Tractor-Trailer Gap Fairing Structure for Drag Reduction

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Solution Overview

Problem

Current fairing structures for tractor-trailer combinations are either bulky and complex, making them difficult to install and impede access, or less effective in reducing aerodynamic drag at the leading forward face of the trailer box, especially under crosswind conditions.

Innovation Solution

A vehicle fairing structure with a top surface and two side surfaces that attach to the roof and sides of the trailer box, respectively, positioned to redirect airflow and fill the gap between the tractor cab and trailer box, reducing transverse and vertical airflow and thus aerodynamic drag by curving inward to form a smaller bounded area within the shear layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If known fairing structures are designed to direct airflow around the gap, then aerodynamic drag is reduced, but the structures become bulky and complex involving moving parts

Engineering Contradiction:

Improveaerodynamic dragVSAvoidfairing structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The fairing structure is divided into multiple panels (front panel, side panels, rear panel) that can be separately manufactured and assembled. Each panel is a discrete component that collectively forms the complete fairing, simplifying manufacturing and installation while maintaining aerodynamic effectiveness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using complex moving parts to adapt to crosswind conditions, the invention uses fixed panels with specific geometric configurations that passively accommodate various wind conditions. The panels are positioned to create aerodynamic efficiency without requiring active adjustment mechanisms

Inventive Principle:

Principle #13The other way round (Inversion)

2Loss of energy

If known fairing structures are designed to direct airflow around the gap, then aerodynamic drag is reduced, but they are difficult to install and impede access to important parts

Engineering Contradiction:

Improveaerodynamic dragVSAvoidinstallation ease and access

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

The fairing is segmented into multiple removable panels that can be independently installed and removed. This allows for easier handling during installation and maintenance, and provides access to components behind the fairing when panels are removed

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The panels are pre-configured with attachment mechanisms and geometric shapes that facilitate straightforward installation. The front panel is designed to attach to the trailer box front face, and side panels are pre-formed to connect to both the front panel and trailer sides, streamlining the installation process

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If a less obtrusive fairing structure is used, then installation is easier and access is improved, but it is less effective in redirecting wind and more susceptible to crosswind conditions

Engineering Contradiction:

Improveinstallation ease and accessVSAvoidaerodynamic performance in crosswind

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Different panels are designed with specific local geometries optimized for their positions. The front panel has a specific shape to manage airflow at the gap, side panels are configured to handle lateral airflow, and the rear panel is designed to manage flow separation. Each panel's local geometry contributes to overall aerodynamic effectiveness

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The panels incorporate curved surfaces rather than flat planes, with the front panel featuring a rounded leading edge and the side panels having curved profiles. These curved surfaces smoothly guide airflow around the gap and reduce turbulence, improving aerodynamic performance while maintaining a compact structure

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

Effectively reduces aerodynamic drag by smoothing airflow around the trailer box, minimizing drag and preventing air from entering the gap, even in crosswind conditions, while being less obtrusive and easier to install.

Implementation Method 1

The amount of power needed to move a vehicle over land or through the air increases with the speed of the vehicle due to aerodynamic drag

Methodology Applied

Scientific EffectAerodynamic drag: Drag

Implementation Method 2

the external faces of the fairing structure, when positioned adjacent the rear vehicular component of the vehicle in the gap, re-directs air from the rear vehicular component and also impedes or otherwise lessens vertical and transverse air flow in the gap

Methodology Applied

Scientific EffectAirflow redirection:

Data Source

PatentUS7604284B2Vehicle fairing structure

Publication Date: 2009.10.20 ZF COMPOSITES NORTH AMERICA LTD

AI summary

A vehicle fairing structure has a top fairing surface adapted to be attached to a trailer box, and first and second side fairing surfaces adapted to be attached to the sides of the trailer box, in the gap between a tractor cab and a trailer box in a tractor-trailer combination. The fairing structure directs air flow away from the gap, and is positioned in the gap to lessen aerodynamic drag, thereby reducing fuel consumption.