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Title:
SYSTEM FOR ACTIVE DECRESE IN THE AERODYNAMIC RESISTANCE OF VEHICLES IN MOTION
Document Type and Number:
WIPO Patent Application WO/2003/084769
Kind Code:
A1
Abstract:
The essence of the invention is in taking away, as much as possible, the medium volume (air at road vehicles) from the slow airflow zone in the space between vehicle bottom and road surface in proportion to vehicle motion speed, or in supplying, as much as possible, the medium volume to the zone behind moving vehicle, also in proportion ti vehicle motion speed. The invention is in active airflow redirection and active part of Moving vehicle aeordynamic resistance reduction system is felloe construction (1) (picture 5) that adds one more function to the wheel. So, beside the role to transform the axel rotation into linear vehicle motion and power transmission to road surface, such wheel with felloe designed as propeller also becomes an axial air turbine /blade (2)/ that produces forced airflow in the direction going fron inside to outside in the front wheel zone and from outside to inside in the rear wheel zone.

Inventors:
Galijasevic, Galibedin (Prilaz Ivana Visine 7, Zagreb, 10000, HR)
Application Number:
PCT/HR2002/000044
Publication Date:
October 16, 2003
Filing Date:
September 19, 2002
Export Citation:
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Assignee:
Galijasevic, Galibedin (Prilaz Ivana Visine 7, Zagreb, 10000, HR)
International Classes:
B60B19/10; B62D37/02; (IPC1-7): B60B21/02; B62D37/02
Foreign References:
US5820203A1998-10-13
DE4231082A11994-03-24
DE2341967A11975-03-13
DE3437855A11986-04-17
EP0937633A11999-08-25
DE3712048A11988-10-27
Attorney, Agent or Firm:
Inova D. O. O. (Trg zrtava fasizma 14, Zagreb, 10000, HR)
Download PDF:
Claims:
PATENT CLAIMS
1. Active aerodynamic resistance reduction system of moving vehicle characterized in that a vehicle having: a pair of front wheels (3) equipped with felloes with blades which during the vehicle motion direct the airflow from under the vehicle to the outside of vehicle. a pair of rear wheels (4) equipped with felloes with blades which during the vehicle motion direct the airflow from outside to under and behind the vehicle.
2. Active aerodynamic resistance reduction system of moving vehicle characterized in that a felloe (1) having blades (2) which during vehicle motion direct airflow from under vehicle to outside of vehicle.
3. Active aerodynamic resistance reduction system of moving vehicle characterized in that a felloe (1) having blades (2) which during vehicle motion direct airflow from outside to under vehicle. SUMMARY The essence of this invention is in taking away, as much as possible, the medium volume (air at road vehicles) from the slow airflow zone in the space between vehicle bottom and road surface in proportion to vehicle motion speed, or in supplying, as much as possible ; the medium volume to the zone behind moving vehicle, also in proportion to vehicle motion speed. The invention is in active airflow redirection and active part of Moving vehicle aerodynamic resistance reduction system is felloe construction (1) (Picture 5) that adds one more function to the wheel. So, beside the role to transform the axel rotation into linear vehicle motion and power transmission to road surface, such wheel with <BR> <BR> felloe designed as a propeller also becomes an axial air turbine/blade (2) /that produces forced airflow in the direction going from inside to outside in the front wheel zone and from outside to inside in the rear wheel zone.
Description:
MOVING VEHICLE ACTIVE AERODYNAMIC RESISTANCE REDUCTION SYSTEM Field of Technology : According to International Patent Classification (IPC) this invention may be divided into the following classes : - B60B 21100-Felloe - B60B 21/02-Classified according to cross section - B60B 3/10-Wheels with openings as imitation of spoke wheels Technical Problem : The technical problem that this invention solves consists of the construction solution to active airflow direction of space between vehicle base, front wheels and road surface away from the vehicle and active airflow direction to low pressure zone that exists just behind the moving vehicle with an aim to reduce motion vehicle aerodynamic resistance/aerodynamic lift force and forces that are caused by slower airflow in space between motion vehicle base, front wheels and the road surface and under pressure zone just behind moving vehicle/with an assumption that changes in the vehicle construction are made, such as: A. Basic changes: - usage of wheels with propeller designed felloe ; that makes it an axial air turbine that produces forced airflow directed from inside to outside at the front wheel area and from outside to inside at the rear wheel area; - moving the position of the rear wheel axis to the back end of the vehicle (in fact, even behind basic vehicle volume) and making adjustments in wheel suspension accordingly ; - construction of felloe having greatest possible diameter (with low profile tires to make active system part more efficient), while the rear felloes must have much bigger diameter (25"or more), all in order to increase active air volume and efficiency.

