Fail-Safe Pneumatic Brake Valve Assembly With Limited Redundancy Pressure
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Solution Overview
Problem
Existing electronically controllable pneumatic braking systems for commercial vehicles face challenges in ensuring safe braking and stopping, especially when redundant systems or levels fail, requiring a solution that optimizes cost and structural space while maintaining safety.
Innovation Solution
An electropneumatic assembly with a failure supply port and a failure safety-valve arrangement that delivers a limited redundancy brake pressure, utilizing a monostable valve and potentially an electromagnetic bistable valve, to ensure safe braking even if primary systems fail, by providing a redundancy brake pressure through a failure supply pressure that is lower than the reservoir pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex redundant braking system with multiple independent systems and dual electrical energy sources is implemented, then the reliability and residual availability improve, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent implements a fail-safe valve arrangement that automatically activates upon detection of system failures (electrical or pneumatic). This beforehand cushioning mechanism ensures that even when primary and redundant systems fail, the vehicle can still be brought to a safe stop through automatic activation of the fail-safe valve, which delivers brake pressure without requiring electrical energy or complex control systems.
Solution Approach 2:
The fail-safe valve arrangement uses a simple, cost-effective design that sacrifices complexity for reliability. The monostable or bistable valve is designed to be activated only in failure scenarios, using a limited amount of stored pneumatic energy rather than requiring continuous electrical power or complex electronic control systems.
2Reliability
If multiple independent redundant systems with dual electrical energy sources are used, then the reliability improves, but the manufacturing cost and structural space requirements increase
Solution Approach 1:
The patent merges the fail-safe braking function into the existing redundant braking system by integrating a fail-safe valve arrangement in the pneumatic line between the second compressed-air reservoir and the redundant brake-pressure generator. This integration allows the system to use existing components (compressed-air reservoirs, pneumatic lines) while adding a simple fail-safe valve mechanism, rather than implementing completely separate redundant systems.
Solution Approach 2:
The second compressed-air reservoir serves multiple functions: it provides pneumatic energy for the redundant braking system during normal operation and serves as an energy source for the fail-safe valve arrangement in case of electrical or pneumatic failures. This multi-functionality reduces the need for separate dedicated failure-safety components.
3Reliability
If a fail-operational state with multiple redundant systems is implemented, then the safety level improves, but the device complexity and structural space increase
Solution Approach 1:
The fail-safe valve arrangement is nested within the existing redundant braking system architecture. The fail-safe valve is positioned in the pneumatic line between the second compressed-air reservoir and the redundant brake-pressure generator, utilizing the existing structural framework and pneumatic pathways rather than requiring separate dedicated space for failure-safety components.
4Ease of manufacture
If limited failure supply pressure is used instead of full reservoir pressure, then the ease of manufacture and structural space improve, but the braking force is reduced
Solution Approach 1:
The fail-safe valve arrangement changes the pressure parameter from full reservoir pressure to a limited failure supply pressure (typically 2-8 bar instead of 10-12 bar). This parameter change is achieved through the design of the monostable or bistable valve, which is configured to deliver a reduced but sufficient brake pressure for safe stopping in failure scenarios, balancing simplicity with adequate braking performance.
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 solution enables safe deceleration and stopping of the vehicle in case of system failures, maintaining safety without the need for complex systems or excessive components, by using a limited failure supply pressure to deliver redundancy brake pressure effectively.
Implementation Method 1
The failure safety-valve arrangement (14) has at least a first monostable failure brake valve (16) and, optionally, an electromagnetic bistable failure brake valve (18)
Implementation Method 2
The electropneumatic assembly (1) has a failure supply port (10) for receiving a failure supply pressure (pAV), which is limited with respect to and lower than the reservoir pressure (pV)
Data Source
AI summary
An electropneumatic assembly is for an electronically controllable pneumatic braking system for a commercial vehicle. The electropneumatic assembly includes a reservoir port for receiving a reservoir pressure, at least one redundancy brake-pressure port for providing a redundancy brake pressure for a first axle and/or a trailer of the vehicle, a failure supply port for providing a failure supply pressure that is limited with respect to and lower than the reservoir pressure, and a failure safety-valve arrangement, which is connected to the failure supply port and the redundancy brake-pressure port, and which has a failure brake valve that is realized as a monostable valve and can be switched in the event of a fault in order, based on the failure supply pressure, to deliver the redundancy brake pressure at the redundancy brake-pressure port.