Vehicle Brake Axle Control Layout for Fail-Operational Braking
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Solution Overview
Problem
Modern air-braked vehicles face limitations in maintaining effective braking when there is a failure in the driver assistance system, as current systems have limited actions to take during such failures.
Innovation Solution
A vehicle braking system with multiple brake axles and control valves that allow continued actuation of brakes across different axles even if one fails, ensuring that at least two out of three brake axles can still be controlled to maintain braking functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a driver assistance system is used for braking, then braking automation and driver support are improved, but system reliability deteriorates due to potential failures in the driver assistance system
Solution Approach 1:
The braking system is segmented into multiple independent brake axles (first, second, and third brake axles) with separate control valves. This segmentation allows the system to maintain braking functionality on remaining axles even when one axle or its control fails, thereby improving reliability while maintaining automation.
Solution Approach 2:
The system prepares for potential failures by establishing redundant brake axles and control pathways in advance. When a failure is detected in the driver assistance system or a brake axle, the system can switch to using remaining functional axles, cushioning against the complete loss of braking capability.
2Device complexity
If multiple brake axles are controlled by a single valve, then device complexity is reduced, but reliability deteriorates because a single failure can affect all brake axles
Solution Approach 1:
The control system is segmented into multiple independent control valves (first control valve for first and second brake axles, second control valve for second and third brake axles). This segmentation ensures that a failure in one control valve does not affect all brake axles, improving reliability while maintaining manageable system complexity.
Solution Approach 2:
The second brake axle is controlled by both the first control valve and the second control valve, creating a merged control pathway. This allows the second brake axle to receive control signals from either valve, ensuring continued functionality even if one control valve fails.
3Reliability
If the driver assistance system fails, then automation is lost, but complete loss of braking functionality occurs with current systems
Solution Approach 1:
The system establishes redundant brake axles and control pathways before failures occur. When the driver assistance system fails, the system can switch to manual control of remaining functional brake axles, cushioning against complete loss of braking functionality while accepting the loss of automation.
Solution Approach 2:
The braking system is designed to serve itself by maintaining inherent braking capability through redundant axles and control valves. Even when the driver assistance system fails, the system can continue to provide braking functionality through remaining functional components without requiring external intervention.
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
Ensures continued braking capability even during failures in the driver assistance system by ensuring sufficient pneumatic pressure is maintained across at least two out of three brake axles, preventing complete loss of braking functionality.
Implementation Method 1
ensuring sufficient pneumatic pressure is maintained across at least two out of three brake axles
Data Source
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AI summary
A vehicle braking system (12) for a vehicle combination (10;14,16) includes a first brake axle (201) including a first actuatable brake (221,1), a second brake axle (202) including a second actuatable brake (222,1), a third brake axle (203) including a third actuatable brake (223,1), a first valve (261) controlling actuation of the first actuatable brake (221,1) and actuation of the second actuatable brake (222,1), and a second valve (262) controlling actuation of the second actuatable brake (222,1) and actuation of the third actuatable brake (223,1). Two more braking systems with similar features are claimed using different wording. Further a method for braking a vehicle combination (10;14,16) is claimed which includes controlling a first group (241) of actuatable brakes (221,222) on a first brake axle (201) and a second brake axle (202), controlling a second group (242) of actuatable brakes (222,223) on the second brake axle (202) and a third brake axle (203), and if one of the actuatable brakes ( e.g. 221) fails to be controlled, continuing to control the respective actuatable brakes (e.g. 222,223) on two of the other brake axles (e.g. 202,203).