydraulic pressure adjustment unit, allowable differential pressure setting means, and hydraulic pressure acquisition means to adjust brake hydraulic pressures for coaxial front and rear wheels, setting allowable differential pressures based on road surface friction coefficients, prohibiting excessive differential pressure application when low friction is detected, and starting lock hydraulic pressure acquisition during the first cycle of anti-lock brake control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the brake hydraulic pressures of the left and right wheel brakes are independently controlled to maintain differential pressure below an allowable value, then vehicle behavioral stability is improved, but control difficulty increases when road surface conditions vary
Solution Approach 1:
The allowable differential pressure is made dynamic by adjusting it according to detected road surface conditions. When low friction is detected, the allowable differential pressure is reduced or prohibited, allowing the system to adapt control parameters in real-time based on environmental conditions, thereby maintaining stability while simplifying control logic through condition-based parameter adjustment
Solution Approach 2:
The system changes the control parameter (allowable differential pressure) based on detected road surface friction conditions. By detecting lock hydraulic pressure and comparing it against thresholds, the system adjusts the allowable differential pressure parameter to match current road conditions, making control easier while maintaining vehicle stability
2Measurement precision
If the allowable differential pressure is set based on the coefficient of friction of the road surface, then control precision is improved, but device complexity increases due to additional detection and calculation requirements
Solution Approach 1:
The system uses the existing lock hydraulic pressure detection capability to infer road surface friction conditions without requiring separate friction sensors. By self-utilizing the already-detected lock pressure data and comparing it against predetermined thresholds, the system determines road conditions and adjusts allowable differential pressure, achieving precise control while avoiding additional complex detection devices
Solution Approach 2:
The lock hydraulic pressure serves as an intermediary parameter that indirectly indicates road surface friction conditions. Instead of directly measuring friction coefficient, the system uses lock pressure as a mediator to infer road conditions and subsequently adjust the allowable differential pressure, simplifying the overall system while maintaining control precision
3Loss of time
If lock hydraulic pressure acquisition is performed during the first cycle of anti-lock brake control, then response time is improved, but measurement accuracy may be affected by pressure fluctuations
Solution Approach 1:
The system performs lock hydraulic pressure acquisition during the first cycle of anti-lock brake control as a preliminary action to quickly determine road surface conditions. This early acquisition allows subsequent control cycles to use the determined allowable differential pressure, achieving fast response while the preliminary nature of the measurement is acceptable since it only needs to establish initial road condition classification
Solution Approach 2:
The system performs pressure acquisition during the first cycle even though pressure fluctuations may affect precision, accepting partial accuracy in exchange for rapid response. The acquired data is sufficient for classifying road conditions into discrete categories (low friction vs. normal), which is adequate for control purposes without requiring highly precise continuous measurement
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A brake hydraulic pressure control device for a vehicle is provided in which operation of a hydraulic pressure adjustment unit that can carry out adjustment involving individually increasing/decreasing brake hydraulic pressures applied to wheel brakes for front wheels and wheel brakes for rear wheels is controlled so as to be an allowable differential pressure between brake hydraulic pressures of the left and right wheel brakes, wherein allowable differential pressure setting means (27) is arranged so that the allowable differential pressure can be set so as to correspond to the coefficient of friction of a road surface, hydraulic pressure acquisition means (29) acquires a lock hydraulic pressure, which is a hydraulic pressure when starting anti-lock brake control for the respective wheel brake, and when the lock hydraulic pressure of the wheel brakes for the front wheels acquired by the hydraulic pressure acquisition means (29) is no greater than a predetermined value which can be determined as to be a low coefficient of friction, application of the allowable differential pressure corresponding to the coefficient of friction of the road surface is prohibited. Thus, it is possible to independently control the brake hydraulic pressure of left and right wheel brakes according to road surface conditions.