FR2514712A1 - Ground effect surface for vehicle - has aerofoil to increase air speed below vehicle to create vacuum - Google Patents

Abstract

The ground effect surface for a Vehicle has a flat plate, or aerofoil, in several sections, faired into the vehicle surface. The surface can be positioned to give a predetermined orientation with the ground. The vehicle engine exhaust can be directed to discharge near the trailing edge of the surface. This speeds up passage of air under the vehicle and reduces the air pressure, causing a downward force on the vehicle chassis.

Description

TITLE: Hyper offset shutters and associated main profile
TECHNICAL SECTOR: Automobile, Aviation.

POSITION OF THE PROBLEM:
Currently racing cars use the effect
ventury to increase their support and therefore their grip which allows them to pass faster in turns.

 By ventury effect is meant the fact that the underside of the vehicle has roughly the shape of an inverted wing profile and is drawn towards the ground by the depression created between the ground and this profile.

OBJECTIVE OF THE INVENTION:
The object of the invention is to use this vacuum phenomenon by effectively accelerating a large quantity of air under the vehicle at a speed significantly higher than what is currently practiced.

 This gives a strong dynamic depression responsible for the aerodynamic suction of the car towards the ground.

PRINCIPLE:
Consider the upper surface of a wing profile facing the ground
I1 estYgros, consisting of 3 parts east could be assimilated to a half carburetor nozzle seen in section. We find indeed the convergent or compressor which aims to accelerate the flow - the neck where the maximum depression prevails
The divergent which allows the device to be connected to external conditions with the least possible losses.

Currently, racing vehicles have a very small presser, a large neck and a large diffuser in which they slow the air too much because they use it to "suck" the ground.

 There is a reason for this: the compressor locally creates lift - and therefore, we tend to minimize it, but doing so we penalize ourselves because we do not create the fantastic speeds under power that a powerful compressor allows.

 The invention aims to eliminate this drawback of local lift of large compressors.

Let's see how a compressor works: I1 takes air at the upstream conditions and gradually transforms the potential energy of the fluid into kinetic energy in support as the law

au point d'arret )
Cette pression statique élevée s'applique au sol d'une part et sous le nez du profil d'autre part - elle a donc tendance b carter ces deux ensembles car il n'existe aucune liaison entre eux. On peut ainsi considérer que, dans ce cas, la pression est une force "externe" au sens du physicien appliquée sous le nez du véhicule.It can be seen at the inlet of such an apparatus that the static pressure is very close to the total pressure

at the stop point)
This high static pressure applies to the ground on the one hand and under the nose of the profile on the other - it therefore tends to squeeze these two sets because there is no connection between them. We can thus consider that, in this case, the pressure is an "external" force in the sense of the physicist applied under the nose of the vehicle.

 Suppose now that the soil is rigidly linked to the profile - in this case the pressure exerted on the "soil" is balanced under the profile and the overall result is zero; no more lift is obtained because there is then a system of "internal" forces - of course the effect of speeding up the air by the compressor function is preserved.

PRACTICAL Rwaiisation
Since fixing the vehicle on the ground is out of the question, the solution is simple
Attach a "ground fax" under the compressor.

In fact this amounts to transforming the half ventury that we mentioned previously into a 4/6 of ventury having a complete convergent and only I / 2 col and I / 2 divergent
This false floor may be a flat plate or a fin, in one or more pieces, being in all converging from the main profile. We will call, from now on, this component hgper spoiler (VHD).

 Note, in passing, that it may be interesting to make the V.H.D. forward: that is, it is no longer completely covered by the main profile. In fact, let's examine, in this configuration, what becomes of the high pressure generated in the compressor that constitutes the V.H.D. + main profile.

 Inside the compressor it acts as we have seen in internal force "and only serves to accelerate the fluid - On the other hand, at the mouth, at the leading edge of the main profile, where the pressure static is the strongest we see that the compression field rises beyond it by influence - if the VHD extends upstream of the mouth it will therefore undergo static pressure on its upper face - or, that -this will not be balanced from above because the main profile is shorter "- we therefore obtain" externdw force "and therefore support in front overhang; which is very interesting.

REs') RQUE:
Between the main profile and the VHD, a flow was created which exits under the neck at very high speed. This creates a fallopian freight "which makes it possible to aspirate and accelerate the flow under the VHD profile and putting it in depression improves the overall downforce of the device all the same; as evidenced by the experimental results that we obtained at
EIFFEL laboratory.

 REhlARQUE (I) - The principle of VHD can be used to make wings with high downforce at low incidence.

 In fact, it is a derivative of the Avant beak of aircraft hypersestanters which, themselves, operate under high incidence.

NOTE (2) - You can use the trunk effect created by the
VHD main profile to accelerate the exhaust of a radiator or an engine compartment, by placing the exhaust orifice near the end of overlap area of the two profiles. This arrangement makes it possible to reduce the cooling time.

NOTE (3) - It is advantageous to use main profiles with high ground clearance (between 0.20 and 0.30 m) with a strong lower curvature and a very low stake angle.

Thus section ratios between the leading edge of the main profile and the neck can go from 1.5 to 5 with this technology.

Claims (1)

 RmENDICATIOlXS I - Hyper-offset flaps allowing to significantly increase the ground support of motor cars.  Made up of a flat plate or a wing profile in one or more pieces  Characterized by the fact that they are all or part covered by all or part of the convergent of the main profile formed by the car or its pontoons.  II - Main profile in the form of an inverted wing profile uses  with hyperporting flap as defined in claim I, making it possible to significantly increase the support of motor cars characterized by the use of a convergent ensuring a section ratio between 2 and 5 between the neck and the edge attack. III - Hyperdéporteur shutter as defined in I, premitting to suck ltéchap can of a radiator or an engine compartment characterized by the fact that the exhaust outlet is W near the end of profile recovery area main and hyperdjporteur profile.