Vehicle Deflector System for Aerodynamic Drag Reduction
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Solution Overview
Problem
Conventional truck designs, particularly the sharp angle at the leading edge of the hood, result in significant pressure drag and turbulence, leading to increased energy expenditure, reduced fuel efficiency, and increased deposition of road grime on the windshield, impairing visibility and increasing maintenance costs.
Innovation Solution
A drag reduction system featuring a pair of deflectors, one positioned near the interface of the vertical grille and horizontal hood, and another near the rearward end of the hood, which redirect and deflect the air stream outwardly and downwardly, minimizing pressure drag and turbulence, and reducing the recirculation of debris onto the windshield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sharp angle is used at the leading edge of the hood, then the structure is simple and manufacturing is easy, but pressure drag increases significantly
Solution Approach 1:
The patent applies curvature by replacing the sharp angle at the hood's leading edge with a rounded transition. This curved geometry allows the air stream to flow more smoothly over the hood, reducing flow separation and turbulence while maintaining structural simplicity and ease of manufacture.
2Device complexity
If a sharp angle is used at the leading edge of the hood, then the structure is simple, but aerodynamic drag increases
Solution Approach 1:
The rounded leading edge geometry reduces aerodynamic drag by enabling smoother airflow attachment to the hood surface, minimizing energy loss from turbulence and wake formation while preserving structural simplicity.
3Stability of the object's composition
If the air stream creates turbulence in the wake region, then the flow pattern is formed, but road grime deposition on the windshield increases
Solution Approach 1:
The rounded leading edge reduces wake turbulence and improves airflow stability, which decreases the recirculation of road grime particles onto the windshield while maintaining necessary flow pattern formation for aerodynamic efficiency.
4Stability of the object's composition
If the air stream separates at the hood leading edge, then the wake region forms, but fuel efficiency decreases
Solution Approach 1:
The rounded leading edge geometry reduces flow separation and minimizes wake region formation, thereby reducing the energy required to move the vehicle through air while maintaining necessary airflow patterns for vehicle functionality.
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 reduces aerodynamic drag, lowers fuel consumption, minimizes windshield turbulence and debris deposition, and enhances windshield wiper performance and visibility, thereby improving safety and reducing operational costs.
Implementation Method 1
The amount of energy expended depends in large part on the aerodynamic drag force exerted on the vehicle by the air
Implementation Method 2
Pressure drag results from the net pressure forces exerted as the air flows around the vehicle
Implementation Method 3
it separates at a leading edge 16 of the hood 18, thereby forming a highly turbulent or wake region 22 of air located directly above the top surface of the hood and aft of the leading edge 16
Data Source
AI summary
A drag reduction system generally comprises a pair of deflectors that conjunctively compensate for the angular designs typical of currently existing vehicles. In one embodiment, the pair of deflectors includes a first deflector positioned proximate the interface between the vertical grille and the hood, for example, near the upper end of the grille crown at the forward end of the hood and a second deflector positioned on the upper hood surface toward the rearward end of the hood, forwardly of the windshield. The first and second deflectors and function in concert, twice maneuvering an air stream to both avoid direct impact with the vehicle and to displace the stream laterally in such a manner that minimizes the amount of work energy expended in its redirection. In one example, the drag reduction system tailors the air stream around the hood and cab sections of the vehicle.