Assembly for protecting a sensor/transmitter of a driver assistance system for a motor vehicle comprising a heating element

Abstract

The invention relates to a motor vehicle assembly for protecting a sensor/transmitter of a driving assistance system comprising a protection device that partially surrounds the sensor/transmitter where the protection device includes a first subassembly (B) with a detection/transmission element positioned facing a sensor/transmitter's surface via which a signal passes, and a second subassembly (C) that includes a motor configured to rotatably drive the first subassembly (B) about a line of transmission/reception of the sensor/transmitter. According to the invention, the protection assembly includes at least one heating element controlled by a control unit that heats an accessory attached to the motor vehicle's body in the detection/transmission element's vicinity, the heating element being outside the protection device and in the vicinity of the first subassembly (B).

Claims

1. A protective assembly configured to protect a sensor/emitter of a driver assistance system of a motor vehicle, comprising: a protective device that surrounds a portion of the sensor/emitter, the protective device including: a first subassembly having a detection/emission element that submerges the sensor/emitter within the detection/emission element through which a signal passes, and a second subassembly having a motor configured to rotatably drive the first subassembly about an emission-reception axis of the sensor/emitter; where the first subassembly is arranged in front of the second subassembly; the protective assembly having at least one heating elements controlled by a control unit for heating at least one accessory fixed to a body of the motor vehicle next to the detection/emission element, the at least one heating element being disposed outside and at a distance from the protective device and adjacent the first subassembly.

2. The protective assembly of claim 1, where the control unit is configured to control an operation of the sensor/emitter.

3. The protective assembly of claim 1, where the at least one heating element has at least one fixed part that is configured to be positioned adjacent the at least one accessory fixed to the body, the at least one fixed part being supplied with current by the control unit.

4. The protective assembly of claim 1, where the at least one heating element is a resistive element supplied with electricity via the control unit, the resistive element forming the at least one fixed part.

5. The protective assembly of claim 1, where the at least one heating element is disposed on a holder secured to the protective device.

6. The protective assembly of claim 1, where a holder has a fixed frame secured to the protective device and a movable assembly to which the at least heating element is fixed and which is able to slide along the emission-reception axis.

7. The protective assembly of claim 1, where the at least one heating element has an electromagnetic induction source forming at least one fixed part and an associated induced metal element which is disposed against an external face of the protective device.

8. The protective assembly of claim 1, where the control unit is configured to activate the at least one heating element when a driver switches on or starts the motor vehicle or when the control unit detects abnormal resistance for driving the first subassembly in rotation.

9. The protective assembly of claim 1, where the control unit is configured to activate the at least one heating element when a temperature outside the motor vehicle is at least 2? C. or less.

10. A motor vehicle comprising an assembly for protecting a sensor/emitter of a driver assistance system of claim 1, where the sensor/emitter is present in the motor vehicle, and the detection/emission element of a protective casing is present at an opening formed in a wall of a body of the motor vehicle, and the at least one heating element are positioned on the wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention will become more clearly apparent from reading the following description, which is given by way of nonlimiting illustrative example, and from the appended drawings, in which:

(2) FIG. 1 shows a schematic and perspective view of a protective casing for a sensor/emitter of a driver assistance system, according to the prior art;

(3) FIG. 2 shows a schematic and perspective exploded view of the protective housing illustrated in FIG. 1;

(4) FIG. 3 shows a face-on view of a motor vehicle, comprising a driver assistance system at its grille;

(5) FIG. 4 schematically shows a partial longitudinal section through a motor vehicle, for example the vehicle in FIG. 3, incorporating a protective device for a sensor/emitter of a driver assistance system, according to a first embodiment of the invention in which a heating element is secured to an accessory fixed to the body and around an opening formed in this accessory fixed to the body and through which the sensor/emitter is able to emit/detect signals;

(6) FIG. 5 shows a perspective view of a protective device for a sensor/emitter of a driver assistance system, according to a second embodiment of the invention in which a heating element is secured to the protective casing via a spring link involved in pressing the heating element against an accessory fixed to the body, facing which the shown protective device is positioned;

(7) FIGS. 6 to 8 schematically show possible arrangements of the heating element around the opening made in the accessory fixed to the body of the vehicle.

DETAILED DESCRIPTION

(8) It should first of all be noted that the figures set out the invention in detail for implementing the invention, it being, of course, possible for said figures to serve to better define the invention if necessary. In these figures, identical elements have the same references. The various embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply to just one embodiment. Individual features of different embodiments can also be combined or interchanged in order to create other embodiments.

