Trailer Aerodynamic Fairings and Diffuser Drag Reduction
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Solution Overview
Problem
Heavy-duty vehicle trailers experience significant drag due to their tall and wide box-shaped profile, leading to increased fuel consumption, and existing drag reduction devices have limitations in effectiveness and integration into fleet operations.
Innovation Solution
The implementation of an aerodynamic rain gutter component, fairings positioned around wheels, aerodynamically shaped wings on axles, and a rear diffuser to direct air smoothly around and underneath the trailer, reducing the wake size and increasing pressure behind the trailer, thereby minimizing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a tall and wide box-shaped profile is used for cargo trailers, then cargo space is maximized, but drag increases significantly
Solution Approach 1:
The trailer is divided into multiple cross-sectional sections along its length, with each section having independently adjustable height. This allows the trailer to maintain a box-shaped cargo space while reducing drag by lowering the profile at certain sections, particularly toward the rear.
Solution Approach 2:
The trailer incorporates adjustable height mechanisms that allow the cross-sectional height to be changed dynamically. The height can be adjusted based on operational conditions - maximized when cargo space is needed and reduced when drag reduction is the priority, such as when traveling without full cargo load.
2Force
If traditional tandem axles with pairs of wheels are used, then load capacity is sufficient, but rolling resistance and drag increase
Solution Approach 1:
One wheel is removed from each tandem axle pair, transitioning from a traditional 8-wheel trailer configuration to a 6-wheel configuration. This extraction of redundant wheels reduces rolling resistance and aerodynamic drag while maintaining sufficient load capacity through the remaining wheels and optimized axle distribution.
3Weight of moving object
If single wide tires replace traditional tire pairs, then vehicle weight is reduced, but wheel component drag remains significant
Solution Approach 1:
Aerodynamic fairings are applied specifically to the wheel components to reduce drag locally. These fairings streamline the airflow around the wheels and other protruding components underneath the trailer, addressing the drag problem at its source without requiring changes to the entire vehicle structure.
Solution Approach 2:
Aerodynamic fairings act as intermediary structures between the wheels and the surrounding air flow. These fairings modify the airflow pattern around the wheels and other undercarriage components, reducing turbulence and drag while allowing the wheels to maintain their functional design.
4Reliability
If landing gear is installed on the trailer, then trailer support capability is improved, but drag increases
Solution Approach 1:
A flexible drag reduction cover is used to enclose the landing gear when it is in the stowed position. This cover streamlines the airflow around the landing gear structure, reducing drag while allowing the landing gear to maintain its support function when deployed. The cover can be adjusted or removed when landing gear functionality is required.
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 configuration results in a 10% reduction in drag, translating to a 5.5% improvement in fuel efficiency for tractor-trailer systems, as demonstrated by computational fluid dynamics modeling and SAE J1321 testing.
Implementation Method 1
an aerodynamic rain gutter component, fairings positioned around wheels, aerodynamically shaped wings on axles, and a rear diffuser to direct air smoothly around and underneath the trailer, reducing the wake size and increasing pressure behind the trailer, thereby minimizing drag
Implementation Method 2
increasing the pressure in the wake
Data Source
AI summary
A vehicle trailer is provided. The vehicle trailer includes one or more side wall fairings having a leading edge and trailing edge. Each side wall fairing has an upward incline and downward incline. The side wall fairings can be utilized with one or more other components that are described herein.