Vehicle Brake Fluid Pressure Control Using Deceleration
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Solution Overview
Problem
Existing vehicle brake fluid pressure control systems struggle to accurately judge road surface friction coefficients, leading to insufficient setting of allowable differential pressures, which affects braking efficiency and stability.
Innovation Solution
A vehicle brake fluid pressure control apparatus that includes a fluid pressure adjusting unit and allowable differential pressure setting means, using estimated vehicle body deceleration to set differential pressures based on road surface friction coefficients, with additional features for judging split and low-friction coefficient roads to adjust settings accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the brake fluid pressure of the wheel coaxial with the control target wheel is used to set allowable differential pressure, then the control system is simple, but the judgment accuracy of road surface friction coefficient deteriorates
Solution Approach 1:
The patent introduces an intermediary parameter (estimated vehicle body deceleration) that mediates between the wheel brake fluid pressure and the road surface friction coefficient judgment. This deceleration value serves as a more reliable indicator of actual road conditions, resolving the contradiction by providing accurate friction coefficient judgment without directly relying on potentially misleading wheel pressure data alone
Solution Approach 2:
The patent replaces the mechanical/physical measurement approach (using wheel brake fluid pressure) with a calculated parameter approach (using estimated vehicle body deceleration). This substitution allows for more accurate road surface friction coefficient judgment by using dynamic vehicle behavior data instead of static pressure measurements
2Loss of time
If the allowable differential pressure is set based on inaccurate friction coefficient judgment, then the control can be applied early, but the braking efficiency deteriorates due to insufficient differential pressure
Solution Approach 1:
The patent implements a feedback mechanism where the estimated vehicle body deceleration continuously informs the allowable differential pressure setting. This feedback loop ensures that the control system applies appropriate differential pressure values based on actual road conditions, optimizing both the timing of control application and the braking efficiency by preventing premature or inappropriate control activation
Data Source
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AI summary
A vehicle brake fluid pressure control apparatus controls operations of a fluid pressure adjusting unit capable of performing adjustment of individually increasing and decreasing brake fluid pressures acting respectively on wheel brakes for front wheels and wheel brakes for rear wheels to be within allowable differential pressures allowable between the brake fluid pressures of the wheel brakes for the left and right coaxial front wheels and the left and right coaxial rear wheels. In the apparatus, estimated vehicle body deceleration calculator calculates an estimated vehicle body deceleration of a vehicle and allowable differential pressure setting device sets the allowable differential pressures matching a road surface friction coefficient based on the estimated vehicle body deceleration calculated by the estimated vehicle body deceleration calculator. This enables accurate judgment of a road surface having a high friction coefficient and setting of sufficiently large allowable differential pressures.