(9) Furthermore, it should be noted that in the description, certain elements may be indexed, with for example a first element or a second element. In this case, the index is simply used to differentiate and denote elements that are similar but not identical. This indexing does not imply that one element takes priority over another and such denominations can easily be interchanged without departing from the scope of the present description.

(10) A driver assistance system according to the invention has at least one sensor/emitter 13 and a protective device 3 arranged around this sensor/emitter, and a heating element configured to remove or weaken a layer of ice or any other deposit preventing the relative movement of the movable part of the protective device with respect to the accessory fixed to the body of the vehicle, close to which the sensor/emitter and the associated protective device are disposed.

(11) The sensor/emitter 13 is for example an image-capturing optical sensor such as a camera. It may be a CCD (charge-coupled device) sensor or a CMOS sensor including a matrix array of miniature photodiodes. According to another variant, without this list otherwise being exhaustive, it may be an infrared-radiation sensor such as an infrared camera, a light emitter such as a headlamp, an optoelectronic device such as an LED (light-emitting diode), an electromagnetic-radiation sensor/emitter such as a LIDAR (laser imaging, detection and ranging) or RADAR (radio detection and ranging). According to another variant, it may be an ultrasonic radiation sensor/emitter.

(12) A first embodiment of the invention will be described first, with reference to FIGS. 1 to 4.

(13) The sensor/emitter 13 has a surface 14 through which a signal passes and an emission-reception axis 15. The surface 14 is for example an optical surface such as a camera objective, which may have one or more lenses depending on the field of view and the resolution that are desired.

(14) The sensor/emitter 13 is mounted at least partially in a protective casing 6 forming a first subassembly B of the protective device 3. To this end, the protective casing 6 has a housing limited by a wall 21. This wall 21 is preferably centered about the emission-reception axis 15 of the sensor/emitter 13. In the example illustrated, the wall 21 has a substantially cylindrical shape.

(15) The protective casing 6 also comprises a detection/emission element 9 that is formed by a transparent wall and is disposed downstream of the surface 14 of the sensor/emitter 13 through which the signal passes. This detection/emission element 9 is advantageously dimensioned so as to cover the entire surface 14. In other words, the detection/emission element 9 is arranged in the emission-detection field of the sensor/emitter 13, the transparent wall making it possible for the effectiveness of the sensor/emitter 13 not to be impaired. The detection/emission element 9 may be formed in one piece with the protective casing 6. As an alternative, the protective casing 6 and the detection/emission element 9 may be two separate parts that are secured together. The transparent wall forming all or part of the detection/emission element 9 may be made of glass or of a plastics material such as polycarbonate. The protective casing 6 may be made of any appropriate material known to a person skilled in the art, preferably from a fluid tight material.

(16) What is meant by the detection/emission element 9 being disposed downstream of the surface 14 through which the signal passes is that the detection/emission element 9 is disposed between the outside of the vehicle and the surface 14 of the sensor/emitter 13, such that the detection/emission element 9 protects the surface 14 from any spattering of dirt or solid debris that could spoil this surface 14. It is therefore an element for protecting, or more precisely a mask for protecting, the sensor/emitter 13, and it is this/emission element 9 that is subject to attacks from the outside, i.e. to water spatter, pollutants, small pieces of stone, and also pollutant deposits or water stains. In order to allow the surface of the detection/emission element 9 to be cleaned by a centrifugal effect, as described above, the protective device 3 has a motor 5 forming a second subassembly C. The motor 5 is coupled to the protective casing 6 so as drive the protective casing 6, and therefore the detection/emission element 9, in rotation about an axis of rotation A1 coincident with the emission-reception axis 15 of the sensor/emitter 13. The motor is controlled by a control unit 10 shown in FIGS. 1 and 4.

(17) The two subassemblies B and C form, when they are assembled, the protective device 3 preventing dirt from reaching the sensor/emitter 13. Note that the protective device 3 also has a support element 17, visible in FIG. 2, secured to a fixed part of the motor 5 such that the sensor/emitter 13 is immovable when the protective casing 6 is pivoted by the motor.

