Automatic rear airfoil for vehicle

Abstract

A twin bag inflatable rear airfoil for truck or transport trailer with attached shelves that bridge the surface gap between the trailer side and top surfaces, and the corresponding side and top surfaces of the inflatable bags. Shelves also bridge the upper surface gap between the two bags and provide a platform to deploy a collapsible yaw control fin. Another set of panels provide airfoil surfaces in the ground domain and are integral to the organised automatic folding and stowage of the apparatus. Interrupted ribs stiffen the inflatable surfaces while allowing them to fold in an orderly manner.

Description

BACKGROUND OF THE INVENTION [0001] The reduction in aerodynamic drag resulting from the addition of a boattail shaped appendage to a boxed shaped vehicle has been well examined. Drag reductions of 30% are realistically possible (NASA / TP-1999-206574, “A Reassessment of Heavy-Duty Truck Aerodynamic Design Features and Priorities”), and would correspond to fuel savings of 15% for a transport truck. There are however several practical requirements that pose difficulties to implementing such a device on a working transport trailer. The device must not impede the operation of the trailer doors, typically swinging double doors on trailers used for long-distance haulage. The device must present a smooth, gently tapering set of boattail (side) and backlight (top) surfaces that connect tightly to the trailer sides and top respectively for optimum aerodynamic performance. Given practical difficulties in tightly fitting an inflatable to the hardware laden trailer door perimeter, the present inv...

AI Technical Summary

Problems solved by technology

There are however several practical requirements that pose difficulties to implementing such a device on a working transport trailer.

Given that the device operates in a physically hostile environment, it must not vibrate to a degree that causes premature wear of its structural components.

Boattail surfaces tend to perform aerodynamically better in cross-wind (higher yaw) conditions, however the backlight loses its' drag reducing function as the angle of yaw rises.

A major difficulty in the deployment of rigid or semi-rigid panels as airfoil surfaces behind a trailer is the weight and complexity of adequate structural reinforcement, particularly if the panels are large enough to perform well aerodynamically and are not collapsed automatically when the trailer stops, thereby exposing them to severe ambient wind gusts.

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