Selected Axle Conditioning for Rail Vehicle Adhesion Control
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Solution Overview
Problem
Rail vehicles face challenges in transmitting sufficient brake forces due to varying friction characteristics between wheels and rails, leading to issues like sliding or spinning, especially on wet or greasy surfaces, which limits the maximum forces that can be transmitted.
Innovation Solution
The method involves conditioning selected axles by regulating wheel slip and applying local measures such as sanding or electromagnetic rail brakes to improve adhesion characteristics, allowing for increased brake forces to be transmitted across the rail vehicle by optimizing friction conditions between wheels and rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If brake force is increased on wet or greasy rails, then braking performance improves, but wheel sliding occurs reducing effective brake force
Solution Approach 1:
The system applies preliminary actions by detecting deteriorating adhesion conditions (wet or greasy rails) before complete sliding occurs, and preemptively adjusts brake forces or applies adhesion improvement measures (sand, gravel, or electromagnetic braking) to prevent wheel lock-up and maintain reliable braking performance
Solution Approach 2:
The system changes physical parameters by introducing sand or gravel particles to alter the friction characteristics between wheel and rail, or by using electromagnetic brakes to change the braking mechanism from friction-based to electromagnetic-based, thereby improving adhesion on wet or greasy rails without causing sliding
2Power
If acceleration force is increased, then acceleration performance improves, but wheel spinning occurs reducing effective tractive force
Solution Approach 1:
The system detects deteriorating adhesion conditions before complete spinning occurs and preemptively reduces acceleration forces or applies adhesion improvement measures to prevent wheel spin-up and maintain reliable acceleration performance
Solution Approach 2:
The system introduces sand or gravel particles to change the friction characteristics between wheel and rail, or uses electromagnetic propulsion to change the driving mechanism, thereby improving traction on wet or greasy rails without causing wheel spinning
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
This approach enhances the overall brake force capability of the rail vehicle by improving friction characteristics across all units, even if initial units experience a decrease in brake force, thereby ensuring safer and more effective braking performance.
Implementation Method 1
electromagnetic rail brakes
Implementation Method 2
sanding or electromagnetic rail brakes to improve adhesion characteristics
Data Source
AI summary
A method for improving the adhesion of a rail vehicle by conditioning selected axle(s), detects whether a higher total brake force can be achieved by changing the manipulated variable of the wheel slip at at least one unit from a current starting wheel slip to a forced wheel slip, and, if so, changes the wheel slip at at least one unit from the current starting wheel slip to the forced wheel slip by regulating the manipulated variable of the brake application force at the unit, whereby the friction ratios between the wheel and the rail changes at the subsequent units, and regulates the manipulated variable of the brake application force at the subsequent units to regulate the wheel slip, which is likewise changed by the changed friction ratios, at the units back to the unchanged manipulated variable of the starting wheel slip, optimized brake forces being produced at the units.