Frame extension device for reducing the aerodynamic drag of ground vehicles

Abstract

A frame extension device for the reduction of aerodynamic drag and for improved performance of ground vehicles by increasing the pressure on the base of the vehicle by stabilizing the wake flow. The device is particularly suited for tractor-trailers utilizing a roll-up type rear door in that it does not block any part of the door opening. The device is of sufficient thickness to support the weight of an unloading device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood in relation to the attached drawings illustrating preferred embodiments, wherein:

FIG. 1 is a rear perspective view of the aft most portion of a trailer of a tractor-trailer truck system with the present invention installed on the rear surface of the trailer;

FIGS. 2A-2B are cross-section views, in planes horizontal to the ground and perpendicular to the ground, of the wake flow conditions for a tractor-trailer system without the present invention installed;

FIGS. 3A-3B are cross section views, in planes horizontal to the ground and perpendicular to the ground, of the wake flow conditions for a tractor-trailer system with the present invention installed;

FIG. 4A-4D are side and top views of various ground vehicles with and without the present invention installed;

FIGS. 5A-5B are perspective and section view drawings of the inset variation for the present invention;

FIGS. 6A-6B are perspective and section view drawings of the linear thickness taper variation for the present invention;

FIGS. 7A-7B are perspective and section view drawings of the stepped inset variation for the present invention;

FIGS. 8A-8B are perspective and section view drawings of the radiused trailing edge variation for the present invention; and

FIGS. 9A-9D are perspective view and cross section views of several fabrication concepts for the present invention.

Claims

1. An aerodynamic frame extension device for reducing aerodynamic drag when attached to the aft surface of a vehicle having a perimeter with a top edge, a bottom edge, and two side edges, the device comprising: a non-foldable frame structure comprised of rigid panels affixed substantially around the perimeter of the aft surface of the vehicle; andwherein each of the panels have a thickness of at least 1% of the width of the vehicle.

2. The frame extension device of claim 1, wherein the panels are joined together into a single piece frame structure.

3. The frame extension device of claim 1, wherein the panels have a linearly tapering thickness in the direction of the air stream.

4. The frame extension device of claim 1, wherein the panels are inset from the outer edge of the door frame.

5. The frame extension device of claim 1, wherein the panels have a thickness which varies step-wise in the direction of the air stream.

6. The frame extension device of claim 1, wherein the panels have a curved thickness from the outer edge of the door frame to the inner edge of the door frame.

7. The frame extension device of claim 1, wherein the device is integrally formed with the door frame.

8. An aerodynamic frame extension device for reducing the aerodynamic drag when attached to a rear door frame of a vehicle, the aft surface of the door frame having a perimeter with a top, bottom and sides that define a door opening, the device comprising: a frame structure comprised of rigid panels affixed around the perimeter of the aft surface of the rear door frame;wherein the frame structure has a vertical height equal to at least the vertical height of the rear door opening and a width equal to at least the width of the rear door opening; andwherein the panel nearest the bottom of the door frame has sufficient thickness to support a device for loading and unloading the vehicle.

9. The frame extension device of claim 8, wherein the panels have a thickness of at least one half the thickness of the door frame.

10. The frame extension device of claim 8, wherein the panels are joined together into a single piece frame structure.

11. The frame extension device of claim 8, wherein the panels have a linearly tapering thickness in the direction of the air stream.

12. The frame extension device of claim 8, wherein the panels are inset from the outer edge of the door frame.

13. The frame extension device of claim 8, wherein the panels have a thickness which varies step-wise in the direction of the air stream.

14. The frame extension device of claim 8, wherein the panels have a curved thickness from the outer edge of the door frame to the inner edge of the door frame.

15. The frame extension device of claim 8, wherein the device is integrally formed with the door frame.

16. An aerodynamic frame extension device for reducing the aerodynamic drag when attached to a rear door frame of a tractor-trailer, the aft surface of the door frame having a perimeter with a top, bottom and sides that define a door opening, the device comprising: a frame structure comprised of four rigid panels integrally connected to each other, the frame being substantially permanently affixed to the perimeter of the aft surface of the rear door frame;wherein the frame structure has a vertical height equal to at least the vertical height of the rear door opening and a width equal to at least the width of the rear door opening; andwherein the panel nearest the bottom of the door frame has sufficient thickness to support a device for loading and unloading the vehicle and the remaining panels have a thickness of at least 1% of the width of the vehicle.

17. The frame extension device of claim 16, wherein the panels are formed of metal, wood, plastic, composite, rubber, or ceramic material.

18. The frame extension device of claim 16, wherein the panel nearest the bottom of the door frame is formed of metal.

19. The frame extension device of claim 16, wherein the device is inset at least one inch from the outer edge of the door frame.

20. The frame extension device of claim 16, wherein the length of the device is about 6 to about 60 inches.