Roof antenna with a Pitot probe

Abstract

The invention relates to a roof antenna (1b) for a motor vehicle, adapted to be mounted on a roof headliner (2), the antenna (1b) comprising an orifice (6) extending along a main axis between an opening (7b) and a bottom, the opening (7b) being adapted to allow the entry of an air flow into the orifice (6), when the antenna (1b) is mounted on the roof headliner (2) and the vehicle is traveling forward, the bottom being adapted to measure a pressure in the orifice (6) resulting from the air flow flowing around the opening (7b) of the orifice (6), the orifice (6) being dimensioned to form part of a Pitot probe. (Figure 2)

Description

Title of the invention: Roof antenna comprising a Pitot probe

[0001] The technical field concerns roof antennas, fairings forming an outer casing of such an antenna and motor vehicles equipped with such an antenna.

[0002] The regulation of ever-increasing automobile traffic is becoming a major challenge for players in the automotive world, who are considering innovative solutions to optimize the use of road infrastructure, in particular convoy driving. Indeed, convoy driving would make it possible to optimize road space, by reducing distances between vehicles, would improve safety by managing vehicle driving in a coordinated manner, with communication systems between vehicles, and finally would allow a reduction in traffic jams.

[0003] Furthermore, in a context where ecological concerns are becoming very important, driving in convoy is of major interest, since it allows the air resistance of the entire convoy to be reduced and each vehicle then benefits from reduced aerodynamic drag. This reduction in drag allows fuel consumption or electricity consumption to be reduced.

[0004] In convoy driving, in addition to the communication and distance regulation capabilities of each vehicle, the optimal distance between two vehicles following each other depends on many factors, such as the aerodynamic characteristics of the vehicles, their weight, their size, or even their braking capabilities. The factors influencing the optimal distance can also vary depending on driving conditions, such as the weather and the state of the road. These multiple factors are difficult to determine in real time, so the distance between each vehicle is not necessarily optimal, at least from an aerodynamic point of view.

[0005] Thus, there is a need for a solution that allows measuring real-life conditions that can influence the aerodynamic efficiency of the vehicle.

[0006] The present invention aims to overcome the problems set out above. In this technical context, one aim of the present invention is to provide an antenna making it possible to provide information on the aerodynamic efficiency of the vehicle.

[0007] To this end, the present invention relates to a roof antenna for a motor vehicle, designed to be mounted on a roof roof, the antenna comprising an orifice extending along a main axis between an opening and a bottom, the opening being designed to allow the entry of an air flow into the orifice, when the antenna is mounted on the roof and the vehicle is traveling forward, the bottom being designed to measure a pressure in the orifice resulting from the air flow flowing around the opening of the orifice, the orifice being sized to form part of a probe Pitot.

[0008] The invention also relates to a fairing for a roof antenna designed to delimit the outer casing of an antenna according to the invention, the fairing having a shark fin shape extending between a leading edge, facing the air flow generated by the movement of the vehicle, when the antenna is mounted on the roof, and a trailing edge opposite the leading edge, the leading edge comprising a hole designed to allow the passage of an air flow through the leading edge.

[0009] The invention finally relates to a motor vehicle comprising a roof panel and an antenna according to the invention fixed to the roof panel.

[0010] Thus, the roof antenna makes it possible to measure a pressure in the orifice resulting from the air flow flowing around the opening of the orifice. The orifice, sized to form part of a Pitot probe, makes it possible to obtain information similar to that obtainable with a Pitot probe: in fact, this pressure makes it possible to determine information relating to the flow of air around the vehicle such as the speed of the air flow or even the aerodynamic drag. Most vehicles are equipped with a roof antenna, for radio communications and / or geolocation. Also, the antenna according to the invention can replace a conventional antenna without modifying the external appearance of the vehicle while benefiting from the advantages of the antenna according to the invention. In addition, the installation area of ​​the roof antenna is located in an area of ​​the vehicle not subject to external damage, such as that which a vehicle may suffer when parking.It is placed in the axis of the vehicle and finally above a smooth surface, so that the information that an antenna according to the invention allows to measure reflects the aerodynamic efficiency of the vehicle in real time. This aerodynamic efficiency in real time allows, for example, to adapt the distance with the preceding vehicle. In addition, knowledge of the aerodynamic efficiency in real time allows a better estimation of the remaining autonomy.

[0011] According to one embodiment of the invention, the orifice is shaped so that the main axis extends in a horizontal plane and is oriented along a longitudinal axis of the vehicle when the antenna is mounted on the roof panel.

[0012] According to one possibility, the orifice is provided in a cylindrical tube, preferably with a circular base, extending between the opening and the bottom, the bottom being designed to be connected to a pressure gauge or a pressure capsule.

