Rail Brake Speed Control Using Friction Temperature Prediction
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Solution Overview
Problem
Rail vehicles face the risk of increased braking distances due to brake fade caused by high brake application speeds, which can lead to overheating of friction braking systems, especially when electrodynamic brakes fail, compromising safety and limiting travel speed.
Innovation Solution
A method to determine an optimum or maximum-permissible speed based on the thermal condition of friction elements, using a predictive temperature model to estimate the temperature increase during defined braking modes, ensuring the friction elements do not exceed their maximum temperature, thereby preventing brake fade and allowing safe operation at higher speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If friction braking is used at high brake application speeds, then the rail vehicle can maintain high travel speed, but the temperature increase of brake disks and brake pads increases causing brake fade and increased braking distances
Solution Approach 1:
The system performs preliminary thermal calculations before braking occurs to predict temperature increases. By calculating the thermal state in advance based on current operating conditions, the system can determine the maximum permissible speed that prevents brake fade, thus maintaining reliability while allowing optimal travel speed.
Solution Approach 2:
The system continuously monitors actual temperature values during operation and compares them with calculated thermal states. This feedback mechanism allows the system to adjust the maximum permissible speed dynamically, ensuring braking performance remains reliable while maximizing travel speed within thermal limits.
2Reliability
If the maximum permissible speed is limited to prevent overheating, then the thermal condition of friction elements is safe, but the rail vehicle cannot travel at the highest possible speed
Solution Approach 1:
The system dynamically adjusts the maximum permissible speed based on real-time thermal conditions and operating parameters. Rather than using a fixed speed limit, the system continuously recalculates the optimal speed threshold that maximizes travel performance while maintaining thermal safety, allowing the vehicle to travel at the highest possible speed within safe thermal boundaries.
3Duration of action of stationary object
If electrodynamic brakes are used to reduce wear on friction braking system, then friction element lifespan is extended, but the system becomes more complex and less reliable when electrodynamic brakes fail
Solution Approach 1:
The system replaces complex electrodynamic braking with a simplified thermal management approach. By using thermal calculations to control friction braking operations, the system extends friction element lifespan through optimized usage patterns without requiring complex electrodynamic systems, thereby reducing overall system 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
Ensures safe and efficient travel by maintaining friction element temperatures below critical levels, enabling the rail vehicle to operate at the highest possible speed without risking overheating or brake failure, thus enhancing safety and performance.
Implementation Method 1
braking, in particular service braking, may have to be performed primarily or exclusively using the friction braking system... the higher the energy input and thus the temperature increase of the brake disks and brake pads
Data Source
AI summary
A method for determining an optimum or maximum-permissible speed of a rail vehicle, dependent on a thermal state of at least one friction element of at least one friction brake of includes detecting at least one parameter which characterizes a current operating situation of the rail vehicle, determining or estimating a first influence on the thermal state of the at least one friction element based on the current operating situation of the rail vehicle, determining or estimating a second influence on the thermal state of the at least one friction element, determining the optimum or maximum-permissible speed of the rail vehicle in such a way that an allowed friction-element maximum temperature of the at least one friction element is not exceeded, or the allowed friction-element maximum temperature of the at least one friction element is substantially obtained, at the at least one friction element under the first or second influence.