Electro-Pneumatic Brake Redundancy for Fail-Operation Slip Control
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Solution Overview
Problem
Existing electro-pneumatic braking systems for commercial vehicles lack a reliable fail-operation mode that ensures safe auxiliary braking and brake slip control in case of central brake control device failure, as they are not adequately addressed by existing solutions designed for hydraulic or fluid-operated systems.
Innovation Solution
An electro-pneumatic braking system with a second brake control device that enables redundant brake control and slip control operations by dividing wheel speed sensors into groups, using direct signal lines, and employing the electric parking brake control device as a secondary controller to manage pneumatic brake cylinders, ensuring reliable operation even in the event of central control device failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second brake control device is added for fail-operation mode, then reliability is improved, but device complexity increases
Solution Approach 1:
The existing electric parking brake control device is made multi-functional by enabling it to perform both parking brake control and fail-operation service braking control. This eliminates the need for a dedicated second brake control device while maintaining redundancy and reliability in the braking system.
Solution Approach 2:
The patent merges the functions of the electric parking brake control device with the fail-operation service braking control functions. By combining these control functions into a single device, the system achieves redundancy without increasing the number of control devices, thus improving reliability while controlling complexity.
2Reliability
If direct signal lines are provided between wheel speed sensors and brake control devices, then reliability is improved, but device complexity increases
Solution Approach 1:
The wheel speed sensors are divided into two groups, with each group connected to a different brake control device via direct signal lines. This segmentation ensures that each control device has direct access to some sensor signals, improving reliability while distributing the signal line complexity across the system rather than requiring all sensors to connect to all controllers.
3Adaptability or versatility
If wheel speed sensors are divided into two groups read by different control devices, then fail-operation brake slip control is enabled, but measurement precision may be affected
Solution Approach 1:
The brake control devices use feedback from the wheel speed sensors to detect wheel slip conditions and adjust braking force accordingly. By dividing sensors into groups and providing direct signal lines, each control device receives real-time wheel speed data needed for feedback-based brake slip control, enabling this capability without compromising measurement precision.
Data Source
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AI summary
The invention relates to an electropneumatic brake system (2) for a utility vehicle (1), having wheel rotational speed sensors which are divided into two wheel rotational speed sensor groups (14A, 114A, 214A, 314A) that are read by a central brake controller or a second brake controller. In a braking operation, the central brake controller controls the wheel brakes and allows a slip control operation. If the central brake controller malfunctions, the second brake controller controls the wheel brakes and allows an alternative slip control operation.