Vehicle Brake Hydraulic Control Device Pressure Adjustment
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Solution Overview
Problem
Brake fluid pressure control devices without sensors for detecting brake operation can lead to continued ABS control when the brake is re-operated, causing a feeling of wrongness and strangeness in drivers due to mismatched pressure increase rates between the master cylinder and ABS control.
Innovation Solution
A brake fluid pressure control device that includes a wheel speed obtaining device and a vehicle body deceleration calculating means, which alters the pressure increasing rate by increasing the time for opening the inlet control valve and reducing the holding time for brake fluid pressure, if vehicle body deceleration remains low for a predetermined period, thereby improving responsiveness and reducing driver discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ABS control continues without detecting brake operation, then wheel lock prevention is maintained, but brake responsiveness deteriorates and driver feels wrongness upon re-operation
Solution Approach 1:
The patent dynamically adjusts the pressure increase rate based on detected brake operation status. When brake operation is detected during ABS control, the system switches to a higher pressure increase rate, making the brake response dynamic and adaptive rather than static. This resolves the contradiction by allowing the system to maintain reliability through continued ABS control while improving ease of operation through accelerated pressure increase when needed.
Solution Approach 2:
The patent changes the parameter of pressure increase rate from a fixed value to a variable that can be adjusted between two levels (first and second pressure increase rates). By changing this parameter based on brake operation detection, the system maintains wheel lock prevention reliability while improving brake responsiveness when the driver re-operates the brake, thereby resolving the technical contradiction.
2Ease of operation
If pressure increase rate is increased to improve brake responsiveness, then driver feeling of wrongness is reduced, but brake fluid pressure control precision may be compromised
Solution Approach 1:
The system dynamically switches between two pressure increase rates based on brake operation detection. The first pressure increase rate is used during normal ABS control to maintain precision, while the second (higher) pressure increase rate is activated when brake operation is detected to improve responsiveness. This dynamic adjustment resolves the contradiction by applying different precision levels appropriate to different operational states.
Solution Approach 2:
The system performs preliminary detection of brake operation status and proactively adjusts the pressure increase rate before the driver actually re-operates the brake. By detecting the driver's intent in advance and preparing the appropriate pressure increase rate, the system ensures both responsiveness and precision without compromising control accuracy.
Data Source
AI summary
A brake fluid pressure control device for a vehicle that includes a wheel speed obtaining device to obtain wheel speed, and a vehicle body deceleration calculating means to calculate a vehicle body deceleration on the basis of the wheel speed. If a condition is satisfied in which the vehicle body deceleration continues to stay at a low rate of less than or equal to a predetermined threshold value for a predetermined period of time, the pressure increasing rate in pressure increasing control is altered to a higher value than before the condition is satisfied. The brake fluid pressure of a brake caliper can quickly be brought close to the fluid pressure of a master cylinder. Therefore, it is possible to improve the brake responsiveness when the brake is re-operated by the driver during the ABS control, thereby reducing the driver's feeling of wrongness and strangeness.