GB2475361A

GB2475361A - Extendable and retractable aerodynamic aid

Info

Publication number: GB2475361A
Application number: GB1003791A
Authority: GB
Inventors: Alasdair Edward Collins
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-11-17
Filing date: 2010-03-08
Publication date: 2011-05-18
Also published as: GB0920091D0; GB201003791D0

Abstract

An extendable/retractable aerodynamic aid 4 which reduces drag produced by the large rear end of a vehicle is provided. The aerodynamic aid 4 may be flexible and may retract into a protective enclosure 3. The aerodynamic aid 4 may extend and retract from and into the protective enclosure 3 using piezoelectric materials and pretensioned flexible materials. The protective enclosure 3 could contain an air intake which aids the extension of the aerodynamic aid 4 and also reduces deformation in crosswinds, a speed sensor which automatically extends and retracts the aerodynamic aid 4 at a certain speed and an array of ultrasonic sensors which govern whether it is safe to extend the aerodynamic aid 4. When in the extended position as in Fig 2 the aerodynamic aid 4 will reduce the size of the turbulent region 2 behind the trailer 1.

Description

Title: Extendable/ Retractable Aerodynamic Aid

Background:

The present invention relates to devices that reduce the air drag produced by, but not limited to, large road going vehicles, such as trucks, tractor trailer units, coaches and other vehicles that have large flat rear ends.

Fuel cost is one of the main expenses for road going vehicles and for large vehicles with a poor aerodynamic efficiency, such as tractor trailer units, fuel costs are particularly high. Improvements in rolling resistance and engine efficiency has reduced fuel consumption over the past years, however little has been done to successfully reduce the amount of air drag produced by the large rear end of the vehicle.

Tractor trailer units are a necessity in our modern life, hauling produce and products around the country, but these vehicles produce high amounts of C02 and other green house gases which are harmful to the environment. It is necessary to reduce the amount of pollution produced by large vehicles as a typical truck made before 2007 could produce up to 150 times more pollution than an average family saloon.

A typical truck has a Coefficient of Drag over 0.6 and has a large surface area. This means that the air drag produced by the truck is quite large. The variables that determine drag, being frontal area, velocity and Coefficient of Drag, are mainly governed by the application of the vehicle they are applied to. As in the case of a truck trailer, the frontal area must be great as the unit must be able to haul large amounts of goods to make the journey financially viable for the company. This is also the case with the velocity of the truck, as it must deliver its goods on time. The only variable that is not totally governed by the application is the Coefficient of Drag. This means that the only way to reduce the air drag produced by a large commercial vehicle is to reduce the Coefficient of Drag.

Statement of Invention:

To overcome the high amounts of fuel consumed and pollution produced by, but not limited to, large road going vehicles, the present invention proposes to modify airflow over the rear of such vehicles creating a more aerodynamic shape, therefore reducing the value for the Coefficient of Drag. This will in turn reduce the air drag for a particular vehicle at a particular velocity.

As the aerodynamic aid must not block the loading doors, it must be retracted into a protective enclosure located on the roof above the loading doors. As drag is not as great at low speeds the aerodynamic aid will be retracted in towns to reduce the length of the vehicle. This function will be automated using an air speed sensor to govern the action.

The protective enclosure will be aerodynamically shaped as the frontal area will have increased. This should reduce the Coefficient of Drag at low speeds, when the aerodynamic aid is retracted, to keep the total air drag at levels close to normal. It will also aid the air flow over the extended aerodynamic aid further reducing drag. It is most likely to be manufactured out of Acrylonitrile Butadiene Styrene, more commonly known as ABS. due to its excellent mechanical properties and ability to be recycled.

The extendable aerodynamic aid itself will be manufactured from a flexible plastic based fabric, most likely to be Polytetrafluoroethylene, partnered with one or more piezoelectric materials allowing for the extension of the material from the protective enclosure. Pretensioned flexible ribbing will run throughout the Polytetrafluoroethylene and the piezoelectric to retract the aerodynamic aid back into the protective enclosure.

It may be necessary to during crosswinds, for example, to support the structures shape as a change in shape would in turn change the air flow over the vehicle and would then reduce its aerodynamic properties. To overcome this deformation there will be an air intake in the protective enclose. This air intake will both aid the extension and reduce deformation. As maximum air flow into the aerodynamic aid from the air intake will not be necessary at all times, the air intake will have the ability to reduce air flow and also cut off air flow completely into the aerodynamic aid.

For safety reasons the there will be an array of ultrasonic sensors to the rear of the protective enclosure. This will ensure that the aerodynamic aid will not extend when there is another vehicle in close proximity as this could obstruct the vehicles view of the road ahead. It will also retract the aerodynamic aid if a vehicle becomes too close to the rear. This will reduce the risk of damage occurring to the.aerodynamic aid and will increase the view of the road from the vehicle behind reducing the risk of road collisions.

Advantages: When the aerodynamic aid is in the extended position it will reduce the air drag produced by the large rear end on the vehicle. This will reduce fuel consumption, reduce emissions and could increase engine longevity.

