Hybrid Brake Control System Mode Switching for Stability
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Solution Overview
Problem
Current brake control systems in two-axle motor vehicles face challenges in balancing driving stability and comfort, particularly when using hybrid brake systems that combine hydraulic and electromechanical brakes, as they can lead to unpleasant brake pedal feedback and instability due to overbraking the rear axle.
Innovation Solution
A brake control system that operates in two modes: initially using only the electromechanical brake system for driver-independent braking, switching to a combined hydraulic and electromechanical mode when stability criteria indicate a critical state, allowing continuous deceleration modulation and preventing instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If driver-independent braking is implemented only via the electromechanical brake system on the rear axle, then driving comfort is improved and brake pedal feel is maintained, but vehicle deceleration capability is limited
Solution Approach 1:
The system dynamically switches between two operating modes based on stability criteria. In the first mode, only the electromechanical brake system is used to maintain comfort. In the second mode, both hydraulic and electromechanical brake systems are activated to provide maximum deceleration when stability issues are detected.
Solution Approach 2:
The system changes the operational parameters by activating different brake systems based on detected stability conditions. When stability criteria are met, the system transitions from using only the electromechanical brake to incorporating the hydraulic brake system as well, effectively changing the braking power distribution.
2Extent of automation
If braking pressure is built up on the rear axle via electromechanical brake, then driver-independent braking intervention is achieved, but lateral force reserves are reduced and vehicle instability may occur
Solution Approach 1:
The system continuously monitors stability criteria such as slip values, lateral acceleration, and road friction coefficients. Based on this feedback, the control system determines when to switch between operating modes to prevent overbraking and maintain vehicle stability.
Solution Approach 2:
The system dynamically adjusts the braking strategy by switching between two operating modes. The first mode uses only electromechanical braking for comfort, while the second mode activates both hydraulic and electromechanical brakes to prevent instability when stability criteria are compromised.
3Power
If both hydraulic and electromechanical brake systems are activated for maximum deceleration, then vehicle deceleration capability is improved, but brake pedal feel deteriorates and driving comfort is reduced
Solution Approach 1:
The system dynamically selects between two operating modes based on stability criteria. The first mode maintains comfort by using only the electromechanical brake, while the second mode prioritizes deceleration power by activating both brake systems when stability issues are detected.
Solution Approach 2:
The system changes operational parameters by transitioning between modes. In the first mode, only the electromechanical brake is active. In the second mode, both hydraulic and electromechanical brakes are activated to provide maximum deceleration when stability criteria are compromised.
4Reliability
If the brake control system switches between two operating modes based on stability criteria, then both driving comfort and vehicle stability are maintained, but system complexity increases
Solution Approach 1:
The brake control system is segmented into two distinct operating modes with clearly defined characteristics. The first mode prioritizes comfort using only electromechanical braking, while the second mode prioritizes stability by activating both brake systems. This segmentation simplifies the control logic compared to a fully continuous system.
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 ensures comfortable and jerk-free braking while maintaining stability by evaluating slip, lateral acceleration, and road friction to transition between modes, preventing unstable driving conditions and enhancing brake pedal feel.
Implementation Method 1
an electromechanical brake system on a second axle of the motor vehicle
Implementation Method 2
a hydraulic brake system on a first axle of the motor vehicle
Implementation Method 3
a first axle of the motor vehicle is braked by means of a hydraulic brake system and a second axle of the motor vehicle is braked by means of an electromechanical brake system
Data Source
AI summary
The method involves controlling electromechanical brake systems and a hydraulic brake system in operation modes (b1, b2). Brake interference is taken in the mode (b1) when brake interference signal exists. Actually determined values of predetermined stability criteria are evaluated in the mode (b1) in such a manner that stability critical condition is changed from the mode (b1) into the mode (b2) during detection of criteria.