Rail Vehicle Air Distribution Box Throttling

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Solution Overview

Problem

Existing air conditioning arrangements for rail vehicles require extensive testing to find suitable settings for air distribution boxes due to the non-linear properties of complex air duct arrangements, leading to increased effort in adjusting air volume flows.

Innovation Solution

Assigning each air outlet a throttle device formed by a perforated plate with specific pressure loss coefficients, allowing for rough adjustments of air volume flow ratios, reducing the need for extensive testing and fine adjustments across different rail vehicle configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If traditional air distribution boxes are used without individual throttling devices at each air outlet, then the device structure remains simple, but extensive testing and adjustment are required to achieve desired air volume flows due to non-linear air duct characteristics

Engineering Contradiction:
Improveadjustment timeVSAvoidthrottling device structure
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The air distribution box is segmented into multiple independent air outlets, each equipped with its own throttling device (perforated plate). This segmentation allows individual control of air volume flow at each outlet, enabling coarse adjustment without extensive system-wide testing and reducing the time required for air duct configuration adjustments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Throttling devices in the form of perforated plates are pre-installed at each air outlet before the air distribution box is put into operation. These preliminary installations provide initial coarse adjustment capabilities, allowing operators to quickly achieve desired air volume flows with minimal fine-tuning, thereby reducing overall adjustment time.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If adjustable louvers are used for throttling at air outlets, then some air flow control is achieved, but the non-linear properties of complex air duct configurations still require a large number of test steps

Engineering Contradiction:
Improveair flow control capabilityVSAvoidadjustment efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention changes the throttling parameter from adjustable louvers to fixed perforated plates with specific pressure loss coefficients. By selecting appropriate pressure loss coefficients for each perforated plate, the system achieves reliable coarse adjustment of air volume flows, reducing the number of test steps required while maintaining adaptability to different air duct configurations.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If fine adjustments are made downstream of air outlets to compensate for non-linear air duct characteristics, then desired air volume flows can be achieved, but the adjustment process becomes time-consuming and complex

Engineering Contradiction:
Improveair volume flow precisionVSAvoidadjustment simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

Perforated plates are introduced as intermediary throttling devices at each air outlet. These intermediaries provide coarse adjustment of air volume flows before the air enters the complex non-linear air duct system, reducing the magnitude of fine adjustments required downstream and simplifying the overall adjustment process while maintaining precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 significantly reduces the effort required to achieve desired air volume flows in air ducts by using perforated plates with rectifying properties to dampen non-linear effects, ensuring consistent performance across various rail vehicle designs.

Implementation Method 1

The pressure loss coefficients of the at least two throttling devices are selected such that a predetermined value results for a ratio of air volume flows at the at least two air outlets

Methodology Applied
Scientific EffectPressure loss: Pressure Drop

Implementation Method 2

The perforated plates can have a thickness-to-diameter ratio greater than 1.5. This has the advantage that the perforated plates act as a rectifier, further reducing the influence of non-linear airflow characteristics

Methodology Applied
Scientific EffectFlow rectification: Turbulence

Data Source

PatentEP2934982B1Air-conditioning assembly for a rail vehicle
Publication Date: 2019.09.18 SIEMENS MOBILITY GMBH
  • EP2934982B1 patent drawingFigure 1
  • EP2934982B1 patent drawingFigure 2

AI summary

The invention relates to an air-conditioning assembly for a rail vehicle, comprising an air distribution box (1), which has an air inlet (2) and at least two air outlets (5, 6) for connecting to outgoing air ducts, wherein a throttling device (7, 8) is associated with each air outlet (5, 6), which throttling device is arranged between the air outlet (5, 6) and an air division chamber (4) inside the air distribution box (1), in which air division chamber the air flow coming from the air inlet (2) is divided into at least two partial air flows, wherein pressure loss factors of the at least two throttling devices (7, 8) are selected in such a way that a specified value results for a ratio of volumetric air flows at the at least two air outlets (5, 6).