The aerodynamic aid will be stored in a protective enclosure when it is not active. This will eliminate the chances of damage occurring when aerodynamic aid is not active, i.e. in the extended position.

This protective enclosure will be located on the roof at the rear of the vehicle. This means it will not obstruct the loading doors when stationary.

The protective enclosure will be fitted with a speed sensor. This will allow the aerodynamic aid to extend and retract automatically at certain preset speeds. The protective enclosure will also be fitted with an array of ultrasonic sensors which will detect a vehicle to the rear of the aerodynamic aid. These sensors will stop the aerodynamic aid from extending if there is a vehicle in too close proximity and will retract the aerodynamic aid if a vehicle becomes too close.

There will be an air intake located at the front of the protective enclosure. The air intake will be able to vary the amount of air that passes through it. It will close once the aerodynamic aid is fully extended to reduce drag caused by the air intake itself. This air intake will aid the extension of the aerodynamic aid from the protective enclosure. It will also be able to open, during crosswinds for example, to keep the aerodynamic aid fully extended. This will mean the aerodynamic aids drag reducing capabilities should not be affected by a crosswind.

The system will have the advantage of not only being able to be incorporated into new trucks and tractor trailers but also being able to be retrofitted to older vehicles maximising the amount of emissions that could be reduced.

As the system is fully automatic, it means that whenever it is safe to do so, the aerodynamic aid will extend. This will maximise the amount of fuel saved and emissions reduced. As the aerodynamic aid is stored in a protective enclosure when it is not extended, it will never "flap" around when it is not active causing an inconvenience to other road users. As the protective enclosure is fitted with an air intake it should stop the aerodynamic aid from dangerously deforming during crosswinds and obstructing other road users view.

Detailed Description of Drawings:

An example of the invention will now be described by referring to the accompanying drawings: * Figure 1 shows a simplified truck trailer (1) and air flow pattern over said trailer. It also shows the turbulent air flow (2) directly behind the trailer which is the main cause of air drag on said trailer.

* Figure 2 shows a simplified truck trailer (1) and air flow pattern over said trailer. Attached to the trailer is an aerodynamic aid (3 and 4) in the fully open position. The aerodynamic aid when extended alters the air flow over the rear of the trailer reducing the size of the turbulent region (2) and therefore reducing the drag.

* Figure 3 shows the truck trailer (1) and the protective enclosure (3) spanning the entire width of the trailer. The aerodynamic aid is in the fully retracted position. It does not obstruct the loading doors when in the retracted position.

* Figure 4 shows the aerodynamic aid in the fully extended position (4) behind the truck trailer (1).

* Figure 5 shows the rear of the extended aerodynamic aid (4). Another vehicle, in this case a truck (5), has come into close proximity. This would obstruct the following drivers view of the road. As this is hazardous the aerodynamic aid (4) will retract into the protective enclosure (3).

* Figure 6 shows the aerodynamic aid fully retracted in the protective enclosure (3). This is position 1. It also shows the air intake (6) and air speed sensor intake (7).

* Figure 7 shows protective enclosure (3) with the aerodynamic aid (4) starting the extensions process. This is position 2.

* Figure 8 shows the aerodynamic aid (4) unravelling from the protective enclosure (3). This is position 3.

* Figure 9 shows the aerodynamic aid (4) fully unravelled from the protective enclosure (3).

This is position 4.

* Figure 10 shows the aerodynamic aid (4) fully unravelled and starting to expand to create the required shape. This is position 5.

* Figure 11 shows the aerodynamic aid (4) at near full extension. This is position 6.

* Figure 12 shows the aerodynamic aid (4) fully extended. This is final position 7.

* Figure 13 shows the protective enclosure (3) and the air intake (7). It also shows an array of ultrasonic sensors (8).

Claims

Claims: 1. An extendable/retractable aerodynamic aid to reduce the drag produced by the large rear end of, but not limited to, large road going vehicles.
2. An extendable/retractable aerodynamic aid according to claim 1, in which the flexible aid itself retracts into a protective enclosure.
3. An extendable/retractable aerodynamic aid according to claim 2, in which the protective enclosure is located on the roof above the loading doors spanning the width of the vehicle.
4. An extendable/retractable aerodynamic aid according to claim 2, in which the protective enclosure is aerodynamically shaped to reduce drag.
5. An extendable/retractable aerodynamic aid according to claim 2, in which there is an air intake located in the protective enclosure to aid the extension and reduce deformation of the flexible aid.
6. An extendable/retractable aerodynamic aid according to claim 1, in which the flexible aid itself will make use of piezoelectric materials to extend itself from the protective enclosure,
7. An extendable/retractable aerodynamic aid according to claim 1, in which the flexible aid itself will make use of flexible materials pretensioned in the fully retracted position to retract the flexible aid itself back into the protective enclosure.
8. An extendable/retractable aerodynamic aid according to claim 2, in which on the protective enclosure there is an array of ultrasonic sensors to detect objects in close proximity to the rear of the vehicle and to determine if it is safe to extend the flexible aid.
9. An extendable/retractable aerodynamic aid according to claim 2, in which the protective enclosure is fitted with a speed sensor which will automatically extend and retract the flexible aid at a certain speed.