[0013] According to one embodiment, the antenna comprises at least one vent designed to allow measurement of a static pressure of the air circulating around the antenna, when the antenna is fixed on the roof panel and to deduce a dynamic pressure resulting from the forces of the air flow around the opening. The pressure dynamic is deduced, for example, by subtracting the static pressure from the total pressure.

[0014] Advantageously, the antenna comprises a fairing delimiting the outer casing of the antenna and having a shark fin shape, extending between a leading edge, facing the air flow generated by the movement of the vehicle when the antenna is mounted on the roof, and a trailing edge opposite the leading edge, the orifice passing through the leading edge of the antenna.

[0015] Advantageously, the tube projects from the leading edge, when the orifice is formed in a cylindrical tube, preferably with a circular base, extending between the opening and the bottom, the bottom being designed to be connected to a pressure gauge or a pressure capsule.

[0016] According to one possibility of the roof antenna, the opening is provided in the leading edge.

[0017] In one embodiment of the fairing, the hole is provided at one end of a cylindrical conduit projecting from the leading edge.

[0018] The invention will be better understood on reading the detailed description which follows, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0019] [Fig-1] [Fig. 1] represents a perspective view of a first embodiment of an antenna according to the invention fixed on a roof of a motor vehicle according to the invention;

[0020] [Fig.2] [Fig.2] represents a perspective view of a second mode of realization installation of an antenna according to the invention fixed to a roof of a motor vehicle according to the invention;

[0021] In these figures, the same references are used to designate the same elements.

[0022] A roof antenna 1a, 1b according to the invention, illustrated in the figures, is intended to equip a motor vehicle according to the invention. The antenna 1a, 1b is designed to be mounted on a roof panel 2, partially illustrated in the figures.

[0023] In the examples illustrated in the figures, the antenna 1a, 1b comprises a fairing 3a, 3b delimiting the outer casing of the antenna 1a, 1b. The fairing 3a, 3b has a shark fin shape extending between a leading edge 4a, 4b and a trailing edge 5, opposite the leading edge 4a, 4b. The leading edge 4a, 4b is designed to face the air flow generated by the movement of the vehicle according to the invention when the antenna 1a, 1b is mounted on the roof 2. The fairing 3a, 3b is, for example, made of plastic.

[0024] The antenna 1a, 1b comprises an orifice 6 extending along a main axis AP, illustrated in [Fig.l], between an opening 7a, 7b and a bottom, not illustrated in the figures. The opening 7a, 7b is designed to allow the entry of an air flow, symbolized by an arrow in [Fig. 2], into the orifice 6, when the antenna 1a, 1b is mounted on the roof 2 and the vehicle is traveling forward. Advantageously, the orifice 6 is shaped so that the main axis AP extends in a horizontal plane and is oriented along a longitudinal axis AL, illustrated in [Fig. 1], of the vehicle according to the invention when the antenna 1a, 1b is mounted on the roof 2.

[0025] In the examples illustrated in the figures, the orifice 6 passes through the leading edge 4a, 4b of the antenna 1a, 1b.

[0026] The bottom is designed to measure a pressure in the orifice 6 resulting from the air flow flowing around the opening 7a, 7b of the orifice 6. The orifice 6 is dimensioned to form part of a Pitot probe. For this purpose, the bottom is connectable to a pressure gauge or a pressure capsule, not shown. The pressure gauge or the pressure capsule are, for example, integrated into the antenna 1a, 1b.

[0027] When the bottom is connected to a pressure gauge, the measured pressure is then a total pressure corresponding to the sum of an atmospheric pressure called static pressure and a dynamic pressure generated by the air flow. When the bottom is connected to a manometric capsule, the measured pressure is then the dynamic pressure, the capsule making it possible to compensate for the static pressure. The dynamic pressure is proportional to the square of the speed of the air flow circulating around the opening 7a, 7b.

[0028] When the pressure measured in the orifice 6 is a total pressure, a dynamic pressure is deduced from the total pressure by subtracting a static pressure measured around the antenna 1a, 1b. Such a static pressure is measured in a region sheltered from the air flow circulating around the opening 7a, 7b. For example, the antenna 1a, 1b comprises at least one vent, not illustrated, designed to allow this static pressure to be measured.

[0029] As illustrated in [Fig.2], the orifice 6 is formed in a cylindrical tube 8 with a circular base extending between the opening 7b and the bottom. For example, in the second embodiment of the antenna 1b, the tube 8 projects from the leading edge 4b. In the first embodiment of the antenna 1a illustrated in [Fig.l], the orifice 6 is, for example, formed in a tube, not illustrated, extending entirely into the fairing 3a of the antenna 1a. The opening 7a is then formed in the leading edge 4a.