B. Additional changes - brake and suspension system redesign so that it does not interfere with airflow through felloe ; - rise vehicle tail; - adjust aerodynamically all parts of vehicle suspension and transmission that are located under vehicle ;

- reduce vehicle bottom roughness.

Existing Technical Solutions Known passive systems try to shape vehicle as close as it possible to ideal aerodynamical form by using spoiler system that (very often unsuccessfully) passively directs airflow and tries to influence vehicle wheel adhesion force to road surface.

"Tail"spoiler has a little more sense since it fills up the aero profile tail volume that is missing in"incomplete"drop-like-form (under pressure zone behind the vehicle) and reduces resultant forces in the opposite direction of vehicle motion, since the spoiler volume is getting closer to the zone centre, and the forces are partly annulled.

Description of Technical Solution Primary goal of this invention is to reduce motion vehicle aerodynamic resistance.

Secondary goal of this invention is to improve moving vehicle stability and handling, reduce fuel consumption and improve vehicle performance (maximal speed, acceleration).

Attached drawings that are included in the description and that are a part of invention description illustrate invention implementation and help in explanation of invention basic principal.

If we observe some body in motion-for example a vehicle through air medium (Picture 1), we can notice that airflow speed over the upper vehicle surface is greater then speed over lower surface that results in aerodynamic lift force. A reason for this is higher airflow resistance through slower airflow zone in the space between vehicle bottom, wheels and road surface (due to static pressure component, vehicle bottom roughness, suspension part resistance, steering parts and other influences, road surface roughness influence and similar). The result of aerodynamic lift force impact on moving vehicle is the reduction of wheels down force to road surface because of which losses are increased as a result of drive wheels sliding. Vehicle-handling characteristics are also reduced.

So, one part of the technical problem that we are examining is aerodynamic lift force and airflow resistance force that are present in the space between moving vehicle bottom, wheels and road surface.

If we analyse with some simplifications medium flow (air) through slower airflow zone in space between vehicle bottom, wheels and road surface and if eliminate the influence of air compression and friction between air particles, the condition can be

observed as a laminar medium flow through two Bernoulli's pipes (Picture 2), where pipe sides are wheels, and Bernoulli's law applied: Pdyn + Pstat = COMSt = ? pv2/2 + pstat = const = p Therefore, dynamic pressure sum-pv2l2 and static pressure- pstat is constant, that means that is equal to the total pressure.

As airflow trough space between vehicle bottom, wheels and road surface in reality is not laminar but eddying, flow speed is slowing down, which causes dynamic component reduction and static component with vector in direction vertical to motion direction is rising. Since one side of the observed system is fixed (road surface), the static pressure component directed vertically to the road surface is added (reduced by air compression coefficient) to static pressure component directed vertically to vehicle bottom. In other words, an air cushion is formed under the vehicle.

The result of everything previously described are two forces having equally directed vectors (in the direction opposite to the Earth gravity vector)-aerodynamic lift force and resultant force as a sum of static pressure component vectors during airflow through the space between vehicle bottom, wheels and road surface.

So, if we succeed to increase airflow speed in the space between vehicle bottom, wheels and road surface and, on the other hand, if reduce air volume that flows through the same space, dynamic pressure component will be increase and static decreased. This will result in the following impacts on moving vehicle: reduction of both pressure components and their influence on moving vehicle and work needed to overcome this resistance. flow speed in space between vehicle bottom and road surface is increased resulting in reduction of aerodynamic lift force and its influence on the moving vehicle (losses because of drive wheels sliding and reduced vehicle handling).

I would like to emphases that the previous description applies to the front Bernoulli pipe, while the situation with the rear pipe is a little different. So let us analyse further body-vehicle motion through air medium.

If we observe any water volume without applying any force on it (e. g. condition without gravity), it will take sphere shape that is caused by cohesion force between water molecules and surface tension force.

If we let such a sphere in free fall through air medium under gravity influence, sphere will be deformed in proportion to the motion speed and it will take on drop form, which is caused by aerodynamic resistance force on the one side and cohesion and surface tension force (Picture 3) on the other side.

The drop is becoming longer and longer until the moment when cohesion forces are overcome and one part of the volume is dismounted and forms a new drop. This process continues until the moment when the forces are in balance and such drops continue to move uniformly and rectilinearly.

If we compare the movement of one such drop with other body of the same mass- m and projection surface on plane vertical to movement direction-A and the same shape but made of solid material of the same surface roughness as water drop, we can notice that both bodies are moving at the same speed (the both bodies are affected by the same force and they are moving uniformly and rectilinearly), which means that aerodynamic resistance-R is the same for both bodies in motion (Picture 4).