(18) In a known manner, the above-described protective device 3 is mounted on a motor vehicle so as to allow a driver assistance system to acquire data relating to a road scene, by virtue of the sensor/emitter 13 present in the protective device 3. For esthetic reasons, the protective device 3 is positioned inside the motor vehicle, behind an accessory 7 fixed to the body of the vehicle. According to the nonlimiting example illustrated in FIG. 3, this accessory 7 fixed to the body consists of the grille of the motor vehicle 100.

(19) In particular, as illustrated in FIG. 4, the sensor/emitter 13, illustrated by dashed lines, and the protective device 3 disposed around this sensor/emitter are positioned facing an internal face 70 of the accessory fixed to the body, said face being internal in that it is oriented toward the interior of the body. Of course, the accessory 7 fixed to the body has an opening 2, the shape and dimensions of which allow the sensor/emitter 13 to acquire data relating to the road. As illustrated in FIG. 4, the sensor/emitter 13 is positioned as close as possible to the accessory fixed to the body, in order not only for the edges of the accessory fixed to the body not to appear in the emission-detection field of the sensor/emitter 13 but also for the exterior appearance to be good.

(20) The detection/emission element 9 extends at least partially into the opening 2 in the protective casing 6. In the example illustrated, the detection/emission element 9 is disposed in the plane defined by the internal face 70 of the accessory 7 fixed to the body, it being understood that this detection/emission element 9 could, without departing from the context of the invention, be disposed in the thickness of the accessory fixed to the body, provided that a space 79 is provided radially to form an operating clearance allowing the rotation of the protective device without impairing the accessory fixed to the body.

(21) It will be understood that FIG. 4 schematically illustrates the protective assembly according to the invention, with a space 79 that is exaggerated to make it visible. By way of example, the opening 2 may have a circular shape with a diameter less than or equal to 5 cm, and the space 79 measures between 0.3 mm and 0.5 cm, preferably between 0.6 and 0.4 mm.

(22) As explained above, in wintry conditions, when the outside temperature becomes negative, a layer of snow and/or ice may build up in the spaces formed at the opening 2 between the protective casing 6, in particular the detection/emission element 9, and the accessory 7 fixed to the body, in this case the grille. The presence of this layer hampers or even prevents the pivoting of the protective casing 6 by the motor 5. It is thus no longer possible to effectively clean the detection/emission element by a centrifugal effect, as described above. The system for cleaning the detection/emission element 9 is thus ineffective or inoperative.

(23) According to the invention, the protective device 3 is associated with at least one heating element 12 positioned outside the protective device 3, and more particularly around the opening 2, formed in the accessory fixed to the body, in abutment against the internal face 70 of this accessory fixed to the body. Advantageously, and as illustrated schematically in FIG. 4, the heating element 12 is disposed as close as possible to the edges delimiting the opening 2. As a result, the starting up of the heating element makes it possible to heat the accessory fixed to the body and to melt, by conduction and convection of heat, the layer of ice that has been able to stick to this accessory fixed to the body and to the protective casing 6. At least incipient cracking of the ice is effected at the accessory fixed to the body, this then making it easier to break the ice by rotation of the detection/emission element 9 provided at the end of the turning protective casing 6. It is particularly advantageous for the heating element to be disposed on the outside of the protective casing and directly in contact with, or at least as close as possible to, the accessory fixed to the body in order that the heat generated by the heating element is able to propagate in the region of the ice without excessive power consumption being necessary.

(24) The protective device 3 and the heating element 12 thus form a protective assembly 1 associated with a sensor/emitter 13 and configured both to ensure cleaning by a centrifugal effect on account of the rotation of a detection/emission element situated facing the sensor/emitter 13 and also to ensure that this cleaning by a centrifugal effect can be operational under any conditions and in particular under very cold climatic conditions.

(25) In the first embodiment of such a protective assembly, and in particular as illustrated in FIG. 4, the protective device 3 and the heating element 12 are two elements that are separate from one another, with the heating element 12 being secured to the accessory 7 fixed to the body.

(26) According to the example illustrated in FIG. 4, the heating element 12 is positioned against the internal face 70 of the accessory fixed to the body, as close as possible to the opening 2, in a cavity 72 provided in the thickness of this internal face 70. It will be understood that the positioning of the heating element 12 on the internal face 70 of the grille allows the heating element 12 not to be visible from outside the motor vehicle 100, in order to preserve the external appearance thereof.

