Dual Electrohydraulic Brake Control System for Automated Driving
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Solution Overview
Problem
Existing brake systems for motor vehicles, especially those intended for highly automated or autonomous driving, face limitations in ensuring high availability of wheel-specific brake pressure control due to reliance on electronic control units, which can fail, reducing their suitability for advanced driving scenarios.
Innovation Solution
A dual electrohydraulic brake control system is introduced, featuring a first and second brake control device connected in series, with each having a pressure control valve assembly and electrically controllable pressure sources, allowing for continued precise wheel-specific brake pressure control even if one device fails, and enabling both hydraulic and electromechanical actuation of wheel brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single electrohydraulic brake control device is used, then the device complexity is reduced, but the reliability of wheel-specific brake pressure control deteriorates due to potential electronic control unit failure
Solution Approach 1:
The brake control system is divided into two independent brake control devices (first and second), each capable of independently controlling brake pressures. This segmentation allows one device to take over if the other fails, thereby improving reliability while maintaining manageable complexity through functional division
Solution Approach 2:
The system changes the operational state of the brake control devices between normal operation (first device active, second device standby) and failure mode (second device becomes active). This parameter change in system configuration ensures continuous availability without permanently increasing operational complexity
2Extent of automation
If electronic control units are used for automated braking, then the extent of automation is improved, but the reliability deteriorates due to potential electronic failures
Solution Approach 1:
The system prepares a standby brake control device (second device) in advance that can immediately take over if the primary electronic control fails. This beforehand cushioning ensures that automated braking capability is maintained even when electronic components fail, addressing the reliability concern while preserving automation
3Reliability
If a redundant brake control system is implemented, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Both brake control devices are designed with universal functionality to perform all brake control operations independently. The second device can function as a complete backup, not just a partial redundancy, which improves reliability while the modular universal design helps manage system complexity
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 configuration ensures high availability and precision of brake pressure control across all wheel brakes, maintaining safety and functionality even if one control device fails, thereby enhancing the system's suitability for automated and autonomous driving.
Implementation Method 1
a pressure control valve assembly for setting wheel-specific brake pressures
Implementation Method 2
an electrically controllable pressure source
Implementation Method 3
wheel brakes
Data Source
AI summary
A second electrohydraulic brake control device for a motor vehicle comprises a pressure control valve assembly, an controllable pressure source and a reservoir connection. For a group of wheel brakes, the second electrohydraulic brake control device is connected in series between the associated output pressure connections of a first or main brake control device and the vehicle wheel brakes.