Reversal Relay Valve Venting for Redundant Spring Brake Release
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Solution Overview
Problem
Existing electropneumatic brake systems for vehicles, particularly utility vehicles, face challenges in ensuring reliable ventilation of spring brake cylinders even in redundancy situations, often requiring complex assembly and potentially restricted system dynamics.
Innovation Solution
An electronically controllable pneumatic brake system with a parking brake device incorporating a reversal relay valve that allows ventilation of spring brake cylinders through two independent paths, utilizing a reversal relay valve with multiple control connections and an electropneumatic valve arrangement independent of the service brake system, ensuring fail-safe operation even in fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single control path is used for ventilating spring brake cylinders, then the system structure is simple, but the reliability is reduced because ventilation cannot be ensured in fault situations
Solution Approach 1:
The control system is segmented into two independent control paths: a primary control path through the parking brake module and a secondary control path through the electropneumatic valve arrangement. This segmentation allows the system to maintain ventilation capability even if one path fails, resolving the contradiction between reliability and complexity by distributing control functions across separate pathways.
Solution Approach 2:
The system changes the control parameter from a single pressure source to multiple independent pressure sources (parking brake pressure and service brake pressure). By allowing different pressure parameters to control the same ventilation function through different paths, the system achieves enhanced reliability without proportionally increasing overall complexity.
2Reliability
If complex assembly measures are implemented to ensure redundant ventilation paths, then the reliability improves, but the ease of manufacture deteriorates
Solution Approach 1:
The reversal relay valve is designed with multi-functionality, serving both as a control element for the spring brake cylinder ventilation and as a integration point for multiple pressure sources. This universal component approach allows redundant control paths to be implemented without requiring entirely separate valve assemblies, thereby improving reliability while maintaining ease of manufacture through component consolidation.
Solution Approach 2:
The system merges the primary control path (parking brake module) and secondary control path (electropneumatic valve arrangement) at the reversal relay valve. By combining multiple control functions into a single valve assembly that accepts multiple pressure inputs, the system achieves redundant ventilation capability without requiring separate complete control assemblies, thus improving manufacturability.
3Reliability
If independent electropneumatic valve arrangement is added for secondary control path, then the reliability of ventilation is improved, but the device complexity increases
Solution Approach 1:
The reversal relay valve acts as an intermediary element that mediates between the two independent control paths (parking brake module and electropneumatic valve arrangement) and the spring brake cylinder. This intermediary component allows the system to incorporate redundant control paths without requiring direct complex interconnections between all components, thereby managing device complexity while maintaining reliability.
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
The system enables reliable and efficient ventilation of spring brake cylinders, ensuring safe parking and braking functions even in the event of faults, reducing assembly complexity and enhancing system dynamics.
Implementation Method 1
The reversal relay valve (4) has a first control connection (p43), a second control connection (p42), a working connection (p2), at least one first reservoir connection (p11) and a vent (p3). The first control connection (p43) is connected to the parking brake pressure connection (p52) in order to receive the parking brake pressure (pF).
Implementation Method 2
The second control connection (p42) is connected to an electropneumatic valve arrangement (6) in order to receive a second control pressure (pS2), wherein the electropneumatic valve arrangement (6) is actuated by an electronic control unit (ECU 2) which is independent of the parking brake module (2).
Implementation Method 3
The parking brakes operate under the action of spring force, can be released by pressurization of spring brake cylinders, and can be arrested by ventilation.
Data Source
AI summary
An electronically controllable pneumatic brake system for a vehicle includes a first service brake circuit having a pressure modulator and an electronic service brake control unit. The brake system furthermore includes a parking brake device having a parking brake module and a reversal relay valve for pressurizing and ventilating at least one first spring brake cylinder. The reversal relay valve has a first control connection, a second control connection, a working connection, a reservoir connection and a vent. The second control connection is connected to an electropneumatic valve arrangement in order to receive a second control pressure. The valve arrangement is actuated by an electronic control unit independent of the electronic service brake control unit. The reversal relay valve is configured to ventilate the spring brake cylinder in a situation wherein the first and second control connection are pressurized and a reservoir pressure prevails at the first reservoir connection.