(27) As will be illustrated in FIGS. 6 to 8, the cavity 72 may have different geometric shapes to allow a heating element with a corresponding shape to be accommodated. The cavity is in this case in the form of a groove made concentrically with the opening 2 that it surrounds, a small strip of material being retained between the cavity and the edge of the accessory fixed to the body delimiting the opening 2. Furthermore, the cavity has a thickness, that is to say in this case the dimension parallel to the emission-reception axis of the sensor/emitter, with dimensions smaller than the corresponding dimensions of the heating element, which thus protrudes toward the interior of the vehicle. It will be understood that this exemplary embodiment could be modified and that the heating element could be embedded in the thickness of the accessory fixed to the body, or be flush with the edge delimiting the opening 2.

(28) In order to ensure the contact of the heating element 12 with the accessory 7 fixed to the body and thus to ensure the best possible conduction and convection of heat, the heating element 12 is preferably held against the internal face 70 of this accessory fixed to the body by appropriate fixing means. By way of example, the heating element may be adhesively bonded to this internal face, or be held by fastening clips secured to the internal face 70 of the accessory fixed to the body, the heating element being able to be fitted in the cavity by snap-fastening.

(29) The protective element according to the invention has at least one heating element 12. As illustrated in FIGS. 6 and 7, a single heating element 12 may be provided, which entirely surrounds the opening 2 in the grille 7. The heating element is thus in the form of an annular ring, which may be circular or elliptical according to FIG. 6 or polygonal according to FIG. 7. Preferably, the form in FIG. 6 will be selected, making it possible to best follow the contour of the opening 2.

(30) According to another variant illustrated in FIG. 8, a plurality of separate heating elements 12 can be employed, for example with a rectilinear shape and arranged perpendicularly with respect to one another.

(31) A heating element 12 according to the invention may consist of an electrical resistance element or a positive temperature coefficient ceramic, in particular in the form of a film. As illustrated, the heating element is in this case integral with the internal face of the accessory fixed to the body.

(32) In an alternative that is not shown, provision may be made for the heating element to consist of an electromagnetic induction system with a fixed part secured to the accessory fixed to the body that is supplied with current and forms an induction coil emitting an electromagnetic field in which there are disposed one or more metal elements forming a second part of the heating element that is disposed around the perimeter of the protective casing 6. This second metal part may in particular consist of a copper ring disposed around the detection/emission element 9, or of metal elements, made for example of titanium and indium, disposed in the transparent layer forming the detection/emission element 9.

(33) In each of these alternatives, the heating element 12, at least the fixed part secured to the accessory fixed to the body, is electrically connected to a control unit 10.

(34) The control unit 10 is configured to control the operation of the heating element(s) 12 present on the accessory 7 fixed to the body of the motor vehicle 100, and in particular to control the electrical power supply of this or these heating element(s). Preferably, the control unit 10 is configured such that the heating element(s) 12 radiate(s) heat in the region of the detection/emission element 9 of the protective casing 6. Thus, advantageously, the heating element(s) 12 also make it possible to rapidly melt a layer of ice covering the detection/emission element 9 and/or disposed in the radial clearance between the protective casing 6 and the accessory 7 fixed to the body.

(35) To this end, the control unit 10 comprises a calculator 18, means 22 for storing at least one control program described below, and a communication interface 23 as illustrated in FIG. 4. The communication interface 23 allows the control unit 10 to dialog by way of known means with an on-board computer 24 of the motor vehicle 100. The on-board computer 24 centralizes all the information of the motor vehicle and the driving actions carried out by the driver. The on-board computer 24 is preferably connected to means, not shown, for measuring the temperature outside the motor vehicle in real time.

(36) In the example illustrated, the communication interface 23 is also connected to the motor 5 so as to be able to control the electrical power supply of this motor and also to measure, in real time, the electrical power consumed by the motor 5 in order to pivot the protective casing 6.

(37) The storage means 22 comprise at least one of the following control programs that allow a particular operating mode of the protective assembly according to the invention.

(38) According to a first example of a control program according to the invention, the control unit 10 is configured to activate at least one heating element 12 for a predefined heating time when a user of the motor vehicle carries out a predefined action. By way of nonlimiting example, the predefined heating time may correspond to a time interval of one or more minutes, or a shorter time interval of a few seconds or tens of seconds, from when the predefined action is effected. The predefined action may for example correspond to the actuation of a remote control button by the user of the vehicle, or to the unlocking of the driver's door of the motor vehicle, or to the switching on or starting of the motor vehicle. This embodiment makes it possible to ensure that a layer of snow and/or ice cannot prevent the rotation of the case and does not cover the transparent wall forming all or part of the detection/emission element, during the first few minutes of driving during which driver assistance systems are usually used to help the driver rejoin a traffic corridor.

