Rail Vehicle Hand Brake Control System Prolonging Pneumatic Release
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Solution Overview
Problem
Existing automatic hand brake systems for rail vehicles do not ensure full release of the parking hand brake due to transient activation of pneumatic cylinders, leading to potential incomplete brake release.
Innovation Solution
A control system that includes a manual valve connected to a source of pressure, a volume, and a choke to prolong the activation of the pneumatic cylinder, ensuring the hand brake is fully released by maintaining pressure for a predetermined period after manual activation, using a combination of pneumatic valves and a manifold to interconnect the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pneumatic cylinder is activated by manual valve only, then the system is simple, but the brake release is incomplete due to transient activation
Solution Approach 1:
The system pre-charges a volume with pressure from the source through the manual valve before the pneumatic cylinder actually activates. This preliminary charging action ensures that when the cylinder needs to activate, sufficient pressure is already available in the volume, preventing transient activation and ensuring complete brake release.
Solution Approach 2:
A choke is introduced as an intermediary component between the volume and exhaust. This choke restricts the flow rate, causing the pressure in the volume to decrease gradually over time. The choke mediates the pressure release process, extending the activation duration of the pneumatic cylinder to ensure complete brake release.
2Reliability
If the activation time is extended to ensure full release, then the brake release is complete, but the response time is delayed
Solution Approach 1:
The system performs preliminary charging of the volume during normal operation, so when brake release is required, the pressure is already prepared. This eliminates the need for time-consuming pressure buildup during the release operation, maintaining fast response while ensuring complete release through the pre-charged volume.
Solution Approach 2:
The system uses periodic or phased pressure application: first charging the volume through the manual valve, then using that stored pressure to activate the pneumatic cylinder through the first pneumatic valve. This phased approach separates the pressure buildup phase from the release execution phase, achieving both speed and completeness.
3Reliability
If manual valve is held activated for prolonged period, then the brake releases fully, but the operation complexity increases
Solution Approach 1:
The system makes the manual valve self-servicing by using it to charge the volume, which then automatically maintains pressure in the pneumatic cylinder through the choke's flow restriction. The manual valve doesn't need to be held activated; it only needs brief activation to charge the volume, after which the system self-regulates the prolonged pressure maintenance.
Solution Approach 2:
The choke creates a feedback mechanism where the decreasing pressure in the volume over time automatically regulates the pneumatic cylinder activation duration. As pressure drops through the choke, the system naturally terminates activation when pressure falls below the threshold, providing automatic feedback control without requiring continuous manual input.
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 ensures complete release of the hand brake by prolonging the activation of the pneumatic cylinder, preventing undesired release and ensuring safety by maintaining pressure for 5 to 10 seconds after manual activation.
Implementation Method 1
A choke connects the volume to exhaust. The volume and the choke prolong the time the source of pressure is connected to the pneumatic cylinder after the manual valve is activated.
Data Source
AI summary
In a rail vehicle hand brake having a release activated by a pneumatic cylinder, the present control system includes a manual valve having an output connected to a source of pressure at an input when manually activated. A volume is to be charged by the source of pressure. A choke connects the volume to exhaust. The volume and the choke prolong the time the source of pressure is connected to the pneumatic cylinder after the manual valve is activated.