[0030] The invention finally relates to the fairing 3a, 3b. In the two embodiments described in the figures, the leading edge 4a, 4b comprises a hole 9a, 9b designed to allow the passage of an air flow through the leading edge 4a, 4b. In the first embodiment of the fairing 3a, the hole 9a is provided in the leading edge 4a which has a usual curved shape of a conventional fin-shaped antenna. shark. In the second embodiment of the fairing 3b, the hole 9b is provided at one end 10 of a cylindrical conduit 11 projecting from the leading edge 4b. The conduit 11 then constitutes a part of the tube 8. Alternatively, the conduit 11 is sized to accommodate a tube inside whose opening exits through the hole 9b.

[0031] Thus, the roof antenna 1a, 1b makes it possible to measure a pressure in the orifice 6 resulting from the air flow flowing around the opening 7a, 7b of the orifice 6 to provide information on the aerodynamic efficiency of the vehicle in real time. This aerodynamic efficiency in real time makes it possible, for example, to adapt the distance with the preceding vehicle. In addition, knowledge of the aerodynamic efficiency in real time allows a better estimation of the remaining autonomy.

[0032] The invention is not limited to the embodiments of the antenna or fairing described above, only by way of example, but other embodiments can be designed by those skilled in the art without departing from the scope and scope of the present invention.

Claims

Claims

1. A roof antenna (1a, 1b) for a motor vehicle, designed to be mounted on a roof roof (2), the antenna (1a, 1b) comprising an orifice (6) extending along a main axis (AP) between an opening (7a, 7b) and a bottom, the opening (7a, 7b) being designed to allow the entry of an air flow into the orifice (6), when the antenna (1a, 1b) is mounted on the roof (2) and the vehicle is traveling forward, the bottom being designed to measure a pressure in the orifice (6) resulting from the air flow flowing around the opening (7a, 7b) of the orifice (6), the orifice (6) being sized to form part of a Pitot probe.

2. Roof antenna (1a, 1b) according to claim 1, characterized in that the orifice (6) is shaped so that the main axis (AP) extends in a horizontal plane and is oriented along a longitudinal axis (AL) of the vehicle when the antenna (1a, 1b) is mounted on the roof panel (2).

3. Roof antenna (1a, 1b) according to claim 1 or 2, characterized in that the orifice (6) is provided in a cylindrical tube (8), preferably with a circular base, extending between the opening (7a, 7b) and the bottom, the bottom being designed to be connected to a pressure gauge or a pressure capsule.

4. Roof antenna (1a, 1b) according to one of claims 1 to 3, characterized in that it comprises at least one vent designed to allow measurement of a static pressure of the air circulating around the antenna (1a, 1b), when the antenna (1a, 1b) is fixed on the roof panel (2) and to deduce a dynamic pressure resulting from the forces of the air flow around the opening (7a, 7b).

5. Roof antenna (1a, 1b) according to one of claims 1 to 4, characterized in that the antenna (1a, 1b) comprises a fairing (3a, 3b) delimiting the outer casing of the antenna (1a, 1b) and having a shark fin shape, extending between a leading edge (4a, 4b), facing the air flow generated by the movement of the vehicle when the antenna (1a, 1b) is mounted on the roof (2), and a trailing edge (5) opposite the leading edge (4a, 4b), the orifice (6) passing through the leading edge (4a, 4b) of the antenna (1a, 1b).

6. Roof antenna (1b) according to claim 5, in combination with claim 3, characterized in that the tube (8) projects from the leading edge (4b).

7. Roof antenna (la) according to claim 5, characterized in that the opening (7a) is provided in the leading edge (4a).

8. A fairing (3a, 3b) for a roof antenna (1a, 1b) designed to delimit the outer casing of an antenna (1a, 1b) according to one of claims 5 to 7, the fairing (3a, 3b) having a shark fin shape extending between a leading edge (4a, 4b), facing the air flow generated by the movement of the vehicle, when the antenna (1a, 1b) is mounted on the roof (2), and a trailing edge (5) opposite the leading edge (4a, 4b), the leading edge (4a, 4b) comprising a hole (9a, 9b) designed to allow the passage of an air flow through the leading edge (4a, 4b).

9. Fairing (3b) according to claim 8, characterized in that the hole (9b) is provided at one end of a cylindrical conduit (11) projecting from the leading edge (4b).

10. Motor vehicle comprising a roof panel (2) and an antenna (1a, 1b) according to one of claims 1 to 7 fixed to the roof panel (2).

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