Electro-pneumatic Brake Control System with Mechanical Parking Brake Backup
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Solution Overview
Problem
Existing electro-pneumatic brake systems for vehicles are complex and prone to errors, particularly in scenarios where electronic defects occur, making it difficult to apply the parking brake independently of the electronic controller.
Innovation Solution
A monostable, pneumatically actuated control valve is introduced, which can vent the spring-loaded brake cylinder using a service brake actuation element, and a series-connected electrically actuated control valve ensures the venting only occurs in the event of an electronic defect, along with a select-high valve for anti-compound function and spring-loaded 2/2-way valves for simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an electronic control unit is used to control the parking brake, then the brake system can be automated and controlled electronically, but the system becomes vulnerable to electronic failures and the driver cannot apply the parking brake independently
Solution Approach 1:
The brake control system is divided into separate functional segments: the electronic control unit for normal operation and the mechanically actuated control valve for emergency operation. This segmentation allows the parking brake to be controlled electronically under normal conditions while maintaining independent mechanical actuation capability during electronic failures.
Solution Approach 2:
A dual-mode control valve is introduced as an intermediary device that can operate in two modes: electronically actuated during normal operation and mechanically actuated during electronic failure. This intermediary component bridges the gap between electronic control and mechanical backup, ensuring continuous functionality.
2Reliability
If a mechanically actuated control valve is added for emergency parking brake application, then reliability during electronic failure is improved, but the device complexity increases
Solution Approach 1:
The control valve is designed with multi-functionality, capable of being actuated both electronically and mechanically. This universal design eliminates the need for completely separate systems for normal and emergency operation, reducing overall complexity while maintaining reliability.
Solution Approach 2:
The electronic and mechanical actuation mechanisms are merged into a single control valve assembly. The mechanical actuation interface is integrated with the electronic control port, allowing one component to fulfill multiple functions and reducing the total number of parts.
3Ease of operation
If the control valve is designed to be always open for mechanical actuation, then ease of operation is improved, but accidental activation during normal operation becomes possible
Solution Approach 1:
The control valve transitions from a static always-open design to a dynamic design that adapts its state based on operating conditions. During normal operation, the valve is electronically controlled to remain closed. During electronic failure, the valve automatically becomes accessible to mechanical actuation, providing ease of operation only when needed.
Solution Approach 2:
The system incorporates preliminary protective measures by electronically controlling the valve to remain closed during normal operation, preventing accidental activation. The mechanical actuation path is prepared in advance but blocked by the electronic control, allowing easy activation only when electronic control fails.
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
Enables the application of the parking brake with minimal technical effort, even in the absence of an electronic controller, preventing accidental activation during power failures and ensuring safe braking.
Implementation Method 1
a spring-loaded brake cylinder, which can be filled and vented independently of an electronic controller
Implementation Method 2
a monostable, pneumatically actuated control valve, comprising a control connection controlled by the service brake supply line
Implementation Method 3
Relay valve connected on the output side to the spring-loaded brake cylinder and controlled by the control line, for outputting the air pressure present in the control line
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an electro-pneumatic brake control system (1) of a vehicle, comprising an electronic control unit (7) for actuating an electro-pneumatic parking brake valve arrangement (5) supplied with compressed air by a compressed air supply unit (2), a control line (8) emerging therefrom for controlling the compressed air supply and ventilation of a spring brake cylinder (12), a relay valve (6) connected via a supply line (10) to the compressed air supply unit (2) on the input side, and to the spring brake cylinder (12) on the output side, and actuated by the control line (8), for outputting the air pressure applied in the control line (8), and a manually operable, mechanical operating brake actuating element (15) for controlling the compressed air feed and ventilation of an operating brake cylinder (16) via an operating brake supply line (14). In a stable switching state, a mono-stable, pneumatically actuatable control valve (19), comprising a control terminal (21) actuated by the operating brake supply line (14), separates an air outlet opening (20) on the output side terminating into the atmosphere and an venting line (17) on the input side from one another, and in an unstable switching state connects the same with one another. The venting line (17) is suited to vent the spring brake cylinder (12) by actuating the operating brake actuating element (15).