Brake System Dual Electrical Redundancy for Fail-Safe Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Brake-by-wire systems in motor vehicles lack a reliable fail-safe mechanism for active pressure build-up in wheel brakes during electrical supply failures, requiring mechanical intervention by the driver in fallback scenarios.
Innovation Solution
The implementation of two separate on-board electrical systems, each feeding a pressure provision device, ensures active pressure build-up in wheel brakes even if one electrical system fails, eliminating the need for mechanical intervention and allowing a dry simulator or master brake cylinder to be used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single electrical system feeds the pressure provision device in brake-by-wire systems, then the system structure is simple, but the reliability fails during electrical supply failures
Solution Approach 1:
The brake system is divided into two independent brake circuits (first and second brake circuits), each with its own pressure provision device fed by a separate electrical system. This segmentation ensures that a failure in one electrical system does not compromise the entire braking function, as the other circuit remains operational.
Solution Approach 2:
The patent implements redundant electrical systems and pressure provision devices as a preemptive measure against electrical supply failures. By providing backup systems before failures occur, the patent ensures continuous brake pressure build-up capability even when one electrical system fails, eliminating the need for mechanical fallback mechanisms.
2Ease of operation
If mechanical intervention is required for fallback braking, then the system is simpler, but the ease of operation deteriorates during electrical failures
Solution Approach 1:
The brake system maintains self-service capability during electrical failures through the redundant electrical system. When one electrical system fails, the other automatically takes over to continue providing brake pressure, eliminating the need for driver intervention or mechanical fallback mechanisms. The system serves itself by automatically switching to the backup electrical system.
3Adaptability or versatility
If hydraulic decoupling is implemented between brake pedal and pressure build-up, then the functionality for ABS/ESC is improved, but the reliability during electrical failures deteriorates
Solution Approach 1:
The hydraulic decoupling is segmented into two independent circuits, each with its own pressure provision device and electrical system. This allows the system to maintain advanced brake control functionalities (ABS, ESC, TCS) while providing fail-safe operation through redundancy. Each circuit can independently provide both advanced control and fallback capability.
Solution Approach 2:
The redundant electrical systems and pressure provision devices are implemented beforehand to cushion against potential failures. This preemptive redundancy ensures that the hydraulic decoupling, which enables advanced functionalities, does not compromise reliability, as the backup systems are already in place to take over immediately upon failure.
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 enables continuous active pressure build-up in all four wheel brakes during electrical failures, providing a reliable by-wire fallback level without requiring hydraulic access, thus ensuring safe and efficient braking.
Implementation Method 1
two pressure provision devices (14, 16) for actively building up pressure in the wheel brakes (4, 6, 8, 10)
Implementation Method 2
each wheel brake (4, 6, 8, 10) is assigned in each case one inlet valve (86, 88, 110, 114) which is open when electrically deenergized
Data Source
AI summary
A brake system, including four hydraulically actuatable wheel brakes. Each wheel brake is assigned in each case one outlet valve which is closed when electrically deenergized. Each wheel brake is assigned in each case one inlet valve which is open when electrically deenergized. The brake system furthermore includes a simulator which is actuatable by a brake pedal, wherein two pressure provision devices are provided for actively building up pressure in the wheel brakes, two brake circuits are hydraulically formed, wherein, in each brake circuit, in each case one pressure provision device is hydraulically connected to two wheel brakes, and wherein two separate on-board electrical systems are provided, and wherein each pressure provision device is fed in each case by one of the two on-board electrical systems.