Adaptive Emergency Braking Detection in Hydraulic Brake Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic brake systems with vacuum brake boosters struggle to effectively implement emergency braking during rapid repeated braking, as the pressure difference between chambers does not have time to establish, making it difficult to reach the emergency braking threshold.
Innovation Solution
A method that detects close repetition of emergency braking by counting the number of braking operations within a predetermined time interval, adapting the emergency braking conditions based on this count, and using a single pressure sensor to determine the pressure and its gradient in the master cylinder, thereby reducing the need for additional hardware and measurement means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emergency braking detection criteria are used during rapid repeated braking, then the system can detect emergency braking situations, but the pressure difference between brake booster chambers does not have time to establish, making it difficult to reach the emergency braking threshold
Solution Approach 1:
The patent applies dynamics by making the emergency braking detection criteria adaptive rather than static. The system dynamically adjusts the pressure threshold and pressure gradient threshold based on the braking history and current system state, allowing the detection criteria to evolve with repeated braking events. This enables reliable detection even when the brake booster pressure difference cannot fully establish between rapid successive braking actions.
Solution Approach 2:
The system implements feedback by continuously monitoring braking operations and using this information to adjust subsequent detection criteria. The control unit tracks the number of braking operations, pressure levels, and pressure gradients, then uses this feedback to adaptively modify the emergency braking detection thresholds. This closed-loop approach ensures reliable detection under varying conditions of repeated braking.
2Measurement precision
If additional pressure sensors and measurement means are added to detect chamber pressure differences, then emergency braking detection accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent applies universality by making the existing master cylinder pressure sensor serve multiple functions. Instead of adding dedicated sensors for each brake booster chamber, the system uses the single master cylinder pressure measurement in combination with braking operation counting and gradient calculation to infer the state of both chambers. This multi-functional approach achieves accurate detection without increasing sensor count.
Solution Approach 2:
The control unit acts as an intermediary that processes the single master cylinder pressure signal along with braking operation history to derive information about chamber pressure differences. Rather than directly measuring each chamber's pressure, the system uses the control unit to calculate pressure gradients and compare them against adaptive thresholds, mediating between the limited sensor input and the comprehensive detection requirement.
3Productivity
If the emergency braking threshold is made less restrictive to account for repeated braking, then the system can detect emergency braking more easily, but false detection of emergency braking situations may increase
Solution Approach 1:
The system applies parameter changes by dynamically adjusting the pressure threshold and pressure gradient threshold based on the current braking context. During repeated braking operations, the thresholds are adaptively modified to maintain appropriate sensitivity. The control unit calculates the pressure gradient and compares it against adaptive thresholds that account for the number of previous braking operations, allowing the parameters to change with system state rather than remaining fixed.
Solution Approach 2:
The detection criteria are made dynamic rather than static, with thresholds that evolve based on braking history. The system continuously adapts the emergency braking detection parameters according to the current operational context, including the count of recent braking operations and the measured pressure gradient. This dynamic adaptation allows the system to remain sensitive to true emergency braking while filtering out normal repeated braking events.
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 approach allows for timely detection and adaptation of emergency braking situations, reducing the braking assistance delivered by the vacuum brake booster and making emergency braking conditions less restrictive when repeated, thus improving the system's ability to handle rapid repeated braking without increasing device costs.
Implementation Method 1
The latter comprises a working chamber separated by a movable piston from a low pressure chamber permanently maintained at a low pressure, under depression with respect to atmospheric pressure, and whose action by a force on the pedal makes it possible to control the setting. to the atmospheric pressure of the working chamber and the corresponding amplification of the force at the pedal by the force acting on the movable piston.
Data Source
Figure 1
Figure 2
AI summary
The invention concerns a method for controlling braking in a motor vehicle equipped with a brake servo unit capable of being implemented in a braking system (10) comprising: a hydraulic master cylinder associated with a vacuum brake booster (18) and with the hydraulic circuits (A, B) supplying the wheel brakes (12A, 14A, 12B, 14B) equipping the vehicle wheels; an ABS hydraulic unit (22A, 22B) with wheel antiskid function, and electronic means (24) for implementing emergency braking assisted by the hydraulic unit (22A, 22B). The method is characterized in that it consists in detecting the serial repetition in time for implementing emergency braking operations and in adapting the conditions for implementing an emergency braking in case of serial repetition.