AU2008101009A4

AU2008101009A4 - Aerodynamic System For Rear of Vehicle

Info

Publication number: AU2008101009A4
Application number: AU2008101009A
Authority: AU
Inventors: Darryl Lanyon
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-10-15
Filing date: 2008-10-15
Publication date: 2008-12-04
Anticipated expiration: 2016-10-15

Description

AERODYNAMIC SYSTEM FOR REAR OF VEHICLES oO _FIELD OF THE INVENTION

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t¢ 5 This invention relates to aerodynamic bodywork components for vehicles. In particular, it is directed to large road transport vehicles, buses and long distance travel passenger coaches.

BACKGROUND OF THE INVENTION 0 SAerodynamic devices fitted to the front of vehicles are well known and manifest themselves in a variety of forms. These devices reduce the air resistance on the forward facing parts of the vehicle. These smooth the flow of air at the front so it travels around the vehicle mass. Air passes over, around and under the vehicle. At the rear of large vehicles a vortex is formed at speed, which increase drag and reduces fuel economy. This vortex is a popular area for cyclists to travel within, at speeds even over 40 kilometres per hour, which dramatically reduced the energy required by the cyclist to propel along with roadway.

With the current situation of global warming and the increasing cost of fuel, making a vehicle more fuel efficient, has become desirable. The present invention could produce fuel savings from three to seven percent, subject to vehicle speed, design and load carried. The rear of a large vehicle can measure up to 2.5 metres to 4.3 metres and in most cases is a large flat, vertical area.

Moving air under a travelling vehicle is a major contributing factor to the vehicle drag, when its discharges are undirected. Ground level air can discharge at 2500cu.m/minute, for a large road transport vehicle travelling at 100km/hour.

Airflow at the rear travels down from the roof along the sides and from under the vehicle. At speed these form tight curves of airflow, which form a vortex at the vehicles rear.

2 o Aircraft have overcome this drag by including an aerodynamic tapered rear. Road vehicles do not have this luxury, as their dimensions are highly regulated by c governments. Road transport vehicle designer use these dimensions to obtain C.) o maximum volume of load space for transporting goods.

There are a number of prior art documents which disclose attempts to reduce drag of vehicles by creating aerodynamic flows. For example, W02004/062953 discloses bodywork components that can be employed individually or in combination to improve the overall drag coefficient of a vehicle. The two main components are a o00 10 cowling mounted on top of the drivers cabin and a scoop fitted midway underneath the trailer section however, these it is difficult to see how these components can (-i improve the streamline flow at the rear of the vehicle.

EP1870322 describes a system for optimising the aerodynamics of the underside of a semi trailer comprising front part, a central part and rear part however, this is costly solution at it only attempts to streamline the flow underneath the vehicle around the tires and again does not address the problem of drag resulting from vortices around the rear of the vehicle.

OBJECT OF THE INVENTION It is therefore an object of the present invention to streamline the airflow at the rear of the vehicle thus reducing turbulence resulting in minimum drag or at least provides an alternative to the prior art solutions.

STATEMENT OF THE INVENTION According to the present invention an aerodynamic system for vehicles comprises a generally scoop shaped member attached to the underside of the rear of the vehicle which streamlines the air flow behind the vehicle.

Preferably the scoop shaped member has flanges on either side which facilitates fixing the device to the underside of the vehicle.

00 Preferably the scoop shaped member is formed with strengthening ribs.

Preferably the system also comprises a convex structure the base of which is attached to the vertical rear surface of the vehicle and which streamlines the upward vertical tn 5 airflow behind the vehicle.

Preferably the convex structure is inflated by the brake air tanks.