(39) According to a second example of a control program according to the invention, the control unit 10 activates at least one heating element 12 for a predefined heating time when the control unit detects abnormal electrical power consumption by the motor 5. Here again, the predefined heating time may correspond to a time interval of one or more minutes, or a shorter time interval of a few seconds or tens of seconds from the moment this abnormal consumption is detected. Abnormal electrical power consumption by the motor 5 is defined as electrical power greater than the usual electrical power for allowing the protective casing 6 to be pivoted. By way of nonlimiting example, the electrical power may be considered to be abnormal when it exceeds the usual electrical power of the motor 5 by more than 20%. This second example of a control program advantageously allows the activation of at least one heating element 12 when a layer of snow and/or ice forms between the protective casing 6 and the accessory 7 fixed to the body, while the motor vehicle 10 is on the move, it being understood that the presence of a layer of ice prevents the rotation of the protective casing and forces the motor to provide more power.

(40) According to a third example of a control program, the actuation of the heating element, or the implementation of the first or second control program, is conditional on the value of the ambient temperature outside the motor vehicle 100. The value of the ambient temperature is for example communicated to the control unit 10 by the on-board computer 24 of the vehicle 100. By way of example, the first control program or the second control program is implemented if, and only if, the value of the temperature outside the motor vehicle is equal to or less than a threshold value for example equal to 0? C., or at least less than 2? C. This embodiment advantageously makes it possible to ensure that the heating element(s) 12 is/are activated only in wintry conditions.

(41) FIG. 5 illustrates a second embodiment of a protective casing according to the invention, which differs from the protective assembly described above in particular by way of the arrangement of the heating element 12.

(42) More particularly, in this case, the heating element is secured to the protective device 3 such that the protective assembly formed by the protective device and by the associated heating element can be assembled and then mounted in its entirety in a single operation on the accessory 7 fixed to the body of the motor vehicle.

(43) The protective device 3 in this case comprises an internal rotor motor 5, that is to say with a fixed external part and a holder 25 secured to the motor 5. This holder 25 has an annular base 250 disposed around the entire perimeter of the fixed part of the motor and has a plurality of uprights 252 protruding from the base along the protective device, parallel to the emission-reception axis of the sensor/emitter and in the direction of the detection/emission element. In the example illustrated, there are two uprights, which are diametrically opposite one another, but it will be understood that there could be a greater number thereof, which are advantageously distributed regularly about the axis. The base 250 and the uprights 252 form a fixed frame for the holder, which is able to cooperate with a movable assembly of the holder that is configured to move axially along the emission-reception axis by virtue of guidance effected by the fixed frame.

(44) The movable assembly of the holder 250 has as many tubes 254 as there are uprights 252, each tube being hollow in order to slide about one of the uprights and having a collar 256 at a free end.

(45) Elastic means 26 are disposed around each of the uprights, between the base 250 and one of the collars 254 formed at one end of a tube 256 that is able to slide about one of the uprights. The springs forming the elastic means 26 are configured to push the corresponding collars 254 away from the base 250 of the holder 25 when the elastic means are compressed.

(46) The free end of the tubes 256 is secured to a disk 27 forming part of the movable assembly of the holder. The disk 27 has a hole at its center so as to form a ring arranged around the detection/emission element 9. As illustrated, the disk 27 has a central opening 28, the dimensions of which are designed such that its edges do not appear in the emission-detection field of the sensor/emitter 13. The front face 29 of the disk 27, that is to say the face that faces away from the holder 25 and the motor 5 and is able to be disposed facing the internal face 70 of the accessory 7 fixed to the body, is covered with a heating element 12.

(47) In this second embodiment, the heating element 12, which forms a crown entirely surrounding the detection/emission element 9, is formed of a resistive film that is able to heat up when supplied with electrical power. The heating means 12 are connected electrically to the control unit via an electrical connection means that is able to pass along the uprights 252 through the elastic means 26.

(48) As described above, the elastic means comprise springs that are mounted under compression so as to allow the disk 27 to press the heating element 12 against a wall of the body of a motor vehicle, for example the internal face 70 of the accessory 7 fixed to the body illustrated in FIG. 4, when the protective assembly 1, formed by the protective device 3 and the heating element 12, approaches the accessory 7 fixed to the body.