Inflatable Skirt Assembly for Railcar Gap Drag Reduction
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Solution Overview
Problem
Intermodal freight rail transportation experiences high fuel consumption due to aerodynamic drag caused by gaps between railcars and skin friction, leading to increased tractive effort and fuel usage, with existing solutions like rigid aerodynamic extensions being cumbersome and inefficient.
Innovation Solution
An aerodynamic control system using inflatable bladders or flexible sheets to fill gaps between vehicles, reducing drag by preventing air ingress and adapting to changing distances between vehicles during movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rigid aerodynamic extensions are added to railcars to reduce drag, then aerodynamic drag is reduced, but device complexity and operational complexity increase due to additional time and effort for adding and removing extensions
Solution Approach 1:
The patent applies the dynamics principle by replacing rigid aerodynamic extensions with a flexible skirt assembly that can dynamically adapt to the gap between railcars. The skirt assembly includes flexible material that can be inflated or deployed to fill the gap, allowing it to adjust to varying distances between cars without requiring manual addition or removal of rigid components.
Solution Approach 2:
The patent applies parameter changes by using an inflatable skirt assembly where the volume and shape of the aerodynamic component can be changed by adjusting the inflation level. This allows the skirt to adapt to different gap sizes between railcars by changing its physical parameters (volume, shape) rather than requiring physical assembly or disassembly of rigid structures.
2Loss of energy
If rigid aerodynamic extensions are added to railcars to reduce drag, then aerodynamic drag is reduced, but loss of time increases due to additional time for adding and removing extensions
Solution Approach 1:
The flexible skirt assembly can be quickly deployed or inflated to fill the gap between railcars, eliminating the time-consuming process of manually adding and removing rigid extensions. The dynamic nature of the skirt allows for rapid adjustment without requiring operational interruptions for assembly or disassembly.
Solution Approach 2:
The skirt assembly can be pre-configured or pre-inflated before the railcars are coupled or positioned, allowing the aerodynamic improvement to be in place before operation begins. This preliminary preparation eliminates the need for time-consuming on-site assembly of rigid extensions.
3Loss of energy
If rigid aerodynamic extensions are added to railcars to reduce drag, then aerodynamic drag is reduced, but manufacturing cost and storage expense increase
Solution Approach 1:
The patent uses flexible material in the form of an inflatable skirt assembly, replacing expensive and bulky rigid extensions. The flexible material can be stored in a compact deflated state and is less expensive to manufacture and store compared to rigid aerodynamic components, while still providing the necessary aerodynamic improvement when deployed.
Solution Approach 2:
The inflatable skirt assembly allows for compact storage when not in use, as it can be deflated to a small volume. This parameter change from inflated to deflated state enables economical storage and reduces the space required for storing aerodynamic components, unlike rigid extensions that require significant storage space regardless of usage state.
4Loss of energy
If rigid aerodynamic extensions are added to railcars to reduce drag, then aerodynamic drag is reduced, but tractive effort increases due to additional weight and resistance from extensions
Solution Approach 1:
The flexible skirt assembly uses thin, lightweight material that inflates to provide aerodynamic coverage without adding significant weight. This reduces the tractive effort required compared to rigid extensions, which would add substantial weight and require additional force to move the railcars.
Solution Approach 2:
The inflatable skirt assembly uses pneumatic pressure to create the aerodynamic shape, eliminating the need for heavy rigid structures. The pneumatic system allows the skirt to be inflated to the required shape without adding significant weight, thereby minimizing the increase in tractive effort while still reducing aerodynamic drag.
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 effectively reduces aerodynamic drag, enhancing fuel efficiency and reducing emissions by filling gaps and changing the shape of trailing ends of vehicles, thereby improving the overall performance of vehicle systems.
Implementation Method 1
a bladder configured to be inflated with a fluid by a fluid source disposed onboard the vehicle system to cause the skirt assembly to expand between the vehicles from a collapsed state to an expanded state
Implementation Method 2
The skirt assembly can reduce aerodynamic drag exerted on the vehicle system during movement of the vehicle system
Data Source
AI summary
An aerodynamic control system includes a skirt assembly configured to be disposed between plural vehicles in a vehicle system formed from the plural vehicles with the vehicles separated by a spatial gap in the vehicle system. The skirt assembly can include a bladder configured to be inflated with a fluid by a fluid source disposed onboard the vehicle system to cause the skirt assembly to expand between the vehicles from a collapsed state to an expanded state such that the skirt assembly at least partially fills the spatial gap between the vehicles. The skirt assembly can reduce aerodynamic drag exerted on the vehicle system during movement of the vehicle system relative to the vehicle system moving without the skirt assembly in the expanded state.