Rail Eddy Current Brake Control via Dynamic Thermal Limits

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Solution Overview

Problem

Eddy current brakes on rail vehicles generate excessive heat in rails, leading to mechanical stress and temperature-related issues, limiting their use, especially in areas with frequent braking and solar radiation, and interfering with safety technology like axle counters.

Innovation Solution

A method to determine and manage the maximum permissible braking force of rail braking systems, particularly eddy current brakes, by collecting and distributing data on energy inputs and rail temperatures across a route section, allowing for controlled use to prevent overheating and ensuring compatibility with existing safety systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If eddy current brakes are used for service braking, then braking performance is improved and wear is eliminated, but rail temperature increases causing mechanical stress and positional instability

Engineering Contradiction:
Improvebraking performanceVSAvoidrail temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The system continuously monitors rail temperature and braking operations, using this feedback to dynamically adjust braking force limits. The evaluation device receives data about performed braking operations and current rail temperature, then determines maximum permissible braking forces accordingly, creating a closed-loop control system that prevents excessive heating while maintaining braking effectiveness

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The maximum permissible braking force is not fixed but dynamically adjusted based on real-time rail temperature conditions and historical braking data. The system adapts braking parameters according to current thermal state, allowing optimal braking performance while preventing temperature-related damage to the rail infrastructure

Inventive Principle:
Principle #15Dynamics

2Productivity

If eddy current brakes are used in areas with frequent braking operations, then braking capacity is increased, but thermal accumulation impairs track stability

Engineering Contradiction:
Improvebraking capacityVSAvoidtrack stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The system evaluates historical braking operation data and current thermal conditions before permitting additional braking operations. By assessing past braking forces and timing, the system predicts thermal accumulation trends and preemptively adjusts maximum permissible braking forces to prevent thermal buildup that would compromise track stability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from recorded braking operations and temperature measurements to continuously refine braking force limitations. This closed-loop approach ensures that braking capacity is optimized while maintaining track stability by preventing excessive thermal accumulation from frequent braking operations

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If eddy current brakes are deployed without restrictions, then service braking capability is enhanced, but magnetic fields disrupt safety technology like axle counters

Engineering Contradiction:
Improveservice braking capabilityVSAvoidmagnetic field interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system applies different braking force limitations to different route sections based on their specific characteristics. Route sections with safety technology susceptible to magnetic field interference receive restricted braking permissions, while other sections allow full service braking capability. This localized approach enables service braking enhancement without compromising safety technology operation

Inventive Principle:
Principle #3Local quality

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 use of eddy current brakes for service braking on routes previously restricted due to thermal concerns, while avoiding excessive heat buildup and minimizing disruptions to safety technology, thereby expanding their operational flexibility.

Implementation Method 1

Eddy currents are generated in the rail by an electromagnet in an eddy current brake on a rail vehicle. The eddy currents generate a magnetic field that counteracts the external field according to Lenz's law.

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

Eddy currents are generated in the rail by an electromagnet in an eddy current brake on a rail vehicle.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

The eddy currents generate a magnetic field that counteracts the external field according to Lenz's law.

Methodology Applied
Scientific EffectLenz's law:

Implementation Method 4

the braking energy to be dissipated is converted into heat in the rails. The rail is subjected to high thermal loads as a result of this energy input.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3145764B1Method for controlling the use of track brake systems, in particular eddy current brake systems, of rail vehicles operated in a railway network
Publication Date: 2018.04.11 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP3145764B1 patent drawingFigure 1
  • EP3145764B1 patent drawingFigure 2~3
  • EP3145764B1 patent drawing

AI summary

The invention relates to a method for controlling the use of track brake systems, in particular eddy current brake systems, of railway vehicles operated in a railway network, in at least one predetermined track section, in which method the railway vehicles transmit to a central data collection station, when the track brake systems are used in the track section, a set of data corresponding to the location, time and braking power of the track brake actuation, in particular of the eddy current brake actuation, and a maximum allowed braking power of the track brake system for braking with the track brake system a following railway vehicle travelling in the track section is determined on the basis of the sets of data for the track section collected within a predetermined period of time, such tat a maximum admissible track temperature is not exceeded.