Rear Fairing System with Hinged Sidewall Foils for Vehicle Aerodynamics
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Solution Overview
Problem
Rear fairings on vehicles are inconvenient for accessing loads and vulnerable to damage when backing, as they can interfere with rear cargo doors and are susceptible to impact during docking.
Innovation Solution
Vertically hinged sidewall foils and tension linkages that strain the foils toward the vehicle rear doors when closed, allowing them to deform elastically and compress against the vehicle, preventing damage while maintaining aerodynamic performance and minimizing extension behind the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rear fairings are installed to reduce drag, then aerodynamic efficiency is improved, but the fairings interfere with rear cargo door access and are vulnerable to impact damage
Solution Approach 1:
The fairing system employs a dynamic design where sidewall foils are hinged to pivot between a fairing position (reducing drag) and a retracted position (allowing door access). The tension linkage system dynamically adjusts foil position based on door state, enabling the fairing to adapt its configuration between operational modes.
Solution Approach 2:
The fairing system is divided into separate modular components: sidewall foils, roof fairings, and tension linkages. This segmentation allows independent movement and positioning of each component, enabling the sidewall foils to pivot independently for door access while maintaining roof fairing position for drag reduction.
2Loss of energy
If rear fairings are installed to reduce drag, then aerodynamic efficiency is improved, but the fairings are vulnerable to impact damage when backing to dock
Solution Approach 1:
The fairing system transitions from a static rigid structure to a dynamic compliant system. The hinged sidewall foils can pivot and the tension linkages can slacken, allowing the fairing to dynamically absorb impact forces through controlled deformation rather than rigid resistance, preventing structural damage.
Solution Approach 2:
The system changes its mechanical parameters (stiffness, position) in response to impact conditions. During normal operation, the fairing maintains its aerodynamic shape with high stiffness. During impact, the parameters change as foils pivot and linkages slacken, transforming the fairing into a compliant structure that absorbs impact energy.
3Loss of energy
If sidewall foils are positioned to maximize drag reduction, then aerodynamic performance is improved, but the foils extend excessively beyond the vehicle rear
Solution Approach 1:
The sidewall foils employ curved aerodynamic profiles that generate effective drag reduction through their shape. The curvature allows the foils to maintain aerodynamic effectiveness while being positioned closer to the vehicle body, reducing the need for excessive extension beyond the vehicle rear.
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 solution enables smooth door opening, reduces drag effectively, and protects the fairings from impact without compromising aerodynamic efficiency or extending excessively beyond the vehicle's rear.
Implementation Method 1
the curvature of these foils provides effective drag reduction without excessive extension aft of the vehicle
Implementation Method 2
Aerodynamic devices have long been employed on vehicles to enhance overall vehicle efficiency by reducing wind resistance, or drag
Implementation Method 3
sidewall foils are vertically hinged to the vehicle sidewalls forward of associated door hinges
Data Source
AI summary
A rear fairing system for a vehicle includes a roof foil on top of the vehicle roof and sidewall foils pivotally mounted to the vehicle sidewalls. The roof foil includes downwardly facing concavity and a roof foil curved convex upper surface extending laterally across the vehicle roof. A spring extends laterally across the vehicle roof in the downwardly facing concavity. A door foil extends aft of the roof foil with a curved convex upper surface continuing the roof foil curved convex upper surface. Cables extend from the vehicle rear doors to the sidewall foils adjacent the sidewall foil free edges. The cables are taut and strain the sidewall foils toward the vehicle rear doors with the vehicle rear doors closed.