In the next example we will compare the motion of the same body, that is, drop- form solid body that is moving uniformly and rectilinearly through air medium, with another body of the same mass-m and projection surface on plane vertical to movement direction-A and the same surface roughness, but which has different shape just because it is"incomplete"-drop-form tail is missing. We can notice that "incomplete drop-form"body is moving slower, which means that it has bigger aerodynamic resistance."Incomplete drop-form"body aerodynamic resistance-R2 will be proportional to the sum of the regular drop-form body aerodynamic resistance- Rs and weight of water volume equal to the volume of the part of the regular drop-form that is missing in"incomplete drop-form"body-S (Picture 3 and 4) because the force needed to create form deformation that is missing in"incomplete drop-form"body is proportional to this volume weight.

Rz-Ri + a m Rz-Rl + a pwater V R2 ~ Rr + a pwater Sh/3 Where is R2-aerodynamic resistance of"incomplete"drop-form body ; R,-aerodynamic resistance of regular drop-form body ; a - acceleration (Earth gravity) ; m-volume mass of the part of

regular drop-form that is missing in"incomplete"drop-form ; p", ter -water density ; V-volume of the part of the regular drop-form that is missing in"incomplete"drop-form (simplified cone) ; S- surface of"incomplete"drop-form tail part (cone base) ; h- heightbof the part of the regular form drop that is missing in "incomplete"drop (height cone) ; Sh/3-cone volume.

By the optimisation of the previous formula, with some experimental support, it is possible to mathematically define Cx aerodynamic resistance coefficient : CX- ? 2/Rl + a pwater V This means that behind"incomplete"drop-form body that is moving through air medium a force with opposite direction to body motion direction appears, which is proportional to the weight of missing volume in the"incomplete"drop in comparison to regular drop water weight. Forces that can be called"incomplete tail aero profile resistance forces"are directed to the centre of the missing virtual tail aero profile volume, which is acting on surface-S with opposite direction vector from body motion direction and causing air eddying motion in this zone. All this increases body motion resistance.

So, the second problem that is observed are"incomplete tail aero profile resistance forces", in other words resultant force of opposite direction to vehicle motion direction that appears in the zone behind moving vehicle as a result of low pressure caused by vehicle imperfect aero profile form.

If we put into this zone behind vehicle that is moving through air (or any other) medium, additional medium volume (airflow), we will reduce"incomplete tail aero profile resistance forces"and resultant motion resistance force. This is accomplished with active motion vehicle aerodynamic resistance reduction system.

The essence of this invention is in taking away, as much as possible, the medium volume (air at road vehicles) from the slow airflow zone in the space between vehicle bottom and road surface in proportion to vehicle motion speed, or in supplying, as much as possible, the medium volume to the zone behind moving vehicle, also in proportion to vehicle motion speed..

The invention is in the active airflow direction from space between vehicle bottom, front wheels and road surface away from the vehicle and active airflow direction to low-pressure zone behind moving vehicle. This airflow direction is accomplished by

felloe constructed in propeller shape (1) (Picture 5) that adds one more function to wheel.

So, beside the role to transform the axel rotation into linear vehicle motion and power transmission to road surface, such wheel with felloe designed as a propeller also becomes an axial air turbine/blade (2) /that produces forced airflow in. the direction going from inside to outside in the front wheel zone and from outside to inside in the rear wheel zone (Picture 6).

This increases airflow speed in the slow airflow zone between front wheels because of which aerodynamic lift force and its influence on moving vehicle is reduced, and both pressure components and their influence on moving vehicle and necessary work to overcome them is reduced as well.

On the other side, bringing additional airflow into zone behind motion vehicle reduces"incomplete tail aero profile resistance forces"and resultant motion resistance force and medium eddy.

It has to be pointed out that felloe efficiency (1) is maximal since rotation that is a primary function of the wheel is utilised and all losses and resistances are already calculated in this activity.

Felloe construction has to fulfil the requirement of maximum airflow outtake from the slow airflow zone in space between vehicle bottom, front wheels and road surface and maximal airflow intake in the low-pressure zone that is formed behind moving vehicle.

The basic guidelines for construction of vehicle based on mentioned principles are (Picture 7) : apply wheels with felloe designed as a propeller, that makes felloe an axial air turbine which produces forced airflow in the direction going from inside to outside in the front wheel zone and from outside to inside in the rear wheel zone; move position of the rear will axis to the back end of the vehicle (actually even behind basic vehicle volume) and make adjustments in wheel suspension accordingly ; apply felloe having greatest possible diameter (with low profile tires to make active system part more efficient), while the rear felloes must have much bigger diameter (25"or more) all in order to make active air volume bigger;

w redesign of brake and suspension system so that it does not interfere with the airflow through the felloe ; rise vehicle tail ; adjust aerodynamically all parts of vehicle suspension and transmission located under vehicle ; reduce roughness of vehicle bottom.