BRIEF DESCRIPTION OF THE DRAWINGS 00 An illustrative embodiment of the present invention will be described with reference to the accompanying figures, in which: FIG. 1A is a perspective view from above of an aerodynamic scoop; FIG. 1B is a perspective view from above of an alternative aerodynamic scoop; FIG.2A is a perspective view from above of an alternative aerodynamic scoop; FIG. 2.B shows the scoop of FIG. 2.A fitted under the rear of the rear of a vehicle; FIG.3A is a top plan view of a traveling vehicle, showing side and rear air flows; FIG.3B is a side elevation view of a traveling vehicle, showing roof and ground air flows; FIG.3C is a rear elevation view of a traveling vehicle, showing roof, side and underside air flows; FIG.4 is a plan view of a traveling vehicle, showing side air flows when the scoop of is a side elevation view of a traveling vehicle, showing roof and underside air flows, when the scoop of Fig. l.A or Fig. 1.B is fitted to the rear of the vehicle; FIG.6 is a perspective of the scoop of Fig.1 .A installed under the rear of a vehicle; FIG.7 is a side elevation of the installed scoop of FIG.6; FIG.8 is a rear elevation of the installed scoop of FIG.6; FIG.9 is a side elevation of a scoop installed under a city passenger bus; is a side elevation of a scoop installed under a long distance passenger coach; FIG. 11 is a perspective of a scoop installed under a small commercial delivery van; FIG. 12 is a perspective of a scoop installed under the rear of a camper van; FIG. 13 is an underside plan view of a scoop with an inflatable cone attached to the rear of vehicle; FIG.14 is a side elevation FIG.13 00 SDETAILED DESCRIPTION OF THE INVENTION o Fig. 1 is a preferred embodiment of the invention in the form of an air deflector 1, tn 5 viewed from above, comprising a large curved base member 2 to deflect moving air.

The base member 2, is supported by two side panels 3, 4. Mounting flanges 5, 6 allow fitment of the invention to the chassis of the vehicle 7. Fasteners (not shown) would be used through the holes 9 in flanges 5, 6.

00oO 10 Fig. 2 shows the preferred embodiments of the invention shown from below. The side panels 3,4 and curved base member 2 may include strengthening comprising of ribs 8.

In a preferred version, the leading edge 10 would have a slightly curved surface 11 flowing to a steep radius 12 leading to the exit edge 13. This shape forces the air traveling under the vehicle, to travel at velocity upward on an obtuse angle.

Fig. 3a shows an example air flow along the side panels 14, 15 of a large traveling vehicle 16. The moving side air 17 forms whirlpools 18 which in turn form a vortex 19. This forms the drag on the traveling vehicle 16 during a forward motion Fig. 3b shows an example of Fig.3a, in side elevation. The air 21 traveling along the roof 22 forms tight whirlpools 23, after it passes the square corner 24 of the vehicles rear 25. The air traveling under the vehicle 26, also forms whirlpools of air 27 at the rear, near the roadway 39.

Fig. 3C shows the vehicles large flat rear 25 and the vortex 19 formed by the air flow from the roof 21, the sides 17 and from under the vehicle 26.

Fig. 4 shows an example, from above, of the invention 1 installed under a traveling vehicle 16. This illustrates the unimpeded airflow of air at the vehicle rear 25. Air traveling along the vehicle sides 14, 15 is allowed to pass smoothly due to the upward passing air 27 forming a mass of moving air, and not allowing a vortex 19 to form, as illustrated on Fig.3a, Fig.3b and Fig.3c.

00 Fig. 5 shows an example, from the side, of the invention 1 showing the airflow at the vehicle rear 25, which does not allow a vortex 19 to form and thereby slow the N traveling vehicle 16.

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n 5 An example of the invention 1 installed under the rear of a vehicle is illustrated in Fig.6. To reduce damage to the invention 1, it would be desirable for it to be fitted between the rear wheel 28 and bumper bar 29.

An example of the rear clearance line 30, is illustrated in Fig.7 which is a line Oo 10 between the rear most wheel 28 and rear bumper bar 29, so the invention will not be damaged by a gutter, drain, rocks or other structural ground items (not shown).

(Ni Fig. 8 shows a rear view and the ground clearance 31 of the invention 1 and the roadway 28. The large void of moving air 32, under the vehicle 16 would be directed into the invention 1 due to the speed of the vehicle 16.

Figs. 9 to 12 show preferred embodiments of the invention used on different road vehicles. Fig. 9, a city passenger bus 33. Fig. 10, a long distance passenger coach 34.

Fig. 11, a delivery vehicle 35 and Fig. 12, a motor home 36. The invention 1 may take several design forms, to perform a practical function under different vehicles.

Fig.13 and Fig.14 illustrate an inflatable rear air deflection convex structure 37. The convex structure 37 can be inflated from compressed air from the brake air tanks 38, via an air filling gun (not illustrated). The convex structure 37 could be used alone on a vehicle, but to increase fuel economy the invention 1 would be installed.

VARIATIONS

It will of course be realized that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

00 Throughout the description and claims this specification the word "comprise" and 0 variations of that word such as "comprises" and "comprising", are not intended to N exclude other additives, components, integers and steps.

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